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  • The theory of evolution applied to software

    - by Michel Grootjans
    I recently realized the many parallels you can draw between the theory of evolution and evolving software. Evolution is not the proverbial million monkeys typing on a million typewriters, where one of them comes up with the complete works of Shakespeare. We would have noticed by now, since the proverbial monkeys are now blogging on the Internet ;-) One of the main ideas of the theory of evolution is the balance between random mutations and natural selection. Random mutations happen all the time: millions of mutations over millions of years. Most of them are totally useless. Some of them are beneficial to the evolved species. Natural selection favors the beneficially mutated species. Less beneficial mutations die off. The mutated rabbit doesn't have to be faster than the fox. It just has to be faster than the other rabbits.   Theory of evolution Evolving software Random mutations happen all the time. Most of these mutations are so bad, the new species dies off, or cannot reproduce. Developers write new code all the time. New ideas come up during the act of writing software. The really bad ones don't get past the stage of idea. The bad ones don't get committed to source control. Natural selection favors the beneficial mutated species Good ideas and new code gets discussed in group during informal peer review. Less than good code gets refactored. Enhanced code makes it more readable, maintainable... A good set of traits makes the species superior to others. It becomes widespread A good design tends to make it easier to add new features, easier to understand the current implementations, easier to optimize for performance...thus superior. The best designs get carried over from project to project. They appear in blogs, articles and books about principles, patterns and practices.   Of course the act of writing software is deliberate. This can hardly be called random mutations. Though it sometimes might seem that code evolves through a will of its own ;-) Does this mean that evolving software (evolution) is better than a big design up front (creationism)? Not necessarily. It's a false idea to think that a project starts from scratch and everything evolves from there. Everyone carries his experience of what works and what doesn't. Up front design is necessary, but is best kept simple and minimal, just enough to get you started. Let the good experiences and ideas help to drive the process, whether they come from you or from others, from past experience or from the most junior developer on your team. Once again, balance is the keyword. Balance design up front with evolution on a daily basis. How do you know what balance is right? Through your own experience of what worked and what didn't (here's evolution again). Notes: The evolution of software can quickly degenerate without discipline. TDD is a discipline that leaves little to chance on that part. Write your test to describe the new behavior. Write just enough code to make it behave as specified. Refactor to evolve the code to a higher standard. The responsibility of good design rests continuously on each developers' shoulders. Promiscuous pair programming helps quickly spreading the design to the whole team.

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  • Linq to SQL DynamicInvoke(System.Object[])' has no supported translation to SQL.

    - by ewwwyn
    I have a class, Users. Users has a UserId property. I have a method that looks something like this: static IQueryable<User> FilterById(this IQueryable<User> p, Func<int, bool> sel) { return p.Where(m => sel(m)); } Inevitably, when I call the function: var users = Users.FilterById(m => m > 10); I get the following exception: Method 'System.Object DynamicInvoke(System.Object[])' has no supported translation to SQL. Is there any solution to this problem? How far down the rabbit hole of Expression.KillMeAndMyFamily() might I have to go? To clarify why I'm doing this: I'm using T4 templates to autogenerate a simple repository and a system of pipes. Within the pipes, instead of writing: new UserPipe().Where(m => m.UserId > 10 && m.UserName.Contains("oo") && m.LastName == "Wee"); I'd like to generate something like: new UserPipe() .UserId(m => m > 10) .UserName(m => m.Contains("oo")) .LastName("Wee");

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  • How to implement DisplayMemberPath for my Wpf UserControl?

    - by Bevan
    I'm writing a WPF User Control for my application, wrapping a ListBox and a few other items. The ListBox has a new ItemTemplate that presents four pieces of information for each item in my list. I can hard code each of the four bindings to specific properties on my list items and they display fine. However, I want my UserControl to be a bit more flexible. On ListBox and ComboBox there is a property DisplayMemberPath (inherited from ItemsControl) that seems to "inject" the appropriate property binding into the standard ItemTemplate. How do I achieve the same result with my user control? I'd like to set up four new properties to allow configuration of the information displayed: public string LabelDisplayPath { get; set; } public string MetricDisplayPath { get; set; } public string TitleDisplayPath { get; set; } public string SubtitleDisplayPath { get; set; } Reviewing ItemsControl.DisplayMemberPath with Reflector seems to go down the rabbit hole, I haven't been able to fathom how it works. Also, if I'm completely off course - and there's another, more "WPF" technique that I should be using instead, please point me in that direction.

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  • Architectural conundrum

    - by Dejan
    The worst thing when working on a one man project is the lack of input that you usually get from your coworkers. And because of the lack of that you tend to make obvious mistakes. After going down that road for some time I would need some help from the community. I started a little home-brew project that should turn into a portal of some sorts. And the main thing that is bothering me is the persistence layer that i have concocted. It should be completely separated from the presentation layer for starters and a OR mapper is also somewhere. This is because I have multiple data stores that have to be used. So the base idea was that the individual "repositories" operate each on their individual database and that the business layer then aggregates the business objects which are then transformed in the presentation layer into view objects. The main problem I face is the following: Multiple classes for the same concept - There is a DAL representation of a user and BL representation of user and a view representation of a user. I can handle the transformation with a tool but is this really the right way. I mean they are all nicely separated, but the overhead is quite something. What do you think? Am I going too deep into the separation of concern rabbit hole or is this still normal?

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  • How to restrain one's self from the overwhelming urge to rewrite everything?

    - by Scott Saad
    Setup Have you ever had the experience of going into a piece of code to make a seemingly simple change and then realizing that you've just stepped into a wasteland that deserves some serious attention? This usually gets followed up with an official FREAK OUT moment, where the overwhelming feeling of rewriting everything in sight starts to creep up. It's important to note that this bad code does not necessarily come from others as it may indeed be something we've written or contributed to in the past. Problem It's obvious that there is some serious code rot, horrible architecture, etc. that needs to be dealt with. The real problem, as it relates to this question, is that it's not the right time to rewrite the code. There could be many reasons for this: Currently in the middle of a release cycle, therefore any changes should be minimal. It's 2:00 AM in the morning, and the brain is starting to shut down. It could have seemingly adverse affects on the schedule. The rabbit hole could go much deeper than our eyes are able to see at this time. etc... Question So how should we balance the duty of continuously improving the code, while also being a responsible developer? How do we refrain from contributing to the broken window theory, while also being aware of actions and the potential recklessness they may cause? Update Great answers! For the most part, there seems to be two schools of thought: Don't resist the urge as it's a good one to have. Don't give in to the temptation as it will burn you to the ground. It would be interesting to know if more people feel any balance exists.

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  • Lucene (.NET) Document stucture and performance suggestions.

    - by Josh Handel
    Hello, I am indexing about 100M documents that consist of a few string identifiers and a hundred or so numaric terms.. I won't be doing range queries, so I haven't dugg too deep into Numaric Field but I'm not thinking its the right choose here. My problem is that the query performance degrades quickly when I start adding OR criteria to my query.. All my queries are on specific numaric terms.. So a document looks like StringField:[someString] and N DataField:[someNumber].. I then query it with something like DataField:((+1 +(2 3)) (+75 +(3 5 52)) (+99 +88 +(102 155 199))). Currently these queries take about 7 to 16 seconds to run on my laptop.. I would like to make sure thats really the best they can do.. I am open to suggestions on field structure and query structure :-). Thanks Josh PS: I have already read over all the other lucene performance discussions on here, and on the Lucene wiki and at lucid imiagination... I'm a bit further down the rabbit hole then that...

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  • Multiple inputs on a single line with Twitter Bootstrap and Simple Form 2.0

    - by noel_g
    I am using simple_form 2.0 with twitter bootstrap. I am trying to determine what is the proper wrapper format in order to get something like [city] [State] [Zip] I believe my form needs to be <div class="control-group"> <%= f.input :city,:wrapper => :small, :placeholder => "City", :input_html => { :class=>"span2", :maxlength => 10},:label => false %> <%= f.input :region, :wrapper => :small , :placeholder => "Region", :input_html => { :class=>"span1", :maxlength => 5}, :label => false %> <%= f.input :postal_code, :wrapper => :small, :placeholder => "Postal Code",:input_html => { :class=>"span2", :maxlength => 10},:label => false %> </div> I tried this wrapper config.wrappers :small, :tag => 'div', :class => 'controls inline-inputs', :error_class => 'error' do |b| b.use :placeholder b.use :label_input end I believe I would need to define the CSS as well, but before I go down a rabbit hole I thought I would ask if this is built in somewhere.

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  • What is the benefit of using ONLY OpenID authentication on a site?

    - by Peter
    From my experience with OpenID, I see a number of significant downsides: Adds a Single Point of Failure to the site It is not a failure that can be fixed by the site even if detected. If the OpenID provider is down for three days, what recourse does the site have to allow its users to login and access the information they own? Takes a user to another sites content and every time they logon to your site Even if the OpenID provider does not have an error, the user is re-directed to their site to login. The login page has content and links. So there is a chance a user will actually be drawn away from the site to go down the Internet rabbit hole. Why would I want to send my users to another company's website? [ Note: my provider no longer does this and seems to have fixed this problem (for now).] Adds a non-trivial amount of time to the signup To sign up with the site a new user is forced to read a new standard, chose a provider, and signup. Standards are something that the technical people should agree to in order to make a user experience frictionless. They are not something that should be thrust on the users. It is a Phisher's Dream OpenID is incredibly insecure and stealing the person's ID as they log in is trivially easy. [ taken from David Arno's Answer below ] For all of the downside, the one upside is to allow users to have fewer logins on the Internet. If a site has opt-in for OpenID then users who want that feature can use it. What I would like to understand is: What benefit does a site get for making OpenID mandatory?

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  • Dynamically loading external HTML in a div using Java Script

    - by user354051
    I have prepared some demo examples for the topic. There is page name "changelog.html" here: http://pantheon-studios.in/test/jquery/changelog.html This is working fine if loaded directly. I am trying to load this page dynamically into: http://pantheon-studios.in/test/jquery/index.html Here changelog.html doesn't behaving as expected. I think the init script on changelog.html is not getting executed or something else is happening when loading it dynamically. Like wise I do have couple of other pages using various jQuery and other java scripts plugins. Some of those needs initialization like animatedcollapse.js in the above example, and couple of them doesn't need initialization, you can directly call the script and go. I also gave a try using: jQuery.getScript("anim.js") after dynamically loading "changelog.html" but doesn't work. The "anim.js" contains animatedcollapse.addDiv('cat', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.addDiv('dog', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.addDiv('rabbit', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.init(); I would really appreciate is some one point me out the right direction. I am completely new to web programming so please have some patience with me. Thanks

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  • Veewee, Vagrant, Puppet, Erlang and RabbitMQ

    - by Tobias
    I am kinda stuck with a problem I am trying to wrap my head around for days now. Here is what I am doing: By using Veewee, I am creating a VirtualBox image and then I create a Vagrant box from it. See here, here Finally I run puppet from Vagrant to install RabbitMQ, see here. Veewee, Vagrant and VirtualBox all run on MacOS X 10.7.4. The vagrant box itself is CentOS 6.2. This worked fine for quite some time until I was recreating the VirtualBox image a couple of days ago. During installation of the rabbitmq-plugins during my puppet run I now get the following error: /Stage[main]/Rabbitmq/Exec[rabbitmq-plugins]/returns: erlexec: HOME must be set My RabbitMQ puppet configuration can be found on my GitHub repo for that project, but here is the most important part: $version = "2.8.7" $url = "http://www.rabbitmq.com/releases/rabbitmq-server/v${version}/rabbitmq-server-${version}-1.noarch.rpm" package{"erlang": ensure => "present", } package{"rabbitmq-server": provider => "rpm", source => $url, require => Package["erlang"] } exec{"rabbitmq-plugins": path => "/usr/bin:/usr/sbin:/bin", command => "rabbitmq-plugins enable rabbitmq_management", require => Package["rabbitmq-server"] } My additional repositories, e.g. epel, are defined in veewees postinstall.sh right at the top of the file. Finally, this is what I get when I do '/etc/init.d/rabbitmq-server status' [{pid,2834}, {running_applications,[{rabbit,"RabbitMQ","2.8.7"}, {ssl,"Erlang/OTP SSL application","4.1.6"}, {public_key,"Public key infrastructure","0.13"}, {crypto,"CRYPTO version 2","2.0.4"}, {mnesia,"MNESIA CXC 138 12","4.5"}, {os_mon,"CPO CXC 138 46","2.2.7"}, {sasl,"SASL CXC 138 11","2.1.10"}, {stdlib,"ERTS CXC 138 10","1.17.5"}, {kernel,"ERTS CXC 138 10","2.14.5"}]}, {os,{unix,linux}}, {erlang_version,"Erlang R14B04 (erts-5.8.5) [source] [64-bit] [rq:1] [async-threads:30] [kernel-poll:true]\n"}, {memory,[{total,24993120}, {processes,10328496}, {processes_used,10321296}, {system,14664624}, {atom,1175905}, {atom_used,1143841}, {binary,17192}, {code,11416020}, {ets,766168}]}, {vm_memory_high_watermark,0.4}, {vm_memory_limit,205851852}, {disk_free_limit,1000000000}, {disk_free,7089795072}, {file_descriptors,[{total_limit,924}, {total_used,4}, {sockets_limit,829}, {sockets_used,2}]}, {processes,[{limit,1048576},{used,131}]}, {run_queue,0}, {uptime,6}] Sources in the web suggest, that I have to set HOME. Of course I was logging into the box if HOME was set, for user vagrant it was '/home/vagrant' and for root it was 'root'. As always, any hints/ideas/suggestions/assumptions are more than welcome. Thanks a lot! Cheers, Tobi

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  • Data Binding to Attached Properties

    - by Chris Gardner
    Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2013/06/14/data-binding-to-attached-properties.aspx When I was working on my C#/XAML game framework, I discovered I wanted to try to data bind my sprites to background objects. That way, I could update my objects and the draw functionality would take care of the work for me. After a little experimenting and web searching, it appeared this concept was an impossible dream. Of course, when has that ever stopped me? In my typical way, I started to massively dive down the rabbit hole. I created a sprite on a canvas, and I bound it to a background object. <Canvas Name="GameField" Background="Black"> <Image Name="PlayerStrite" Source="Assets/Ship.png" Width="50" Height="50" Canvas.Left="{Binding X}" Canvas.Top="{Binding Y}"/> </Canvas> Now, we wire the UI item to the background item. public MainPage() { this.InitializeComponent(); this.Loaded += StartGame; }   void StartGame( object sender, RoutedEventArgs e ) { BindingPlayer _Player = new BindingPlayer(); _Player.X = Window.Current.Bounds.Height - PlayerSprite.Height; _Player.X = ( Window.Current.Bounds.Width - PlayerSprite.Width ) / 2.0; } Of course, now we need to actually have our background object. public class BindingPlayer : INotifyPropertyChanged { private double m_X; public double X { get { return m_X; } set { m_X = value; NotifyPropertyChanged(); } }   private double m_Y; public double Y { get { return m_Y; } set { m_Y = value; NotifyPropertyChanged(); } }   public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } } I fired this baby up, and my sprite was correctly positioned on the screen. Maybe the sky wasn't falling after all. Wouldn't it be great if that was the case? I created some code to allow me to move the sprite, but nothing happened. This seems odd. So, I start debugging the application and stepping through code. Everything appears to be working. Time to dig a little deeper. After much profanity was spewed, I stumbled upon a breakthrough. The code only looked like it was working. What was really happening is that there was an exception being thrown in the background thread that I never saw. Apparently, the key call was the one to PropertyChanged. If PropertyChanged is not called on the UI thread, the UI thread ignores the call. Actually, it throws an exception and the background thread silently crashes. Of course, you'll never see this unless you're looking REALLY carefully. This seemed to be a simple problem. I just need to marshal this to the UI thread. Unfortunately, this object has no knowledge of this mythical UI Thread in which we speak. So, I had to pull the UI Thread out of thin air. Let's change our PropertyChanged call to look this. public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal, new Windows.UI.Core.DispatchedHandler( () => { PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } ) ); } Now, we raised our notification on the UI thread. Everything is fine, people are happy, and the world moves on. You may have noticed that I didn't await my call to the dispatcher. This was intentional. If I am trying to update a slew of sprites, I don't want thread being hung while I wait my turn. Thus, I send the message and move on. It is worth nothing that this is NOT the most efficient way to do this for game programming. We'll get to that in another blog post. However, it is perfectly acceptable for a business app that is running a background task that would like to notify the UI thread of progress on a periodic basis. It is worth noting that this code was written for a Windows Store App. You can do the same thing with WP8 and WPF. The call to the marshaler changes, but it is the same idea.

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  • Week in Geek: New Security Flaw Confirmed for Internet Explorer Edition

    - by Asian Angel
    This week we learned how to use a PC to stay entertained while traveling for the holidays, create quality photo prints with free software, share links between any browser and any smartphone, create perfect Christmas photos using How-To Geek’s 10 best how-to photo guides, and had fun decorating Firefox with a collection of Holiday 2010 Personas themes. Photo by Repoort. Random Geek Links Photo by Asian Angel. Critical 0-Day Flaw Affects All Internet Explorer Versions, Microsoft Warns Microsoft has confirmed a zero-day vulnerability affecting all supported versions of Internet Explorer, including IE8, IE7 and IE6. Note: Article contains link to Microsoft Security Advisory detailing two work-arounds until a security update is released. Hackers targeting human rights, indie media groups Hackers are increasingly hitting the Web sites of human rights and independent media groups in an attempt to silence them, says a new study released this week by Harvard University’s Berkman Center for Internet & Society. OpenBSD: audits give no indication of back doors So far, the analyses of OpenBSD’s crypto and IPSec code have not provided any indication that the system contains back doors for listening to encrypted VPN connections. But the developers have already found two bugs during their current audits. Sophos: Beware Facebook’s new facial-recognition feature Facebook’s new facial recognition software might result in undesirable photos of users being circulated online, warned a security expert, who urged users to keep abreast with the social network’s privacy settings to prevent the abovementioned scenario from becoming a reality. Microsoft withdraws flawed Outlook update Microsoft has withdrawn update KB2412171 for Outlook 2007, released last Patch Tuesday, after a number of user complaints. Skype: Millions still without service Skype was still working to right itself going into the holiday weekend from a major outage that began this past Wednesday. Mozilla improves sync setup and WebGL in Firefox 4 beta 8 Firefox 4.0 beta 8 brings better support for WebGL and introduces an improved setup process for Firefox Sync that simplifies the steps for configuring the synchronization service across multiple devices. Chrome OS the litmus test for cloud The success or failure of Google’s browser-oriented Chrome OS will be the litmus test to decide if the cloud is capable of addressing user needs for content and services, according to a new Ovum report released Monday. FCC Net neutrality rules reach mobile apps The Federal Communications Commission (FCC) finally released its long-expected regulations on Thursday and the related explanations total a whopping 194 pages. One new item that was not previously disclosed: mobile wireless providers can’t block “applications that compete with the provider’s” own voice or video telephony services. KDE and the Document Foundation join Open Invention Network The KDE e.V. and the Document Foundation (TDF) have both joined the Open Invention Network (OIN) as licensees, expanding the organization’s roster of supporters. Report: SEC looks into Hurd’s ousting from HP The scandal surrounding Mark Hurd’s departure from the world’s largest technology company in August has officially drawn attention from the U.S. Securities and Exchange Commission. Report: Google requests delay of new Google TVs Google TV is apparently encountering a bit of static that has resulted in a programming change. Geek Video of the Week This week we have a double dose of geeky video goodness for you with the original Mac vs PC video and the trailer for the sequel. Photo courtesy of Peacer. Mac vs PC Photo courtesy of Peacer. Mac vs PC 2 Trailer Random TinyHacker Links Awesome Tools To Extract Audio From Video Here’s a list of really useful, and free tools to rip audio from videos. Getting Your iPhone Out of Recovery Mode Is your iPhone stuck in recovery mode? This tutorial will help you get it out of that state. Google Shared Spaces Quickly create a shared space and collaborate with friends online. McAfee Internet Security 2011 – Upgrade not worthy of a version change McAfee has released their 2011 version of security products. And as this review details, the upgrades are minimal when compared to their 2010 products. For more information, check out the review. 200 Countries Plotted Hans Rosling’s famous lectures combine enormous quantities of public data with a sport’s commentator’s style to reveal the story of the world’s past, present and future development. Now he explores stats in a way he has never done before – using augmented reality animation. Super User Questions Enjoy looking through this week’s batch of popular questions and answers from Super User. How to restore windows 7 to a known working state every time it boots? Is there an easy way to mass-transfer all files between two computers? Coffee spilled inside computer, damaged hard drive Computer does not boot after ram upgrade Keyboard not detected when trying to install Ubuntu 10.10 How-To Geek Weekly Article Recap Have you had a super busy week while preparing for the holiday weekend? Then here is your chance to get caught up on your reading with our five hottest articles for the week. Ask How-To Geek: Rescuing an Infected PC, Installing Bloat-free iTunes, and Taming a Crazy Trackpad How to Use the Avira Rescue CD to Clean Your Infected PC Eight Geektacular Christmas Projects for Your Day Off VirtualBox 4.0 Rocks Extensions and a Simplified GUI Ask the Readers: How Many Monitors Do You Use with Your Computer? One Year Ago on How-To Geek Here are more great articles from one year ago for you to read and enjoy during the holiday break. Enjoy Distraction-Free Writing with WriteMonkey Shutter is a State of Art Screenshot Tool for Ubuntu Get Hex & RGB Color Codes the Easy Way Find User Scripts for Your Favorite Websites the Easy Way Access Your Unsorted Bookmarks the Easy Way (Firefox) The Geek Note That “wraps” things up for this week and we hope that everyone enjoys the rest of their holiday break! Found a great tip during the break? Then be sure to send it in to us at [email protected]. Photo by ArSiSa7. Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Simon’s Cat Explores the Christmas Tree! [Video] The Outdoor Lights Scene from National Lampoon’s Christmas Vacation [Video] The Famous Home Alone Pizza Delivery Scene [Classic Video] Chronicles of Narnia: The Voyage of the Dawn Treader Theme for Windows 7 Cardinal and Rabbit Sharing a Tree on a Cold Winter Morning Wallpaper An Alternate Star Wars Christmas Special [Video]

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  • Waterfall Model (SDLC) vs. Prototyping Model

    The characters in the fable of the Tortoise and the Hare can easily be used to demonstrate the similarities and differences between the Waterfall and Prototyping software development models. This children fable is about a race between a consistently slow moving but steadfast turtle and an extremely fast but unreliable rabbit. After closely comparing each character’s attributes in correlation with both software development models, a trend seems to appear in that the Waterfall closely resembles the Tortoise in that Waterfall Model is typically a slow moving process that is broken up in to multiple sequential steps that must be executed in a standard linear pattern. The Tortoise can be quoted several times in the story saying “Slow and steady wins the race.” This is the perfect mantra for the Waterfall Model in that this model is seen as a cumbersome and slow moving. Waterfall Model Phases Requirement Analysis & Definition This phase focuses on defining requirements for a project that is to be developed and determining if the project is even feasible. Requirements are collected by analyzing existing systems and functionality in correlation with the needs of the business and the desires of the end users. The desired output for this phase is a list of specific requirements from the business that are to be designed and implemented in the subsequent steps. In addition this phase is used to determine if any value will be gained by completing the project. System Design This phase focuses primarily on the actual architectural design of a system, and how it will interact within itself and with other existing applications. Projects at this level should be viewed at a high level so that actual implementation details are decided in the implementation phase. However major environmental decision like hardware and platform decision are typically decided in this phase. Furthermore the basic goal of this phase is to design an application at the system level in those classes, interfaces, and interactions are defined. Additionally decisions about scalability, distribution and reliability should also be considered for all decisions. The desired output for this phase is a functional  design document that states all of the architectural decisions that have been made in regards to the project as well as a diagrams like a sequence and class diagrams. Software Design This phase focuses primarily on the refining of the decisions found in the functional design document. Classes and interfaces are further broken down in to logical modules based on the interfaces and interactions previously indicated. The output of this phase is a formal design document. Implementation / Coding This phase focuses primarily on implementing the previously defined modules in to units of code. These units are developed independently are intergraded as the system is put together as part of a whole system. Software Integration & Verification This phase primarily focuses on testing each of the units of code developed as well as testing the system as a whole. There are basic types of testing at this phase and they include: Unit Test and Integration Test. Unit Test are built to test the functionality of a code unit to ensure that it preforms its desired task. Integration testing test the system as a whole because it focuses on results of combining specific units of code and validating it against expected results. The output of this phase is a test plan that includes test with expected results and actual results. System Verification This phase primarily focuses on testing the system as a whole in regards to the list of project requirements and desired operating environment. Operation & Maintenance his phase primarily focuses on handing off the competed project over to the customer so that they can verify that all of their requirements have been met based on their original requirements. This phase will also validate the correctness of their requirements and if any changed need to be made. In addition, any problems not resolved in the previous phase will be handled in this section. The Waterfall Model’s linear and sequential methodology does offer a project certain advantages and disadvantages. Advantages of the Waterfall Model Simplistic to implement and execute for projects and/or company wide Limited demand on resources Large emphasis on documentation Disadvantages of the Waterfall Model Completed phases cannot be revisited regardless if issues arise within a project Accurate requirement are never gather prior to the completion of the requirement phase due to the lack of clarification in regards to client’s desires. Small changes or errors that arise in applications may cause additional problems The client cannot change any requirements once the requirements phase has been completed leaving them no options for changes as they see their requirements changes as the customers desires change. Excess documentation Phases are cumbersome and slow moving Learn more about the Major Process in the Sofware Development Life Cycle and Waterfall Model. Conversely, the Hare shares similar traits with the prototyping software development model in that ideas are rapidly converted to basic working examples and subsequent changes are made to quickly align the project with customers desires as they are formulated and as software strays from the customers vision. The basic concept of prototyping is to eliminate the use of well-defined project requirements. Projects are allowed to grow as the customer needs and request grow. Projects are initially designed according to basic requirements and are refined as requirement become more refined. This process allows customer to feel their way around the application to ensure that they are developing exactly what they want in the application This model also works well for determining the feasibility of certain approaches in regards to an application. Prototypes allow for quickly developing examples of implementing specific functionality based on certain techniques. Advantages of Prototyping Active participation from users and customers Allows customers to change their mind in specifying requirements Customers get a better understanding of the system as it is developed Earlier bug/error detection Promotes communication with customers Prototype could be used as final production Reduced time needed to develop applications compared to the Waterfall method Disadvantages of Prototyping Promotes constantly redefining project requirements that cause major system rewrites Potential for increased complexity of a system as scope of the system expands Customer could believe the prototype as the working version. Implementation compromises could increase the complexity when applying updates and or application fixes When companies trying to decide between the Waterfall model and Prototype model they need to evaluate the benefits and disadvantages for both models. Typically smaller companies or projects that have major time constraints typically head for more of a Prototype model approach because it can reduce the time needed to complete the project because there is more of a focus on building a project and less on defining requirements and scope prior to the start of a project. On the other hand, Companies with well-defined requirements and time allowed to generate proper documentation should steer towards more of a waterfall model because they are in a position to obtain clarified requirements and have to design and optimal solution prior to the start of coding on a project.

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  • The Presentation Isn't Over Until It's Over

    - by Phil Factor
    The senior corporate dignitaries settled into their seats looking important in a blue-suited sort of way. The lights dimmed as I strode out in front to give my presentation.  I had ten vital minutes to make my pitch.  I was about to dazzle the top management of a large software company who were considering the purchase of my software product. I would present them with a dazzling synthesis of diagrams, graphs, followed by  a live demonstration of my software projected from my laptop.  My preparation had been meticulous: It had to be: A year’s hard work was at stake, so I’d prepared it to perfection.  I stood up and took them all in, with a gaze of sublime confidence. Then the laptop expired. There are several possible alternative plans of action when this happens     A. Stare at the smoking laptop vacuously, flapping ones mouth slowly up and down     B. Stand frozen like a statue, locked in indecision between fright and flight.     C. Run out of the room, weeping     D. Pretend that this was all planned     E. Abandon the presentation in favour of a stilted and tedious dissertation about the software     F. Shake your fist at the sky, and curse the sense of humour of your preferred deity I started for a few seconds on plan B, normally referred to as the ‘Rabbit in the headlamps of the car’ technique. Suddenly, a little voice inside my head spoke. It spoke the famous inane words of Yogi Berra; ‘The game isn't over until it's over.’ ‘Too right’, I thought. What to do? I ran through the alternatives A-F inclusive in my mind but none appealed to me. I was completely unprepared for this. Nowadays, longevity has since taught me more than I wanted to know about the wacky sense of humour of fate, and I would have taken two laptops. I hadn’t, but decided to do the presentation anyway as planned. I started out ignoring the dead laptop, but pretending, instead that it was still working. The audience looked startled. They were expecting plan B to be succeeded by plan C, I suspect. They weren’t used to denial on this scale. After my introductory talk, which didn’t require any visuals, I came to the diagram that described the application I’d written.  I’d taken ages over it and it was hot stuff. Well, it would have been had it been projected onto the screen. It wasn’t. Before I describe what happened then, I must explain that I have thespian tendencies.  My  triumph as Professor Higgins in My Fair Lady at the local operatic society is now long forgotten, but I remember at the time of my finest performance, the moment that, glancing up over the vast audience of  moist-eyed faces at the during the poignant  scene between Eliza and Higgins at the end, I  realised that I had a talent that one day could possibly  be harnessed for commercial use I just talked about the diagram as if it was there, but throwing in some extra description. The audience nodded helpfully when I’d done enough. Emboldened, I began a sort of mime, well, more of a ballet, to represent each slide as I came to it. Heaven knows I’d done my preparation and, in my mind’s eye, I could see every detail, but I had to somehow project the reality of that vision to the audience, much the same way any actor playing Macbeth should do the ghost of Banquo.  My desperation gave me a manic energy. If you’ve ever demonstrated a windows application entirely by mime, gesture and florid description, you’ll understand the scale of the challenge, but then I had nothing to lose. With a brief sentence of description here and there, and arms flailing whilst outlining the size and shape of  graphs and diagrams, I used the many tricks of mime, gesture and body-language  learned from playing Captain Hook, or the Sheriff of Nottingham in pantomime. I set out determinedly on my desperate venture. There wasn’t time to do anything but focus on the challenge of the task: the world around me narrowed down to ten faces and my presentation: ten souls who had to be hypnotized into seeing a Windows application:  one that was slick, well organized and functional I don’t remember the details. Eight minutes of my life are gone completely. I was a thespian berserker.  I know however that I followed the basic plan of building the presentation in a carefully controlled crescendo until the dazzling finale where the results were displayed on-screen.  ‘And here you see the results, neatly formatted and grouped carefully to enhance the significance of the figures, together with running trend-graphs!’ I waved a mime to signify an animated  window-opening, and looked up, in my first pause, to gaze defiantly  at the audience.  It was a sight I’ll never forget. Ten pairs of eyes were gazing in rapt attention at the imaginary window, and several pairs of eyes were glancing at the imaginary graphs and figures.  I hadn’t had an audience like that since my starring role in  Beauty and the Beast.  At that moment, I realized that my desperate ploy might work. I sat down, slightly winded, when my ten minutes were up.  For the first and last time in my life, the audience of a  ‘PowerPoint’ presentation burst into spontaneous applause. ‘Any questions?’ ‘Yes,  Have you got an agent?’ Yes, in case you’re wondering, I got the deal. They bought the software product from me there and then. However, it was a life-changing experience for me and I have never ever again trusted technology as part of a presentation.  Even if things can’t go wrong, they’ll go wrong and they’ll kill the flow of what you’re presenting.  if you can’t do something without the techno-props, then you shouldn’t do it.  The greatest lesson of all is that great presentations require preparation and  ‘stage-presence’ rather than fancy graphics. They’re a great supporting aid, but they should never dominate to the point that you’re lost without them.

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  • Visual Studio 2010 Productivity Tips and Tricks&ndash;Part 1: Extensions

    - by ToStringTheory
    I don’t know about you, but when it comes to development, I prefer my environment to be as free of clutter as possible.  It may surprise you to know that I have tried ReSharper, and did not like it, for the reason that I stated above.  In my opinion, it had too much clutter.  Don’t get me wrong, there were a couple of features that I did like about it (inversion of if blocks, code feedback), but for the most part, I actually felt that it was slowing me down. Introduction Another large factor besides intrusiveness/speed in my choice to dislike ReSharper would probably be that I have become comfortable with my current setup and extensions.  I believe I have a good collection, and am quite happy with what I can accomplish in a short amount of time.  I figured that I would share some of my tips/findings regarding Visual Studio productivity here, and see what you had to say. The first section of things that I would like to cover, are Visual Studio Extensions.  In case you have been living under a rock for the past several years, Extensions are available under the Tools menu in Visual Studio: The extension manager enables integrated access to the Microsoft Visual Studio Gallery online with access to a few thousand different extensions.  I have tried many extensions, but for reasons of lack reliability, usability, or features, have uninstalled almost all of them.  However, I have come across several that I find I can not do without anymore: NuGet Package Manager (Microsoft) Perspectives (Adam Driscoll) Productivity Power Tools (Microsoft) Web Essentials (Mads Kristensen) Extensions NuGet Package Manager To be honest, I debated on whether or not to put this in here.  Most people seem to have it, however, there was a time when I didn’t, and was always confused when blogs/posts would say to right click and “Add Package Reference…” which with one of the latest updates is now “Manage NuGet Packages”.  So, if you haven’t downloaded the NuGet Package Manager yet, or don’t know what it is, I would highly suggest downloading it now! Features Simply put, the NuGet Package Manager gives you a GUI and command line to access different libraries that have been uploaded to NuGet. Some of its features include: Ability to search NuGet for packages via the GUI, with information in the detail bar on the right. Quick access to see what packages are in a solution, and what packages have updates available, with easy 1-click updating. If you download a package that requires references to work on other NuGet packages, they will be downloaded and referenced automatically. Productivity Tip If you use any type of source control in Visual Studio as well as using NuGet packages, be sure to right-click on the solution and click "Enable NuGet Package Restore". What this does is add a NuGet package to the solution so that it will be checked in along side your solution, as well as automatically grab packages from NuGet on build if needed. This is an extremely simple system to use to manage your package references, instead of having to manually go into TFS and add the Packages folder. Perspectives I can't stand developing with just one monitor. Especially if it comes to debugging. The great thing about Visual Studio 2010, is that all of the panels and windows are floatable, and can dock to other screens. The only bad thing is, I don't use the same toolset with everything that I am doing. By this, I mean that I don't use all of the same windows for debugging a web application, as I do for coding a WPF application. Only thing is, Visual Studio doesn't save the screen positions for all of the undocked windows. So, I got curious one day and decided to check and see if there was an extension to help out. This is where I found Perspectives. Features Perspectives gives you the ability to configure window positions across any or your monitors, and then to save the positions in a profile. Perspectives offers a Panel to manage different presets/favorites, and a toolbar to add to the toolbars at the top of Visual Studio. Ability to 'Favorite' a profile to add it to the perspectives toolbar. Productivity Tip Take the time to setup profiles for each of your scenarios - debugging web/winforms/xaml, coding, maintenance, etc. Try to remember to use the profiles for a few days, and at the end of a week, you may find that your productivity was never better. Productivity Power Tools Ah, the Productivity Power Tools... Quite possibly one of my most used extensions, if not my most used. The tool pack gives you a variety of enhancements ranging from key shortcuts, interface tweaks, and completely new features to Visual Studio 2010. Features I don't want to bore you with all of the features here, so here are my favorite: Quick Find - Unobtrusive search box in upper-right corner of the code window. Great for searching in general, especially in a file. Solution Navigator - The 'Solution Explorer' on steroids. Easy to search for files, see defined members/properties/methods in files, and my favorite feature is the 'set as root' option. Updated 'Add Reference...' Dialog - This is probably my favorite enhancement period... The 'Add Reference...' dialog redone in a manner that resembles the Extension/Package managers. I especially love the ability to search through all of the references. "Ctrl - Click" for Definition - I am still getting used to this as I usually try to use my keyboard for everything, but I love the ability to hold Ctrl and turn property/methods/variables into hyperlinks, that you click on to see their definitions. Great for travelling down a rabbit hole in an application to research problems. While there are other commands/utilities, I find these to be the ones that I lean on the most for the usefulness. Web Essentials If you have do any type of web development in ASP .Net, ASP .Net MVC, even HTML, I highly suggest grabbing the Web Essentials right NOW! This extension alone is great for productivity in web development, and greatly decreases my development time on new features. Features Some of its best features include: CSS Previews - I say 'previews' because of the multiple kinds of previews in CSS that you get font-family, color, background/background-image previews. This is great for just tweaking UI slightly in different ways and seeing how they look in the CSS window at a glance. Live Preview - One word - awesome! This goes well with my multi-monitor setup. I put the site on one monitor in a Live Preview panel, and then as I make changes to CSS/cshtml/aspx/html, the preview window will update with each save/build automatically. For CSS, you can even turn on live-update, so as you are tweaking CSS, the style changes in real time. Great for tweaking colors or font-sizes. Outlining - Small, but I like to be able to collapse regions/declarations that are in the way of new work, or are just distracting. Commenting Shortcuts - I don't know why it wasn't included by default, but it is nice to have the key shortcuts for commenting working in the CSS editor as well. Productivity Tip When working on a site, hit CTRL-ALT-ENTER to launch the Live Preview window. Dock it to another monitor. When you make changes to the document/css, just save and glance at the other monitor. No need to alt tab, then alt tab before continuing editing. Conclusion These extensions are only the most useful and least intrusive - ones that I use every day. The great thing about Visual Studio 2010 is the extensibility options that it gives developers to utilize. Have an extension that you use that isn't intrusive, but isn't listed here? Please, feel free to comment. I love trying new things, and am always looking for new additions to my toolset of the most useful. Finally, please keep an eye out for Part 2 on key shortcuts in Visual Studio. Also, if you are visiting my site (http://tostringtheory.com || http://geekswithblogs.net/tostringtheory) from an actual browser and not a feed, please let me know what you think of the new styling!

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  • Metrics - A little knowledge can be a dangerous thing (or 'Why you're not clever enough to interpret metrics data')

    - by Jason Crease
    At RedGate Software, I work on a .NET obfuscator  called SmartAssembly.  Various features of it use a database to store various things (exception reports, name-mappings, etc.) The user is given the option of using either a SQL-Server database (which requires them to have Microsoft SQL Server), or a Microsoft Access MDB file (which requires nothing). MDB is the default option, but power-users soon switch to using a SQL Server database because it offers better performance and data-sharing. In the fashionable spirit of optimization and metrics, an obvious product-management question is 'Which is the most popular? SQL Server or MDB?' We've collected data about this fact, using our 'Feature-Usage-Reporting' technology (available as part of SmartAssembly) and more recently our 'Application Metrics' technology: Parameter Number of users % of total users Number of sessions Number of usages SQL Server 28 19.0 8115 8115 MDB 114 77.6 1449 1449 (As a disclaimer, please note than SmartAssembly has far more than 132 users . This data is just a selection of one build) So, it would appear that SQL-Server is used by fewer users, but more often. Great. But here's why these numbers are useless to me: Only the original developers understand the data What does a single 'usage' of 'MDB' mean? Does this happen once per run? Once per option change? On clicking the 'Obfuscate Now' button? When running the command-line version or just from the UI version? Each question could skew the data 10-fold either way, and the answers only known by the developer that instrumented the application in the first place. In other words, only the original developer can interpret the data - product-managers cannot interpret the data unaided. Most of the data is from uninterested users About half of people who download and run a free-trial from the internet quit it almost immediately. Only a small fraction use it sufficiently to make informed choices. Since the MDB option is the default one, we don't know how many of those 114 were people CHOOSING to use the MDB, or how many were JUST HAPPENING to use this MDB default for their 20-second trial. This is a problem we see across all our metrics: Are people are using X because it's the default or are they using X because they want to use X? We need to segment the data further - asking what percentage of each percentage meet our criteria for an 'established user' or 'informed user'. You end up spending hours writing sophisticated and dubious SQL queries to segment the data further. Not fun. You can't find out why they used this feature Metrics can answer the when and what, but not the why. Why did people use feature X? If you're anything like me, you often click on random buttons in unfamiliar applications just to explore the feature-set. If we listened uncritically to metrics at RedGate, we would eliminate the most-important and more-complex features which people actually buy the software for, leaving just big buttons on the main page and the About-Box. "Ah, that's interesting!" rather than "Ah, that's actionable!" People do love data. Did you know you eat 1201 chickens in a lifetime? But just 4 cows? Interesting, but useless. Often metrics give you a nice number: '5.8% of users have 3 or more monitors' . But unless the statistic is both SUPRISING and ACTIONABLE, it's useless. Most metrics are collected, reviewed with lots of cooing. and then forgotten. Unless a piece-of-data could change things, it's useless collecting it. People get obsessed with significance levels The first things that lots of people do with this data is do a t-test to get a significance level ("Hey! We know with 99.64% confidence that people prefer SQL Server to MDBs!") Believe me: other causes of error/misinterpretation in your data are FAR more significant than your t-test could ever comprehend. Confirmation bias prevents objectivity If the data appears to match our instinct, we feel satisfied and move on. If it doesn't, we suspect the data and dig deeper, plummeting down a rabbit-hole of segmentation and filtering until we give-up and move-on. Data is only useful if it can change our preconceptions. Do you trust this dodgy data more than your own understanding, knowledge and intelligence?  I don't. There's always multiple plausible ways to interpret/action any data Let's say we segment the above data, and get this data: Post-trial users (i.e. those using a paid version after the 14-day free-trial is over): Parameter Number of users % of total users Number of sessions Number of usages SQL Server 13 9.0 1115 1115 MDB 5 4.2 449 449 Trial users: Parameter Number of users % of total users Number of sessions Number of usages SQL Server 15 10.0 7000 7000 MDB 114 77.6 1000 1000 How do you interpret this data? It's one of: Mostly SQL Server users buy our software. People who can't afford SQL Server tend to be unable to afford or unwilling to buy our software. Therefore, ditch MDB-support. Our MDB support is so poor and buggy that our massive MDB user-base doesn't buy it.  Therefore, spend loads of money improving it, and think about ditching SQL-Server support. People 'graduate' naturally from MDB to SQL Server as they use the software more. Things are fine the way they are. We're marketing the tool wrong. The large number of MDB users represent uninformed downloaders. Tell marketing to aggressively target SQL Server users. To choose an interpretation you need to segment again. And again. And again, and again. Opting-out is correlated with feature-usage Metrics tends to be opt-in. This skews the data even further. Between 5% and 30% of people choose to opt-in to metrics (often called 'customer improvement program' or something like that). Casual trial-users who are uninterested in your product or company are less likely to opt-in. This group is probably also likely to be MDB users. How much does this skew your data by? Who knows? It's not all doom and gloom. There are some things metrics can answer well. Environment facts. How many people have 3 monitors? Have Windows 7? Have .NET 4 installed? Have Japanese Windows? Minor optimizations.  Is the text-box big enough for average user-input? Performance data. How long does our app take to start? How many databases does the average user have on their server? As you can see, questions about who-the-user-is rather than what-the-user-does are easier to answer and action. Conclusion Use SmartAssembly. If not for the metrics (called 'Feature-Usage-Reporting'), then at least for the obfuscation/error-reporting. Data raises more questions than it answers. Questions about environment are the easiest to answer.

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  • Recursion in the form of a Recursive Func&lt;T, T&gt;

    - by ToStringTheory
    I gotta admit, I am kind of surprised that I didn’t realize I could do this sooner.  I recently had a problem which required a recursive function call to come up with the answer.  After some time messing around with a recursive method, and creating an API that I was not happy with, I was able to create an API that I enjoy, and seems intuitive. Introduction To bring it to a simple example, consider the summation to n: A mathematically identical formula is: In a .NET function, this can be represented by a function: Func<int, int> summation = x => x*(x+1)/2 Calling summation with an input integer will yield the summation to that number: var sum10 = summation(4); //sum10 would be equal to 10 But what if I wanted to get a second level summation…  First some to n, and then use that argument as the input to the same function, to find the second level summation: So as an easy example, calculate the summation to 3, which yields 6.  Then calculate the summation to 6 which yields 21. Represented as a mathematical formula - So what if I wanted to represent this as .NET functions.  I can always do: //using the summation formula from above var sum3 = summation(3); //sets sum3 to 6 var sum3_2 = summation(sum3); //sets sum3 to 21 I could always create a while loop to perform the calculations too: Func<int, int> summation = x => x*(x+1)/2; //for the interests of a smaller example, using shorthand int sumResultTo = 3; int level = 2; while(level-- > 0) { sumResultTo = summation(sumResultTo); } //sumResultTo is equal to 21 now. Or express it as a for-loop, method calls, etc…  I really didn’t like any of the options that I tried.  Then it dawned on me – since I was using a Func<T, T> anyways, why not use the Func’s output from one call as the input as another directly. Some Code So, I decided that I wanted a recursion class.  Something that I would be generic and reusable in case I ever wanted to do something like this again. It is limited to only the Func<T1, T2> level of Func, and T1 must be the same as T2. The first thing in this class is a private field for the function: private readonly Func<T, T> _functionToRecurse; So, I since I want the function to be unchangeable, I have defined it as readonly.  Therefore my constructor looks like: public Recursion(Func<T, T> functionToRecurse) { if (functionToRecurse == null) { throw new ArgumentNullException("functionToRecurse", "The function to recurse can not be null"); } _functionToRecurse = functionToRecurse; } Simple enough.  If you have any questions, feel free to post them in the comments, and I will be sure to answer them. Next, I want enough. If be able to get the result of a function dependent on how many levels of recursion: private Func<T, T> GetXLevel(int level) { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } if (level == 1) return _functionToRecurse; return _GetXLevel(level - 1, _functionToRecurse); } So, if you pass in 1 for the level, you get just the Func<T,T> back.  If you say that you want to go deeper down the rabbit hole, it calls a method which accepts the level it is at, and the function which it needs to use to recurse further: private Func<T, T> _GetXLevel(int level, Func<T, T> prevFunc) { if (level == 1) return y => prevFunc(_functionToRecurse(y)); return _GetXLevel(level - 1, y => prevFunc(_functionToRecurse(y))); } That is really all that is needed for this class. If I exposed the GetXLevel function publicly, I could use that to get the function for a level, and pass in the argument..  But I wanted something better.  So, I used the ‘this’ array operator for the class: public Func<T,T> this[int level] { get { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } return this.GetXLevel(level); } } So, using the same example above of finding the second recursion of the summation of 3: var summator = new Recursion<int>(x => (x * (x + 1)) / 2); var sum_3_level2 = summator[2](3); //yields 21 You can even find just store the delegate to the second level summation, and use it multiple times: var summator = new Recursion<int>(x => (x * (x + 1)) / 2); var sum_level2 = summator[2]; var sum_3_level2 = sum_level2(3); //yields 21 var sum_4_level2 = sum_level2(4); //yields 55 var sum_5_level2 = sum_level2(5); //yields 120 Full Code Don’t think I was just going to hold off on the full file together and make you do the hard work…  Copy this into a new class file: public class Recursion<T> { private readonly Func<T, T> _functionToRecurse; public Recursion(Func<T, T> functionToRecurse) { if (functionToRecurse == null) { throw new ArgumentNullException("functionToRecurse", "The function to recurse can not be null"); } _functionToRecurse = functionToRecurse; } public Func<T,T> this[int level] { get { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } return this.GetXLevel(level); } } private Func<T, T> GetXLevel(int level) { if (level < 1) { throw new ArgumentOutOfRangeException("level", level, "The level of recursion must be greater than 0"); } if (level == 1) return _functionToRecurse; return _GetXLevel(level - 1, _functionToRecurse); } private Func<T, T> _GetXLevel(int level, Func<T, T> prevFunc) { if (level == 1) return y => prevFunc(_functionToRecurse(y)); return _GetXLevel(level - 1, y => prevFunc(_functionToRecurse(y))); } } Conclusion The great thing about this class, is that it can be used with any function with same input/output parameters.  I strived to find an implementation that I found clean and useful, and I finally settled on this.  If you have feedback – good or bad, I would love to hear it!

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  • Apache/PHP serving file multiple times

    - by easement
    I have a system with a download.php page. The page takes and id and loads a file based on from the DB Record and then serves it up. I've noticed a couple instances where files are requested multiple times in short time spans (20ms). Times that are too quick for human input. There are plenty of instances where the downloader functions fine. However, in taking a closer look at the downloader’s usage, I did see some interesting behavior. For instance, the IP address xxx.xxx.xxx.xxx (which is one in a range owned by xxxxxx.de in Germany) came to the site through Google. They browsed around and then came to the page http://site.com/xxxx/press+125.php There they issued a request for /download.php?id=/ZZ/n+aH55Y= (a PDF) at 9:04:23AM. That alone is not a big deal. However, what is interesting is that the server seems to have been quite preoccupied with serving that request. In the logs the request first completes between 9:09:48 and 9:10:00. It looks like the user must have gotten tired of waiting during that time and requested the document two more times. Between 09:14:47 and 09:15:00 the same request appears again, except it is from 9:04:43AM, 20ms later than the first request. Then it pops up a third time, with a request that started at 09:05:06 completing between 09:19:55 and 09:19:58! I’m suspicious of that document. In looking through the logs I see other instances where it takes the server a little while to handle that specific file. Check out this list of requests from zzz.zzz.zzz.zzz[different than above] for the file /download.php?id=/ZZ/n+aH55Y= (the same docuemnt as before): Request time Complete Time 04:32:43 04:33:36 04:32:50 04:33:36 04:32:51 04:33:38 04:33:05 04:33:38 04:33:34 04:33:42 04:33:05 04:33:42 So something is definitely going on. Whether it has to do with this specific document tripping up the server, the download.php page’s code, or if we’re just seeing the evidence of some server level overload as it plays out in real time I’m not yet sure. In fairness, there are other instances of people downloading /download.php?id=/ZZ/n+aH55Y= (the same PDF) without error. However, it is interesting that the multiple processes only seem to happen with this one file, and then only when it is accessed through the page http://site.com/press+125.php . It bears further investigation if there’s something amiss inside the code that causes the system to fire off multiple download requests that occupy the server. I don't know if this press+125.php is a rabbit hole, but there is weird consicence. Any ideas? I'm totally out of ideas. Apache maxed out? Things like that. ///DOWNLOAD.php $file = new files(); $file->comparison_filter("id", "=", $id); //sql to load if ($file->load()) { $file->serve(); } //FILES function serve() { if ($this->is_loaded) { if (file_exists($this->get_value("filename"))) { if ($this->get_value("content_type") != "") { header("Content-Type: " . $this->get_value("content_type")); } header("Content-Length: " . filesize($this->get_value("filename"))); if ($this->get_value("flag_image") == 0 || $this->get_value("flag_image") == false) { header("Cache-Control: private"); header("Content-Disposition: attachment; filename=" . urlencode($this->get_value("original_filename"))); } set_time_limit(0); @readfile($this->get_value("filename")); exit; } } }

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  • CodePlex Daily Summary for Thursday, November 15, 2012

    CodePlex Daily Summary for Thursday, November 15, 2012Popular ReleasesMVC Bootstrap: MVC Boostrap 0.5.6: A small demo site, based on the default ASP.NET MVC 3 project template, showing off some of the features of MVC Bootstrap. Added features to the Membership provider, a "lock out" feature to help fight brute force hacking of accounts. After a set number of log in attempts, the account is locked for a set time. If you download and use this project, please give some feedback, good or bad!Home Access Plus+: v8.4: This release only contains fixes for the 97576 release, you can download the v8.3 release files which aren't in this release from 97576 Changes: Fixed: Setup.aspx wrong jquery reference Fixed: Issue with loading the user's photo Changed: The JSON Urls to use a number of a date rather than a string Added: Code to hopefully, finally, fix the AD Browser not working some times File Changes: ~/bin/hap.ad.dll ~/bin/hap.web.dll ~/bin/hap.web.configuration.dll ~/bin/hap.web.livetiles.dl...OnTopReplica: Release 3.4: Update to the 3 version with major fixes and improvements. Compatible with Windows 8. Now runs (and requires) .NET Framework v.4.0. Added relative mode for region selection (allows the user to select regions as margins from the borders of the thumbnail, useful for windows which have a variable size but fixed size controls, like video players). Improved window seeking when restoring cloned thumbnail or cloning a window by title or by class. Improved settings persistence. Improved co...DotSpatial: DotSpatial 1.4: This is a Minor Release. See the changes in the issue tracker. Minimal -- includes DotSpatial core and essential extensions Extended -- includes debugging symbols and additional extensions Tutorials are available. Just want to run the software? End user (non-programmer) version available branded as MapWindow Want to add your own feature? Develop a plugin, using the template and contribute to the extension feed (you can also write extensions that you distribute in other ways). Components ...JSLint for Resharper: 0.2.4701 (Resharper 7.1): Added settings dialog. May now prioritize before Resharper JS messages JSLint settings may be set as default. (For example browser: true, indent: 2) Added support for JSLint directives in mixed language files. Upgraded to Resharper 7.1.WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.5: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features Attachable Behaviors AwaitableUI extensions Controls Converters Debugging helpers Extension methods Imaging helpers IO helpers VisualTree helpers Samples Recent changes Docum...Social Network Importer for NodeXL: SocialNetImporter(v.1.6.1): This new version includes: - Fixes for some reported bugs. To use the new graph data provider, do the following: Unzip the Zip file into the "PlugIns" folder that can be found in the NodeXL installation folder (i.e "C:\Program Files\Social Media Research Foundation\NodeXL Excel Template\PlugIns") Open NodeXL template and you can access the new importer from the "Import" menuAcDown?????: AcDown????? v4.3: ??●AcDown??????????、??、??、???????。????,????,?????????????????????????。???????????Acfun、????(Bilibili)、??、??、YouTube、??、???、??????、SF????、????????????。 ●??????AcPlay?????,??????、????????????????。 ● AcDown??????????????????,????????????????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7/8 ???? 32??64? ???Linux ????(1)????????Windows XP???,????????.NET Framework 2.0???(x86),?????"?????????"??? (2)???????????Linux???,????????Mono?? ??2...SoftRenderer: SoftRenderer v0.2: SPONZA DEMO SoftRender is a CPU based renderer. It render 3D scene only on CPU. It's a project for learning purpose. SoftRender ????????,??????????。 http://i3.codeplex.com/Download?ProjectName=sr&DownloadId=528732 ?????????????,???compilehwshader.bat???????shader SoftRenderer.exe?vc10???????bin?? SoftRenderer_avx.exe?intel????????avx???cpu?????bin??WallSwitch: WallSwitch 1.2.1: Version 1.2.1 Changes: Improved collage image distribution to overlap older images first. Set default collage background blur distance to 4 (provides a more gradual effect). Fixed issue where wallpaper not displayed on Windows Vista when Cross-Fade transitions enabled. Fixed issue with duplicated themes not updating history view correctly.????: ???? 1.0: ????Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office ??? ?????、Unicode IVS?????????????????Unicode IVS???????????????。??、??????????????、?????????????????????????????。Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.74: fix for issue #18836 - sometimes throws null-reference errors in ActivationObject.AnalyzeScope method. add back the Context object's 8-parameter constructor, since someone has code that's using it. throw a low-pri warning if an expression statement is == or ===; warn that the developer may have meant an assignment (=). if window.XXXX or window"XXXX" is encountered, add XXXX (as long as it's a valid JavaScript identifier) to the known globals so subsequent references to XXXX won't throw ...???????: Monitor 2012-11-11: This is the first releasehttpclient?????????: httpclient??????? 1.0: httpclient??????? (1)?????????? (2)????????? (3)??2012-11-06??,???????。VidCoder: 1.4.5 Beta: Removed the old Advanced user interface and moved x264 preset/profile/tune there instead. The functionality is still available through editing the options string. Added ability to specify the H.264 level. Added ability to choose VidCoder's interface language. If you are interested in translating, we can get VidCoder in your language! Updated WPF text rendering to use the better Display mode. Updated HandBrake core to SVN 5045. Removed logic that forced the .m4v extension in certain ...ImageGlass: Version 1.5: http://i1214.photobucket.com/albums/cc483/phapsuxeko/ImageGlass/1.png v1.5.4401.3015 Thumbnail bar: Increase loading speed Thumbnail image with ratio Support personal customization: mouse up, mouse down, mouse hover, selected item... Scroll to show all items Image viewer Zoom by scroll, or selected rectangle Speed up loading Zoom to cursor point New background design and customization and others... v1.5.4430.483 Thumbnail bar: Auto move scroll bar to selected image Show / Hi...Building Windows 8 Apps with C# and XAML: Full Source Chapters 1 - 10 for Windows 8 Fix 002: This is the full source from all chapters of the book, compiled and tested on Windows 8 RTM. Includes: A fix for the Netflix example from Chapter 6 that was missing a service reference A fix for the ImageHelper issue (images were not being saved) - this was due to the buffer being inadequate and required streaming the writeable bitmap to a buffer first before encoding and savingmyCollections: Version 2.3.2.0: New in this version : Added TheGamesDB.net API for Games and NDS Added Support for Windows Media Center Added Support for myMovies Added Support for XBMC Added Support for Dune HD Added Support for Mede8er Added Support for WD HDTV Added Fast search options Added order by Artist/Album for music You can now create covers and background for games You can now update your ID3 tag with the info of myCollections Fixed several provider Performance improvement New Splash ...Draw: Draw 1.0: Drawing PadNew ProjectsCreatorRSS: CreatorRSS - A Simple Desktop tray RSS Reader This is a simple desktop RSS reader that will help in managing your feeds and get notifications. CreatorRSS is based on .NET framework 2.0 and is coded in C#. This was tested only on Windows Xp Professional Sp2 but it should work on any Windows operating systems that support .NET framework. Extensions Library: Extension Library adds several helpful extensions to your project including: - SharePoint Logging - Event Viewer Logging - Exception Handling - .Net ExtensionsHoliday Calendar: This project contains a holiday calendar user control to be used in Windows Form applications.InputSQL: C# InputSQLInstall Visual Basic 6 in Windows 8: Please see the home page.KaartenSolution: A very simple card game.MezanmiNet_TaxiReviews: just a review application on the mobile platformMSHelpMeHD: A Windows 8 Store App.ProjectSocial: This is just a project to try coding.Rabbit MQ Client for Windows Store apps: rabbitmq client support for windows apps storeRFC 822 DateTime: Parse or write a date and time formatted according to the RFC 822 specification. RxJS TypeScript difinition: TypeScript d.ts files for RxJS(ReactiveExtensions for JavaScript)Samurai Blades - Webapp: A mimic of a classic board game (Shogun) created for web using HTML5 and ASP.NET MVC 4 (including the new typescript js compiler). servicehook: testSIMS Bulk Import: SIMS .net is the most popular MIS system used by schools across the UK. This tool allows you to bulk import email addresses and information into UDF fields.SpaceFlight: This project is a browser for the SloanDigital Sky Survey Data sets that allows for unconstrained movement within the data set.Sparse matrix format converter: Convert matrix market files to CSR0, CSR1 format. SPAutoSuggestion: A JavaScript application to show auto-suggestions in SharePoint search site's text boxes like in Google.SpreadsheetLight by Vincent Tan: For the latest release of SpreadsheetLight always go to http://www.spreadsheetlight.com, Anele MbangaSSTU: SSTU - this is simple client for Russian "Saratov State Technical University" web-site.Username generator library: Helps generate usernamesVideoStream: First attempt at a Windows Store Style App, aims to make it easy to browse videos from links provided in social media streams.WP8 Async WebClient: Provides async/await (TPL) capability to WebClient within Windows Phone 8wsccprototype: this is a prototype of what the main website will look like. Every other customization will be made in time.wsubi: A spiced-up way to manage scripts. This is a Windows port of the the 'sub' project from 37signals (https://github.com/37signals/sub).??C#????????: ?????????????ROYcms?????????! 1.?????????,?????? 2.????????,?????????? 3.?????,?????,????????????????,??????????? 4.???????????,????

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  • How do I prevent TCP connection freezes over an OpenVPN network?

    - by Jason R
    New details added at the end of this question; it's possible that I'm zeroing in on the cause. I have a UDP OpenVPN-based VPN set up in tap mode (I need tap because I need the VPN to pass multicast packets, which doesn't seem to be possible with tun networks) with a handful of clients across the Internet. I've been experiencing frequent TCP connection freezes over the VPN. That is, I will establish a TCP connection (e.g. an SSH connection, but other protocols have similar issues), and at some point during the session, it seems that traffic will cease being transmitted over that TCP session. This seems to be related to points at which large data transfers occur, such as if I execute an ls command in an SSH session, or if I cat a long log file. Some Google searches turn up a number of answers like this previous one on Server Fault, indicating that the likely culprit is an MTU issue: that during periods of high traffic, the VPN is trying to send packets that get dropped somewhere in the pipes between the VPN endpoints. The above-linked answer suggests using the following OpenVPN configuration settings to mitigate the problem: fragment 1400 mssfix This should limit the MTU used on the VPN to 1400 bytes and fix the TCP maximum segment size to prevent the generation of any packets larger than that. This seems to mitigate the problem a bit, but I still frequently see the freezes. I've tried a number of sizes as arguments to the fragment directive: 1200, 1000, 576, all with similar results. I can't think of any strange network topology between the two ends that could trigger such a problem: the VPN server is running on a pfSense machine connected directly to the Internet, and my client is also connected directly to the Internet at another location. One other strange piece of the puzzle: if I run the tracepath utility, then that seems to band-aid the problem. A sample run looks like: [~]$ tracepath -n 192.168.100.91 1: 192.168.100.90 0.039ms pmtu 1500 1: 192.168.100.91 40.823ms reached 1: 192.168.100.91 19.846ms reached Resume: pmtu 1500 hops 1 back 64 The above run is between two clients on the VPN: I initiated the trace from 192.168.100.90 to the destination of 192.168.100.91. Both clients were configured with fragment 1200; mssfix; in an attempt to limit the MTU used on the link. The above results would seem to suggest that tracepath was able to detect a path MTU of 1500 bytes between the two clients. I would assume that it would be somewhat smaller due to the fragmentation settings specified in the OpenVPN configuration. I found that result somewhat strange. Even stranger, however: if I have a TCP connection in the stalled state (e.g. an SSH session with a directory listing that froze in the middle), then executing the tracepath command shown above causes the connection to start up again! I can't figure out any reasonable explanation for why this would be the case, but I feel like this might be pointing toward a solution to ultimately eradicate the problem. Does anyone have any recommendations for other things to try? Edit: I've come back and looked at this a bit further, and have found only more confounding information: I set the OpenVPN connection to fragment at 1400 bytes, as shown above. Then, I connected to the VPN from across the Internet and used Wireshark to look at the UDP packets that were sent to the VPN server while the stall occurred. None were greater than the specified 1400 byte count, so the fragmentation seems to be functioning properly. To verify that even a 1400-byte MTU would be sufficient, I pinged the VPN server using the following (Linux) command: ping <host> -s 1450 -M do This (I believe) sends a 1450-byte packet with fragmentation disabled (I at least verified that it didn't work if I set it to an obviously-too-large value like 1600 bytes). These seem to work just fine; I get replies back from the host with no issue. So, maybe this isn't an MTU issue at all. I'm just confused as to what else it might be! Edit 2: The rabbit hole just keeps getting deeper: I've now isolated the problem a bit more. It seems to be related to the exact OS that the VPN client uses. I have successfully duplicated the problem on at least three Ubuntu machines (versions 12.04 through 13.04). I can reliably duplicate an SSH connection freeze within a minute or so by just cat-ing a large log file. However, if I do the same test using a CentOS 6 machine as a client, then I don't see the problem! I've tested using the exact same OpenVPN client version as I was using on the Ubuntu machines. I can cat log files for hours without seeing the connection freeze. This seems to provide some insight as to the ultimate cause, but I'm just not sure what that insight is. I have examined the traffic over the VPN using Wireshark. I'm not a TCP expert, so I'm not sure what to make of the gory details, but the gist is that at some point, a UDP packet gets dropped due to the limited bandwidth of the Internet link, causing TCP retransmissions inside the VPN tunnel. On the CentOS client, these retransmissions occur properly and things move on happily. At some point with the Ubuntu clients, though, the remote end starts retransmitting the same TCP segment over and over (with the transmit delay increasing between each retransmission). The client sends what looks like a valid TCP ACK to each retransmission, but the remote end still continues to transmit the same TCP segment periodically. This extends ad infinitum and the connection stalls. My question here would be: Does anyone have any recommendations for how to troubleshoot and/or determine the root cause of the TCP issue? It's as if the remote end isn't accepting the ACK messages sent by the VPN client. One common difference between the CentOS node and the various Ubuntu releases is that Ubuntu has a much more recent Linux kernel version (from 3.2 in Ubuntu 12.04 to 3.8 in 13.04). A pointer to some new kernel bug maybe? I'm assuming that if that were so, then I wouldn't be the only one experiencing the problem; I don't think this seems like a particularly exotic setup.

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  • CodePlex Daily Summary for Friday, March 04, 2011

    CodePlex Daily Summary for Friday, March 04, 2011Popular ReleasesyoutubeFisher: YouTubeFisher v3.0 Beta: Adding support for more video formats including the Super HD (e.g. http://www.youtube.com/watch?v=MrrHs2bnHPA) Minor change related to the video title due to change in YouTube pageSnippet Designer: Snippet Designer 1.3.1: Snippet Designer 1.3.1 for Visual Studio 2010This is a bug fix release. Change logFixed bug where Snippet Designer would fail if you had the most recent Productivity Power Tools installed Fixed bug where "Export as Snippet" was failing in non-english locales Fixed bug where opening a new .snippet file would fail in non-english localesChiave File Encryption: Chiave 1.0: Final Relase for Chave 1.0 Stable: Application for file encryption and decryption using 512 Bit rijndael encyrption algorithm with simple to use UI. Its written in C# and compiled in .Net version 3.5. It incorporates features of Windows 7 like Jumplists, Taskbar progress and Aero Glass. Now with added support to Windows XP! Change Log from 0.9.2 to 1.0: ==================== Added: > Added Icon Overlay for Windows 7 Taskbar Icon. >Added Thumbnail Toolbar buttons to make the navigation easier...AutoLoL: AutoLoL v1.6.3: Fixes some bugs in the previous releaseNetwork Monitor Decryption Expert: NMDecrypt 2.3: The NMDecryption Expert has been updated. In general these changes are: Updated Logging Support for multiple sessions that use the same cert with Session ID resuse. Fixed some bugs with IPv6 traffic and tunneled traffic Updated Version Info Made changes for assignment to Outercurve Foundation See the release blog for more information.DirectQ: Release 1.8.7 (RC1): Release candidate 1 of 1.8.7Chirpy - VS Add In For Handling Js, Css, DotLess, and T4 Files: Margogype Chirpy (ver 2.0): Chirpy loves Americans. Chirpy hates Americanos.ASP.NET: Sprite and Image Optimization Preview 3: The ASP.NET Sprite and Image Optimization framework is designed to decrease the amount of time required to request and display a page from a web server by performing a variety of optimizations on the page’s images. This is the third preview of the feature and works with ASP.NET Web Forms 4, ASP.NET MVC 3, and ASP.NET Web Pages (Razor) projects. The binaries are also available via NuGet: AspNetSprites-Core AspNetSprites-WebFormsControl AspNetSprites-MvcAndRazorHelper It includes the foll...Document.Editor: 2011.9: Whats new for Document.Editor 2011.9: New Templates System New Plug-in System New Replace dialog New reset settings Minor Bug Fix's, improvements and speed upsTortoiseHg: TortoiseHg 2.0: TortoiseHg 2.0 is a complete rewrite of TortoiseHg 1.1, switching from PyGtk to PyQtSandcastle Help File Builder: SHFB v1.9.2.0 Release: This release supports the Sandcastle June 2010 Release (v2.6.10621.1). It includes full support for generating, installing, and removing MS Help Viewer files. This new release is compiled under .NET 4.0, supports Visual Studio 2010 solutions and projects as documentation sources, and adds support for projects targeting the Silverlight Framework. NOTE: The included help file and the online help have not been completely updated to reflect all changes in this release. A refresh will be issue...Network Monitor Open Source Parsers: Microsoft Network Monitor Parsers 3.4.2554: The Network Monitor Parsers packages contain parsers for more than 400 network protocols, including RFC based public protocols and protocols for Microsoft products defined in the Microsoft Open Specifications for Windows and SQL Server. NetworkMonitor_Parsers.msi is the base parser package which defines parsers for commonly used public protocols and protocols for Microsoft Windows. In this release, we have added 4 new protocol parsers and updated 79 existing parsers in the NetworkMonitor_Pa...Image Resizer for Windows: Image Resizer 3 Preview 1: Prepare to have your minds blown. This is the first preview of what will eventually become 39613. There are still a lot of rough edges and plenty of areas still under construction, but for your basic needs, it should be relativly stable. Note: You will need the .NET Framework 4 installed to use this version. Below is a status report of where this release is in terms of the overall goal for version 3. If you're feeling a bit technically ambitious and want to check out some of the features th...JSON Toolkit: JSON Toolkit 1.1: updated GetAllJsonObjects() method and GetAllProperties() methods to JsonObject and Properties propertiesFacebook Graph Toolkit: Facebook Graph Toolkit 1.0: Refer to http://computerbeacon.net for Documentation and Tutorial New features:added FQL support added Expires property to Api object added support for publishing to a user's friend / Facebook Page added support for posting and removing comments on posts added support for adding and removing likes on posts and comments added static methods for Page class added support for Iframe Application Tab of Facebook Page added support for obtaining the user's country, locale and age in If...ASP.NET MVC Project Awesome, jQuery Ajax helpers (controls): 1.7.1: A rich set of helpers (controls) that you can use to build highly responsive and interactive Ajax-enabled Web applications. These helpers include Autocomplete, AjaxDropdown, Lookup, Confirm Dialog, Popup Form, Popup and Pager small improvements for some helpers and AjaxDropdown has Data like the Lookup except it's value gets reset and list refilled if any element from data gets changedManaged Extensibility Framework: MEF 2 Preview 3: This release aims .net 4.0 and Silverlight 4.0. Accordingly, there are two solutions files. The assemblies are named System.ComponentModel.Composition.Codeplex.dll as a way to avoid clashing with the version shipped with the 4th version of the framework. Introduced CompositionOptions to container instantiation CompositionOptions.DisableSilentRejection makes MEF throw an exception on composition errors. Useful for diagnostics Support for open generics Support for attribute-less registr...PHPExcel: PHPExcel 1.7.6 Production: DonationsDonate via PayPal via PayPal. If you want to, we can also add your name / company on our Donation Acknowledgements page. PEAR channelWe now also have a full PEAR channel! Here's how to use it: New installation: pear channel-discover pear.pearplex.net pear install pearplex/PHPExcel Or if you've already installed PHPExcel before: pear upgrade pearplex/PHPExcel The official page can be found at http://pearplex.net. Want to contribute?Please refer the Contribute page.WPF Application Framework (WAF): WPF Application Framework (WAF) 2.0.0.4: Version: 2.0.0.4 (Milestone 4): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Remark The sample applications are using Microsoft’s IoC container MEF. However, the WPF Application Framework (WAF) doesn’t force you to use the same IoC container in your application. You can use ...VidCoder: 0.8.2: Updated auto-naming to handle seconds and frames ranges as well. Deprecated the {chapters} token for auto-naming in favor of {range}. Allowing file drag to preview window and enabling main window shortcut keys to work no matter what window is focused. Added option in config to enable giving custom names to audio tracks. (Note that these names will only show up certain players like iTunes or on the iPod. Players that support custom track names normally may not show them.) Added tooltips ...New Projects.NET Serial To TCP proxy server: serial2tcp written to share your hardware serial ports as TCP port. You can easily turn your physical PC into terminal server. View session input/output or send commands to the physical port. Very useful when automating work with embedded devices. Developed in C#.Amazon SES SMTP: The C# code for a simple SMTP Server that forwards emails to Amazon Simple Email Service, either by acting as a SmartHost behind IIS SMTP Server or as a standalone SMTP server. It can be run in the background as either a Windows Service or a Console/Windows Application Azure Membership, Role, and Profile Providers: Complete ASP.NET solution that uses the Azure Table Storage and Azure Blob storage as a data source for a custom Membership, Role, and Profile providers. Developed in C# on the .NET 4 framework using Azure SDK V1.3. Helps you get up and running with Azure in no time. MIT license.CRM 2011 Code Snippets for Visual Studio: A set of JavaScript and C# code snippets to facilitate common Microsoft Dynamics CRM 2011 development for Visual Studio 2010.DDRMenu: DDRMenu is a templated menu provider for DotNetNuke that can produce any menu style you wish. In particular it comes with templates to upgrade a standard DNNMenu or SolPartMenu to provide true hyperlinks, SEO friendliness and animated transitions.Entity Framework CTP5 Extensions Library: The ADO.NET Entity Framework Extensions library contains a set of utility classes with additional functionality to Entity Framework CTP5.eTrader Pro: An easy-to-use, lightweight and customisable e-commerce solution developed in ASP.NET and SQL Server. Build an online shop in no time. Skin using ASP.NET themes. Localised for English and Spanish with integral CMS, order management and e-marketing tools.euler 12 problem: euler 12 problemeuler 19 problem: euler 19 problemeuler23: euler 23eXed: eXed (eXtended XML editor) is an XSD-based XML editor, i.e. it assumes that you have a working XSD file. The XSD is used to improve your editing experience, provide you with dynamic help, and validation. It is therefore not for those who want to write an XML file from scratch.FIM PowerShell Workflow Activity: The FIM WF Activity for PowerShell makes is easy to use PowerShell inside FIM workflows. The activity is also a good example of using diagnostic tracing inside FIM WF.FremyCompany Math Equation Editor: A WPF Component that can import MathML and LaTeX to be edited in a WYSIWYG word processor. It is intended to allow both visual and computer-comprehensive (formula in programming language) exportation. Scope and functionnalites are intended to be expanded over time.Geenie OS: A New Cosmos OSGeoBot: Monitoring and ControllingiRODS .NET: To be populated laterLicensePlateRecognition: A software for recognizing a car license plate number.LINQ for .NET 2.0: Backport of LINQ and Linq.Dynamic to the .NET Framework 2.0. The sources used to port it are taken from the mono project. http://ftp.novell.com/pub/mono/sources-stable/ It requires Visual Studio 2010 to compile. It won't compile on Visual Studio 2005.mobilestandards: MobileStandards project-creating a web2.0 BannerMy MVC store Implementation: My implementation of MVC music storeOrchard Localization JP: Localizing Project of Orchard. This project is intended to host localizing project to Japanes. Orchard ???????????。 ??????????、???????????????????。 ???????????。Paragon: Expands the basic functionality of the .NET Framework. It takes into consider basic defensive coding practices and reduces the common coding tasks.Project Unity: Research and EUA, spamming across the Halo-AA and Blam Game Engines, developed by Bungie LLC. This Project is NOT endorsed/supported by Bungie, Gearbox, Microsogy Game Studios In any way.Rabbit Framework: A lightweight framework for building dynamic web sites using ASP.NET Web Pages.ScrollableList: Just to make the project looking betterSharePoint Kerberos Buddy: The SharePoint Kerberos Buddy provides an intelligent client application that examines a mixed tier SharePoint environment locating commonly misconfigured Kerberos configuration elements. The application can detect errors on SharePoint, SSAS, SSRS, and on the client.SMI 2.0: This project is the creation of the next generation of the SMI app (previously written in VB6).SPChainGang: SPChainGang is a custom application aimed to simplify scanning, reporting, and fixing broken links in a SharePoint 2007 or SharePoint 2010 farm. SPProperties: SPProperties is a console app (command-line) that allows listing all properties of an SPWeb (property bag) and adding or updating properties. Relates to SharePoint site properties.State Machine DSL: State Machine DSL is extension to Visual Studio 2010 to provide simple and visualized way of programming state machines. It uses T4 Text Templates for code generation.tBrowser: Browser based on the IEuMoveDocType: uMoveDocType attempts to intelligently move your selected Umbraco Doc Type to a new parent.Virtual 8085: Virtual 8085 is a tool which enables students to run programs written in 8085 assembly language on a personal computer instead of a microprocessor kit. Virtual 8085 do not actually simulate the real hardware of Intel 8085, but it interprets the 8085 assembly language programs.WinAppTranslate: WinAppTranslate or WAT, Helps Visual Studio Programmers to translate Windows Applications. It is not based on the framework localization program… and it is a console application to run via VS post builds ????: ??????

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • Where should I start with debugging my exchange server?

    - by joadha
    I'm (foolishly?) attempting to install Exchange on top of Windows Server 2008 (64-bit) over Virtual Box running on Mac OSX Lion. Everything went smoothly until I got to the "Readiness Checks" tab. Readiness failed spectacularly on Hub Transport Role and Mailbox Role prereqs. Before I go too far down the rabbit hole in attempting to remedy this, I was hoping I could get some input on where to start in all of this. I already set up the following Active Directory roles, but it didn't seem to help: Active Directory Domain Services Active Directory Lightweight Directory Services I also enabled an Application Server role. Those three are the only roles I've set up-- I cannot locate within Server Manager the Organization Manager role or any of the other roles referenced in the list of borkedness below. Is this a typical experience in Exchange installation? Is there a tutorial created by somebody outside of Microsoft? Here's the output from Readiness Checks: Summary: 5 item(s). 2 succeeded, 3 failed. Elapsed time: 00:00:53 Configuring Prerequisites Completed Elapsed Time: 00:00:00 Languages Prerequisites Completed Elapsed Time: 00:00:09 Hub Transport Role Prerequisites Failed Error: Active Directory does not exist or cannot be contacted. Click here for help... http://go.microsoft.com/fwlink/? linkid=30939&l=en&v=ExBPA.14&id=51e5500d-8b18-4eee-bb8e-925d063b60a1 Error: You must be a member of the 'Organization Management' role group or 'Enterprise Admins' group to continue. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=1d750594-9222-44d7-8f80-45e522e889e6 Error: Setup encountered a problem while validating the state of Active Directory: Could not find information about the local domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: You must be logged on as an Exchange organization administrator to install or upgrade the first Hub Transport server role in the topology. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=e58f51fd-2c66-4a4b-914a-628dccf9a09f Error: The 'IIS 6 Metabase Compatibility' component is not installed. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=0a71c4f6-68de-40f7-94cf-74b73cbda37b Error: The 'IIS 7 Basic Authentication' component required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Windows Authentication' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 .NET Extensibility' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=5f29a861-f472-4f11-a23a-04155373f5ed Error: This computer is not part of a Windows domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: The user is not logged on to a Windows domain Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Warning: This computer requires the Microsoft Office 2010 Filter Packs. Please install the software from http://go.microsoft.com/fwlink/?LinkID=191548 Warning: The 'IIS 6 Management Console' component is recommended as it allows for the administration of all server roles. Install the component via Server Manager. Warning: Setup cannot verify that the 'Host' (A) record for this computer exists within the DNS database on server 10.1.10.1. Elapsed Time: 00:00:15 Client Access Role Prerequisites Failed Error: Active Directory does not exist or cannot be contacted. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=51e5500d-8b18-4eee-bb8e-925d063b60a1 Error: Unable to read data from the Metabase. Ensure that Microsoft Internet Information Services is installed. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=a4a4d339-4009-4fb7-b842-ca2ba79f13f0 Error: The World Wide Web (W3SVC) service is either disabled or not installed on this computer. You must exit Setup, install the required component, then restart the Setup process. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=9eeaa77f-4d46-4d9a-9c36-f262a075392b Error: You must be a member of the 'Organization Management' role group or 'Enterprise Admins' group to continue. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=1d750594-9222-44d7-8f80-45e522e889e6 Error: Setup encountered a problem while validating the state of Active Directory: Could not find information about the local domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: You must be logged on as an Exchange organization administrator to install or upgrade the first Client Access server role in the topology. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=e58f51fd-2c66-4a4b-914a-628dccf9a09f Error: The 'IIS 6 Metabase Compatibility' component is not installed. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=0a71c4f6-68de-40f7-94cf-74b73cbda37b Error: The 'IIS 6 Management Console' component is not installed. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=0a71c4f6-68de-40f7-94cf-74b73cbda37b Error: The 'IIS 7 Dynamic Content Compression' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/? linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Static Content Compression' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Basic Authentication' component required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Windows Authentication' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Digest Authentication' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 .NET Extensibility' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=5f29a861-f472-4f11-a23a-04155373f5ed Error: This computer is not part of a Windows domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: The user is not logged on to a Windows domain Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Warning: Setup cannot verify that the 'Host' (A) record for this computer exists within the DNS database on server 10.1.10.1. Elapsed Time: 00:00:14 Mailbox Role Prerequisites Failed Error: Active Directory does not exist or cannot be contacted. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=51e5500d-8b18-4eee-bb8e-925d063b60a1 Error: Unable to read data from the Metabase. Ensure that Microsoft Internet Information Services is installed. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=a4a4d339-4009-4fb7-b842-ca2ba79f13f0 Error: The World Wide Web (W3SVC) service is either disabled or not installed on this computer. You must exit Setup, install the required component, then restart the Setup process. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=9eeaa77f-4d46-4d9a-9c36-f262a075392b Error: You must be a member of the 'Organization Management' role group or 'Enterprise Admins' group to continue. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=1d750594-9222-44d7-8f80-45e522e889e6 Error: Setup encountered a problem while validating the state of Active Directory: Could not find information about the local domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: You must be logged on as an Exchange organization administrator to install or upgrade the first Mailbox server role in the topology. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=e58f51fd-2c66-4a4b-914a-628dccf9a09f Error: The 'IIS 6 Metabase Compatibility' component is not installed. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=0a71c4f6-68de-40f7-94cf-74b73cbda37b Error: The 'IIS 6 Management Console' component is not installed. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=0a71c4f6-68de-40f7-94cf-74b73cbda37b Error: The 'IIS 7 Basic Authentication' component required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 Windows Authentication' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=41a25c5e-0d39-4e55-a1f0-7be885982236 Error: The 'IIS 7 .NET Extensibility' component is required. Install the component via Server Manager. Click here for help... http://go.microsoft.com/fwlink/?linkid=30939&l=en&v=ExBPA.14&id=5f29a861-f472-4f11-a23a-04155373f5ed Error: This computer is not part of a Windows domain. Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Error: The user is not logged on to a Windows domain Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.1.218.11&e=ms.exch.err.Ex28883C&l=0&cl=cp Warning: This computer requires the Microsoft Office 2010 Filter Packs. Please install the software from http://go.microsoft.com/fwlink/?LinkID=191548 Warning: Setup cannot verify that the 'Host' (A) record for this computer exists within the DNS database on server 10.1.10.1. Elapsed Time: 00:00:14

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  • Python script is exiting with no output and I have no idea why

    - by Adam Tuttle
    I'm attempting to debug a Subversion post-commit hook that calls some python scripts. What I've been able to determine so far is that when I run post-commit.bat manually (I've created a wrapper for it to make it easier) everything succeeds, but when SVN runs it one particular step doesn't work. We're using CollabNet SVNServe, which I know from the documentation removes all environment variables. This had caused some problems earlier, but shouldn't be an issue now. Before Subversion calls a hook script, it removes all variables - including $PATH on Unix, and %PATH% on Windows - from the environment. Therefore, your script can only run another program if you spell out that program's absolute name. The relevant portion of post-commit.bat is: echo -------------------------- >> c:\svn-repos\company\hooks\svn2ftp.out.log set SITENAME=staging set SVNPATH=branches/staging/wwwroot/ "C:\Python3\python.exe" C:\svn-repos\company\hooks\svn2ftp.py ^ --svnUser="svnusername" ^ --svnPass="svnpassword" ^ --ftp-user=ftpuser ^ --ftp-password=ftppassword ^ --ftp-remote-dir=/ ^ --access-url=svn://10.0.100.6/company ^ --status-file="C:\svn-repos\company\hooks\svn2ftp-%SITENAME%.dat" ^ --project-directory=%SVNPATH% "staging.company.com" %1 %2 >> c:\svn-repos\company\hooks\svn2ftp.out.log echo -------------------------- >> c:\svn-repos\company\hooks\svn2ftp.out.log When I run post-commit.bat manually, for example: post-commit c:\svn-repos\company 12345, I see output like the following in svn2ftp.out.log: -------------------------- args1: c:\svn-repos\company args0: staging.company.com abspath: c:\svn-repos\company project_dir: branches/staging/wwwroot/ local_repos_path: c:\svn-repos\company getting youngest revision... done, up-to-date -------------------------- However, when I commit something to the repo and it runs automatically, the output is: -------------------------- -------------------------- svn2ftp.py is a bit long, so I apologize but here goes. I'll have some notes/disclaimers about its contents below it. #!/usr/bin/env python """Usage: svn2ftp.py [OPTION...] FTP-HOST REPOS-PATH Upload to FTP-HOST changes committed to the Subversion repository at REPOS-PATH. Uses svn diff --summarize to only propagate the changed files Options: -?, --help Show this help message. -u, --ftp-user=USER The username for the FTP server. Default: 'anonymous' -p, --ftp-password=P The password for the FTP server. Default: '@' -P, --ftp-port=X Port number for the FTP server. Default: 21 -r, --ftp-remote-dir=DIR The remote directory that is expected to resemble the repository project directory -a, --access-url=URL This is the URL that should be used when trying to SVN export files so that they can be uploaded to the FTP server -s, --status-file=PATH Required. This script needs to store the last successful revision that was transferred to the server. PATH is the location of this file. -d, --project-directory=DIR If the project you are interested in sending to the FTP server is not under the root of the repository (/), set this parameter. Example: -d 'project1/trunk/' This should NOT start with a '/'. 2008.5.2 CKS Fixed possible Windows-related bug with tempfile, where the script didn't have permission to write to the tempfile. Replaced this with a open()-created file created in the CWD. 2008.5.13 CKS Added error logging. Added exception for file-not-found errors when deleting files. 2008.5.14 CKS Change file open to 'rb' mode, to prevent Python's universal newline support from stripping CR characters, causing later comparisons between FTP and SVN to report changes. """ try: import sys, os import logging logging.basicConfig( level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s', filename='svn2ftp.debug.log', filemode='a' ) console = logging.StreamHandler() console.setLevel(logging.ERROR) logging.getLogger('').addHandler(console) import getopt, tempfile, smtplib, traceback, subprocess from io import StringIO import pysvn import ftplib import inspect except Exception as e: logging.error(e) #capture the location of the error frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace) print(stack_trace) #end capture sys.exit(1) #defaults host = "" user = "anonymous" password = "@" port = 21 repo_path = "" local_repos_path = "" status_file = "" project_directory = "" remote_base_directory = "" toAddrs = "[email protected]" youngest_revision = "" def email(toAddrs, message, subject, fromAddr='[email protected]'): headers = "From: %s\r\nTo: %s\r\nSubject: %s\r\n\r\n" % (fromAddr, toAddrs, subject) message = headers + message logging.info('sending email to %s...' % toAddrs) server = smtplib.SMTP('smtp.company.com') server.set_debuglevel(1) server.sendmail(fromAddr, toAddrs, message) server.quit() logging.info('email sent') def captureErrorMessage(e): sout = StringIO() traceback.print_exc(file=sout) errorMessage = '\n'+('*'*80)+('\n%s'%e)+('\n%s\n'%sout.getvalue())+('*'*80) return errorMessage def usage_and_exit(errmsg): """Print a usage message, plus an ERRMSG (if provided), then exit. If ERRMSG is provided, the usage message is printed to stderr and the script exits with a non-zero error code. Otherwise, the usage message goes to stdout, and the script exits with a zero errorcode.""" if errmsg is None: stream = sys.stdout else: stream = sys.stderr print(__doc__, file=stream) if errmsg: print("\nError: %s" % (errmsg), file=stream) sys.exit(2) sys.exit(0) def read_args(): global host global user global password global port global repo_path global local_repos_path global status_file global project_directory global remote_base_directory global youngest_revision try: opts, args = getopt.gnu_getopt(sys.argv[1:], "?u:p:P:r:a:s:d:SU:SP:", ["help", "ftp-user=", "ftp-password=", "ftp-port=", "ftp-remote-dir=", "access-url=", "status-file=", "project-directory=", "svnUser=", "svnPass=" ]) except getopt.GetoptError as msg: usage_and_exit(msg) for opt, arg in opts: if opt in ("-?", "--help"): usage_and_exit() elif opt in ("-u", "--ftp-user"): user = arg elif opt in ("-p", "--ftp-password"): password = arg elif opt in ("-SU", "--svnUser"): svnUser = arg elif opt in ("-SP", "--svnPass"): svnPass = arg elif opt in ("-P", "--ftp-port"): try: port = int(arg) except ValueError as msg: usage_and_exit("Invalid value '%s' for --ftp-port." % (arg)) if port < 1 or port > 65535: usage_and_exit("Value for --ftp-port must be a positive integer less than 65536.") elif opt in ("-r", "--ftp-remote-dir"): remote_base_directory = arg elif opt in ("-a", "--access-url"): repo_path = arg elif opt in ("-s", "--status-file"): status_file = os.path.abspath(arg) elif opt in ("-d", "--project-directory"): project_directory = arg if len(args) != 3: print(str(args)) usage_and_exit("host and/or local_repos_path not specified (" + len(args) + ")") host = args[0] print("args1: " + args[1]) print("args0: " + args[0]) print("abspath: " + os.path.abspath(args[1])) local_repos_path = os.path.abspath(args[1]) print('project_dir:',project_directory) youngest_revision = int(args[2]) if status_file == "" : usage_and_exit("No status file specified") def main(): global host global user global password global port global repo_path global local_repos_path global status_file global project_directory global remote_base_directory global youngest_revision read_args() #repository,fs_ptr #get youngest revision print("local_repos_path: " + local_repos_path) print('getting youngest revision...') #youngest_revision = fs.youngest_rev(fs_ptr) assert youngest_revision, "Unable to lookup youngest revision." last_sent_revision = get_last_revision() if youngest_revision == last_sent_revision: # no need to continue. we should be up to date. print('done, up-to-date') return if last_sent_revision or youngest_revision < 10: # Only compare revisions if the DAT file contains a valid # revision number. Otherwise we risk waiting forever while # we parse and uploading every revision in the repo in the case # where a repository is retroactively configured to sync with ftp. pysvn_client = pysvn.Client() pysvn_client.callback_get_login = get_login rev1 = pysvn.Revision(pysvn.opt_revision_kind.number, last_sent_revision) rev2 = pysvn.Revision(pysvn.opt_revision_kind.number, youngest_revision) summary = pysvn_client.diff_summarize(repo_path, rev1, repo_path, rev2, True, False) print('summary len:',len(summary)) if len(summary) > 0 : print('connecting to %s...' % host) ftp = FTPClient(host, user, password) print('connected to %s' % host) ftp.base_path = remote_base_directory print('set remote base directory to %s' % remote_base_directory) #iterate through all the differences between revisions for change in summary : #determine whether the path of the change is relevant to the path that is being sent, and modify the path as appropriate. print('change path:',change.path) ftp_relative_path = apply_basedir(change.path) print('ftp rel path:',ftp_relative_path) #only try to sync path if the path is in our project_directory if ftp_relative_path != "" : is_file = (change.node_kind == pysvn.node_kind.file) if str(change.summarize_kind) == "delete" : print("deleting: " + ftp_relative_path) try: ftp.delete_path("/" + ftp_relative_path, is_file) except ftplib.error_perm as e: if 'cannot find the' in str(e) or 'not found' in str(e): # Log, but otherwise ignore path-not-found errors # when deleting, since it's not a disaster if the file # we want to delete is already gone. logging.error(captureErrorMessage(e)) else: raise elif str(change.summarize_kind) == "added" or str(change.summarize_kind) == "modified" : local_file = "" if is_file : local_file = svn_export_temp(pysvn_client, repo_path, rev2, change.path) print("uploading file: " + ftp_relative_path) ftp.upload_path("/" + ftp_relative_path, is_file, local_file) if is_file : os.remove(local_file) elif str(change.summarize_kind) == "normal" : print("skipping 'normal' element: " + ftp_relative_path) else : raise str("Unknown change summarize kind: " + str(change.summarize_kind) + ", path: " + ftp_relative_path) ftp.close() #write back the last revision that was synced print("writing last revision: " + str(youngest_revision)) set_last_revision(youngest_revision) # todo: undo def get_login(a,b,c,d): #arguments don't matter, we're always going to return the same thing try: return True, "svnUsername", "svnPassword", True except Exception as e: logging.error(e) #capture the location of the error frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace) #end capture sys.exit(1) #functions for persisting the last successfully synced revision def get_last_revision(): if os.path.isfile(status_file) : f=open(status_file, 'r') line = f.readline() f.close() try: i = int(line) except ValueError: i = 0 else: i = 0 f = open(status_file, 'w') f.write(str(i)) f.close() return i def set_last_revision(rev) : f = open(status_file, 'w') f.write(str(rev)) f.close() #augmented ftp client class that can work off a base directory class FTPClient(ftplib.FTP) : def __init__(self, host, username, password) : self.base_path = "" self.current_path = "" ftplib.FTP.__init__(self, host, username, password) def cwd(self, path) : debug_path = path if self.current_path == "" : self.current_path = self.pwd() print("pwd: " + self.current_path) if not os.path.isabs(path) : debug_path = self.base_path + "<" + path path = os.path.join(self.current_path, path) elif self.base_path != "" : debug_path = self.base_path + ">" + path.lstrip("/") path = os.path.join(self.base_path, path.lstrip("/")) path = os.path.normpath(path) #by this point the path should be absolute. if path != self.current_path : print("change from " + self.current_path + " to " + debug_path) ftplib.FTP.cwd(self, path) self.current_path = path else : print("staying put : " + self.current_path) def cd_or_create(self, path) : assert os.path.isabs(path), "absolute path expected (" + path + ")" try: self.cwd(path) except ftplib.error_perm as e: for folder in path.split('/'): if folder == "" : self.cwd("/") continue try: self.cwd(folder) except: print("mkd: (" + path + "):" + folder) self.mkd(folder) self.cwd(folder) def upload_path(self, path, is_file, local_path) : if is_file: (path, filename) = os.path.split(path) self.cd_or_create(path) # Use read-binary to avoid universal newline support from stripping CR characters. f = open(local_path, 'rb') self.storbinary("STOR " + filename, f) f.close() else: self.cd_or_create(path) def delete_path(self, path, is_file) : (path, filename) = os.path.split(path) print("trying to delete: " + path + ", " + filename) self.cwd(path) try: if is_file : self.delete(filename) else: self.delete_path_recursive(filename) except ftplib.error_perm as e: if 'The system cannot find the' in str(e) or '550 File not found' in str(e): # Log, but otherwise ignore path-not-found errors # when deleting, since it's not a disaster if the file # we want to delete is already gone. logging.error(captureErrorMessage(e)) else: raise def delete_path_recursive(self, path): if path == "/" : raise "WARNING: trying to delete '/'!" for node in self.nlst(path) : if node == path : #it's a file. delete and return self.delete(path) return if node != "." and node != ".." : self.delete_path_recursive(os.path.join(path, node)) try: self.rmd(path) except ftplib.error_perm as msg : sys.stderr.write("Error deleting directory " + os.path.join(self.current_path, path) + " : " + str(msg)) # apply the project_directory setting def apply_basedir(path) : #remove any leading stuff (in this case, "trunk/") and decide whether file should be propagated if not path.startswith(project_directory) : return "" return path.replace(project_directory, "", 1) def svn_export_temp(pysvn_client, base_path, rev, path) : # Causes access denied error. Couldn't deduce Windows-perm issue. # It's possible Python isn't garbage-collecting the open file-handle in time for pysvn to re-open it. # Regardless, just generating a simple filename seems to work. #(fd, dest_path) = tempfile.mkstemp() dest_path = tmpName = '%s.tmp' % __file__ exportPath = os.path.join(base_path, path).replace('\\','/') print('exporting %s to %s' % (exportPath, dest_path)) pysvn_client.export( exportPath, dest_path, force=False, revision=rev, native_eol=None, ignore_externals=False, recurse=True, peg_revision=rev ) return dest_path if __name__ == "__main__": logging.info('svnftp.start') try: main() logging.info('svnftp.done') except Exception as e: # capture the location of the error for debug purposes frame = inspect.currentframe() stack_trace = traceback.format_stack(frame) logging.debug(stack_trace[:-1]) print(stack_trace) # end capture error_text = '\nFATAL EXCEPTION!!!\n'+captureErrorMessage(e) subject = "ALERT: SVN2FTP Error" message = """An Error occurred while trying to FTP an SVN commit. repo_path = %(repo_path)s\n local_repos_path = %(local_repos_path)s\n project_directory = %(project_directory)s\n remote_base_directory = %(remote_base_directory)s\n error_text = %(error_text)s """ % globals() email(toAddrs, message, subject) logging.error(e) Notes/Disclaimers: I have basically no python training so I'm learning as I go and spending lots of time reading docs to figure stuff out. The body of get_login is in a try block because I was getting strange errors saying there was an unhandled exception in callback_get_login. Never figured out why, but it seems fine now. Let sleeping dogs lie, right? The username and password for get_login are currently hard-coded (but correct) just to eliminate variables and try to change as little as possible at once. (I added the svnuser and svnpass arguments to the existing argument parsing.) So that's where I am. I can't figure out why on earth it's not printing anything into svn2ftp.out.log. If you're wondering, the output for one of these failed attempts in svn2ftp.debug.log is: 2012-09-06 15:18:12,496 INFO svnftp.start 2012-09-06 15:18:12,496 INFO svnftp.done And it's no different on a successful run. So there's nothing useful being logged. I'm lost. I've gone way down the rabbit hole on this one, and don't know where to go from here. Any ideas?

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