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  • An XEvent a Day (20 of 31) – Mapping Extended Events to SQL Trace

    - by Jonathan Kehayias
    One of the biggest problems that I had with getting into Extended Events was mapping the Events available in Extended Events to the Events that I knew from SQL Trace. With so many Events to choose from in Extended Events, and a different organization of the Events, it is really easy to get lost when trying to find things. Add to this the fact that Event names don’t match up to Trace Event names in SQL Server 2008 and 2008 R2, and not all of the Events from Trace are implemented in SQL Server 2008...(read more)

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  • 10 PowerShell One Liners

    - by BizTalk Visionary
    Here are a few one-liners that use NetCmdlets. Some of these I've blogged about before, some are new. Let me know if you have questions, which ones you find useful, or how you altered these to suit your own needs. Send email to a list of recipient addresses: import-csv users.csv | % { send-email -to $_.email -from [email protected] -subject "Important Email" –message "Hello World!" -server 10.0.1.1 } Show the access control list for a specific Exchange folder: get-imap -server $mymailserver -cred $mycred -folder INBOX.RESUMES –acl Add look and read permissions on an Exchange folder, for a list of accounts pulled from a CSV file: import-csv users.csv | % { set-imap -server -acluser $_.username $mymailserver -cred $mycred -folder INBOX.RESUMES –acl “lr”  } Sync system time with an Internet time server: get-time -server clock.psu.edu –set To remotely sync the time on a set of computers: import-csv computers.csv | % { Invoke-Command -computerName $_.computer -cred $mycred -scriptblock { get-time -server clock.psu.edu –set } } Delete all emails from an Exchange folder that match a certain criteria.  For example, delete all emails from [email protected]: get-imap -server $mailserver –cred $mycred | ? {$_.FromEmail -eq [email protected]} | %{ set-imap -server $mailserver –cred $mycred-message $_.Id -delete } Update Twitter status from PowerShell: get-http –url "http://twitter.com/statuses/update.xml" –cred $mycred -variablename status -variablevalue "Tweeting with NetCmdlets!" A test-path that works over FTP, FTPS (SSL), and SFTP (SSH) connections: get-ftp -server $remoteserver –cred $mycred -path /remote/path/to/checkfor* Don't forget the *.  Also, to use SSL or SSH just add an –ssl or –ssh parameter. List disabled user accounts in Active Directory (or any other LDAP server): get-ldap -server $ad -cred $mycred -dn dc=yourdc -searchscope wholesubtree     -search "(&(objectclass=user)(objectclass=person)(company=*)(userAccountControl:1.2.840.113556.1.4.803:=2))" List Active Directory groups and their members: get-ldap -server testman -cred $mycred -dn dc=NS2 -searchscope wholesubtree -search "(&(objectclass=group)(cn=*admin*))" | select ResultDN, member Display the last initialization time (e.g. last reboot time) of all discoverable SNMP agents on a network: import-csv computers.csv | % { get-snmp -agent $_.computer -oid sysUpTime.0 | %{([datetime]::Now).AddSeconds(-($_.OIDValue/100))} } Not mentioned here:  data conversion (Yenc, QP, UUencoding, MD5, SHA1, base64, etc), DNS, News Groups (NNTP/UseNet), POP mail, RSS feeds, Amazon S3, Syslog, TFTP, TraceRoute, SNMP Traps, UDP, WebDAV, whois, Rexec/Rshell/Telnet, Zip files, sending IMs (Jabber/GoogleTalk/XMPP), sending text messages and pages, ping, and more. Original Source: Lance's Textbox

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  • Asp.net session on browser close

    - by budugu
    Note: Cross posted from Vijay Kodali's Blog. Permalink How to capture logoff time when user closes browser? Or How to end user session when browser closed? These are some of the frequently asked questions in asp.net forums. In this post I'll show you how to do this when you're building an ASP.NET web application. Before we start, one fact: There is no full-proof technique to catch the browser close event for 100% of time. The trouble lies in the stateless nature of HTTP. The Web server is out of the picture as soon as it finishes sending the page content to the client. After that, all you can rely on is a client side script. Unfortunately, there is no reliable client side event for browser close. Solution: The first thing you need to do is create the web service. I've added web service and named it AsynchronousSave.asmx.    Make this web service accessible from Script, by setting class qualified with the ScriptServiceAttribute attribute...  Add a method (SaveLogOffTime) marked with [WebMethod] attribute. This method simply accepts UserId as a string variable and writes that value and logoff time to text file. But you can pass as many variables as required. You can then use this information for many purposes. To end user session, you can just call Session.Abandon() in the above web method. To enable web service to be called from page’s client side code, add script manager to page. Here i am adding to SessionTest.aspx page When the user closes the browser, onbeforeunload event fires on the client side. Our final step is adding a java script function to that event, which makes web service calls. The code is simple but effective My Code HTML:( SessionTest.aspx ) C#:( SessionTest.aspx.cs ) That’s’ it. Run the application and after browser close, open the text file to see the log off time. The above code works well in IE 7/8. If you have any questions, leave a comment.

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  • Asp.net session on browser close

    - by budugu
    Note: Cross posted from Vijay Kodali's Blog. Permalink How to capture logoff time when user closes browser? Or How to end user session when browser closed? These are some of the frequently asked questions in asp.net forums. In this post I'll show you how to do this when you're building an ASP.NET web application. Before we start, one fact: There is no full-proof technique to catch the browser close event for 100% of time. The trouble lies in the stateless nature of HTTP. The Web server is out of the picture as soon as it finishes sending the page content to the client. After that, all you can rely on is a client side script. Unfortunately, there is no reliable client side event for browser close. Solution: The first thing you need to do is create the web service. I've added web service and named it AsynchronousSave.asmx.    Make this web service accessible from Script, by setting class qualified with the ScriptServiceAttribute attribute...  Add a method (SaveLogOffTime) marked with [WebMethod] attribute. This method simply accepts UserId as a string variable and writes that value and logoff time to text file. But you can pass as many variables as required. You can then use this information for many purposes. To end user session, you can just call Session.Abandon() in the above web method. To enable web service to be called from page’s client side code, add script manager to page. Here i am adding to SessionTest.aspx page When the user closes the browser, onbeforeunload event fires on the client side. Our final step is adding a java script function to that event, which makes web service calls. The code is simple but effective My Code HTML:( SessionTest.aspx ) C#:( SessionTest.aspx.cs ) That’s’ it. Run the application and after browser close, open the text file to see the log off time. The above code works well in IE 7/8. If you have any questions, leave a comment.

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  • Google lance la version 1.0 stable de mod_pagespeed, le module du serveur Apache pour « rendre le Web plus rapide »

    Google sort un module d'optimisation pour Apache HTTP Server Qui automatise 15 opérations et peut diminuer de moitié le temps de chargement des pages Après avoir mis à la disposition des développeurs Page Speed, un outil interne d'analyse et d'optimisation des performances des sites Web, Google récidive aujourd'hui et sort un module pour les serveurs Apache. Appelé à juste titre « mod_pagespeed », cet outil automatise bon nombre des conseils et bonne pratiques jusque-là seulement suggérés aux développeurs dans l'add-on du même nom qui se greffe à Firebug dans sa version pour Firefox. Le module « mod_pagespeed » pour Apache HTTP Server, automatise ainsi 15 opération...

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  • Using the HTML5 &lt;input type=&quot;file&quot; multiple=&quot;multiple&quot;&gt; Tag in ASP.NET

    - by Rick Strahl
    Per HTML5 spec the <input type="file" /> tag allows for multiple files to be picked from a single File upload button. This is actually a very subtle change that's very useful as it makes it much easier to send multiple files to the server without using complex uploader controls. Please understand though, that even though you can send multiple files using the <input type="file" /> tag, the process of how those files are sent hasn't really changed - there's still no progress information or other hooks that allow you to automatically make for a nicer upload experience without additional libraries or code. For that you will still need some sort of library (I'll post an example in my next blog post using plUpload). All the new features allow for is to make it easier to select multiple images from disk in one operation. Where you might have required many file upload controls before to upload several files, one File control can potentially do the job. How it works To create a file input box that allows with multiple file support you can simply do:<form method="post" enctype="multipart/form-data"> <label>Upload Images:</label> <input type="file" multiple="multiple" name="File1" id="File1" accept="image/*" /> <hr /> <input type="submit" id="btnUpload" value="Upload Images" /> </form> Now when the file open dialog pops up - depending on the browser and whether the browser supports it - you can pick multiple files. Here I'm using Firefox using the thumbnail preview I can easily pick images to upload on a form: Note that I can select multiple images in the dialog all of which get stored in the file textbox. The UI for this can be different in some browsers. For example Chrome displays 3 files selected as text next to the Browse… button when I choose three rather than showing any files in the textbox. Most other browsers display the standard file input box and display the multiple filenames as a comma delimited list in the textbox. Note that you can also specify the accept attribute in the <input> tag, which specifies a mime-type to specify what type of content to allow.Here I'm only allowing images (image/*) and the browser complies by just showing me image files to display. Likewise I could use text/* for all text formats registered on the machine or text/xml to only show XML files (which would include xml,xst,xsd etc.). Capturing Files on the Server with ASP.NET When you upload files to an ASP.NET server there are a couple of things to be aware of. When multiple files are uploaded from a single file control, they are assigned the same name. In other words if I select 3 files to upload on the File1 control shown above I get three file form variables named File1. This means I can't easily retrieve files by their name:HttpPostedFileBase file = Request.Files["File1"]; because there will be multiple files for a given name. The above only selects the first file. Instead you can only reliably retrieve files by their index. Below is an example I use in app to capture a number of images uploaded and store them into a database using a business object and EF 4.2.for (int i = 0; i < Request.Files.Count; i++) { HttpPostedFileBase file = Request.Files[i]; if (file.ContentLength == 0) continue; if (file.ContentLength > App.Configuration.MaxImageUploadSize) { ErrorDisplay.ShowError("File " + file.FileName + " is too large. Max upload size is: " + App.Configuration.MaxImageUploadSize); return View("UploadClassic",model); } var image = new ClassifiedsBusiness.Image(); var ms = new MemoryStream(16498); file.InputStream.CopyTo(ms); image.Entered = DateTime.Now; image.EntryId = model.Entry.Id; image.ContentType = "image/jpeg"; image.ImageData = ms.ToArray(); ms.Seek(0, SeekOrigin.Begin); // resize image if necessary and turn into jpeg Bitmap bmp = Imaging.ResizeImage(ms.ToArray(), App.Configuration.MaxImageWidth, App.Configuration.MaxImageHeight); ms.Close(); ms = new MemoryStream(); bmp.Save(ms,ImageFormat.Jpeg); image.ImageData = ms.ToArray(); bmp.Dispose(); ms.Close(); model.Entry.Images.Add(image); } This works great and also allows you to capture input from multiple input controls if you are dealing with browsers that don't support multiple file selections in the file upload control. The important thing here is that I iterate over the files by index, rather than using a foreach loop over the Request.Files collection. The files collection returns key name strings, rather than the actual files (who thought that was good idea at Microsoft?), and so that isn't going to work since you end up getting multiple keys with the same name. Instead a plain for loop has to be used to loop over all files. Another Option in ASP.NET MVC If you're using ASP.NET MVC you can use the code above as well, but you have yet another option to capture multiple uploaded files by using a parameter for your post action method.public ActionResult Save(HttpPostedFileBase[] file1) { foreach (var file in file1) { if (file.ContentLength < 0) continue; // do something with the file }} Note that in order for this to work you have to specify each posted file variable individually in the parameter list. This works great if you have a single file upload to deal with. You can also pass this in addition to your main model to separate out a ViewModel and a set of uploaded files:public ActionResult Edit(EntryViewModel model,HttpPostedFileBase[] uploadedFile) You can also make the uploaded files part of the ViewModel itself - just make sure you use the appropriate naming for the variable name in the HTML document (since there's Html.FileFor() extension). Browser Support You knew this was coming, right? The feature is really nice, but unfortunately not supported universally yet. Once again Internet Explorer is the problem: No shipping version of Internet Explorer supports multiple file uploads. IE10 supposedly will, but even IE9 does not. All other major browsers - Chrome, Firefox, Safari and Opera - support multi-file uploads in their latest versions. So how can you handle this? If you need to provide multiple file uploads you can simply add multiple file selection boxes and let people either select multiple files with a single upload file box or use multiples. Alternately you can do some browser detection and if IE is used simply show the extra file upload boxes. It's not ideal, but either one of these approaches makes life easier for folks that use a decent browser and leaves you with a functional interface for those that don't. Here's a UI I recently built as an alternate uploader with multiple file upload buttons: I say this is my 'alternate' uploader - for my primary uploader I continue to use an add-in solution. Specifically I use plUpload and I'll discuss how that's implemented in my next post. Although I think that plUpload (and many of the other packaged JavaScript upload solutions) are a better choice especially for large uploads, for simple one file uploads input boxes work well enough. The advantage of this solution is that it's very easy to handle on the server side. Any of the JavaScript controls require special handling for uploads which I'll also discuss in my next post.© Rick Strahl, West Wind Technologies, 2005-2012Posted in HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Video on Architecture and Code Quality using Visual Studio 2012&ndash;interview with Marcel de Vries and Terje Sandstrom by Adam Cogan

    - by terje
    Find the video HERE. Adam Cogan did a great Web TV interview with Marcel de Vries and myself on the topics of architecture and code quality.  It was real fun participating in this session.  Although we know each other from the MVP ALM community,  Marcel, Adam and I haven’t worked together before. It was very interesting to see how we agreed on so many terms, and how alike we where thinking.  The basics of ensuring you have a good architecture and how you could document it is one thing.  Also, the same agreement on the importance of having a high quality code base, and how we used the Visual Studio 2012 tools, and some others (NDepend for example)  to measure and ensure that the code quality was where it should be.  As the tools, methods and thinking popped up during the interview it was a lot of “Hey !  I do that too!”.  The tools are not only for “after the fact” work, but we use them during the coding.  That way the tools becomes an integrated part of our coding work, and helps us to find issues we may have overlooked.  The video has a bunch of call outs, pinpointing important things to remember. These are also listed on the corresponding web page. I haven’t seen that touch before, but really liked this way of doing it – it makes it much easier to spot the highlights.  Titus Maclaren and Raj Dhatt from SSW have done a terrific job producing this video.  And thanks to Lei Xu for doing the camera and recording job.  Thanks guys ! Also, if you are at TechEd Amsterdam 2012, go and listen to Adam Cogan in his session on “A modern architecture review: Using the new code review tools” Friday 29th, 10.15-11.30 and Marcel de Vries session on “Intellitrace, what is it and how can I use it to my benefit” Wednesday 27th, 5-6.15 The highlights points out some important practices.  I’ll elaborate on a few of them here: Add instructions on how to compile the solution.  You do this by adding a text file with instructions to the solution, and keep it under source control.  These instructions should contain what is needed on top of a standard install of Visual Studio.  I do a lot of code reviews, and more often that not, I am not even able to compile the program, because they have used some tool or library that needs to be installed.  The same applies to any new developer who enters into the team, so do this to increase your productivity when the team changes, or a team member switches computer. Don’t forget to document what you have to configure on the computer, the IIS being a common one. The more automatic you can do this, the better.  Use NuGet to get down libraries. When the text document gets more than say, half a page, with a bunch of different things to do, convert it into a powershell script instead.  The metrics warning levels.  These are very conservatively set by Microsoft.  You rarely see anything but green, and besides, you should have color scales for each of the metrics.  I have a blog post describing a more appropriate set of levels, based on both research work and industry “best practices”.  The essential limits are: Cyclomatic complexity and coupling:  Higher numbers are worse On method levels: Green :  From 0 to 10 Yellow:  From 10 to 20  (some say 15).   Acceptable, but have a look to see if there is something unneeded here. Red: From 20 to 40:   Action required, get these down. Bleeding Red: Above 40   This is the real red alert.  Immediate action!  (My invention, as people have asked what do I do when I have cyclomatic complexity of 150.  The only answer I could think of was: RUN! ) Maintainability index:  Lower numbers are worse, scale from 0 to 100. On method levels: Green:  60 to 100 Yellow:  40 – 60.    You will always have methods here too, accept the higher ones, take a look at those who are down to the lower limit.  Check up against the other metrics.) Red:  20 – 40:  Action required, fix these. Bleeding red:  Below 20.  Immediate action required. When doing metrics analysis, you should leave the generated code out.  You do this by adding attributes, unfortunately Microsoft has “forgotten” to add these to all their stuff, so you might have to add them to some of the code.  It most cases it can be done so that it is not overwritten by a new round of code generation.  Take a look a my blog post here for details on how to do that. Class level metrics might also be useful, at least for coupling and maintenance.  But it is much more difficult to set any fixed limits on those.  Any metric aggregations on higher level tend to be pretty useless, as the number of methods vary pretty much, and there are little science on what number of methods can be regarded as good or bad.  NDepend have a recommendation, but they say it may vary too.  And in these days of data binding, the number might be pretty high, as properties counts as methods.  However, if you take the worst case situations, classes with more than 20 methods are suspicious, and coupling and cyclomatic complexity go red above 20, so any classes with more than 20x20 = 400 for these measures should be checked over. In the video we mention the SOLID principles, coined by “Uncle Bob” (Richard Martin). One of them, the Dependency Inversion principle we discuss in the video.  It is important to note that this principle is NOT on whether you should use a Dependency Inversion Container or not, it is about how you design the interfaces and interactions between your classes.  The Dependency Inversion Container is just one technique which is based on this principle, but which main purpose is to isolate things you would like to change at runtime, for example if you implement a plug in architecture.  Overuse of a Dependency Inversion Container is however, NOT a good thing.  It should be used for a purpose and not as a general DI solution.  The general DI solution and thinking however is useful far beyond the DIC.   You should always “program to an abstraction”, and not to the concreteness.  We also talk a bit about the GRASP patterns, a term coined by Craig Larman in his book Applying UML and design patterns. GRASP patterns stand for General Responsibility Assignment Software Patterns and describe fundamental principles of object design and responsibility assignment.  What I find great with these patterns is that they is another way to focus on the responsibility of a class.  One of the things I most often found that is broken in software designs, is that the class lack responsibility, and as a result there are a lot of classes mucking around in the internals of the other classes.  We also discuss the term “Code Smells”.  This term was invented by Kent Beck and Martin Fowler when they worked with Fowler’s “Refactoring” book. A code smell is a set of “bad” coding practices, which are the drivers behind a corresponding set of refactorings.  Here is a good list of the smells, and their corresponding refactor patterns. See also this.

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  • Google I/O 2011: Smart App Design

    Google I/O 2011: Smart App Design Travis Green, Max Lin, Robert Kaplow, Jóhannes Kristinsson, Ryan McGee Learn how to recommend the unexpected, automate the repetitive, and distill the essential using machine learning. This session will show you how you can easily add smarts to your apps with the Prediction API, and how to create apps that rapidly adapt to new data. From: GoogleDevelopers Views: 10078 47 ratings Time: 01:01:04 More in Science & Technology

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  • how to reset gnome panel?

    - by Matt
    I think my gnome-panel is messed up because I alt+right click it and nothing pops up. I'm on 12.04, classic gnome desktop. so I used locate and found gnome-panel in .gconf somewhere, how do I clear just gnome-panel's settings so that I can add things to my panel again? edit: matt: ~/.gconf $ find|grep -iw panel ./desktop/ibus/panel ./desktop/ibus/panel/%gconf.xml ./apps/gnome-settings/gnome-panel ./apps/gnome-settings/gnome-panel/%gconf.xml

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  • Acer Aspire blank screen

    - by Gerep
    I'm using Ubuntu 11.04 Natty and when I installed it I had a problem with blank screen on startup and found a solution but I have the same problem when it is inactive and goes blank screen, it won't come back, so I have to restart. Any ideas? Thanks in advance for any help. This is what solved my first problem: When you start editing the /etc/rc.local and add before exit 0: setpci -s 00:02.0 F4.B=00 Edit /etc/default/grub, edit the line GRUB_CMDLINE_LINUX_DEFAULT: GRUB_CMDLINE_LINUX_DEFAULT = "quiet splash acpi_osi = Linux" Update grub with: sudo update-grub2

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  • Daily tech links for .net and related technologies - Mar 18-21, 2010

    - by SanjeevAgarwal
    Daily tech links for .net and related technologies - Mar 18-21, 2010 Web Development TDD kata for ASP.NET MVC controllers (part 2) -David Take Control Of Web Control ClientID Values in ASP.NET 4.0 - Scott Mitchell Inside the ASP.NET MVC Controller Factory - Dino Esposito Microsoft, jQuery, and Templating - stephen walther Cross Domain AJAX Request with YQL and jQuery - Jeffrey Way T4MVC Add-In to auto run template -Wayne Web Design Website Content Planning The Right Way - Kristin Wemmer Microsoft...(read more)

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  • The Proper Use of the VM Role in Windows Azure

    - by BuckWoody
    At the Professional Developer’s Conference (PDC) in 2010 we announced an addition to the Computational Roles in Windows Azure, called the VM Role. This new feature allows a great deal of control over the applications you write, but some have confused it with our full infrastructure offering in Windows Hyper-V. There is a proper architecture pattern for both of them. Virtualization Virtualization is the process of taking all of the hardware of a physical computer and replicating it in software alone. This means that a single computer can “host” or run several “virtual” computers. These virtual computers can run anywhere - including at a vendor’s location. Some companies refer to this as Cloud Computing since the hardware is operated and maintained elsewhere. IaaS The more detailed definition of this type of computing is called Infrastructure as a Service (Iaas) since it removes the need for you to maintain hardware at your organization. The operating system, drivers, and all the other software required to run an application are still under your control and your responsibility to license, patch, and scale. Microsoft has an offering in this space called Hyper-V, that runs on the Windows operating system. Combined with a hardware hosting vendor and the System Center software to create and deploy Virtual Machines (a process referred to as provisioning), you can create a Cloud environment with full control over all aspects of the machine, including multiple operating systems if you like. Hosting machines and provisioning them at your own buildings is sometimes called a Private Cloud, and hosting them somewhere else is often called a Public Cloud. State-ful and Stateless Programming This paradigm does not create a new, scalable way of computing. It simply moves the hardware away. The reason is that when you limit the Cloud efforts to a Virtual Machine, you are in effect limiting the computing resources to what that single system can provide. This is because much of the software developed in this environment maintains “state” - and that requires a little explanation. “State-ful programming” means that all parts of the computing environment stay connected to each other throughout a compute cycle. The system expects the memory, CPU, storage and network to remain in the same state from the beginning of the process to the end. You can think of this as a telephone conversation - you expect that the other person picks up the phone, listens to you, and talks back all in a single unit of time. In “Stateless” computing the system is designed to allow the different parts of the code to run independently of each other. You can think of this like an e-mail exchange. You compose an e-mail from your system (it has the state when you’re doing that) and then you walk away for a bit to make some coffee. A few minutes later you click the “send” button (the network has the state) and you go to a meeting. The server receives the message and stores it on a mail program’s database (the mail server has the state now) and continues working on other mail. Finally, the other party logs on to their mail client and reads the mail (the other user has the state) and responds to it and so on. These events might be separated by milliseconds or even days, but the system continues to operate. The entire process doesn’t maintain the state, each component does. This is the exact concept behind coding for Windows Azure. The stateless programming model allows amazing rates of scale, since the message (think of the e-mail) can be broken apart by multiple programs and worked on in parallel (like when the e-mail goes to hundreds of users), and only the order of re-assembling the work is important to consider. For the exact same reason, if the system makes copies of those running programs as Windows Azure does, you have built-in redundancy and recovery. It’s just built into the design. The Difference Between Infrastructure Designs and Platform Designs When you simply take a physical server running software and virtualize it either privately or publicly, you haven’t done anything to allow the code to scale or have recovery. That all has to be handled by adding more code and more Virtual Machines that have a slight lag in maintaining the running state of the system. Add more machines and you get more lag, so the scale is limited. This is the primary limitation with IaaS. It’s also not as easy to deploy these VM’s, and more importantly, you’re often charged on a longer basis to remove them. your agility in IaaS is more limited. Windows Azure is a Platform - meaning that you get objects you can code against. The code you write runs on multiple nodes with multiple copies, and it all works because of the magic of Stateless programming. you don’t worry, or even care, about what is running underneath. It could be Windows (and it is in fact a type of Windows Server), Linux, or anything else - but that' isn’t what you want to manage, monitor, maintain or license. You don’t want to deploy an operating system - you want to deploy an application. You want your code to run, and you don’t care how it does that. Another benefit to PaaS is that you can ask for hundreds or thousands of new nodes of computing power - there’s no provisioning, it just happens. And you can stop using them quicker - and the base code for your application does not have to change to make this happen. Windows Azure Roles and Their Use If you need your code to have a user interface, in Visual Studio you add a Web Role to your project, and if the code needs to do work that doesn’t involve a user interface you can add a Worker Role. They are just containers that act a certain way. I’ll provide more detail on those later. Note: That’s a general description, so it’s not entirely accurate, but it’s accurate enough for this discussion. So now we’re back to that VM Role. Because of the name, some have mistakenly thought that you can take a Virtual Machine running, say Linux, and deploy it to Windows Azure using this Role. But you can’t. That’s not what it is designed for at all. If you do need that kind of deployment, you should look into Hyper-V and System Center to create the Private or Public Infrastructure as a Service. What the VM Role is actually designed to do is to allow you to have a great deal of control over the system where your code will run. Let’s take an example. You’ve heard about Windows Azure, and Platform programming. You’re convinced it’s the right way to code. But you have a lot of things you’ve written in another way at your company. Re-writing all of your code to take advantage of Windows Azure will take a long time. Or perhaps you have a certain version of Apache Web Server that you need for your code to work. In both cases, you think you can (or already have) code the the software to be “Stateless”, you just need more control over the place where the code runs. That’s the place where a VM Role makes sense. Recap Virtualizing servers alone has limitations of scale, availability and recovery. Microsoft’s offering in this area is Hyper-V and System Center, not the VM Role. The VM Role is still used for running Stateless code, just like the Web and Worker Roles, with the exception that it allows you more control over the environment of where that code runs.

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  • How to make your File Adapter pick only one file at a time from a location

    - by anirudh.pucha(at)oracle.com
    In SOA 11g, you use File adapter to read files from the given location.With this read operation it picks all the files at time.You want to configure File Adapters that it should pick one file at time from the given location with given polling interval.Solution :You set the "SingleThreadModel" and "MaxRaiseSize" properties for your file adapter. Edit the adapter's jca file and add the following properties:property name="SingleThreadModel" value="true"property name="MaxRaiseSize" value="1"You can set these properties also through jdeveloper, by opening composite.xml, selecting the adapter and then changing the properties through the properties panel.

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  • Programming doesn&rsquo;t have to be Magic

    - by Wes McClure
    In the show LOST, the Swan Station had a button that “had to be pushed” every 100 minutes to avoid disaster.  Several characters in the show took it upon themselves to have faith and religiously push the button, resetting the clock and averting the unknown “disaster”.  There are striking similarities in this story to the code we write every day.  Here are some common ones that I encounter: “I don’t know what it does but the application doesn’t work without it” “I added that code because I saw it in other similar places, I didn’t understand it, but thought it was necessary.” (for consistency, or to make things “work”) “An error message recommended it” “I copied that code” (and didn’t look at what it was doing) “It was suggested in a forum online and it fixed my problem so I left it” In all of these cases we haven’t done our due diligence to understand what the code we are writing is actually doing.  In the rush to get things done it seems like we’re willing to push any button (add any line of code) just to get our desired result and move on.  All of the above explanations are common things we encounter, and are valid ways to work through a problem we have, but when we find a solution to a task we are working on (whether a bug or a feature), we should take a moment to reflect on what we don’t understand.  Remove what isn’t necessary, comprehend and simplify what is.  Why is it detrimental to commit code we don’t understand? Perpetuates unnecessary code If you copy code that isn’t necessary, someone else is more likely to do so, especially peers Perpetuates tech debt Adding unnecessary code leads to extra code that must be understood, maintained and eventually cleaned up in longer lived projects Tech debt begets tech debt as other developers copy or use this code as guidelines in similar situations Increases maintenance How do we know the code is simplified if we don’t understand it? Perpetuates a lack of ownership Makes it seem ok to commit anything so long as it “gets the job done” Perpetuates the notion that programming is magic If we don’t take the time to understand every line of code we add, then we are contributing to the notion that it is simply enough to make the code work, regardless of how. TLDR Don’t commit code that you don’t understand, take the time to understand it, simplify it and then commit it!

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  • How to Customize Your How-To Geek RSS Feeds (We’re Changing Things)

    - by The Geek
    If you’re an RSS subscriber, you’ll soon notice that we’re making a few changes. Why? It’s time to simplify our system, while providing you a little more control over which articles you want to see. The point, of course, is that people like different things, and that’s OK. What’s not so great is getting complaints—Linux users are always whining about Windows posts, and Windows users are whining when we write Linux posts. It’s also worth pointing out that if you aren’t interested in a post—you don’t have to click on it to read it. This is probably fairly obvious to reasonable people. The New Feeds Here’s the new set of feeds you can subscribe to. We’ll probably add more fine-grained feeds in the future, as we get some more things straightened out. Everything we publish (news, how-tos, features) Just the Feature Articles (the absolute best stuff) Just News (ETC) Posts Just Windows Articles Just Linux Articles Just Apple Articles Just Desktop Fun Articles You can obviously subscribe to one or many of them if you feel like it. The Once Daily Summary Feed! If you’d rather get all your How-To Geek in a single dose each day, you can subscribe to the summary feed, which is pretty much the same as our daily email newsletter. You can subscribe to this summary feed by clicking here. Note: we’re working on a lot of backend changes to hopefully make things a little better for you, the reader. One of the things we’ve consistently had feedback on is the comment system, which we’ll tackle a little later. Also, if you suddenly saw a barrage of posts earlier… oops! Our mistake. Latest Features How-To Geek ETC Ask How-To Geek: How Can I Monitor My Bandwidth Usage? Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide CyanogenMod Updates; Rolls out Android 2.3 to the Less Fortunate MyPaint is an Open-Source Graphics App for Digital Painters Can the Birds and Pigs Really Be Friends in the End? [Angry Birds Video] Add the 2D Version of the New Unity Interface to Ubuntu 10.10 and 11.04 MightyMintyBoost Is a 3-in-1 Gadget Charger Watson Ties Against Human Jeopardy Opponents

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  • How to setup Dual Head with "radeon" driver for R770?

    - by user1709408
    I want to make dual head setup without xrandr but with Xinerama. I put "Screen 1" line into xorg.conf, but card still show identical output on DVI-2 and DVI-3 It is important to use xinerama for me (to glue three monitors), that's why i decide not to use ranrd (randr is incompatible with xinerama as i read somewhere) Here is my videocard (HD 4850 X2): lspci | grep R700 03:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI R700 [Radeon HD 4850] 04:00.0 Display controller: Advanced Micro Devices [AMD] nee ATI R700 [Radeon HD 4850] Here is how monitors are connected: grep "DVI" /var/log/Xorg.0.log [ 1210.002] (II) RADEON(0): Output DVI-0 using monitor section Monitor0 [ 1210.048] (II) RADEON(0): Output DVI-1 has no monitor section [ 1210.079] (II) RADEON(0): EDID for output DVI-0 [ 1210.080] (II) RADEON(0): Printing probed modes for output DVI-0 [ 1210.128] (II) RADEON(0): EDID for output DVI-1 [ 1210.128] (II) RADEON(0): Output DVI-0 connected [ 1210.128] (II) RADEON(0): Output DVI-1 disconnected [ 1210.128] (II) RADEON(0): Output DVI-0 using initial mode 1920x1200 [ 1210.160] (II) RADEON(1): Output DVI-2 using monitor section Monitor2 [ 1210.215] (II) RADEON(1): Output DVI-3 has no monitor section [ 1210.246] (II) RADEON(1): EDID for output DVI-2 [ 1210.247] (II) RADEON(1): Printing probed modes for output DVI-2 [ 1210.299] (II) RADEON(1): EDID for output DVI-3 [ 1210.300] (II) RADEON(1): Printing probed modes for output DVI-3 [ 1210.300] (II) RADEON(1): Output DVI-2 connected [ 1210.300] (II) RADEON(1): Output DVI-3 connected [ 1210.300] (II) RADEON(1): Output DVI-2 using initial mode 1920x1200 [ 1210.300] (II) RADEON(1): Output DVI-3 using initial mode 1920x1200 Here is my /etc/X11/xorg.conf Section "ServerFlags" Option "RandR" "0" Option "Xinerama" "1" EndSection Section "ServerLayout" Identifier "Three Head Layout" Screen "MyPrecious0" Screen "MyPrecious2" RightOf "MyPrecious0" Screen "MyPrecious3" LeftOf "MyPrecious0" EndSection Section "Screen" Identifier "MyPrecious0" Monitor "Monitor0" Device "Device300" EndSection Section "Screen" Identifier "MyPrecious2" Monitor "Monitor2" Device "Device400" EndSection Section "Screen" Identifier "MyPrecious3" Monitor "Monitor3" Device "Device401" EndSection Section "Device" Identifier "Device300" BusID "PCI:3:0:0" Screen 0 Driver "radeon" EndSection Section "Device" Identifier "Device400" BusID "PCI:4:0:0" Screen 0 Driver "radeon" EndSection Section "Device" Identifier "Device401" BusID "PCI:4:0:0" Screen 1 Driver "radeon" EndSection Section "Monitor" Identifier "Monitor0" EndSection Section "Monitor" Identifier "Monitor2" EndSection Section "Monitor" Identifier "Monitor3" EndSection I tried to switch to vesa driver (didn't work for me) I tried to add options like Option "ZaphodHeads" "DVI-2" and Option "ZaphodHeads" "DVI-3" into sections "Device 400" and "Device 401" (this didn't help because "ZaphodHeads" option is for ranrd, and randr is disabled by decision) I tried to merge sections "Device 400" and "Device 401" into one section and add Option "ZaphodHeads" "DVI-2,DVI-3" (see comment about randr above) single section setup helps to change log line RADEON(1): Output DVI-3 has no monitor section into RADEON(1): Output DVI-3 using monitor section Monitor3 but nothing was enough to switch from screen cloning to separate screens. This problem (lack of documentation on radeon driver) is similar to these: Radeon display driver clones monitors while using Xinerama (moderators decision to close that problem was wrong) Ubuntu 12.10 multi-monitor setup isn't working The problem is solvable, because this hardware worked as three headed for me earlier with gentoo/xorg-server-1.3 Xorg -configure creates setup for the first monitor on the first GPU Please don't advise to use fglrx/aticonfig/amdcccle (this goes against my religion beliefs)

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  • How to make Connect Communications VPN connection in 10.10?

    - by Bilal Mohammad Qazi
    these steps were send by my iSP admin for ver10.10 and i'm using 11.10... step 1 sucessfully implemented till point 7 after that the problems are marked after '//' Step 2 i cannot completely do the step 2 How to make Connect Communications VPN connection in Ubuntu 10.10. 1st Step:- 1- Go to System > Administration > Synaptic Package Manage 2- Search for “PPTP”, check “network-manager-PPTP” and click “Apply” 3- Click on the Network Manager tray icon with your right mouse button and choose “Edit Connections…”. 4- Go to the “VPN” tab and click “Add”. 5- Choose “Point-to-Point Tunneling Protocol (PPTP)” as the VPN Connection Type 6- Check the VPN Connection Type and click “Create”. 7- Give your VPN connection a name and assign all the necessary information • Gateway = blue.connect.net.pk if you got Blue Package or • Gateway = green.connect.net.pk if you got Green Package or • Gateway = blueplus.connect.net.pk if you got BluePlus Package or • Gateway = red.connect.net.pk if you got Red Package • User name = Connect Communications Userid • Password = Connect Communications Password 8- Now Click on “Advanced” Authentication • Unchecked “PAP" // cannot uncheck • Unchecked “MSCHAP" // cannot uncheck • Unchecked “CHAP" • Checked only “MSCHAPv2" EAP shown in ver11.10 and cannot be unchecked Security And Compression. • Unchecked “Use Point-to-Point encryption (MPPE)”. • Unchecked “Allow statefull encryption”. • Unchecked “Allow BSD data Compression”. • Unchecked “Allow Deflate data Compression”. • Unchecked “Use TCP Header Compression”. • Unchecked “Send PPP echo Packets” Then Press “OK” then “Apply”. 9-Now you are able to connect to the specified VPN connection via the Networking Manager Then you can connect to VPN in the menu bar and your Internet icon will have a lock when the connection is successful. 2nd Step:- Open Terminal window. First, you open a terminal (Applications > Accessories > Terminal): Run command “sudo” Now gave root Password. Then run command “netstat -r -n” It will show some lines and for example from the last line pick the IP from 2nd column like 10.111.0.1 0.0.0.0 10.111.0.1 0.0.0.0 UG 0 0 0 eth0 Now run the fallowing command. echo “route add -net 10.101.8.0 netmask 255.255.252.0 gw 10.152.24.1” > /etc/rc.local note :- 10.111.0.1 is an example IP now run “ sh /etc/rc.local “

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  • Reading All Users Session

    - by imran_ku07
      Introduction :            InProc Session is the widely used state management. Storing the session state Inproc is also the fastest method and is well-suited to small amounts of volatile data. Reading and writing current user Session is very easy. But some times we need to read all users session before taking a decision or sometimes we may need to check which users are currently active with the help of Session. But unfortunately there is no class in .Net Framework (i don't found myself) to read all user InProc Session Data. In this article i will use reflection to read all user Inproc Session.   Description :              This code will work equally in both MVC and webform, but for demonstration i will use a simple webform example. So let's create a simple Website and Add two aspx pages, Default.aspx and Default2.aspx. In Default.aspx just add a link to navigate to Default2.aspx and in Default.aspx.cs just add a Session. Default.aspx: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Default" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html ><head runat="server">    <title>Untitled Page</title></head><body>    <form id="form1" runat="server">    <div>        <a href="Default2.aspx">Click to navigate to next page</a>    </div>    </form></body></html>  Default.aspx.cs:  using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;public partial class Default : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        Session["User"] = "User" + DateTime.Now;    }} Now when every user click this link will navigate to Default2.aspx where all the magic appears.Default2.aspx.cs: using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Reflection;using System.Web.SessionState;public partial class Default2 : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        object obj = typeof(HttpRuntime).GetProperty("CacheInternal", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null, null);        Hashtable c2 = (Hashtable)obj.GetType().GetField("_entries", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(obj);        foreach (DictionaryEntry entry in c2)        {            object o1 = entry.Value.GetType().GetProperty("Value", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(entry.Value, null);            if (o1.GetType().ToString() == "System.Web.SessionState.InProcSessionState")            {                SessionStateItemCollection sess = (SessionStateItemCollection)o1.GetType().GetField("_sessionItems", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(o1);                if (sess != null)                {                    if (sess["User"] != null)                    {                        Label1.Text += sess["User"] + " is Active.<br>";                    }                }            }        }    }}            Now just open more than one browsers or more than one browser instance and then navigate to Default.aspx and click the link, you will see all the user's Session data.    How this works :        InProc session data is stored in the HttpRuntime’s internal cache in an implementation of ISessionStateItemCollection that implements ICollection. In this code, first of all i got CacheInternal Static Property of HttpRuntime class and then with the help of this object i got _entries private member which is of type ICollection. Then simply enumerate this dictionary and only take object of type System.Web.SessionState.InProcSessionState and finaly got SessionStateItemCollection for each user.Summary :        In this article, I shows you how you can get all current user Sessions. However one thing you will find when executing this code is that it will not show the current user Session which is set in the current request context because Session will be saved after all the Page Events.

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  • Creating extendible applications with MEF

    - by Visual WebGui
    Ever wanted to create an application that is easy to maintain and even more easy to extend? Then the following piece by Michael Hensen about Microsoft Extension Framework (MEF) could be a solution for your needs! With MEF, which is part of VS2010 own extensions platform, you can write parts of an application is an enclosed dll. This way you can build up your application the normal way and based on the requirements of a client you can add or remove functions as easy as removing a dll from the base...(read more)

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  • PowerShell PowerPack Download

    - by BuckWoody
    I read Jeffery Hicks’ article in this month’s Redmond Magazine on a new add-in for Windows PowerShell 2.0. It’s called the PowerShell Pack and it has a some great new features that I plan to put into place on my production systems as soon as I finished learning and testing them. You can download the pack here if you have PowerShell 2.0. I’m having a lot of fun with it, and I’ll blog about what I’m learning here in the near future, but you should check it out. The only issue I have with it right now is that you have to load a module and then use get-help to find out what it does, because I haven’t found a lot of other documentation so far. The most interesting modules for me are the ones that can run a command elevated (in PSUserTools), the task scheduling commands (in TaskScheduler) and the file system checks and tools (in FileSystem). There’s also a way to create simple Graphical User Interface panels (in ). I plan to string all these together to install a management set of tools on my SQL Server Express Instances, giving the user “task buttons” to backup or restore a database, add or delete users and so on. Yes, I’ll be careful, and yes, I’ll make sure the user is allowed to do that. For now, I’m testing the download, but I thought I would share what I’m up to. If you have PowerShell 2.0 and you download the pack, let me know how you use it. Script Disclaimer, for people who need to be told this sort of thing: Never trust any script, including those that you find here, until you understand exactly what it does and how it will act on your systems. Always check the script on a test system or Virtual Machine, not a production system. Yes, there are always multiple ways to do things, and this script may not work in every situation, for everything. It’s just a script, people. All scripts on this site are performed by a professional stunt driver on a closed course. Your mileage may vary. Void where prohibited. Offer good for a limited time only. Keep out of reach of small children. Do not operate heavy machinery while using this script. If you experience blurry vision, indigestion or diarrhea during the operation of this script, see a physician immediately. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • API Message Localization

    - by Jesse Taber
    In my post, “Keep Localizable Strings Close To Your Users” I talked about the internationalization and localization difficulties that can arise when you sprinkle static localizable strings throughout the different logical layers of an application. The main point of that post is that you should have your localizable strings reside as close to the user-facing modules of your application as possible. For example, if you’re developing an ASP .NET web forms application all of the localizable strings should be kept in .resx files that are associated with the .aspx views of the application. In this post I want to talk about how this same concept can be applied when designing and developing APIs. An API Facilitates Machine-to-Machine Interaction You can typically think about a web, desktop, or mobile application as a collection “views” or “screens” through which users interact with the underlying logic and data. The application can be designed based on the assumption that there will be a human being on the other end of the screen working the controls. You are designing a machine-to-person interaction and the application should be built in a way that facilitates the user’s clear understanding of what is going on. Dates should be be formatted in a way that the user will be familiar with, messages should be presented in the user’s preferred language, etc. When building an API, however, there are no screens and you can’t make assumptions about who or what is on the other end of each call. An API is, by definition, a machine-to-machine interaction. A machine-to-machine interaction should be built in a way that facilitates a clear and unambiguous understanding of what is going on. Dates and numbers should be formatted in predictable and standard ways (e.g. ISO 8601 dates) and messages should be presented in machine-parseable formats. For example, consider an API for a time tracking system that exposes a resource for creating a new time entry. The JSON for creating a new time entry for a user might look like: 1: { 2: "userId": 4532, 3: "startDateUtc": "2012-10-22T14:01:54.98432Z", 4: "endDateUtc": "2012-10-22T11:34:45.29321Z" 5: }   Note how the parameters for start and end date are both expressed as ISO 8601 compliant dates in UTC. Using a date format like this in our API leaves little room for ambiguity. It’s also important to note that using ISO 8601 dates is a much, much saner thing than the \/Date(<milliseconds since epoch>)\/ nonsense that is sometimes used in JSON serialization. Probably the most important thing to note about the JSON snippet above is the fact that the end date comes before the start date! The API should recognize that and disallow the time entry from being created, returning an error to the caller. You might inclined to send a response that looks something like this: 1: { 2: "errors": [ {"message" : "The end date must come after the start date"}] 3: }   While this may seem like an appropriate thing to do there are a few problems with this approach: What if there is a user somewhere on the other end of the API call that doesn’t speak English?  What if the message provided here won’t fit properly within the UI of the application that made the API call? What if the verbiage of the message isn’t consistent with the rest of the application that made the API call? What if there is no user directly on the other end of the API call (e.g. this is a batch job uploading time entries once per night unattended)? The API knows nothing about the context from which the call was made. There are steps you could take to given the API some context (e.g.allow the caller to send along a language code indicating the language that the end user speaks), but that will only get you so far. As the designer of the API you could make some assumptions about how the API will be called, but if we start making assumptions we could very easily make the wrong assumptions. In this situation it’s best to make no assumptions and simply design the API in such a way that the caller has the responsibility to convey error messages in a manner that is appropriate for the context in which the error was raised. You would work around some of these problems by allowing callers to add metadata to each request describing the context from which the call is being made (e.g. accepting a ‘locale’ parameter denoting the desired language), but that will add needless clutter and complexity. It’s better to keep the API simple and push those context-specific concerns down to the caller whenever possible. For our very simple time entry example, this can be done by simply changing our error message response to look like this: 1: { 2: "errors": [ {"code": 100}] 3: }   By changing our error error from exposing a string to a numeric code that is easily parseable by another application, we’ve placed all of the responsibility for conveying the actual meaning of the error message on the caller. It’s best to have the caller be responsible for conveying this meaning because the caller understands the context much better than the API does. Now the caller can see error code 100, know that it means that the end date submitted falls before the start date and take appropriate action. Now all of the problems listed out above are non-issues because the caller can simply translate the error code of ‘100’ into the proper action and message for the current context. The numeric code representation of the error is a much better way to facilitate the machine-to-machine interaction that the API is meant to facilitate. An API Does Have Human Users While APIs should be built for machine-to-machine interaction, people still need to wire these interactions together. As a programmer building a client application that will consume the time entry API I would find it frustrating to have to go dig through the API documentation every time I encounter a new error code (assuming the documentation exists and is accurate). The numeric error code approach hurts the discoverability of the API and makes it painful to integrate with. We can help ease this pain by merging our two approaches: 1: { 2: "errors": [ {"code": 100, "message" : "The end date must come after the start date"}] 3: }   Now we have an easily parseable numeric error code for the machine-to-machine interaction that the API is meant to facilitate and a human-readable message for programmers working with the API. The human-readable message here is not intended to be viewed by end-users of the API and as such is not really a “localizable string” in my opinion. We could opt to expose a locale parameter for all API methods and store translations for all error messages, but that’s a lot of extra effort and overhead that doesn’t add a lot real value to the API. I might be a bit of an “ugly American”, but I think it’s probably fine to have the API return English messages when the target for those messages is a programmer. When resources are limited (which they always are), I’d argue that you’re better off hard-coding these messages in English and putting more effort into building more useful features, improving security, tweaking performance, etc.

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  • Abstracting away the type of a property

    - by L. De Leo
    In Python luckily most of the times you don't have to write getters and setters to get access to class properties. That said sometimes you'll have to remember that a certain property is a list or whatnot and a property would save you there by abstracting the type and providing a setter to add something to such list for example rather than exposing the list directly. Where do you draw the line between exposing the type directly or wrapping its access in a property? What's the general "pythonic" advice?

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  • C#/.NET Little Wonders: The Timeout static class

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

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  • Adding RSS to tags in Orchard

    - by Bertrand Le Roy
    A year ago, I wrote a scary post about RSS in Orchard. RSS was one of the first features we implemented in our CMS, and it has stood the test of time rather well, but the post was explaining things at a level that was probably too abstract whereas my readers were expecting something a little more practical. Well, this post is going to correct this by showing how I built a module that adds RSS feeds for each tag on the site. Hopefully it will show that it's not very complicated in practice, and also that the infrastructure is pretty well thought out. In order to provide RSS, we need to do two things: generate the XML for the feed, and inject the address of that feed into the existing tag listing page, in order to make the feed discoverable. Let's start with the discoverability part. One might be tempted to replace the controller or the view that are responsible for the listing of the items under a tag. Fortunately, there is no need to do any of that, and we can be a lot less obtrusive. Instead, we can implement a filter: public class TagRssFilter : FilterProvider, IResultFilter .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } On this filter, we can implement the OnResultExecuting method and simply check whether the current request is targeting the list of items under a tag. If that is the case, we can just register our new feed: public void OnResultExecuting(ResultExecutingContext filterContext) { var routeValues = filterContext.RouteData.Values; if (routeValues["area"] as string == "Orchard.Tags" && routeValues["controller"] as string == "Home" && routeValues["action"] as string == "Search") { var tag = routeValues["tagName"] as string; if (! string.IsNullOrWhiteSpace(tag)) { var workContext = _wca.GetContext(); _feedManager.Register( workContext.CurrentSite + " – " + tag, "rss", new RouteValueDictionary { { "tag", tag } } ); } } } The registration of the new feed is just specifying the title of the feed, its format (RSS) and the parameters that it will need (the tag). _wca and _feedManager are just instances of IWorkContextAccessor and IFeedManager that Orchard injected for us. That is all that's needed to get the following tag to be added to the head of our page, without touching an existing controller or view: <link rel="alternate" type="application/rss+xml" title="VuLu - Science" href="/rss?tag=Science"/> Nifty. Of course, if we navigate to the URL of that feed, we'll get a 404. This is because no implementation of IFeedQueryProvider knows about the tag parameter yet. Let's build one that does: public class TagFeedQuery : IFeedQueryProvider, IFeedQuery IFeedQueryProvider has one method, Match, that we can implement to take over any feed request that has a tag parameter: public FeedQueryMatch Match(FeedContext context) { var tagName = context.ValueProvider.GetValue("tag"); if (tagName == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } This is just saying that if there is a tag parameter, we will handle it. All that remains to be done is the actual building of the feed now that we have accepted to handle it. This is done by implementing the Execute method of the IFeedQuery interface: public void Execute(FeedContext context) { var tagValue = context.ValueProvider.GetValue("tag"); if (tagValue == null) return; var tagName = (string)tagValue.ConvertTo(typeof (string)); var tag = _tagService.GetTagByName(tagName); if (tag == null) return; var site = _services.WorkContext.CurrentSite; var link = new XElement("link"); context.Response.Element.SetElementValue("title", site.SiteName + " - " + tagName); context.Response.Element.Add(link); context.Response.Element.SetElementValue("description", site.SiteName + " - " + tagName); context.Response.Contextualize(requestContext => link.Add(GetTagUrl(tagName, requestContext))); var items = _tagService.GetTaggedContentItems(tag.Id, 0, 20); foreach (var item in items) { context.Builder.AddItem(context, item.ContentItem); } } This code is resolving the tag content item from its name and then gets content items tagged with it, using the tag services provided by the Orchard.Tags module. Then we add those items to the feed. And that is it. To summarize, we handled the request unobtrusively in order to inject the feed's link, then handled requests for feeds with a tag parameter and generated the list of items for that tag. It remains fairly simple and still it is able to handle arbitrary content types. That makes me quite happy about our little piece of over-engineered code from last year. The full code for this can be found in the Vandelay.TagCloud module: http://orchardproject.net/gallery/List/Modules/ Orchard.Module.Vandelay.TagCloud/1.2

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