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  • after .htaccess url rewrite, cannot perform logoff in some of the url rewrited page

    - by Patrick
    Recently, I was doing .htaccess url rewrite, make all my php url into html, in some page, the logout button wont work properly. for example, in page ‘quotedetails/Q9999.html’ (rewrited from ‘quotedetails.php?quoteID=Q9999'), when I click logout button in this page, it wont do the trick, but when i use the old php url of this page, it works again, other rewrited pages like index.html (index.php), search.html(search.php), all works perfectly. I use firebug to debug, after I click the logout button, it stays in the same page without redirect me to the index.html, but I saw the the ‘logoff’ params has been passed through, but just dont let me logout and redirect to index page. I’ve changed all the relavent file path to absolute path, still no luck…..help please. I’ve also noticed from firebug, that page cannot get the redirect ‘location’ as I tried in other pages, their response headers come with ‘location: index.html’, but in that no-workin-page, there is no such line called ‘location: index.html’ in its response headers. Here is my .htaccess file, no-workin-pages are related to the first four ReweiteRules Options +FollowSymlinks RewriteEngine on RewriteRule ^reps/all,all.html$ rep.php?repID=all&repName=all RewriteRule ^reps/([A-Z]+),([A-Za-z\sA-Za-z]+).html$ rep.php?repID=$1&repName=$2 RewriteRule ^reps/([A-Za-z]+),([A-Za-z\sA-Za-z]+),([0-9]+).html$ rep.php?repID=$1repName=$2&page=$3 RewriteRule ^quotedetails/(Q[0-9]+).html$ quotedetails.php?quoteID=$1 RewriteRule ^index.html$ index.php RewriteRule ^addquote.html$ addquote.php RewriteRule ^search.html$ search.php RewriteRule ^viewall.html$ viewall.php RewriteRule ^howto.html$ howto.php

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  • How to achieve high availability?

    - by tanyehzheng
    My boss wants to have a system that takes into concern of continent wide catastrophic event. He wants to have two servers in US and two servers in Asia (1 login server and 1 worker server in each continent). In the event that earthquake breaks the connection between the two continents, both should work alone. When the connection is revived, they should sync each other back to normal. External cloud system not allowed as he has no confidence. The system should take into account of scalability which means addition of new servers should be easy to configure. The servers should be load balanced. The connection between the servers should be very secure(encrypted and send through SSL although SSL takes care of encryption). The system should let one and only one user log in with one account. (beware of latency between continent and two users sharing account may reach both login server at the same time) Please help. I'm already at the end of my wit. Thank you in advance.

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  • Calling a subclass method from a superclass

    - by Shaun
    Preface: This is in the context of a Rails application. The question, however, is specific to Ruby. Let's say I have a Media object. class Media < ActiveRecord::Base end I've extended it in a few subclasses: class Image < Media def show # logic end end class Video < Media def show # logic end end From within the Media class, I want to call the implementation of show from the proper subclass. So, from Media, if self is a Video, then it would call Video's show method. If self is instead an Image, it would call Image's show method. Coming from a Java background, the first thing that popped into my head was 'create an abstract method in the superclass'. However, I've read in several places (including Stack Overflow) that abstract methods aren't the best way to deal with this in Ruby. With that in mind, I started researching typecasting and discovered that this is also a relic of Java thinking that I need to banish from my mind when dealing with Ruby. Defeated, I started coding something that looked like this: def superclass_method # logic this_media = self.type.constantize.find(self.id) this_media.show end I've been coding in Ruby/Rails for a while now, but since this was my first time trying out this behavior and existing resources didn't answer my question directly, I wanted to get feedback from more-seasoned developers on how to accomplish my task. So, how can I call a subclass's implementation of a method from the superclass in Rails? Is there a better way than what I ended up (almost) implementing?

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  • What techniques can be used to detect so called "black holes" (a spider trap) when creating a web crawler?

    - by Tom
    When creating a web crawler, you have to design somekind of system that gathers links and add them to a queue. Some, if not most, of these links will be dynamic, which appear to be different, but do not add any value as they are specifically created to fool crawlers. An example: We tell our crawler to crawl the domain evil.com by entering an initial lookup URL. Lets assume we let it crawl the front page initially, evil.com/index The returned HTML will contain several "unique" links: evil.com/somePageOne evil.com/somePageTwo evil.com/somePageThree The crawler will add these to the buffer of uncrawled URLs. When somePageOne is being crawled, the crawler receives more URLs: evil.com/someSubPageOne evil.com/someSubPageTwo These appear to be unique, and so they are. They are unique in the sense that the returned content is different from previous pages and that the URL is new to the crawler, however it appears that this is only because the developer has made a "loop trap" or "black hole". The crawler will add this new sub page, and the sub page will have another sub page, which will also be added. This process can go on infinitely. The content of each page is unique, but totally useless (it is randomly generated text, or text pulled from a random source). Our crawler will keep finding new pages, which we actually are not interested in. These loop traps are very difficult to find, and if your crawler does not have anything to prevent them in place, it will get stuck on a certain domain for infinity. My question is, what techniques can be used to detect so called black holes? One of the most common answers I have heard is the introduction of a limit on the amount of pages to be crawled. However, I cannot see how this can be a reliable technique when you do not know what kind of site is to be crawled. A legit site, like Wikipedia, can have hundreds of thousands of pages. Such limit could return a false positive for these kind of sites. Any feedback is appreciated. Thanks.

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  • How to simulate OutOfMemory exception

    - by Gacek
    I need to refactor my project in order to make it immune to OutOfMemory exception. There are huge collections used in my project and by changing one parameter I can make my program to be more accurate or use less of the memory... OK, that's the background. What I would like to do is to run the routines in a loop: Run the subroutines with the default parameter. Catch the OutOfMemory exception, change the parameter and try to run it again. Do the 2nd point until parameters allow to run the subroutines without throwing the exception (usually, there will be only one change needed). Now, I would like to test it. I know, that I can throw the OutOfMemory exception on my own, but I would like to simulate some real situation. So the main question is: Is there a way of setting some kind of memory limit for my program, after reaching which the OutOfMemory exception will be thrown automatically? For example, I would like to set a limit, let's say 400MB of memory for my whole program to simulate the situation when there is such an amount of memory available in the system. Can it be done?

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  • DB2 Driver Connection Hanging in Glassfish Connection Pool

    - by Ant
    We have an intermittent issue around the DB2 used from a Glassfish connection pool. What happens is this: Under situations where the database (DB2 on ZOS) is under stress, our application (which is a multi-threaded application using connections to DB2 via a Glassfish connection pool) stops doing anything. The following are observed: 1) Looking at the server using JConsole, we can see a thread waiting indefinitely in the DB2 driver's getConnection() method. We can also see that it has gained a lock on a Vector within the driver. Several other threads are also calling the getConnection() method in the driver, and are hanging waiting for the lock on the Vector to be released. 2) Looking at the database itself, we can see that there are connections from the Glassfish server open and waiting to be used. It seems that there is some sort of mismatch between the connection pool on Glassfish and the connections actually open to DB2. Has anyone come across this issue before? Or something similar? If you need any more information that I haven't provided, then please let me know!

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  • Ditching Django's models for Ajax/Web Services

    - by Igor Ganapolsky
    Recently I came across a problem at work that made me rethink Django's models. The app I am developing resides on a Linux server. Its a simple model/view/controller app that involves user interaction and updating data in the database. The problem is that this data resides in a MS SQL database on a Windows machine. So in order to use Django's models, I would have to leverage an ODBC driver on linux, and the use a python add-on like pyodbc. Well, let me tell you, setting up a reliable and functional ODBC connection on linux is no easy feat! So much so, that I spent several hours maneuvering this on my CentOS with no luck, and was left with frustration and lots of dumb system errors. In the meantime I have a deadline to meet, and suddenly the very agile and rapid Django application is a roadblock rather than a pleasure to work with. Someone on my team suggested writing this app in .NET. But there are a few problems with that: it won't be deployable on a linux machine, and I won't be able to work on it since I don't know ASP.net. Then a much better suggestion was made: keep the app in django, but instead of using models, do straight up ajax/web services calls in the template. And then it dawned on me - what a great idea. Django's models seem like a nuissance and hindrance in this case, and I can just have someone else write .Net services on their side, that I can call from my template. As a result my app will be leaner and more compact. So, I was wondering if you guys ever came across a similar dillema and what you decided to do about it.

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  • Why do bind1st and bind2nd require constant function objects?

    - by rlbond
    So, I was writing a C++ program which would allow me to take control of the entire world. I was all done writing the final translation unit, but I got an error: error C3848: expression having type 'const `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>' would lose some const-volatile qualifiers in order to call 'void `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>::operator ()(const point::Point &,const int &)' with [ T=SideCounter, BinaryFunction=std::plus<int> ] c:\program files (x86)\microsoft visual studio 9.0\vc\include\functional(324) : while compiling class template member function 'void std::binder2nd<_Fn2>::operator ()(point::Point &) const' with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] c:\users\****\documents\visual studio 2008\projects\TAKE_OVER_THE_WORLD\grid_divider.cpp(361) : see reference to class template instantiation 'std::binder2nd<_Fn2>' being compiled with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] I looked in the specifications of binder2nd and there it was: it took a const AdaptibleBinaryFunction. So, not a big deal, I thought. I just used boost::bind instead, right? Wrong! Now my take-over-the-world program takes too long to compile (bind is used inside a template which is instantiated quite a lot)! At this rate, my nemesis is going to take over the world first! I can't let that happen -- he uses Java! So can someone tell me why this design decision was made? It seems like an odd decision. I guess I'll have to make some of the elements of my class mutable for now...

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  • Is it possible from Spring to inject the result of calling a method on a ref bean?

    - by Alex Worden
    Hi, Is it possible from Spring to inject the result of calling a method on a ref bean? I'm trying to refactor some cut/pasted code from two separate projects into a common class. In one of the projects, the code lives in a class I'll call "MyClient" that is being instantiated from Spring. It is injected with another spring-instantiated class "MyRegistry", then the MyClient class uses that class to look up an endpoint. All I really need is the endpoint String in my refactored class, which can be initialized via a Setter. I really cannot have a dependency on MyRegistry from MyClient in the refactored code. So, my question is this... is there a way I can inject the endpoint String from spring that was looked up in the MyRegistry class. So, I currently have: <bean id="registryService" class="foo.MyRegistry"> ...properties set etc... </bean> <bean id="MyClient" class="foo.MyClient"> <property name="registry" ref="registryService"/> </bean> But I'd like to have (and I know this is imaginary Spring syntax) <bean id="MyClient" class="foo.MyClient"> <property name="endPoint" value="registryService.getEndPoint('bar')"/> </bean> where MyRegistry will have a method getEndPoint(Stirng endPointName) Hope that makes sense from a the standpoint of what I'm trying to achieve. Please let me know if something like this is possible in Spring!

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  • Paypal Error - IPN Validation Failed.

    - by user504178
    Hello , I am getting below error. [12/26/2010 5:48 AM] - FAIL: IPN Validation Failed. IPN POST Vars from Paypal: auth=A76zglTH7sCSLAVjZISTEp38SYXWAoNlO1uurxDvnlFy40uy-mlrvqkp_S5q3bFhVBbO2GwpJRvdYDvfQuM0581EYkEITS1SnDzfWV-ju60OZm_VzHsc8o2Q8K7mmZuDs9ANFwW9iIP2Ig8fGPSwZN8APK2PtCMIda28rBnNMJ2FWaeNKgmzTCuG5HnpzLD7ZtTCElp4MC05kyx9Ro-9ggqzVx7OU1zleJ_c1W, form_charset=UTF-8, IPN Response from Paypal Server: HTTP/1.1 200 OK Date: Sun, 26 Dec 2010 10:48:50 GMT Server: Apache Set-Cookie: c9MWDuvPtT9GIMyPc3jwol1VSlO=Ejohjh-kFgFpKAeNiYlgG8LwsLOi5Sir4Ut7tXINWaRmWM2eNXfFkJRQmO09WqBbXWIpXd0ydzrS7JMWO0sHZMg0Wfdd4gt6UcpSswiiUl2EfiP_ykxKJOFOzcjMrn_6xzc8GG%7c5mvwkJOzeFg-vpKR1fovKAVDyvmzI5sFbPatUC6gbf9Wk4Llel4btOJa7uQbYSLhuprHVG%7c537g5xvn4Hns8l-HE1pnyQ2GUAxcSINm-oVJENMuU6yS_bYa4IAw4QlGP-0zq80pjZa5j0%7c1293360531; domain=.paypal.com; path=/ Set-Cookie: cookie_check=yes; expires=Wed, 23-Dec-2020 10:48:51 GMT; domain=.paypal.com; path=/ Set-Cookie: navcmd=_notify-validate; domain=.paypal.com; path=/ Set-Cookie: navlns=0.0; expires=Sat, 21-Dec-2030 10:48:51 GMT; domain=.paypal.com; path=/ Set-Cookie: Apache=10.191.196.11.222161293360530699; path=/; expires=Sat, 12-Nov-04 04:20:34 GMT Connection: close Transfer-Encoding: chunked Content-Type: text/html; charset=UTF-8 7 INVALID 0 Can anyone please let me know whats wrong over here. Regards, Atul

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  • How to contain the Deepwater Horizon oil spill? [closed]

    - by Yarin
    This is obviously not programming, but it's important and we're smart people, so let's give it a shot. (BP has actually begun soliciting suggestions for how to deal with the crisis http://www.deepwaterhorizonresponse.com/go/doc/2931/546759/, confirming that they don't have a clue) I'll start with my own proposal... Anchored Chute: A large-diameter, collapsible, flexible tube/hose with a wide mouth on one end is anchored over the leak. There's no need for a hermetic seal, the opening just needs to be big enough to form a canopy over the leak area. The rest of the tubing can just be dumped on the sea floor. Since oil is denser than water, the oily water that flows into the mouth eventually inflates the tube and raises the opposite end to the surface, where it can be collected (Like those inflatable dancing air socks at car dealerships). Further buoyancy could be added with floats attached to the tube at intervals. I think this method would not be as susceptible to the problems BP had with the containment dome, where a rigid, metal casing froze up with crystallized hydrates, as we would not be trying to contain the full pressure of the well, but would be using the natural buoyancy of the oil to channel its flow, and with a much larger opening.

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  • When is a good time to start thinking about scaling?

    - by Slokun
    I've been designing a site over the past couple days, and been doing some research into different aspects of scaling a site horizontally. If things go as planned, in a few months (years?) I know I'd need to worry about scaling the site up and out, since the resources it would end up consuming would be huge. So, this got me to thinking, when is the best time to start thinking about, and designing for, scalability? If you start too early on, you could easily over complicate your design, and make it impossible to actually build. You could also get too caught up in the details, the architecture, whatever, and wind up getting nothing done. Also, if you do get it working, but the site never takes off, you may have wasted a good chunk of extra effort. On the other hand, you could be saving yourself a ton of effort down the road. Designing it from the ground up to be big would make it much easier later on to let it grow big, with very little rewriting going on. I know for what I'm working on, I've decided to make at least a few choices now on the side of scaling, but I'm not going to do a complete change of thinking to get it to scale completely. Notably, I've redesigned my database from a conventional relational design to one similar to what was suggested on the Reddit site linked below, and I'm going to give memcache a try. So, the basic question, when is a good time to start thinking or worrying about scaling, and what are some good designs, tips, etc. for when doing so? A couple of things I've been reading, for those who are interested: http://www.codinghorror.com/blog/2009/06/scaling-up-vs-scaling-out-hidden-costs.html http://highscalability.com/blog/2010/5/17/7-lessons-learned-while-building-reddit-to-270-million-page.html http://developer.yahoo.com/performance/rules.html

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  • How to deploy a number of disparate project types?

    - by niteice
    This question is similar to http://stackoverflow.com/questions/1900269/whats-the-best-way-to-deploy-an-executable-process-on-a-web-server. The situation is this: I'm developing a product that needs to be deployed to a web server. It consists of 4 website projects, a background service, a couple of command-line tools, and two assemblies shared by all of these components. Now, I also happen to administer the server that this product will be deployed on. So I'm familiar with everything that may need to be done to perform an update: Copy website files Replace the service binary Install updated components in the GAC Configure IIS Update database schema After some research it seems that, to reduce deployment time and to be able to let the other sysadmins handle deployment, I want to deploy all of these as an MSI, except that I don't know a thing about installers. I know VS can generate web deployment projects, but where do I go from there? Being able to simply click Next a few times on an installer is my goal for deploying updates. It would also be nice to modularize it, so for example, I could distribute the four websites among multiple servers and have everything appear as individual components in the installer, and as one entity in Add/Remove Programs. Is all of this too much to ask in a single package?

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  • Working with extra fields in an Inline form - save_model, save_formset, can't make sense of the diff

    - by magicrebirth
    Suppose I am in the usual situation where there're extra fields in the many2many relationship: class Person(models.Model): name = models.CharField(max_length=128) class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(Person, through='Membership') class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) date_joined = models.DateField() invite_reason = models.CharField(max_length=64) # other models which are unrelated to the ones above.. class Trip(models.Model): placeVisited = models.ForeignKey(Place) visitor = models.ForeignKey(Person) pleasuretrip = models.Boolean() class Place(models.Model): name = models.CharField(max_length=128) I want to add some extra fields in the Membership form that gets displayed through the Inline. These fields basically are a shortcut to the instantiation of another model (Trip). Trip can have its own admin views, but these shortcuts are needed because when my project partners are entering 'Membership' data in the system they happen to have also the 'Trip' information handy (and also because some of the info in Membership can just be copied over to Trip etc. etc.). So all I want to have is two extra fields in the Membership Inline - placeVisited and pleasuretrip - which together with the Person instance will let me instantiate the Trip model in the background... I found out I can easily add extra fields to the inline view by defining my own form. But once the data have been entered, how and when to reference to them in order to perform the save operations I need to do? class MyForm(forms.ModelForm): place = forms.ModelChoiceField(required=False, queryset=Place.objects.all(), label="place",) pleasuretrip = forms.BooleanField(required=False, label="...") class MembershipInline(admin.TabularInline): model = Membership form = MyForm def save_model(self, request, obj, form, change): place = form.place pleasuretrip = form.pleasuretrip person = form.person .... # now I can create Trip instances with those data .... obj.save() class GroupAdmin(admin.ModelAdmin): model = Group .... inlines = (MembershipInline,) This doesn't seem to work... I'm also a bit puzzled by the save_formset method... maybe is that the one I should be using? Many thanks in advance for the help!!!!

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  • How to accommodate for the iPhone 4 screen resolution?

    - by dontWatchMyProfile
    This is a programming question! Read on before you vote to close! According to Apple, the iPhone 4 has a new and better screen resolution: 3.5-inch (diagonal) widescreen Multi-Touch display 960-by-640-pixel resolution at 326 ppi This little detail affects our apps in a heavy way. Most of the demo apps on the net have one thing in common: They position views in the believe that the screen has a fixed size of 320 x 480 pixels. So what most -if not all- developers do is: They designed everything in such a way, that a touchable area is -for example- 50 x 50 pixels big. Just enough to tap it. Things have been positioned relative to the upper left, to reach a specific position on screen - let's say the center, or somewhere at the bottom. Edit: It seems Apple has integrated an switch that allows to tell if an app is highRes or not. Nice. When we develop high-resolution apps, they probably won't work on older devices. And if they do, they would suffer a lot from 4-times the size of any image, having to scale them down in memory.

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  • What is the best way to return result from business layer to presentation layer when using linq - I

    - by samsur
    I have a business layer that has DTOs that are used in the presentation layer. This application uses entity framework. Here is an example of a class called RoleDTO public class RoleDTO { public Guid RoleId { get; set; } public string RoleName { get; set; } public string RoleDescription { get; set; } public int? OrganizationId { get; set; } } In the BLL I want to have a method that returns a list of DTO.. I would like to know which is the better approach: returning IQueryable or list of DTOs. Although i feel that returning Iqueryable is not a good idea because the connection needs to be open. Here are the 2 different methods using the different approaches public class RoleBLL { private servicedeskEntities sde; public RoleBLL() { sde = new servicedeskEntities(); } public IQueryable<RoleDTO> GetAllRoles() { IQueryable<RoleDTO> role = from r in sde.Roles select new RoleDTO() { RoleId = r.RoleID, RoleName = r.RoleName, RoleDescription = r.RoleDescription, OrganizationId = r.OrganizationId }; return role; } Note: in the above method the datacontext is a private attribute and set in the constructor, so that the connection stays opened. Second approach public static List GetAllRoles() { List roleDTO = new List(); using (servicedeskEntities sde = new servicedeskEntities()) { var roles = from pri in sde.Roles select new { pri.RoleID, pri.RoleName, pri.RoleDescription }; //Add the role entites to the DTO list and return. This is necessary as anonymous types can be returned acrosss methods foreach (var item in roles) { RoleDTO roleItem = new RoleDTO(); roleItem.RoleId = item.RoleID; roleItem.RoleDescription = item.RoleDescription; roleItem.RoleName = item.RoleName; roleDTO.Add(roleItem); } return roleDTO; } Please let me know, if there is a better approach - Thanks,

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  • Basic Contact Form in PHP

    - by NessDan
    I'm working on a contact form for my church website. The church has an email already registered (it's POP3) and the hosting company says their mail server is mymail.brinkster.com . With all that information, how can you send the form using mail()? The server won't show PHP errors. The current code looks like this: $headers = 'MIME-Version: 1.0' . "\r\n"; $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n"; $headers .= 'From: *ChurchsEmail*' . "\r\n"; if(mail("*MyEmailHere*", "Setting Up PHP Email", "This would be the body of the email.", $headers)) { echo "The email was successfully sent."; } else { echo "The email was NOT sent."; } All I get back is "The email was NOT sent." So does anyone have any experience setting up an email form like this? My thanks to anyone who can help me out and any efficient ways of doing this, let me know!

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  • Independent name of a class

    - by tobi
    We have class lua. In lua class there is a method registerFunc() which is defined: void lua::registerFun() { lua_register( luaState, "asd", luaApi::asd); lua_register( luaState, "zxc", luaApi::zxc); } lua_register is a built-in function from lua library: http://pgl.yoyo.org/luai/i/lua_register it takes static methods from luaApi class as an 3rd argument. Now some programmer wants to use the lua class, so he is forced to create his own class with definitions of the static methods, like: class luaApi { public: static int asd(); static int zxc(); }; and now is the point. I don't want (as a programmer) to create class named exactly "luaApi", but e.g. myClassForLuaApi. But for now it's not possible because it is explicitly written in the code - in lua class: lua_register( luaState, "asd", luaApi::asd); I would have to change it to: lua_register( luaState, "asd", myClassForLuaApi::asd); but I don't want to (let's assume that the programmer has no access there). If it's still not understandable, I give up. :) Thanks.

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  • What is the preferred way to update database schemas in multiple production environments

    - by rmarimon
    I am about to install some 20 servers with the same web application in multiple locations connected to their own local database. I will be updating the web applications remotely (perhaps using debian's package manager) and I'm sure will eventually need to update the database schemas. Since each server could be eventually be using a different release of the web application, I need a way to apply the incremental changes to the servers. I'm thinking something like this. Let's start with database.schema.1 as the original release of the database and assume this number increases with each new version of the schema. I eventually could end up with database.schema.17 as the current release. For a new installation this would be the schema to install. It seems to me that I would need consecutive translations like database.translation.1.2 which would convert database.schema.1 into database.schema.2, database.translation.2.3 to convert from 2 to 3 and so on until 17. It seems that whenever I change a schema I need to alter the database but perhaps I need to run some script to update the data which might be done with SQL but might require an external non sql script. What is the appropriate way to organize all these files? What is the automatic way to apply those upgrades to the schema? Where do I store the current version number of the schema?

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  • How to benchmark on multi-core processors

    - by Pascal Cuoq
    I am looking for ways to perform micro-benchmarks on multi-core processors. Context: At about the same time desktop processors introduced out-of-order execution that made performance hard to predict, they, perhaps not coincidentally, also introduced special instructions to get very precise timings. Example of these instructions are rdtsc on x86 and rftb on PowerPC. These instructions gave timings that were more precise than could ever be allowed by a system call, allowed programmers to micro-benchmark their hearts out, for better or for worse. On a yet more modern processor with several cores, some of which sleep some of the time, the counters are not synchronized between cores. We are told that rdtsc is no longer safe to use for benchmarking, but I must have been dozing off when we were explained the alternative solutions. Question: Some systems may save and restore the performance counter and provide an API call to read the proper sum. If you know what this call is for any operating system, please let us know in an answer. Some systems may allow to turn off cores, leaving only one running. I know Mac OS X Leopard does when the right Preference Pane is installed from the Developers Tools. Do you think that this make rdtsc safe to use again? More context: Please assume I know what I am doing when trying to do a micro-benchmark. If you are of the opinion that if an optimization's gains cannot be measured by timing the whole application, it's not worth optimizing, I agree with you, but I cannot time the whole application until the alternative data structure is finished, which will take a long time. In fact, if the micro-benchmark were not promising, I could decide to give up on the implementation now; I need figures to provide in a publication whose deadline I have no control over.

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  • In C++, what is the scope resolution ("order of precedence") for shadowed variable names?

    - by Emile Cormier
    In C++, what is the scope resolution ("order of precedence") for shadowed variable names? I can't seem to find a concise answer online. For example: #include <iostream> int shadowed = 1; struct Foo { Foo() : shadowed(2) {} void bar(int shadowed = 3) { std::cout << shadowed << std::endl; // What does this output? { int shadowed = 4; std::cout << shadowed << std::endl; // What does this output? } } int shadowed; }; int main() { Foo().bar(); } I can't think of any other scopes where a variable might conflict. Please let me know if I missed one. What is the order of priority for all four shadow variables when inside the bar member function?

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  • PHP File Upload, using the FILES superglobal array

    - by jnkrois
    Hello everybody, I just have a quick question. Let's say that I'm setting up an upload feature for a project. I'm using PHP5, and I was wondering if by using the $_FILES superglobal array, I could have access to the "tmp_name" array key , which is the temporary path and name of the file being uploaded to display a preview of the image, before moving it to the "uploads" folder in the server. What I had in mind is something like this: Use jQuery to detect when the "file" input filed changes (when the user selects an image file), then place an ajax call to upload the the file, which will move it to the temp folder even before I use "move_uploaded_file". If I can somehow access the "tmp_name" array key, I could probably put it into and "img" tag to display a preview. Later move the file to it's final location when the submit button is clicked. I'm not asking for any code examples or anything, since I'd be thrilled to accomplish this on my own, I just want to find out if there is access to that array key in any way. Thanks in advance.

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  • Properly design a code editor application

    - by Hemaulo
    I'm working on personal project which is basically a code editor. Imagine standard File menu with menu items New, Open, Save, Save As, Save All, Close, Close All. I'm stuck with proper design. Currently I have: A Document class which represents a document - code editing control, respective tab in tab bar and various properties such as Caption, Filename, IsModified etc. A Documents class which represents all open documents. Contains methods like New, Open(FileName), ... The problem is that I can't figure out which class / menu command is responsible for which tasks. For example, with File-New menu command is simple - call Documents.New and that's it. But what for File-Open? The Documents.Open method expects filename as a parameter. So before calling this method I need to open an file selection dialog, let user select files and for each file call Documents.Open(FileName). Where is best place for this supporting code, in menu command, rewrite Documents.Open and put it there? The same with Save actions. Which is responsible for saving? Is it Documents class which uses Document.Editor.SaveToFile(FileName) or better create Save method in Document class? Somewhere in the middle also need to ask user if he wants to save current document... I'm stuck. Any ideas? Edited: The programming language is Delphi.

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  • One big executable or many small DLL's?

    - by Patrick
    Over the years my application has grown from 1MB to 25MB and I expect it to grow further to 40, 50 MB. I don't use DLL's, but put everything in this one big executable. Having one big executable has certain advantages: Installing my application at the customer is really: copy and run. Upgrades can be easily zipped and sent to the customer There is no risk of having conflicting DLL's (where the customer has version X of the EXE, but version Y of the DLL) The big disadvantage of the big EXE is that linking times seem to grow exponentially. Additional problem is that a part of the code (let's say about 40%) is shared with another application. Again, the advantages are that: There is no risk on having a mix of incorrect DLL versions Every developer can make changes on the common code which speeds up developments. But again, this has a serious impact on compilation times (everyone compiles the common code again on his PC) and on linking times. The question http://stackoverflow.com/questions/2387908/grouping-dlls-for-use-in-executable mentions the possibility of mixing DLL's in one executable, but it looks like this still requires you to link all functions manually in your application (using LoadLibrary, GetProcAddress, ...). What is your opinion on executable sizes, the use of DLL's and the best 'balance' between easy deployment and easy/fast development?

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  • Why doesn't IB see my IBAction?

    - by Dan Ray
    I've been staring at this for way too long. There's nothing fancy happening here, and I've done this dozens of times, yet Interface Builder steadfastly refuses to provide me an action target for -(IBAction)slideDirections. I'm at the point where I'm willing to post publicly and feel stupid. So let 'er rip. Here's my .h: #import <UIKit/UIKit.h> #import <MapKit/MapKit.h> @interface PulseDetailController : UIViewController { NSDictionary *pulse; IBOutlet MKMapView *map; IBOutlet UIWebView *directions; IBOutlet UIView *directionsSlider; BOOL directionsExtended; IBOutlet UILabel *vendor; IBOutlet UILabel *offer; IBOutlet UILabel *offerText; IBOutlet UILabel *hours; IBOutlet UILabel *minutes; IBOutlet UILabel *seconds; IBOutlet UILabel *distance } @property (nonatomic, retain) NSDictionary *pulse; @property (nonatomic, retain) MKMapView *map; @property (nonatomic, retain) UIWebView *directions; @property (nonatomic, retain) UIView *directionsSlider; @property (nonatomic) BOOL directionsExtended; @property (nonatomic, retain) UILabel *vendor; @property (nonatomic, retain) UILabel *offer; @property (nonatomic, retain) UILabel *offerText; @property (nonatomic, retain) UILabel *hours; @property (nonatomic, retain) UILabel *minutes; @property (nonatomic, retain) UILabel *seconds; @property (nonatomic, retain) UILabel *distance; -(IBAction)slideDirections; @end

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