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  • Best practice to structure large html-based project

    - by AntonAL
    I develop Rails based website, enjoying using partials for some common "components" Recently, i faced a problem, that states with CSS interference. Styles for one component (described in css) override styles for another components. For example, one component has ... <ul class="items"> ... and another component has it too. But that ul's has different meaning in these two components. On the other hand, i want to "inherit" some styles for one component from another. For example: Let, we have one component, called "post" <div class="post"> <!-- post's stuff --> <ul class="items"> ... </ul> </div And another component, called "new-post": <div class="new-post"> <!-- post's stuff --> <ul class="items"> ... </ul> <!-- new-post's stuff --> <div class="tools">...</div> </div Post and new-post have something similar ("post's stuff") and i want to make CSS rules to handle both "post" and "new-post" New post has "subcomponents", for example - editing tools, that has also: <ul class="items"> This is where CSS rules starting to interfer - some rules, targeted for ul.items (in post and new-post) applies subcomponent of new-post, called "tools" On the one hand - i want to inherit some styles On the other hand, i want to get better incapsulation What are the best practices, to avoid such kind of problems ?

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  • Identify server that made call to web service

    - by sleepybobos
    I am working within an intranet environment. We have both a production and development sharepoint server (WSS 3). We have a 3rd party workflow product which runs on top of sharepoint. It is installed on both the production and development sharepoint servers. The workflow product can call web services I have written which are hosted on our web server. How would I have the web services determine which sharepoint server made the call to the web service, be it the production or development server? I would then use this information to server specific information from web.config or database etc. Currently the site hosting web services is setup to allow anonymous access so code such as System.Web.HttpContext.Current.User.Identity.Name; returns and empty string. If windows authenticaion is used it returns the identity of the currently logged in user, which is no user in identifying the server the call was made from. I need a push in the right direction to address what I believe is probably a common scenario please.

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  • Immutable classes in C++

    - by ereOn
    Hi, In one of my projects, I have some classes that represent entities that cannot change once created, aka. immutable classes. Example : A class RSAKey that represent a RSA key which only has const methods. There is no point changing the existing instance: if you need another one, you just create one. My objects sometimes are heavy and I enforced the use of smart pointers to avoid copy. So far, I have the following pattern for my classes: class RSAKey : public boost::noncopyable, public boost::enable_shared_from_this<RSAKey> { public: /** * \brief Some factory. * \param member A member value. * \return An instance. */ static boost::shared_ptr<const RSAKey> createFromMember(int member); /** * \brief Get a member. * \return The member. */ int getMember() const; private: /** * \brief Constructor. * \param member A member. */ RSAKey(int member); /** * \brief Member. */ const int m_member; }; So you can only get a pointer (well, a smart pointer) to a const RSAKey. To me, it makes sense, because having a non-const reference to the instance is useless (it only has const methods). Do you guys see any issue regarding this pattern ? Are immutable classes something common in C++ or did I just created a monster ? Thank you for your advices !

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  • How to upload files to server using JSP/Servlet?

    - by Thang Pham
    How can I upload files to server using JSP/Servlet? I tried this: <form action="upload" method="post"> <input type="text" name="description" /> <input type="file" name="file" /> <input type="submit" /> </form> However, I only get the file name, not the file content. When I add enctype="multipart/form-data" to the <form>, then request.getParameter() returns null. During research I stumbled upon Apache Common FileUpload. I tried this: FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List items = upload.parseRequest(request); // This line is where it died. Unfortunately, the servlet threw an exception without a clear message and cause. Here is the stacktrace: SEVERE: Servlet.service() for servlet UploadServlet threw exception javax.servlet.ServletException: Servlet execution threw an exception at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:313) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:637)

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  • How do I use Perl's LWP to log in to a web application?

    - by maxjackie
    I would like to write a script to login to a web application and then move to other parts of the application: use HTTP::Request::Common qw(POST); use LWP::UserAgent; use Data::Dumper; $ua = LWP::UserAgent->new(keep_alive=>1); my $req = POST "http://example.com:5002/index.php", [ user_name => 'username', user_password => "password", module => 'Users', action => 'Authenticate', return_module => 'Users', return_action => 'Login', ]; my $res = $ua->request($req); print Dumper(\$res); if ( $res->is_success ) { print $res->as_string; } When I try this code I am not able to login to the application. The HTTP status code returned is 302 that is found, but with no data. If I post username/password with all required things then it should return the home page of the application and keep the connection live to move other parts of the application.

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  • Give a reference to a python instance attribute at class definition

    - by Guenther Jehle
    I have a class with attributes which have a reference to another attribute of this class. See class Device, value1 and value2 holding a reference to interface: class Interface(object): def __init__(self): self.port=None class Value(object): def __init__(self, interface, name): self.interface=interface self.name=name def get(self): return "Getting Value \"%s\" with interface \"%s\""%(self.name, self.interface.port) class Device(object): interface=Interface() value1=Value(interface, name="value1") value2=Value(interface, name="value2") def __init__(self, port): self.interface.port=port if __name__=="__main__": d1=Device("Foo") print d1.value1.get() # >>> Getting Value "value1" with interface "Foo" d2=Device("Bar") print d2.value1.get() # >>> Getting Value "value1" with interface "Bar" print d1.value1.get() # >>> Getting Value "value1" with interface "Bar" The last print is wrong, cause d1 should have the interface "Foo". I know whats going wrong: The line interface=Interface() line is executed, when the class definition is parsed (once). So every Device class has the same instance of interface. I could change the Device class to: class Device(object): interface=Interface() value1=Value(interface, name="value1") value2=Value(interface, name="value2") def __init__(self, port): self.interface=Interface() self.interface.port=port So this is also not working: The values still have the reference to the original interface instance and the self.interface is just another instance... The output now is: >>> Getting Value "value1" with interface "None" >>> Getting Value "value1" with interface "None" >>> Getting Value "value1" with interface "None" So how could I solve this the pythonic way? I could setup a function in the Device class to look for attributes with type Value and reassign them the new interface. Isn't this a common problem with a typical solution for it? Thanks!

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  • How do you verify that 2 copies of a VB 6 executable came from the same code base?

    - by Tim Visher
    I have a program under version control that has gone through multiple releases. A situation came up today where someone had somehow managed to point to an old copy of the program and thus was encountering bugs that have since been fixed. I'd like to go back and just delete all the old copies of the program (keeping them around is a company policy that dates from before version control was common and should no longer be necessary) but I need a way of verifying that I can generate the exact same executable that is better than saying "The old one came out of this commit so this one should be the same." My initial thought was to simply MD5 hash the executable, store the hash file in source control, and be done with it but I've come up against a problem which I can't even parse. It seems that every time the executable is generated (method: Open Project. File Make X.exe) it hashes differently. I've noticed that Visual Basic messes with files every time the project is opened in seemingly random ways but I didn't think that would make it into the executable, nor do I have any evidence that that is indeed what's happening. To try to guard against that I tried generating the executable multiple times within the same IDE session and checking the hashes but they continued to be different every time. So that's: Generate Executable Generate MD5 Checksum: md5sum X.exe > X.md5 Verify MD5 for current executable: md5sum -c X.md5 Generate New Executable Verify MD5 for new executable: md5sum -c X.md5 Fail verification because computed checksum doesn't match. I'm not understanding something about either MD5 or the way VB 6 is generating the executable but I'm also not married to the idea of using MD5. If there is a better way to verify that two executables are indeed the same then I'm all ears. Thanks in advance for your help!

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  • Where is the "ListViewItemPlaceholderBackgroundThemeBrush" located?

    - by Dimi Toulakis
    I have a problem understanding one style definition in Windows 8 metro apps. When you create a metro style application with VS, there is also a folder named Common created. Inside this folder there is file called StandardStyles.xaml Now the following snippet is from this file: <!-- Grid-appropriate 250 pixel square item template as seen in the GroupedItemsPage and ItemsPage --> <DataTemplate x:Key="Standard250x250ItemTemplate"> <Grid HorizontalAlignment="Left" Width="250" Height="250"> <Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}"> <Image Source="{Binding Image}" Stretch="UniformToFill"/> </Border> <StackPanel VerticalAlignment="Bottom" Background="{StaticResource ListViewItemOverlayBackgroundThemeBrush}"> <TextBlock Text="{Binding Title}" Foreground="{StaticResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextStyle}" Height="60" Margin="15,0,15,0"/> <TextBlock Text="{Binding Subtitle}" Foreground="{StaticResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/> </StackPanel> </Grid> </DataTemplate> What I do not understand here is the static resource definition, e.g. for the Border Background="{StaticResource ListViewItemPlaceholderBackgroundThemeBrush}" It is not about how you work with templates and binding and resources. Where is this ListViewItemPlaceholderBackgroundThemeBrush located? Many thanks for your help. Dimi

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  • PHP check http referer for form submitted by AJAX, secure?

    - by Michael Mao
    Hi all: This is the first time I am working for a front-end project that requires server-side authentication for AJAX requests. I've encountered problems like I cannot make a call of session_start as the beginning line of the "destination page", cuz that would get me a PHP Warning : Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\xampp\htdocs\comic\app\ajaxInsert Book.php:1) in C:\xampp\htdocs\comic\app\common.php on line 10 I reckon this means I have to figure out a way other than checking PHP session variables to authenticate the "caller" of this PHP script, and this is my approach : I have a "protected" PHP page, which must be used as the "container" of my javascript that posts the form through jQuery $.ajax(); method In my "receiver" PHP script, what I've got is: <?php define(BOOKS_TABLE, "books"); define(APPROOT, "/comic/"); define(CORRECT_REFERER, "/protected/staff/addBook.php"); function isRefererCorrect() { // the following line evaluates the relative path for the referer uri, // Say, $_SERVER['HTTP_REFERER'] returns "http://localhost/comic/protected/staff/addBook.php" // Then the part we concern is just this "/protected/staff/addBook.php" $referer = substr($_SERVER['HTTP_REFERER'], 6 + strrpos($_SERVER['HTTP_REFERER'], APPROOT)); return (strnatcmp(CORRECT_REFERER, $referer) == 0) ? true : false; } //http://stackoverflow.com/questions/267546/correct-http-header-for-json-file header('Content-type: application/json charset=UTF-8'); header('Cache-Control: no-cache, must-revalidate'); echo json_encode(array ( "feedback"=>"ok", "info"=>isRefererCorrect() )); ?> My code works, but I wonder is there any security risks in this approach? Can someone manipulate the post request so that he can pretend that the caller javascript is from the "protected" page? Many thanks to any hints or suggestions.

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  • How to detect that the internet connection has got disconnected through a java desktop application?

    - by Yatendra Goel
    I am developing a Java Desktop Application that access internet. It is a multi-threaded application, each thread do the same work (means each thread is an instance of same Thread class). Now, as all the threads need internet connection to be active, there should be some mechanism that detects whether an internet connection is active or not. Q1. How to detect whether the internet connection is active or not? Q2. Where to implement this internet-status-check-mechanism code? Should I start a separate thread for checking internet status regularly and notifies all the threads when the status changes from one state to another? Or should I let each thread check for the internet-status itself? Q3. This issue should be a very common issue as every application accessing an internet should deal with this problem. So how other developers usually deal with this problem? Q4. If you could give me a reference to a good demo application that addresses this issue then it would greatly help me.

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  • Including partial views when applying the Mode-View-ViewModel design pattern

    - by Filip Ekberg
    Consider that I have an application that just handles Messages and Users I want my Window to have a common Menu and an area where the current View is displayed. I can only work with either Messages or Users so I cannot work simultaniously with both Views. Therefore I have the following Controls MessageView.xaml UserView.xaml Just to make it a bit easier, both the Message Model and the User Model looks like this: Name Description Now, I have the following three ViewModels: MainWindowViewModel UsersViewModel MessagesViewModel The UsersViewModel and the MessagesViewModel both just fetch an ObserverableCollection<T> of its regarding Model which is bound in the corresponding View like this: <DataGrid ItemSource="{Binding ModelCollection}" /> The MainWindowViewModel hooks up two different Commands that have implemented ICommand that looks something like the following: public class ShowMessagesCommand : ICommand { private ViewModelBase ViewModel { get; set; } public ShowMessagesCommand (ViewModelBase viewModel) { ViewModel = viewModel; } public void Execute(object parameter) { var viewModel = new ProductsViewModel(); ViewModel.PartialViewModel = new MessageView { DataContext = viewModel }; } public bool CanExecute(object parameter) { return true; } public event EventHandler CanExecuteChanged; } And there is another one a like it that will show Users. Now this introduced ViewModelBase which only holds the following: public UIElement PartialViewModel { get { return (UIElement)GetValue(PartialViewModelProperty); } set { SetValue(PartialViewModelProperty, value); } } public static readonly DependencyProperty PartialViewModelProperty = DependencyProperty.Register("PartialViewModel", typeof(UIElement), typeof(ViewModelBase), new UIPropertyMetadata(null)); This dependency property is used in the MainWindow.xaml to display the User Control dynamicly like this: <UserControl Content="{Binding PartialViewModel}" /> There are also two buttons on this Window that fires the Commands: ShowMessagesCommand ShowUsersCommand And when these are fired, the UserControl changes because PartialViewModel is a dependency property. I want to know if this is bad practice? Should I not inject the User Control like this? Is there another "better" alternative that corresponds better with the design pattern? Or is this a nice way of including partial views?

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  • Git merge 2 new file with removed content and added content

    - by Loïc Faure-Lacroix
    So we are working in with 2 different repositories and both designers modified the same file. the problem is quite simple but I have no ideas how to solve it yet. Both files are marked as new since they have almost nothing in common except that file. When I try to merge from branch A to B it mark the parts added in A deleted in B and on the other side, what was added in B appears deleted in A. git seems to try to outsmart me when I know that I need almost every changes and nothing should be mark as deletion. I have 2 other branch that should merge without problem after these 2 branch. I can't merge them yet since there are some recent changes that may not merge really well too. I have to merge A and B = E then C and D = F and then hopefully E and F So the big question here is how can I do a completely manual merge that will mark every changes as conflict anything deleted anything added should be marked as conflict that I can solve by myself using an editor. Git is trying to outsmart me and fail terribly at it.

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  • Tool to detect use/abuse of String.Concat (where StringBuilder should be used)

    - by Mark Rushakoff
    It's common knowledge that you shouldn't use a StringBuilder in place of a small number of concatenations: string s = "Hello"; if (greetingWorld) { s += " World"; } s += "!"; However, in loops of a significant size, StringBuilder is the obvious choice: string s = ""; foreach (var i in Enumerable.Range(1,5000)) { s += i.ToString(); } Console.WriteLine(s); Is there a tool that I can run on either raw C# source or a compiled assembly to identify where in the source code that String.Concat is being called? (If you're not familiar, s += "foo" is mapped to String.Concat in the IL output.) Obviously, I can't realistically search through an entire project and evaluate every += to identify whether the lvalue is a string. Ideally, it would only point out calls inside a for/foreach loop, but I would even put up with all the false positives of noting every String.Concat. Also, I'm aware that there are some refactoring tools that will automatically refactor my code to use StringBuilder, but I am only interested in identifying the Concat usage at this point. I routinely run Gendarme and FxCop on my code, and neither of those tools identify what I've described.

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  • Why is debugging better in an IDE?

    - by Bill Karwin
    I've been a software developer for over twenty years, programming in C, Perl, SQL, Java, PHP, JavaScript, and recently Python. I've never had a problem I could not debug using some careful thought, and well-placed debugging print statements. I respect that many people say that my techniques are primitive, and using a real debugger in an IDE is much better. Yet from my observation, IDE users don't appear to debug faster or more successfully than I can, using my stone knives and bear skins. I'm sincerely open to learning the right tools, I've just never been shown a compelling advantage to using visual debuggers. Moreover, I have never read a tutorial or book that showed how to debug effectively using an IDE, beyond the basics of how to set breakpoints and display the contents of variables. What am I missing? What makes IDE debugging tools so much more effective than thoughtful use of diagnostic print statements? Can you suggest resources (tutorials, books, screencasts) that show the finer techniques of IDE debugging? Sweet answers! Thanks much to everyone for taking the time. Very illuminating. I voted up many, and voted none down. Some notable points: Debuggers can help me do ad hoc inspection or alteration of variables, code, or any other aspect of the runtime environment, whereas manual debugging requires me to stop, edit, and re-execute the application (possibly requiring recompilation). Debuggers can attach to a running process or use a crash dump, whereas with manual debugging, "steps to reproduce" a defect are necessary. Debuggers can display complex data structures, multi-threaded environments, or full runtime stacks easily and in a more readable manner. Debuggers offer many ways to reduce the time and repetitive work to do almost any debugging tasks. Visual debuggers and console debuggers are both useful, and have many features in common. A visual debugger integrated into an IDE also gives you convenient access to smart editing and all the other features of the IDE, in a single integrated development environment (hence the name).

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  • Returning HTML in the JS portion of a respond_to block throws errors in IE

    - by Horace Loeb
    Here's a common pattern in my controller actions: respond_to do |format| format.html {} format.js { render :layout => false } end I.e., if the request is non-AJAX, I'll send the HTML content in a layout on a brand new page. If the request is AJAX, I'll send down the same content, but without a layout (so that it can be inserted into the existing page or put into a lightbox or whatever). So I'm always returning HTML in the format.js portion, yet Rails sets the Content-Type response header to text/javascript. This causes IE to throw this fun little error message: Of course I could set the content-type of the response every time I did this (or use an after_filter or whatever), but it seems like I'm trying to do something relatively standard and I don't want to add additional boilerplate code. How do I fix this problem? Alternatively, if the only way to fix the problem is to change the content-type of the response, what's the best way to achieve the behavior I want (i.e., sending down content with layout for non-AJAX and the same content without a layout for AJAX) without having to deal with these errors? Edit: This blog post has some more info

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  • Hibernate 3.5.0 causes extreme performance problems

    - by user303396
    I've recently updated from hibernate 3.3.1.GA to hibernate 3.5.0 and I'm having a lot of performance issues. As a test, I added around 8000 entities to my DB (which in turn cause other entities to be saved). These entities are saved in batches of 20 so that the transactions aren't too large for performance reasons. When using hibernate 3.3.1.GA all 8000 entities get saved in about 3 minutes. When using hibernate 3.5.0 it starts out slower than with hibernate 3.3.1. But it gets slower and slower. At around 4,000 entities, it sometimes takes 5 minutes just to save a batch of 20. If I then go to a mysql console and manually type in an insert statement from the mysql general query log, half of them run perfect in 0.00 seconds. And half of them take a long time (maybe 40 seconds) or timeout with "ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction" from MySQL. Has something changed in hibernate's transaction management in version 3.5.0 that I should be aware of? The ONLY thing I changed to experience these unusable performance issues is replace the following hibernate 3.3.1.GA jar files: com.springsource.org.hibernate-3.3.1.GA.jar, com.springsource.org.hibernate.annotations-3.4.0.GA.jar, com.springsource.org.hibernate.annotations.common-3.3.0.ga.jar, com.springsource.javassist-3.3.0.ga.jar with the new hibernate 3.5.0 release hibernate3.jar and javassist-3.9.0.GA.jar. Thanks.

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  • Single log file for multiple webapps

    - by Ashish Aggarwal
    In my tomcat there are multiple webapps deployed and they communicate with each other. Currently they all have their own log file. But when there is some issue comes from call I have to 1st check with the app to whom I made a call and check log file of respective apps involved in the call. So I want that, as all apps is deployed in same tomcat and sharing a common log4j, if a call made to any app then all logs should be in a single log file and no matters how my webapps are involved all error comes from any webapp during the call should be in a single log file. I have no idea how can I achieve this. So any help is appreciable. Edited: I think my question is not cleared so updated with use case: I have three webapps A, B, C having logs files as A.log, B.log and C.log. I made two calls. 1st one to A (that internally calls C) and 2nd to B (that internally calls C). Now logging of first call must be in A.log (with the logs of every step performed inside the webapp c) and second call must be in B.log (with the logs of every step performed inside the webapp c).

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  • Visual Studio and .NET programming

    - by Vit
    Hi, I just want to ask wheather I am right or not about .NET. So, .NET is new framework that enables you to easily implement new and old windows functions. It is similiar to java in the way that its also compiled into "bytecode", but its name is Common Language Infrastructure, or CLI. This language is interpreted by .NET Framework, so code generated by programming using .NET cannot be executed directly by CPU. Now, few languages can be compiled to CLI. First, it was Microsoft-developed C#, than J#, C++ others. I suspect that this is in general right, at least I hope I understand it right. But, what I am still missing is, can you write to machine code compiled code in C#? And, if using Visual Studio 2005, when I select Win32 project, it is compiled into machine code, so only thing you need to run this apps are windows dynamic-link libraries, since static libraries code is implemented into app durink linking phase. And those dynamic-link libraries are implemented in every windows installation, or provided by DirectX installations. But when I select CLR in Visual Studio 2005, than app is compiled into CLI code, and it first executes .NET framework, and than .NET framework executes that program, since its not in machine code. So, I am right? I ask becouse you can read these infos on the internet, but I have noone to tell me wheather I understand it right or not. Thanks.

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  • Best practice to test a web application, regarding domain name and integration with external service

    - by ycseattle
    I have run into these problems several times and was never able to find a comfortable solution. Let's say my website has the domain name MyDomain.com. When I run the tests on the test machine (a continuous integration server), I will modify the HOSTS file on this machine so the MyDomain.com is mapped to this local machine instead of the real production server. This doesn't work very well for many situations. For example, my application will create subdomain names user1.MyDomain.com dynamically but this is difficult to keep the testing flexible. Another problem is my web application will interact with Amazon S3, and sometimes other service like Amazon Simple Message Queue. I am only comfortable to include these interaction in my tests but I am never happy with my solution for mixing testing and production on Amazon services. Could somebody offer some tips on these issues? I would like to make my testing framework clean and flexible. I am sure this is a common question for all web applications and there must be a mature way to deal with these. Thanks!

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  • Is there a way to increase the efficiency of shared_ptr by storing the reference count inside the co

    - by BillyONeal
    Hello everyone :) This is becoming a common pattern in my code, for when I need to manage an object that needs to be noncopyable because either A. it is "heavy" or B. it is an operating system resource, such as a critical section: class Resource; class Implementation : public boost::noncopyable { friend class Resource; HANDLE someData; Implementation(HANDLE input) : someData(input) {}; void SomeMethodThatActsOnHandle() { //Do stuff }; public: ~Implementation() { FreeHandle(someData) }; }; class Resource { boost::shared_ptr<Implementation> impl; public: Resource(int argA) explicit { HANDLE handle = SomeLegacyCApiThatMakesSomething(argA); if (handle == INVALID_HANDLE_VALUE) throw SomeTypeOfException(); impl.reset(new Implementation(handle)); }; void SomeMethodThatActsOnTheResource() { impl->SomeMethodThatActsOnTheHandle(); }; }; This way, shared_ptr takes care of the reference counting headaches, allowing Resource to be copyable, even though the underlying handle should only be closed once all references to it are destroyed. However, it seems like we could save the overhead of allocating shared_ptr's reference counts and such separately if we could move that data inside Implementation somehow, like boost's intrusive containers do. If this is making the premature optimization hackles nag some people, I actually agree that I don't need this for my current project. But I'm curious if it is possible.

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  • implementing cryptographic algorithms, specifically the key expansion part

    - by masseyc
    Hey, recently I picked up a copy of Applied Cryptography by Bruce Schneier and it's been a good read. I now understand how several algorithms outlined in the book work, and I'd like to start implementing a few of them in C. One thing that many of the algorithms have in common is dividing an x-bit key, into several smaller y-bit keys. For example, blowfish's key, X, is 64-bits, but you are required to break it up into two 32-bit halves; Xl and Xr. This is where I'm getting stuck. I'm fairly decent with C, but I'm not the strongest when it comes to bitwise operators and the like. After some help on IRC, I managed to come up with these two macros: #define splitup(a, b, c) {b = a >> 32; c = a & 0xffffffff; } #define combine(a, b, c) {a = (c << 32) | a;} Where a is 64 bits and b and c are 32 bits. However, the compiler warns me about the fact that I'm shifting a 32 bit variable by 32 bits. My questions are these: what's bad about shifting a 32-bit variable 32 bits? I'm guessing it's undefined, but these macros do seem to be working. Also, would you suggest I go about this another way? As I said, I'm fairly familiar with C, but bitwise operators and the like still give me a headache.

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  • [Database] How to model this one-to-one relation?

    - by pbean
    I have several entities which respresent different types of users who need to be able to log in to a particular system. Additionally, they have different types of information associated with them. For example: a "general user", which has an e-mail address and "admin user", which has a workstation number (note that this a hypothetical case). Both entities also share common properties like first name, surname, address and telephone number. Finally, they naturally need to have a (unique) user name and a password to log in. In the application, the user just has to fill in his user name and password, and the functionality of the application changes slightly according to the type of the user. You can imagine that the username needs to be unique for this work. How should I model this effectively? I can't just create two tables, because then I can't force a unique constaint on the user name. I also can't put them all in just one table, because they have different types of specific information associated to them. I think I might need 3 seperate tables, one for "users" (with user name and password), one for the "general users" and another one for the "admin users", but how would the relations between these work? Or is there another solution? (By the way, the target DBMS is MySQL, so I don't think generalization is supported in the database system itself).

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  • Export GridView to Excel (not working)

    - by Chiramisu
    I've spent the last two days trying to get some bloody data to export to Excel. After much research I determined that the best and most common way is using HttpResponse headers as shown in my code below. After stepping through countless times in debug mode, I have confirmed that the data is in fact there and both filtered and sorted the way I want it. However, it does not download as an Excel file, or do anything at all for that matter. I suspect this may have something to do with my UpdatePanel or perhaps the ImageButton not posting back properly, but I'm not sure. What am I doing wrong? Please help me to debug this issue. I will be eternally grateful. Thank you. :) Markup <asp:UpdatePanel ID="statusUpdatePanel" runat="server" UpdateMode="Conditional"> <Triggers> <asp:AsyncPostBackTrigger ControlID="btnExportXLS" EventName="Click" /> </Triggers> <ContentTemplate> <asp:GridView ID="GridView1" runat="server" AllowPaging="True" PageSize="10" AllowSorting="True" DataSourceID="GridView1SDS" DataKeyNames="ID"> </asp:GridView> <span><asp:ImageButton ID="btnExportXLS" runat="server" /></span> </ContentTemplate> </asp:UpdatePanel> Codebehind Protected Sub ExportToExcel() Handles btnExportXLS.Click Dim dt As New DataTable() Dim da As New SqlDataAdapter(SelectCommand, ConnectionString) da.Fill(dt) Dim gv As New GridView() gv.DataSource = dt gv.DataBind() Dim frm As HtmlForm = New HtmlForm() frm.Controls.Add(gv) Dim sw As New IO.StringWriter() Dim hw As New System.Web.UI.HtmlTextWriter(sw) Response.ContentType = "application/vnd.ms-excel" Response.AddHeader("content-disposition", "attachment;filename=Report.xls") Response.Charset = String.Empty gv.RenderControl(hw) Response.Write(sw.ToString()) Response.End() End Sub

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  • Web Hosting: Any web host that supports files more than 50,000 in number?

    - by Devner
    Hi all, For my PHP & mySQL based application, I am trying to buy website hosting from a host who does not have a limit on the number of files I carry in my hosting account. Almost all the websites have a common limit of 50,000 files (some websites call it 50,000 nodes). The rest(to the extent of my search) are not even close. I have gone through the various websites, Googled lot of information, have spoken with the customer service of the hosting companies and they said that they have a limit of 50,000 files and that's why they call it the LIMIT. Now I have my application, which is a kind of social networking website, where people can upload various files of varying file size. So say if 50,000 users were to join the website and upload 1 file each, the limit of 50,000 will be reached very easily and my 50,001 customer will start facing file upload problems (& so will my account). So I would like to know if there's any website hosting services that do NOT levy such restrictions. In summary, I need the following options: No maximum file limit (more than 50,000 files in account). No maximum file upload limit in server setting (10MB, 12MB, 15MB, 20MB, etc.). Ability to upload files of various types (zip, flv, jg, png, etc.). Ability to stream Audio and Video (live audio & video not necessary). Access to .htaccess Access to php.ini, my.cnf or my.ini (this would be a plus) Supports SSL. Provides dedicated hosting(& IP) as well. Monthly payments without contracts are a plus. If you know of any such website hosting services, please post a reply ( a link to the same will be appreciated ). Thank you.

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  • Achieving Thread-Safety

    - by Smasher
    Question How can I make sure my application is thread-safe? Are their any common practices, testing methods, things to avoid, things to look for? Background I'm currently developing a server application that performs a number of background tasks in different threads and communicates with clients using Indy (using another bunch of automatically generated threads for the communication). Since the application should be highly availabe, a program crash is a very bad thing and I want to make sure that the application is thread-safe. No matter what, from time to time I discover a piece of code that throws an exception that never occured before and in most cases I realize that it is some kind of synchronization bug, where I forgot to synchronize my objects properly. Hence my question concerning best practices, testing of thread-safety and things like that. mghie: Thanks for the answer! I should perhaps be a little bit more precise. Just to be clear, I know about the principles of multithreading, I use synchronization (monitors) throughout my program and I know how to differentiate threading problems from other implementation problems. But nevertheless, I keep forgetting to add proper synchronization from time to time. Just to give an example, I used the RTL sort function in my code. Looked something like FKeyList.Sort (CompareKeysFunc); Turns out, that I had to synchronize FKeyList while sorting. It just don't came to my mind when initially writing that simple line of code. It's these thins I wanna talk about. What are the places where one easily forgets to add synchronization code? How do YOU make sure that you added sync code in all important places?

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