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  • Implementation review for a MVC.NET app with custom membership

    - by mrjoltcola
    I'd like to hear if anyone sees any problems with how I implemented the security in this Oracle based MVC.NET app, either security issues, concurrency issues or scalability issues. First, I implemented a CustomOracleMembershipProvider to handle the database interface to the membership store. I implemented a custom Principal named User which implements IPrincipal, and it has a hashtable of Roles. I also created a separate class named AuthCache which has a simple cache for User objects. Its purpose is simple to avoid return trips to the database, while decoupling the caching from either the web layer or the data layer. (So I can share the cache between MVC.NET, WCF, etc.) The MVC.NET stock MembershipService uses the CustomOracleMembershipProvider (configured in web.config), and both MembershipService and FormsService share access to the singleton AuthCache. My AccountController.LogOn() method: 1) Validates the user via the MembershipService.Validate() method, also loads the roles into the User.Roles container and then caches the User in AuthCache. 2) Signs the user into the Web context via FormsService.SignIn() which accesses the AuthCache (not the database) to get the User, sets HttpContext.Current.User to the cached User Principal. In global.asax.cs, Application_AuthenticateRequest() is implemented. It decrypts the FormsAuthenticationTicket, accesses the AuthCache by the ticket.Name (Username) and sets the Principal by setting Context.User = user from the AuthCache. So in short, all these classes share the AuthCache, and I have, for thread synchronization, a lock() in the cache store method. No lock in the read method. The custom membership provider doesn't know about the cache, the MembershipService doesn't know about any HttpContext (so could be used outside of a web app), and the FormsService doesn't use any custom methods besides accessing the AuthCache to set the Context.User for the initial login, so it isn't dependent on a specific membership provider. The main thing I see now is that the AuthCache will be sharing a User object if a user logs in from multiple sessions. So I may have to change the key from just UserId to something else (maybe using something in the FormsAuthenticationTicket for the key?).

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  • Rails - difference between config.cache_store and config.action_controller.cache_store?

    - by gsmendoza
    If I set this in my environment config.action_controller.cache_store = :mem_cache_store ActionController::Base.cache_store will use a memcached store but Rails.cache will use a memory store instead: $ ./script/console >> ActionController::Base.cache_store => #<ActiveSupport::Cache::MemCacheStore:0xb6eb4bbc @data=<MemCache: 1 servers, ns: nil, ro: false>> >> Rails.cache => #<ActiveSupport::Cache::MemoryStore:0xb78b5e54 @data={}> In my app, I use Rails.cache.fetch(key){ object } to cache objects inside my helpers. All this time, I assumed that Rails.cache uses the memcached store so I'm surprised that it uses memory store. If I change the cache_store setting in my environment to config.cache_store = :mem_cache_store both ActionController::Base.cache_store and Rails.cache will now use the same memory store, which is what I expect: $ ./script/console >> ActionController::Base.cache_store => #<ActiveSupport::Cache::MemCacheStore:0xb7b8e928 @data=<MemCache: 1 servers, ns: nil, ro: false>, @middleware=#<Class:0xb7b73d44>, @thread_local_key=:active_support_cache_mem_cache_store_local_cache> >> Rails.cache => #<ActiveSupport::Cache::MemCacheStore:0xb7b8e928 @data=<MemCache: 1 servers, ns: nil, ro: false>, @middleware=#<Class:0xb7b73d44>, @thread_local_key=:active_support_cache_mem_cache_store_local_cache> However, when I run the app, I get a "marshal dump" error in the line where I call Rails.cache.fetch(key){ object } no marshal_dump is defined for class Proc Extracted source (around line #1): 1: Rails.cache.fetch(fragment_cache_key(...), :expires_in => 15.minutes) { ... } vendor/gems/memcache-client-1.8.1/lib/memcache.rb:359:in 'dump' vendor/gems/memcache-client-1.8.1/lib/memcache.rb:359:in 'set_without_newrelic_trace' What gives? Is Rails.cache meant to be a memory store? Should I call controller.cache_store.fetch in the places where I call Rails.cache.fetch?

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  • System.Threading.Timer keep reference to it.

    - by Daniel Bryars
    According to [http://msdn.microsoft.com/en-us/library/system.threading.timer.aspx][1] you need to keep a reference to a System.Threading.Timer to prevent it from being disposed. I've got a method like this: private void Delay(Action action, Int32 ms) { if (ms <= 0) { action(); } System.Threading.Timer timer = new System.Threading.Timer( (o) => action(), null, ms, System.Threading.Timeout.Infinite); } Which I don't think keeps a reference to the timer, I've not seen any problems so far, but that's probably because the delay periods used have been pretty small. Is the code above wrong? And if it is, how to I keep a reference to the Timer? I'm thinking something like this might work: class timerstate { internal volatile System.Threading.Timer Timer; }; private void Delay2(Action action, Int32 ms) { if (ms <= 0) { action(); } timerstate state = new timerstate(); lock (state) { state.Timer = new System.Threading.Timer( (o) => { lock (o) { action(); ((timerstate)o).Timer.Dispose(); } }, state, ms, System.Threading.Timeout.Infinite); } The locking business is so I can get the timer into the timerstate class before the delegate gets invoked. It all looks a little clunky to me. Perhaps I should regard the chance of the timer firing before it's finished constructing and assigned to the property in the timerstace instance as negligible and leave the locking out.

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  • Passenger: "Missing these required gems redgreen"

    - by Michael Stum
    Hello, total ruby newbie, trying to setup a Rails/MongoDB application on Mac OS X Snow leopard. Installed Ruby 1.9.1 and RubyGems 1.3.7, which ruby and which gem point to the same directory. I'm using the Snow Leopard built-in apache and Passenger 2.2.11. I'm using the rails template from the mongo-site which seems to work okay overall. The exact error that passenger gives me is: /Users/User/Sites/feuerapp/vendor/rails/railties/lib/rails/gem_dependency.rb:119:Warning: Gem::Dependency#version_requirements is deprecated and will be removed on or after August 2010. Use #requirement **Notice: C extension not loaded. This is required for optimum MongoDB Ruby driver performance. You can install the extension as follows: gem install bson_ext If you continue to receive this message after installing, make sure that the bson_ext gem is in your load path and that the bson_ext and mongo gems are of the same version. Missing these required gems: redgreen You're running: ruby 1.9.1.376 at /usr/local/bin/ruby rubygems 1.3.7 at /Users/User/.gem/ruby/1.9.1, /usr/local/lib/ruby/gems/1.9.1 Runrake gems:installto install the missing gems. The weird thing is that redgreen is installed and looks fine to me: Dahlia:feuerapp User$ ls -la vendor/gems/ total 0 drwxr-xr-x 7 User staff 238 May 18 22:56 . drwxr-xr-x 5 User staff 170 May 18 23:00 .. drwxr-xr-x 11 User staff 374 May 18 22:56 factory_girl-1.2.4 drwxr-xr-x 11 User staff 374 May 18 22:56 mocha-0.9.8 drwxr-xr-x 7 User staff 238 May 18 22:56 mongo_mapper-0.7.6 drwxr-xr-x 7 User staff 238 May 18 22:56 redgreen-1.2.2 drwxr-xr-x 11 User staff 374 May 18 22:56 shoulda-2.10.3 Commenting out this line in environment.rb "solves" the issue, but that's not really want I want: config.gem 'redgreen' I don't understand anything of gems yet, but from my limited understanding, redgreen should be there and found?

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  • C# Win Forms Access Violation Exception

    - by Goober
    I keep getting the following error: System.AccessViolationException was unhandled Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Source="FEDivaNET" StackTrace: at Diva.Handles.FEDivaObject.dropReference() at Diva.Handles.FEDivaObject.!FEDivaObject() at Diva.Handles.FEDivaObject.Dispose(Boolean ) at Diva.Handles.FEDivaObject.Finalize() InnerException: Any ideas what the issue could be? - I'm using a library that is written in C++ and isn't designed for multithreading, yet I'm hammering it about 3000 times with requests every 6 minutes. CODE delegate void SetTextCallback(string mxID, string text); public void UpdateLog(string mxID, string text) { //lock (thisLock) //{ if (listBoxProcessLog.InvokeRequired) { SetTextCallback d = new SetTextCallback(UpdateLog); this.BeginInvoke(d, new object[] { mxID, text }); } else { //Get a reference to the datatable assigned as the datasource. //DataTable logDT = (DataTable)listBoxProcessLog.DataSource; //logDT.Rows.Add(DateTime.Now + " - " + mxID + ": " + text); if (text.Contains("COMPLETE") || (text.Contains("FAILED"))) { if (progressBar1.Value <= progressBar1.MaxValue) { progressBar1.Value += 1; } } } //} } Baring in mind that even when the Lock and the DataTable weren't commented out, the error still occurred!

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  • .NET Working with Locking and Threads

    - by aherrick
    Work on this small test application to learn threading/locking. I have the following code, I would think that the line should only write to console once. However it doesn't seem to be working as expected. Any thoughts on why? What I'm trying to do is add this Lot object to a List, then if any other threads try and hit that list, it would block. Am i completely misusing lock here? class Program { static void Main(string[] args) { int threadCount = 10; //spin up x number of test threads Thread[] threads = new Thread[threadCount]; Work w = new Work(); for (int i = 0; i < threadCount; i++) { threads[i] = new Thread(new ThreadStart(w.DoWork)); } for (int i = 0; i < threadCount; i++) { threads[i].Start(); } // don't let the console close Console.ReadLine(); } } public class Work { List<Lot> lots = new List<Lot>(); private static readonly object thisLock = new object(); public void DoWork() { Lot lot = new Lot() { LotID = 1, LotNumber = "100" }; LockLot(lot); } private void LockLot(Lot lot) { // i would think that "Lot has been added" should only print once? lock (thisLock) { if(!lots.Contains(lot)) { lots.Add(lot); Console.WriteLine("Lot has been added"); } } } }

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  • Lost Update Anomaly in Sql Server Update Command

    - by Javed
    Hi, I am very much confused. I have a transaction in ReadCommitted Isolation level. Among other things I am also updating a counter value in it, something similar to below: Update tblCount set counter = counter + 1 My application is a desktop application and this transaction happens to occur quite frequently and concurrently. We recently noticed an error that sometimes the counter value doesn't get updated or is missed. We also insert one record on each counter update so we are sure that records have been inserted but somehow counter fails to update. This happens once in 2000 simulaneous transactions. I seriously doubt it is a lost update anomaly I am facing but if you look at the command above, it's just update the counter from its own value: if I have started a transaction and the transaction has reached this statement, it should have locked the row. This should not cause lost update, but it's happening somehow. Is the thing that this update command works in two parts? Like first it reads the counter value (during which it doesn't get the exclusive lock) and then writes the new calculated value (when it does get an exclusive lock)? Please help, I have got really confused.

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  • doublechecking: no db-wide 'unicode switch' for sql server in the foreseeable future, i.e. like Orac

    - by user72150
    Hi all, I believe I know the answer to this question, but wanted to confirm: Question Does Sql server (or will it in the foreseeable future), offer a database-wide "unicode switch" which says "store all characters in unicode (UTF-16, UCS-2, etc)", i.e. like Oracle. The Context Our application has provided "CJK" (Chinese-Japanese-Korean) support for years--using Oracle as the db store. Recently folks have been asking for the same support in sql server. We store our db schema definition in xml and generate the vendor-specific definitions (oracle, sql server) using vendor-specific xsl. We can make the change easily. The problem is for upgrades. Generated scripts would need to change the column types for 100+ columns from varchar to nvarchar, varchar(max) to nvarchar(max), etc. These changes require dropping and recreating indexes and foreign keys if the any indexes/fk's exist on the column. Non-trivial. Risky. DB-wide character encodings for us would eliminate programming changes. (I.e. we would not to change the column types from varchar to nvarchar; sql server would correctly store unicode data in varchar columns). I had thought that eventually sql server would "see the light" and allow storing unicode in varchar/clob columns. Evidently not yet. Recap So just to triple check: does mssql offer a database-wide switch for character encoding? Will it in SQL2008R3? or 2010? thanks, bill

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  • IHttpAsyncHandler and IObservable web requests

    - by McLovin
    Within Async handler I'm creating an IObservable from webrequest which returns a redirect string. I'm subscribing to that observable and calling AsyncResult.CompleteCall() but I'm forced to use Thread.Sleep(100) in order to get it executed. And it doesn't work every time. I'm pretty sure this is not correct. Could you please shine some light. Thank you! public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object state) { _context = context; _ar = new AsyncResult(cb, state); _tweet = context.Request["tweet"]; string url = context.Request["url"]; if(String.IsNullOrEmpty(_tweet) || String.IsNullOrEmpty(url)) { DisplayError("<h2>Tweet or url cannot be empty</h2>"); return _ar; } _oAuth = new oAuthTwitterRx(); using (_oAuth.AuthorizationLinkGet().Subscribe(p => { _context.Response.Redirect(p); _ar.CompleteCall(); }, exception => DisplayError("<h2>Unable to connect to twitter, please try again</h2>") )) return _ar; } public class AsyncResult : IAsyncResult { private AsyncCallback _cb; private object _state; private ManualResetEvent _event; private bool _completed = false; private object _lock = new object(); public AsyncResult(AsyncCallback cb, object state) { _cb = cb; _state = state; } public Object AsyncState { get { return _state; } } public bool CompletedSynchronously { get { return false; } } public bool IsCompleted { get { return _completed; } } public WaitHandle AsyncWaitHandle { get { lock (_lock) { if (_event == null) _event = new ManualResetEvent(IsCompleted); return _event; } } } public void CompleteCall() { lock (_lock) { _completed = true; if (_event != null) _event.Set(); } if (_cb != null) _cb(this); } }

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  • Syncronization Exception

    - by Kurru
    Hi I have two threads, one thread processes a queue and the other thread adds stuff into the queue. I want to put the queue processing thread to sleep when its finished processing the queue I want to have the 2nd thread tell it to wake up when it has added an item to the queue However these functions call System.Threading.SynchronizationLockException: Object synchronization method was called from an unsynchronized block of code on the Monitor.PulseAll(waiting); call, because I havent syncronized the function with the waiting object. [which I dont want to do, i want to be able to process while adding items to the queue]. How can I achieve this? Queue<object> items = new Queue<object>(); object waiting = new object(); 1st Thread public void ProcessQueue() { while (true) { if (items.Count == 0) Monitor.Wait(waiting); object real = null; lock(items) { object item = items.Dequeue(); real = item; } if(real == null) continue; .. bla bla bla } } 2nd Thread involves public void AddItem(object o) { ... bla bla bla lock(items) { items.Enqueue(o); } Monitor.PulseAll(waiting); }

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  • Delphi: Alternative to using Assign/ReadLn for text file reading

    - by Ian Boyd
    i want to process a text file line by line. In the olden days i loaded the file into a StringList: slFile := TStringList.Create(); slFile.LoadFromFile(filename); for i := 0 to slFile.Count-1 do begin oneLine := slFile.Strings[i]; //process the line end; Problem with that is once the file gets to be a few hundred megabytes, i have to allocate a huge chunk of memory; when really i only need enough memory to hold one line at a time. (Plus, you can't really indicate progress when you the system is locked up loading the file in step 1). The i tried using the native, and recommended, file I/O routines provided by Delphi: var f: TextFile; begin Assign(filename, f); while ReadLn(f, oneLine) do begin //process the line end; Problem withAssign is that there is no option to read the file without locking (i.e. fmShareDenyNone). The former stringlist example doesn't support no-lock either, unless you change it to LoadFromStream: slFile := TStringList.Create; stream := TFileStream.Create(filename, fmOpenRead or fmShareDenyNone); slFile.LoadFromStream(stream); stream.Free; for i := 0 to slFile.Count-1 do begin oneLine := slFile.Strings[i]; //process the line end; So now even though i've gained no locks being held, i'm back to loading the entire file into memory. Is there some alternative to Assign/ReadLn, where i can read a file line-by-line, without taking a sharing lock? i'd rather not get directly into Win32 CreateFile/ReadFile, and having to deal with allocating buffers and detecting CR, LF, CRLF's. i thought about memory mapped files, but there's the difficulty if the entire file doesn't fit (map) into virtual memory, and having to maps views (pieces) of the file at a time. Starts to get ugly. i just want Assign with fmShareDenyNone!

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  • Using graphical ActiveX (COM) controls in WinForms project

    - by alex
    I have a collection (set) of ActiveX controls. I recieved them from our vendor company. I created a wrappers for them using tlbimp.exe and aximp.exe. All non-graphical controls work good. All graphical controls don't react on some methods. When I call their methods I get: TargetInvocativeException (InnerException is null). or Attempt to read/write protected memory. Our vendor company assure that their graphical activex controls work good. But they don't provide support service, so I have to find solution of my problem alone. And some more, All graphical activex controls don't react on mouseclick or any other mouse manipulations. But documentation says: it must change the color on mouse click. Maybe, someone have same symptoms and can help me ! I googled over that problem many pages but they don't help me. Maybe it's some Visual Studio settings or compiler options ? I use VS 2005.

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  • WPF binding fails with custom add and remove accessors for INotifyPropertyChanged.PropertyChanged

    - by emddudley
    I have a scenario which is causing strange behavior with WPF data binding and INotifyPropertyChanged. I want a private member of the data binding source to handle the INotifyPropertyChanged.PropertyChanged event. I get some exceptions which haven't helped me debug, even when I have "Enable .NET Framework source stepping" checked in Visual Studio's options: A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll A first chance exception of type 'System.InvalidOperationException' occurred in PresentationCore.dll Here's the source code: XAML <Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="TestApplication.MainWindow" DataContext="{Binding RelativeSource={RelativeSource Self}}" Height="100" Width="100"> <StackPanel> <CheckBox IsChecked="{Binding Path=CheckboxIsChecked}" Content="A" /> <CheckBox IsChecked="{Binding Path=CheckboxIsChecked}" Content="B" /> </StackPanel> </Window> Normal implementation works public partial class MainWindow : Window, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public bool CheckboxIsChecked { get { return this.mCheckboxIsChecked; } set { this.mCheckboxIsChecked = value; PropertyChangedEventHandler handler = this.PropertyChanged; if (handler != null) handler(this, new PropertyChangedEventArgs("CheckboxIsChecked")); } } private bool mCheckboxIsChecked = false; public MainWindow() { InitializeComponent(); } } Desired implementation doesn't work public partial class MainWindow : Window, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged { add { lock (this.mHandler) { this.mHandler.PropertyChanged += value; } } remove { lock (this.mHandler) { this.mHandler.PropertyChanged -= value; } } } public bool CheckboxIsChecked { get { return this.mHandler.CheckboxIsChecked; } set { this.mHandler.CheckboxIsChecked = value; } } private HandlesPropertyChangeEvents mHandler = new HandlesPropertyChangeEvents(); public MainWindow() { InitializeComponent(); } public class HandlesPropertyChangeEvents : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public bool CheckboxIsChecked { get { return this.mCheckboxIsChecked; } set { this.mCheckboxIsChecked = value; PropertyChangedEventHandler handler = this.PropertyChanged; if (handler != null) handler(this, new PropertyChangedEventArgs("CheckboxIsChecked")); } } private bool mCheckboxIsChecked = false; } }

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  • Adding titles and descriptions to images in Refinerycms-Portfolio

    - by John Deely
    I'm using the Refinery content management system with a the Portfolio plugin see http://github.com/resolve/refinerycms I wanted to create a title and description for images uploaded to Refinery using Refinerycms-Portfolio so far I have done the following; added the columns to the images table $script/generate migration AddTitleToImages title:string $script/generate migration AddBodyToImages body:text $rake db:migrate modified the field div in this file, * highlighted vendor/plugins/images/app/views/admin/images/_form.html.erb Use current image or, replace it with this one... ***** ***** ***** ***** "wymeditor", :rows = 7 % Added these lines to the main image partial in vendor/plugins/refinerycms-portolio/app/views/portfolio/ _main_image.html.erb <%= @image.body % This works in the back-end except for a few visual bugs. The problem with this is when i click through the thumbnails in the front-end the titles and descriptions keep stacking on top of the previous titles and descriptions. The main image changes fine, but instead of refreshing the title and description, it adds the new one above the previous titles and descriptions. How can i stop this repetition so that only one title and description will show at a time? I'm new to Rails and I am using Rails-2.3.5 and I suspect this can be solved using Java Script thanks in advance, John

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  • Is Structuremap singleton thread safe?

    - by Ben
    Hi, Currently I have the following class: public class PluginManager { private static bool s_initialized; private static object s_lock = new object(); public static void Initialize() { if (!s_initialized) { lock (s_lock) { if (!s_initialized) { // initialize s_initialized = true; } } } } } The important thing here is that Initialize() should only be executed once whilst the application is running. I thought that I would refactor this into a singleton class since this would be more thread safe?: public sealed class PluginService { static PluginService() { } private static PluginService _instance = new PluginService(); public static PluginService Instance { get { return _instance; } } private bool s_initialized; public void Initialize() { if (!s_initialized) { // initialize s_initialized = true; } } } Question one, is it still necessary to have the lock here (I have removed it) since we will only ever be working on the same instance? Finally, I want to use DI and structure map to initialize my servcices so I have refactored as below: public interface IPluginService { void Initialize(); } public class NewPluginService : IPluginService { private bool s_initialized; public void Initialize() { if (!s_initialized) { // initialize s_initialized = true; } } } And in my registry: ForRequestedType<IPluginService>() .TheDefaultIsConcreteType<NewPluginService>().AsSingletons(); This works as expected (singleton returning true in the following code): var instance1 = ObjectFactory.GetInstance<IPluginService>(); var instance2 = ObjectFactory.GetInstance<IPluginService>(); bool singleton = (instance1 == instance2); So my next question, is the structure map solution as thread safe as the singleton class (second example). The only downside is that this would still allow NewPluginService to be instantiated directly (if not using structure map). Many thanks, Ben

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  • .htaccess equivalent of baseurl?

    - by Ryan
    Hello, I'm trying to install Symfony on a shared server and am attempting to duplicate the httpd.conf command: # Be sure to only have this line once in your configuration NameVirtualHost 127.0.0.1:8080 # This is the configuration for your project Listen 127.0.0.1:8080 <VirtualHost 127.0.0.1:8080> DocumentRoot "/home/sfproject/web" DirectoryIndex index.php <Directory "/home/sfproject/web"> AllowOverride All Allow from All </Directory> Alias /sf /home/sfproject/lib/vendor/symfony/data/web/sf <Directory "/home/sfproject/lib/vendor/symfony/data/web/sf"> AllowOverride All Allow from All </Directory> </VirtualHost> I need to do so using .htaccess The redirect portion was done in the root using the following: Options +FollowSymlinks RewriteEngine on rewritecond %{http_host} ^symfony.mysite.ca [nc] rewriterule ^(.*)$ http://symfony.mysite.ca/web/$1 [r=301,nc] For the alias, I've tried using: RewriteBase / but no success. The main issue is that the index.php file residing in the /web folder uses the /web path in its path to images and scripts. So instead of href="/css/main.css" //this would work it uses href="/web/css/main.css" //this doesn't work, already in the /web/ directory! Any ideas? Thanks!

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  • Synchronization of Nested Data Structures between Threads in Java

    - by Dominik
    I have a cache implementation like this: class X { private final Map<String, ConcurrentMap<String, String>> structure = new HashMap...(); public String getValue(String context, String id) { // just assume for this example that there will be always an innner map final ConcurrentMap<String, String> innerStructure = structure.get(context); String value = innerStructure.get(id); if(value == null) { synchronized(structure) { // can I be sure, that this inner map will represent the last updated // state from any thread? value = innerStructure.get(id); if(value == null) { value = getValueFromSomeSlowSource(id); innerStructure.put(id, value); } } } return value; } } Is this implementation thread-safe? Can I be sure to get the last updated state from any thread inside the synchronized block? Would this behaviour change if I use a java.util.concurrent.ReentrantLock instead of a synchronized block, like this: ... if(lock.tryLock(3, SECONDS)) { try { value = innerStructure.get(id); if(value == null) { value = getValueFromSomeSlowSource(id); innerStructure.put(id, value); } } finally { lock.unlock(); } } ... I know that final instance members are synchronized between threads, but is this also true for the objects held by these members? Maybe this is a dumb question, but I don't know how to test it to be sure, that it works on every OS and every architecture.

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  • android logging sdcard

    - by Abhi Rao
    Hello, With Android-Emulator I am not able to write/create a file on the SD Card (for logging). Here is what I have done so far - Run mksdcard 8192K C:\android-dev\emu_sdcard\emu_logFile - Create a new AVD, when assign emu_logFile to it so that when I view the AVD Details it says C:\android-dev\emu_sdcard\emu_logFile against the field "SD Card" - Here is the relevant code public class ZLogger { static PrintWriter zLogWriter = null; private static void Initialize() { try { File sdDir = Environment.getExternalStorageDirectory(); if (sdDir.canWrite()) { : File logFile = new File (sdDir, VERSION.RELEASE + "_" + ".log"); FileWriter logFileWriter = new FileWriter(logFile); zLogWriter = new PrintWriter(logFileWriter); zLogWriter.write("\n\n - " + date + " - \n"); } } catch (IOException e) { Log.e("ZLogger", "Count not write to file: " + e.getMessage()); } } sdDir.canWrite returns false - please note it not the exception from adb shell when I do ls I see sdcard as link to /mnt/sdcard. When I do ls -l /mnt here is what I see ls -l /mnt ls -l /mnt drwxr-xr-x root system 2010-12-24 03:41 asec drwx------ root root 2010-12-24 03:41 secure d--------- system system 2010-12-24 03:41 sdcard whereas if I go to the directory where I created emu_sdcard - I see a lock has been issued, as shown here C:dir android-dev\emu_sdcard Volume in drive C is Preload Volume Serial Number is A4F3-6C29 Directory of C:\android-dev\emu_sdcard 12/24/2010 03:41 AM . 12/24/2010 03:41 AM .. 12/24/2010 03:17 AM 8,388,608 emu_logFile 12/24/2010 03:41 AM emu_logFile.lock 1 File(s) 8,388,608 bytes 3 Dir(s) 50,347,704,320 bytes free I have looked at these and other SO questions Android Emulator sdcard push error: Read-only file system (2) Not able to view SDCard folder in the FileExplorer of Android Eclipse I have added the following to AndroidManifest.xml **uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" ** Please let me know your thoughts - what am I missing here? Why does canWrite return false? What should I do to add permissions to sdcard?

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  • MySQL return Deadlock with insert row and FK is locked 'for update'

    - by constantin-slednev
    Hello developers! I get deadlock error in my mysql transaction. The simple example of my situation: Thread1 > set autocommit=0; Query OK, 0 rows affected (0.00 sec) Thread1 > SET TRANSACTION ISOLATION LEVEL READ COMMITTED; Query OK, 0 rows affected (0.00 sec) Thread1 > SELECT * FROM A WHERE ID=1000 FOR UPDATE; 1 row in set (0.00 sec) Thread2 > set autocommit=0; Query OK, 0 rows affected (0.00 sec) Thread2 > SET TRANSACTION ISOLATION LEVEL READ COMMITTED; Query OK, 0 rows affected (0.00 sec) Thread2 > INSERT INTO B (AID, NAME) VALUES (1000, 'Hello world'); SLEEP Query OK, 1 row affected (4.99 sec) Thread1 > INSERT INTO B (AID, NAME) VALUES (1000, 'Hello world2'); ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction B.AID -> FK -> A.ID I see three solutions: catch deadlock error in code and retry query. use innodb_locks_unsafe_for_binlog in my.cnf lock (for update) table A in Thread2 before insert Can you give me more solutions ? Current solutions do not fit me.

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  • Semaphore race condition?

    - by poindexter12
    I have created a "Manager" class that contains a limited set of resources. The resources are stored in the "Manager" as a Queue. I initialize the Queue and a Semaphore to the same size, using the semaphore to block a thread if there are no resources available. I have multiple threads calling into this class to request a resource. Here is the psuedo code: public IResource RequestResource() { IResource resource = null; _semaphore.WaitOne(); lock (_syncLock) { resource = _resources.Dequeue(); } return resource; } public void ReleaseResource(IResource resource) { lock (_syncLock) { _resources.Enqueue(resource); } _semaphore.Release(); } While running this application, it seems to run fine for a while. Then, it seems like my Queue is giving out the same object. Does this seem like its possible? I'm pulling my hair out over here, and any help would be greatly appreciated. Feel free to ask for more information if you need it. Thanks!

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  • Passing JSON object from Controller to View(jsp)

    - by user752233
    I am trying to send JSON object to my view from controller but unable to send it. Please help me out! I am using following code public class SystemController extends AbstractController{ protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception { ModelAndView mav = new ModelAndView("SystemInfo", "System", "S"); response.setContentType("application/json;charset=UTF-8"); response.setHeader("Cache-Control", "no-cache"); JSONObject jsonResult = new JSONObject(); jsonResult.put("JVMVendor", System.getProperty("java.vendor")); jsonResult.put("JVMVersion", System.getProperty("java.version")); jsonResult.put("JVMVendorURL", System.getProperty("java.vendor.url")); jsonResult.put("OSName", System.getProperty("os.name")); jsonResult.put("OSVersion", System.getProperty("os.version")); jsonResult.put("OSArchitectire", System.getProperty("os.arch")); response.getWriter().write(jsonResult.toString()); // response.getWriter().close(); return mav; // return modelandview object } } and in the view side I am using <script type="text/javascript"> Ext.onReady(function(response) { //Ext.MessageBox.alert('Hello', 'The DOM is ready!'); var showExistingScreen = function () { Ext.Ajax.request({ url : 'system.htm', method : 'POST', scope : this, success: function ( response ) { alert('1'); var existingValues = Ext.util.JSON.decode(response.responseText); alert('2'); } }); }; return showExistingScreen(); });

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  • Transaction Isolation Level of Serializable not working for me

    - by Shahriar
    I have a website which is used by all branches of a store and what it does is that it records customer purchases into a table called myTransactions.myTransactions table has a column named SerialNumber.For each purchase i create a record in the transactions table and assign a serial to it.The stored procedure that does this calls a UDF function to get a new serialNumber before inserting the record.Like below : Create Procedure mytransaction_Insert as begin insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2,Value3,...., getTransactionNSerialNumber()) end Create function getTransactionNSerialNumber as begin RETURN isnull(SELECT TOP (1) SerialNumber FROM myTransactions READUNCOMMITTED ORDER BY SerialNumber DESC),0) + 1 end The website is being used by so many users in different stores at the same time and it is creating many duplicate serialNumbers(same SerialNumbers).So i added a Sql transaction with ReadCommitted level to the transaction and i still got duplicate transaction numbers.I changed it to SERIALIZABLE in order to lock the resources and i not only got duplicate transaction numbers(!!HOW!!) but i also got sporadic deadlocks between the same stored procedure calls.This is what i tried : (With ommissions of try catch blocks and rollbacks) Create Procedure mytransaction_Insert as begin SET TRANSACTION ISOLATION LEVEL SERIALIZABLE BEGIN TRASNACTION ins insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2 , Value3, ...., getTransactionNSerialNumber()) COMMIT TRANSACTION ins SET TRANSACTION ISOLATION READCOMMITTED end I even copied the function that gets the serial number directly into the stored procedure instead of the UDF function call and still got duplicate serialNumbers.So,How can a stored procedure line create something Like the c# lock() {} block. By the way,i have to implement the transaction serial number using the same pattern and i can't change the serialNumber to any other identity field or whatever.And for some reasons i need to generate the serialNumber inside the databse and i can't move SerialNumber generation to application level. Thank you.

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  • question about InnoDB deadlock in MySQL?

    - by WilliamLou
    I found this kind of interesting problem in MySQL InnoDB engine, could anyone explain why the engine always claim it's a deadlock. First, I created a table with a single row, single column: CREATE TABLE `SeqNum` (`current_seq_num` bigint(30) NOT NULL default '0', PRIMARY KEY (`current_seq_num`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 | Now, I have two MySQL connector threads, In thread1: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; Query OK, 1 row affected (0.00 sec) Now, in thread2, I did the exactly same: mysql> begin; Query OK, 0 rows affected (0.00 sec) mysql> select `current_seq_num` into @curr_seq FROM SeqNum FOR UPDATE; before the default innodb_lock_wait_timeout, the thread2 just wait for thread1 to release its exclusive lock on the table, and it's normal. However, in thread1, if I input the following update query: mysql> update SeqNum set `current_seq_num` = 8; ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction Now, thread2 get the select query finished because thread1 quits. In addition, in thread1, if I input the update query with a where clause, it can be executed very well: mysql> update SeqNum set `current_seq_num` = 8 where `current_seq_num` =5 Query OK, 1 row affected (0.00 sec) Could anyone explain this?

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  • How do you handle your "Project Manager"

    - by Vecdid
    I currently work for a company who recently has downsized. I do all in house work, client installs, builds,q.a, well basically all the in house work. My direct boss is VERY untechnical and lately I have found it VERY hard to deal with his lack of knowledge. The biggest issues I have had are as follows: I am on many deadlines at a time. I get stopped to put together a half fast quote as I cannot be late on the deadline, in the meantime, three support calls comes in, I give quote, time too much so they outsource it. I then I have to fix everything the vendor broke. I get asked, when an issue arrises, why is the issue occurring and explain in detail, yet that detail means absolutly nothing to him. All he cares about are deadlines, yet he is the one who schdules everything. "I am a programmer not a graphic designer, meaqns nothing to him" I was hired as a .NET programmer, yet they let a vendor choose wordpress for many sites(yeah I had to learn all about it quick) I guess I can go on and on, but has anyone had to deal with this type of project manager? What is some advice, other than finding another job. Thanks in advance, and I made this a wiki, so please don't close...

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  • A copy of ApplicationController has been removed from the module tree but is still active

    - by Matchu
    Whenever two concurrent HTTP requests go to my Rails app, the second always returns the following error: A copy of ApplicationController has been removed from the module tree but is still active! From there it gives an unhelpful stack trace to the effect of "we went through the standard server stuff, ran your first before_filter on ApplicationController (and I checked; it's just whichever filter runs first)", then offers the following: /home/matchu/rails/torch/vendor/rails/activesupport/lib/active_support/dependencies.rb:414:in `load_missing_constant' /home/matchu/rails/torch/vendor/rails/activesupport/lib/active_support/dependencies.rb:96:in `const_missing' which I'm assuming is a generic response and doesn't really say much. Google seems to tell me that people developing Rails Engines will encounter this, but I don't do that. All I've done is upgrade my Rails app from 2.2 (2.1?) to 2.3. What are some possible causes for this error, and how can I go about tracking down what's really going on? I know this question is vague, so would any other information be helpful? More importantly: I tried doing a test run in a "production" environment just now, and the error doesn't seem to persist. Does this only affect development, then, and need I not worry too much?

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