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• Issues in Ajax based applications

  - by Sinuhe

  I'm very interested in developing Ajax based applications. This is, loading almost all of the content of the application via XMLHttpRequest, instead of only some combos and widgets. But if I try to do this form scratch, soon I find some problems without an easy solution. I wonder if there is some framework (both client and server side) to deal with this issues. As far as I know, there isn't (but I've searched mainly in Java world). So I am seriously thinking of doing my own framework, at least for my projects. Therefore, in this question I ask for several things. First, the possible problems of an ajax based development. Then, I'm looking for some framework or utility in order to deal with them. Finally, if there is no framework available, what features must it have. Here are the issues I thought: 1 - JavaScript must be enabled. Security paranoia isn't the only problem: a lot of mobile devices couldn't use the application, too. 2 - Sometimes you need to update more than one DIV (e.g. main content, menu and breadcrumbs). 3 - Unknown response type: when you make an Ajax call, you set the callback function too, usually specifying if expected response is a javascript object or in which DIV put the result. But this fails when you get another type of response: for example when the session has expired and the user must log in again. 4 - Browser's refresh, back and forward buttons can be a real pain. User will expect different behaviors depending on the situation. 5 - When search engines indexes a site, only follow links. Thus, content load by Ajax won't "exist" for who doesn't know about it yet. 6 - Users can ask for open a link in a different window/tab. 7 - Address bar doesn't show the "real" page you are in. So, you can't copy the location and send it to a friend or bookmark the page. 8 - If you want to monetize the site, you can put some advertisings. As you don't refresh entire page and you want to change the ad after some time, you have to refresh only the DIV where the ad is. But this can violate the Terms and Conditions of your ad service. In fact, it can go against AdSense TOS. 9 - When you refresh an entire page, all JavaScript gets "cleaned". But in Ajax calls, all JavaScript objects will remain. 10 - You can't easily change your CSS properties.

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• Correct way to use Drupal 7 Entities and Field API

  - by Martin Petts

  I'm trying to use Drupal 7's entities and field API to correctly build a new module. What I have been unable to understand from the documentation is the correct way to use the new API to create a 'content type' (not a node type) with a number of set fields, such as Body. I'm trying to set up the entity using hook_entity_info, then I believe I need to add the body field using field_create_instance, but I can't seem to get it to work. In mycontenttype.module: /** * Implements hook_entity_info(). */ function mycontenttype_entity_info() { $return = array( 'mycontenttype' => array( 'label' => t('My Content Type'), 'controller class' => 'MyContentTypeEntityController', 'base table' => 'content_type', 'uri callback' => 'content_type_uri', 'entity keys' => array( 'id' => 'cid', 'label' => 'title' ), 'bundles' => array( 'mycontenttype' => array( 'label' => 'My Content Type', 'admin' => array( 'path' => 'admin/contenttype', 'access arguments' => array('administer contenttype') ) ) ), 'fieldable' => true ) ); return $return; } /** * Implements hook_field_extra_fields(). */ function mycontenttype_field_extra_fields() { $return['mycontenttype']['mycontenttype'] = array( 'form' = array( 'body' = array( 'label' = 'Body', 'description' = t('Body content'), 'weight' = 0, ), ), ); return $return; } Then does this go in the .install file? function mycontenttype_install() { $field = array( 'field_name' => 'body', 'type' => 'text_with_summary', 'entity_types' => array('survey'), 'translatable' => TRUE, ); field_create_field($field); $instance = array( 'entity_type' => 'mycontenttype', 'field_name' => 'body', 'bundle' => 'mycontenttype', 'label' => 'Body', 'widget_type' => 'text_textarea_with_summary', 'settings' => array('display_summary' => TRUE), 'display' => array( 'default' => array( 'label' => 'hidden', 'type' => 'text_default', ), 'teaser' => array( 'label' => 'hidden', 'type' => 'text_summary_or_trimmed', ) ) ); field_create_instance($instance); }

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• C - How to use both aio_read() and aio_write().

  - by Slav

  I implement game server where I need to both read and write. So I accept incoming connection and start reading from it using aio_read() but when I need to send something, I stop reading using aio_cancel() and then use aio_write(). Within write's callback I resume reading. So, I do read all the time but when I need to send something - I pause reading. It works for ~20% of time - in other case call to aio_cancel() fails with "Operation now in progress" - and I cannot cancel it (even within permanent while cycle). So, my added write operation never happens. How to use these functions well? What did I missed? EDIT: Used under Linux 2.6.35. Ubuntu 10 - 32 bit. Example code: void handle_read(union sigval sigev_value) { /* handle data or disconnection */ } void handle_write(union sigval sigev_value) { /* free writing buffer memory */ } void start() { const int acceptorSocket = socket(AF_INET, SOCK_STREAM, 0); struct sockaddr_in addr; memset(&addr, 0, sizeof(struct sockaddr_in)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = INADDR_ANY; addr.sin_port = htons(port); bind(acceptorSocket, (struct sockaddr*)&addr, sizeof(struct sockaddr_in)); listen(acceptorSocket, SOMAXCONN); struct sockaddr_in address; socklen_t addressLen = sizeof(struct sockaddr_in); for(;;) { const int incomingSocket = accept(acceptorSocket, (struct sockaddr*)&address, &addressLen); if(incomingSocket == -1) { /* handle error ... */} else { //say socket to append outcoming messages at writing: const int currentFlags = fcntl(incomingSocket, F_GETFL, 0); if(currentFlags < 0) { /* handle error ... */ } if(fcntl(incomingSocket, F_SETFL, currentFlags | O_APPEND) == -1) { /* handle another error ... */ } //start reading: struct aiocb* readingAiocb = new struct aiocb; memset(readingAiocb, 0, sizeof(struct aiocb)); readingAiocb->aio_nbytes = MY_SOME_BUFFER_SIZE; readingAiocb->aio_fildes = socketDesc; readingAiocb->aio_buf = mySomeReadBuffer; readingAiocb->aio_sigevent.sigev_notify = SIGEV_THREAD; readingAiocb->aio_sigevent.sigev_value.sival_ptr = (void*)mySomeData; readingAiocb->aio_sigevent.sigev_notify_function = handle_read; if(aio_read(readingAiocb) != 0) { /* handle error ... */ } } } } //called at any time from server side: send(void* data, const size_t dataLength) { //... some thread-safety precautions not needed here ... const int cancellingResult = aio_cancel(socketDesc, readingAiocb); if(cancellingResult != AIO_CANCELED) { //this one happens ~80% of the time - embracing previous call to permanent while cycle does not help: if(cancellingResult == AIO_NOTCANCELED) { puts(strerror(aio_return(readingAiocb))); // "Operation now in progress" /* don't know what to do... */ } } //otherwise it's okay to send: else { aio_write(...); } }

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• Moving Function With Arguments To RequireJS

  - by Jazimov

  I'm not only relatively new to JavaScript but also to RequireJS (coming from string C# background). Currently on my web page I have a number of JavaScript functions. Each one takes two arguments. Imagine that they look like this: functionA(x1, y1) { ... } functionB(x2, y2) { ... } functionC(x3, y3) { ... } Currently, these functions exist in a tag on my HTML page and I simply call each as needed. My functions have dependencies on KnockoutJS, jQuery, and some other JS libraries. I currently have Script tags that synchronously load those external .js dependencies. But I want to use RequireJS so that they're loaded asynchronously, as needed. To do this, I plan to move all three functions above into an external .js file (a type of AMD "module") called MyFunctions.js. That file will have a define() call (to RequireJS's define function) that will look something like this: define(["knockout", "jquery", ...], function("ko","jquery", ...) {???} ); My question is how to "wrap" my functionA, functionB, and functionC functions where the ??? is above so that I can use those functions on my page as needed. For example, in the onclick event handler for a button on my HTML page, I would want to call functionA and pass two it two arguments; same for functionB and functionC. I don't fully understand how to expose those functions when they're wrapped in a define that itself is located in an external .js file. I know that define assures that my listed libraries are loaded asynchronously before the callback function is called, but after that's done I don't understand how the web page's script tags would use my functions. Would I need to use require to ensure they're available, such as: require(["myfunctions"],function({not sure what to put here})] I think I understand the basics of RequireJS but I don't understand how to wrap my functions so that they're in external .js files, don't pollute the global namespace, and yet can still be called from the main page so that arguments can be passed to them. I imagine they're are many ways to do this but in reviewing the RequireJS docs and some videos out there, I can't say I understand how... Thank you for any help.

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• Where are the function literals c++?

  - by academicRobot

  First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one.

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• How to fix this Speech Recognition wicked bug?

  - by aF

  I have this code in my C# project: public void startRecognition(string pName) { presentationName = pName; if (WaveNative.waveInGetNumDevs() > 0) { string grammar = System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Presentations\\" + presentationName + "\\SpeechRecognition\\soundlog.cfg"; if (File.Exists(grammar)) { File.Delete(grammar); } executeCommand(); /// Create an instance of SpSharedRecoContextClass which will be used /// to interface with the incoming audio stream recContext = new SpSharedRecoContextClass(); // Create the grammar object recContext.CreateGrammar(1, out recGrammar); //recContext.CreateGrammar(2, out recGrammar2); // Set up dictation mode //recGrammar2.SetDictationState(SpeechLib.SPRULESTATE.SPRS_ACTIVE); //recGrammar2.SetGrammarState(SPGRAMMARSTATE.SPGS_ENABLED); // Set appropriate grammar mode if (File.Exists(grammar)) { recGrammar.LoadCmdFromFile(grammar, SPLOADOPTIONS.SPLO_STATIC); //recGrammar.SetDictationState(SpeechLib.SPRULESTATE.SPRS_INACTIVE); recGrammar.SetGrammarState(SPGRAMMARSTATE.SPGS_ENABLED); recGrammar.SetRuleIdState(0, SPRULESTATE.SPRS_ACTIVE); } /// Bind a callback to the recognition event which will be invoked /// When a dictated phrase has been recognised. recContext.Recognition += new _ISpeechRecoContextEvents_RecognitionEventHandler(handleRecognition); // System.Windows.Forms.MessageBox.Show(recContext.ToString()); // gramática compilada } } private static void handleRecognition(int StreamNumber, object StreamPosition, SpeechLib.SpeechRecognitionType RecognitionType, SpeechLib.ISpeechRecoResult Result) { string temp = Result.PhraseInfo.GetText(0, -1, true); _recognizedText = ""; // System.Windows.Forms.MessageBox.Show(temp); // System.Windows.Forms.MessageBox.Show(recognizedWords.Count.ToString()); foreach (string word in recognizedWords) { if (temp.Contains(word)) { // System.Windows.Forms.MessageBox.Show("yes"); _recognizedText = word; } } } This codes generates a dll that I use in another application. Now, the wicked bug: - when I run the startRecognition method in the beginning of the execution of the other application, this codes works very well. But when I run it some time after the beginning, this codes works but the handleRecognition method is never called. I see that the words are recognized because they appear on the Microsoft Speech Recognition app, but the handler method is never called. Do you know what's the problem with this code? NOTE: this project has some code that is allways being executed. Might that be the problem? Because the other code is running it doesn't allow it to this to run?

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• Django save_m2m() and excluded field

  - by jul

  hi, in a ModelForm I replaced a field by excluding it and adding a new one with the same name, as shown below in AddRestaurantForm. When saving the form with the code shown below, I get an error in form.save_m2m() ("Truncated incorrect DOUBLE value"), which seems to be due to the function to attempt to save the tag field, while it is excluded. Is the save_m2m() function supposed to save excluded fields? Is there anything wrong in my code? Thanks Jul (...) new_restaurant = form.save(commit=False) new_restaurant.city = city new_restaurant.save() tags = form.cleaned_data['tag'] if(tags!=''): tags=tags.split(',') for t in tags: tag, created = Tag.objects.get_or_create(name = t.strip()) tag.save() new_restaurant.tag.add(tag) new_restaurant.save() form.save_m2m() models.py class Tag(models.Model): name = models.CharField(max_length=100, unique=True) class Restaurant(models.Model): name = models.CharField(max_length=50) city=models.ForeignKey(City) category=models.ManyToManyField(Category) tag=models.ManyToManyField(Tag, blank=True, null=True) forms.py class AddRestaurantForm(ModelForm): name = forms.CharField(widget=forms.TextInput(attrs=classtext)) city = forms.CharField(widget=forms.TextInput(attrs=classtext), max_length=100) tag = forms.CharField(widget=forms.TextInput(attrs=classtext), required=False) class Meta: model = Restaurant exclude = ('city','tag') Traceback: File "/var/lib/python-support/python2.5/django/core/handlers/base.py" in get_response 92. response = callback(request, *callback_args, **callback_kwargs) File "/home/jul/atable/../atable/resto/views.py" in addRestaurant 498. form.save_m2m() File "/var/lib/python-support/python2.5/django/forms/models.py" in save_m2m 75. f.save_form_data(instance, cleaned_data[f.name]) File "/var/lib/python-support/python2.5/django/db/models/fields/ related.py" in save_form_data 967. setattr(instance, self.attname, data) File "/var/lib/python-support/python2.5/django/db/models/fields/ related.py" in set 627. manager.add(*value) File "/var/lib/python-support/python2.5/django/db/models/fields/ related.py" in add 430. self._add_items(self.source_col_name, self.target_col_name, *objs) File "/var/lib/python-support/python2.5/django/db/models/fields/ related.py" in _add_items 497. [self._pk_val] + list(new_ids)) File "/var/lib/python-support/python2.5/django/db/backends/util.py" in execute 19. return self.cursor.execute(sql, params) File "/var/lib/python-support/python2.5/django/db/backends/mysql/ base.py" in execute 84. return self.cursor.execute(query, args) File "/var/lib/python-support/python2.5/MySQLdb/cursors.py" in execute 168. if not self._defer_warnings: self._warning_check() File "/var/lib/python-support/python2.5/MySQLdb/cursors.py" in _warning_check 82. warn(w[-1], self.Warning, 3) File "/usr/lib/python2.5/warnings.py" in warn 62. globals) File "/usr/lib/python2.5/warnings.py" in warn_explicit 102. raise message Exception Type: Warning at /restaurant/add/ Exception Value: Truncated incorrect DOUBLE value: 'a'

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• [C++] FillRect won't draw anything

  - by kaykun

  I'm trying to create a simple window in Win32 and draw a rectangle in it, but for some reason FillRect isn't working for me. Here's my source: #include <windows.h> #include "resource.h" RECT rect; LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) { static PAINTSTRUCT ps; static HDC hDC; switch(msg) { case WM_PAINT: hDC = BeginPaint(hWnd, &ps); FillRect(hDC, &rect, (HBRUSH)(COLOR_WINDOW+1)); EndPaint(hWnd, &ps); break; case WM_CLOSE: DestroyWindow(hWnd); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hWnd, msg, wParam, lParam); } return 0; } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { WNDCLASSEX wc; HWND hWnd; MSG msg; rect.left = 0; rect.right = 0; rect.top = 100; rect.bottom = 100; wc.cbSize = sizeof(WNDCLASSEX); wc.style = 0; wc.lpfnWndProc = WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon(NULL, IDI_APPLICATION); wc.hCursor = LoadCursor(NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH)(COLOR_ACTIVEBORDER+1); wc.lpszMenuName = MAKEINTRESOURCE(IDR_MAIN_MENU); wc.lpszClassName = "Main"; wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION); RegisterClassEx(&wc); hWnd = CreateWindowEx(NULL, "Main", "Main", WS_SYSMENU | WS_MINIMIZEBOX, CW_USEDEFAULT, CW_USEDEFAULT, 240, 360, NULL, NULL, hInstance, NULL); ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); while(GetMessage(&msg, NULL, 0, 0) > 0) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } Is there something I'm missing or doing wrong in my code? Thanks in advance

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• Secure WS client with UsernameToken(SOAP security header)

  - by user79163

  Hi, I'm trying to secure my WS client to be able to call the WS. My code looks like this: SendSmsService smsService = new SendSmsService(); SendSms sendSMS = smsService.getSendSms(); BindingProvider stub = (BindingProvider)sendSMS; //Override endpoint with local copy of wsdl. String URL ="";//here is the wsdl url Map<String,Object> requestContext = stub.getRequestContext(); requestContext.put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY, URL); //Set usernametoken URL fileURL = loader.getResource("client-config.xml"); File file = new File(fileURL.getFile()); FileInputStream clientConfig = null; try { clientConfig = new FileInputStream(file); } catch (FileNotFoundException e) { e.printStackTrace(); } XWSSecurityConfiguration config = null; try { config = SecurityConfigurationFactory.newXWSSecurityConfiguration(clientConfig); } catch (Exception e) { e.printStackTrace(); log.warn("Exception: "+e.getMessage()); } requestContext.put(XWSSecurityConfiguration.MESSAGE_SECURITY_CONFIGURATION, config); //Invoke the web service String requestId = null; try { requestId = sendSMS.sendSms(addresses, senderName, charging, message, receiptRequest); } catch (PolicyException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (ServiceException e) { // TODO Auto-generated catch block e.printStackTrace(); } and the config file looks like this: <xwss:JAXRPCSecurity xmlns:xwss="http://java.sun.com/xml/ns/xwss/config" optimize="true"> <xwss:Service> <xwss:SecurityConfiguration dumpMessages="true" xmlns:xwss="http://java.sun.com/xml/ns/xwss/config"> <xwss:UsernameToken name="username" password="password> </xwss:SecurityConfiguration> </xwss:Service> <xwss:SecurityEnvironmentHandler> util.SecurityEnvironmentHandler </xwss:SecurityEnvironmentHandler> </xwss:JAXRPCSecurity> The SecurityEnviromentHandler is a dummy class that implements javax.security.auth.callback.CallbackHandler. Authentication must be in compliance with Oasis Web Services Security Username Token Profile 1.0. But I'm constantly getting "Security header not valid" error. Where am I going wrong, can anyone tell me. I used wsimport(JAX_WS 2.1 to generate classes for my client) Note:Only thing I know about this WS is WSDL URL and user&pass for authentication

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• Unable to find assembly, C#

  - by PlasmaCube

  So, here's the deal. I've got two ASP.NET applications, both of which use SQLServer Session State management. They also both use the same server. I've got a custom session class in an external DLL, which fully implements serialization, and which both applications have referenced. Each application, in turn, has a class which inherits from the DLL class, and both applications use their own respective classes for their session state. Now, what I was trying to accomplish was that if you wanted to go to the other application, it could look in the session (they all use the same session key) and treat the existing object there as the base (the one from the DLL), extract whatever login info you need, then overwrite the session object with your own. Unfortunately, when the second application attempts to read the session, it seems that it looks for the DLL of the first application, and when it can't find it, it throws an exception. Is there a flaw in my logic? Here's an example: // Global.asax of the 1st app protected void Session_Start(object sender, EventArgs e) { Session.Add( "UserSessionKey", new FirstUserSession()); // FirstUserSession inherits from BaseUserSession } Now the second application: // Global.asax of 2nd app protected void Session_Start(object sender, EventArgs e) { if (Session["UserSessionKey"] != null) { BaseUserSession existing = (BaseUserSession)Session["UserSessionKey"]; SecondUserSession session = new SecondUserSession(); // This also inherits from BaseUserSession session.Authenticated = existing.Authenticated; session.Id = existing.Id; session.Role = existing.Role; Session.Add("UserSessionKey", session); } else { Session.Add("UserSessionKey", new SecondUserSession()); } } Here's the exception stack trace. In this case, "MyCBC" is the real name of the first app, and "ASPTesting" is the second app. [SerializationException: Unable to find assembly 'MyCBC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.] System.Runtime.Serialization.Formatters.Binary.BinaryAssemblyInfo.GetAssembly() +1871092 System.Runtime.Serialization.Formatters.Binary.ObjectReader.GetType(BinaryAssemblyInfo assemblyInfo, String name) +7545734 System.Runtime.Serialization.Formatters.Binary.ObjectMap..ctor(String objectName, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +120 System.Runtime.Serialization.Formatters.Binary.ObjectMap.Create(String name, String[] memberNames, BinaryTypeEnum[] binaryTypeEnumA, Object[] typeInformationA, Int32[] memberAssemIds, ObjectReader objectReader, Int32 objectId, BinaryAssemblyInfo assemblyInfo, SizedArray assemIdToAssemblyTable) +52 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryObjectWithMapTyped record) +190 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.ReadObjectWithMapTyped(BinaryHeaderEnum binaryHeaderEnum) +61 System.Runtime.Serialization.Formatters.Binary.__BinaryParser.Run() +253 System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +168 System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +203 System.Web.Util.AltSerialization.ReadValueFromStream(BinaryReader reader) +788 System.Web.SessionState.SessionStateItemCollection.ReadValueFromStreamWithAssert() +55 System.Web.SessionState.SessionStateItemCollection.DeserializeItem(String name, Boolean check) +281 System.Web.SessionState.SessionStateItemCollection.get_Item(String name) +19 System.Web.SessionState.HttpSessionStateContainer.get_Item(String name) +13 System.Web.SessionState.HttpSessionState.get_Item(String name) +13 ASPTesting._Default.Page_Load(Object sender, EventArgs e) in C:\Documents and Settings\sarsstu\My Documents\Projects\Testing\ASPTesting\ASPTesting\Default.aspx.cs:20 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627 Thanks to everyone in advance.

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• How to fix this Speech Recognition on C# wicked bug?

  - by aF

  Hello, I have this code in my C# project: public void startRecognition(string pName) { presentationName = pName; if (WaveNative.waveInGetNumDevs() > 0) { string grammar = System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Presentations\\" + presentationName + "\\SpeechRecognition\\soundlog.cfg"; if (File.Exists(grammar)) { File.Delete(grammar); } executeCommand(); /// Create an instance of SpSharedRecoContextClass which will be used /// to interface with the incoming audio stream recContext = new SpSharedRecoContextClass(); // Create the grammar object recContext.CreateGrammar(1, out recGrammar); //recContext.CreateGrammar(2, out recGrammar2); // Set up dictation mode //recGrammar2.SetDictationState(SpeechLib.SPRULESTATE.SPRS_ACTIVE); //recGrammar2.SetGrammarState(SPGRAMMARSTATE.SPGS_ENABLED); // Set appropriate grammar mode if (File.Exists(grammar)) { recGrammar.LoadCmdFromFile(grammar, SPLOADOPTIONS.SPLO_STATIC); //recGrammar.SetDictationState(SpeechLib.SPRULESTATE.SPRS_INACTIVE); recGrammar.SetGrammarState(SPGRAMMARSTATE.SPGS_ENABLED); recGrammar.SetRuleIdState(0, SPRULESTATE.SPRS_ACTIVE); } /// Bind a callback to the recognition event which will be invoked /// When a dictated phrase has been recognised. recContext.Recognition += new _ISpeechRecoContextEvents_RecognitionEventHandler(handleRecognition); // System.Windows.Forms.MessageBox.Show(recContext.ToString()); // gramática compilada } } private static void handleRecognition(int StreamNumber, object StreamPosition, SpeechLib.SpeechRecognitionType RecognitionType, SpeechLib.ISpeechRecoResult Result) { string temp = Result.PhraseInfo.GetText(0, -1, true); _recognizedText = ""; // System.Windows.Forms.MessageBox.Show(temp); // System.Windows.Forms.MessageBox.Show(recognizedWords.Count.ToString()); foreach (string word in recognizedWords) { if (temp.Contains(word)) { // System.Windows.Forms.MessageBox.Show("yes"); _recognizedText = word; } } } This codes generates a dll that I use in another application. Now, the wicked bug: - when I run the startRecognition method in the beginning of the execution of the other application, this codes works very well. But when I run it some time after the beginning, this codes works but the handleRecognition method is never called. I see that the words are recognized because they appear on the Microsoft Speech Recognition app, but the handler method is never called. Do you know what's the problem with this code? Thanks in advance :D

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• FillRect won't draw anything

  - by kaykun

  I'm trying to create a simple window in Win32 and draw a rectangle in it, but for some reason FillRect isn't working for me. Here's my source: #include <windows.h> #include "resource.h" RECT rect; LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam) { static PAINTSTRUCT ps; static HDC hDC; switch(msg) { case WM_PAINT: hDC = BeginPaint(hWnd, &ps); FillRect(hDC, &rect, (HBRUSH)(COLOR_WINDOW+1)); EndPaint(hWnd, &ps); break; case WM_CLOSE: DestroyWindow(hWnd); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hWnd, msg, wParam, lParam); } return 0; } int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { WNDCLASSEX wc; HWND hWnd; MSG msg; rect.left = 0; rect.right = 0; rect.top = 100; rect.bottom = 100; wc.cbSize = sizeof(WNDCLASSEX); wc.style = 0; wc.lpfnWndProc = WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon(NULL, IDI_APPLICATION); wc.hCursor = LoadCursor(NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH)(COLOR_ACTIVEBORDER+1); wc.lpszMenuName = MAKEINTRESOURCE(IDR_MAIN_MENU); wc.lpszClassName = "Main"; wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION); RegisterClassEx(&wc); hWnd = CreateWindowEx(NULL, "Main", "Main", WS_SYSMENU | WS_MINIMIZEBOX, CW_USEDEFAULT, CW_USEDEFAULT, 240, 360, NULL, NULL, hInstance, NULL); ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); while(GetMessage(&msg, NULL, 0, 0) > 0) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } Is there something I'm missing or doing wrong in my code? Thanks in advance

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• Node.js Cron Job Messing with Date Object

  - by PazoozaTest Pazman

  I'm trying to schedule several cron jobs to generate serial numbers for different entities within my web app. However I am running into this problem, when I'm looping each table, it says it has something to do with date.js. I'm not doing anything with a date object ? Not at this stage anyway. A couple of guesses is that the cron object is doing a date thing in its code and is referencing date.js. I'm using date.js to get access to things like ISO date. for (t in config.generatorTables) { console.log("t = " + config.generatorTables[t] + "\n\n"); var ts3 = azure.createTableService(); var jobSerialNumbers = new cronJob({ //cronTime: '*/' + rndNumber + ' * * * * *', cronTime: '*/1 * * * * *', onTick: function () { //console.log(new Date() + " calling topUpSerialNumbers \n\n"); manageSerialNumbers.topUpSerialNumbers(config.generatorTables[t], function () { }); }, start: false, timeZone: "America/Los_Angeles" }); ts3.createTableIfNotExists(config.generatorTables[t], function (error) { if (error === null) { var query = azure.TableQuery .select() .from(config.generatorTables[t]) .where('PartitionKey eq ?', '0') ts3.queryEntities(query, function (error, serialNumberEntities) { if (error === null && serialNumberEntities.length == 0) { manageSerialNumbers.generateNewNumbers(config.maxNumber, config.serialNumberSize, config.generatorTables[t], function () { jobSerialNumbers.start(); }); } else jobSerialNumbers.start(); }); } }); } And this is the error message I'm getting when I examine the server.js.logs\0.txt file: C:\node\w\WebRole1\public\javascripts\date.js:56 onsole.log('isDST'); return this.toString().match(/(E|C|M|P)(S|D)T/)[2] == "D" ^ TypeError: Cannot read property '2' of null at Date.isDST (C:\node\w\WebRole1\public\javascripts\date.js:56:110) at Date.getTimezone (C:\node\w\WebRole1\public\javascripts\date.js:56:228) at Object._getNextDateFrom (C:\node\w\WebRole1\node_modules\cron\lib\cron.js:88:30) at Object.sendAt (C:\node\w\WebRole1\node_modules\cron\lib\cron.js:51:17) at Object.getTimeout (C:\node\w\WebRole1\node_modules\cron\lib\cron.js:58:30) at Object.start (C:\node\w\WebRole1\node_modules\cron\lib\cron.js:279:33) at C:\node\w\WebRole1\server.js:169:46 at Object.generateNewNumbers (C:\node\w\WebRole1\utils\manageSerialNumbers.js:106:5) at C:\node\w\WebRole1\server.js:168:45 at C:\node\w\WebRole1\node_modules\azure\lib\services\table\tableservice.js:485:7 I am using this line in my database.js file: require('../public/javascripts/date'); is that correct that I only have to do this once, because date.js is global? I.e. it has a bunch of prototypes (extensions) for the inbuilt date object. Within manageSerialNumbers.js I am just doing a callback, their is no code executing as I've commented it all out, but still receiving this error. Any help or advice would be appreciated.

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• AudioTrack lag: obtainBuffer timed out

  - by BTR

  I'm playing WAVs on my Android phone by loading the file and feeding the bytes into AudioTrack.write() via the FileInputStream BufferedInputStream DataInputStream method. The audio plays fine and when it is, I can easily adjust sample rate, volume, etc on the fly with nice performance. However, it's taking about two full seconds for a track to start playing. I know AudioTrack has an inescapable delay, but this is ridiculous. Every time I play a track, I get this: 03-13 14:55:57.100: WARN/AudioTrack(3454): obtainBuffer timed out (is the CPU pegged?) 0x2e9348 user=00000960, server=00000000 03-13 14:55:57.340: WARN/AudioFlinger(72): write blocked for 233 msecs, 9 delayed writes, thread 0xba28 I've noticed that the delayed write count increases by one every time I play a track -- even across multiple sessions -- from the time the phone has been turned on. The block time is always 230 - 240ms, which makes sense considering a minimum buffer size of 9600 on this device (9600 / 44100). I've seen this message in countless searches on the Internet, but it usually seems to be related to not playing audio at all or skipping audio. In my case, it's just a delayed start. I'm running all my code in a high priority thread. Here's a truncated-yet-functional version of what I'm doing. This is the thread callback in my playback class. Again, this works (only playing 16-bit, 44.1kHz, stereo files right now), it just takes forever to start and has that obtainBuffer/delayed write message every time. public void run() { // Load file FileInputStream mFileInputStream; try { // mFile is instance of custom file class -- this is correct, // so don't sweat this line mFileInputStream = new FileInputStream(mFile.path()); } catch (FileNotFoundException e) {} BufferedInputStream mBufferedInputStream = new BufferedInputStream(mFileInputStream, mBufferLength); DataInputStream mDataInputStream = new DataInputStream(mBufferedInputStream); // Skip header try { if (mDataInputStream.available() > 44) mDataInputStream.skipBytes(44); } catch (IOException e) {} // Initialize device mAudioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, ConfigManager.SAMPLE_RATE, AudioFormat.CHANNEL_CONFIGURATION_STEREO, AudioFormat.ENCODING_PCM_16BIT, ConfigManager.AUDIO_BUFFER_LENGTH, AudioTrack.MODE_STREAM); mAudioTrack.play(); // Initialize buffer byte[] mByteArray = new byte[mBufferLength]; int mBytesToWrite = 0; int mBytesWritten = 0; // Loop to keep thread running while (mRun) { // This flag is turned on when the user presses "play" while (mPlaying) { try { // Check if data is available if (mDataInputStream.available() > 0) { // Read data from file and write to audio device mBytesToWrite = mDataInputStream.read(mByteArray, 0, mBufferLength); mBytesWritten += mAudioTrack.write(mByteArray, 0, mBytesToWrite); } } catch (IOException e) { } } } } If I can get past the artificially long lag, I can easily deal with the inherit latency by starting my write at a later, predictable position (ie, skip past the minimum buffer length when I start playing a file).

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• jquery animation problem using stop

  - by Flanders

  Hi! When running a Jquery animation like slideDown(), it looks like a number of element-specific css properties is set to be updated at a specific interval and when the animation is complete these properties are unset and the display property is simply set to auto or whatever. At least in firebug you can't see those temporary properties any more. The problem I've encountered is the scenario where we stop the slide down with stop(). The element is then left with the current temporary css values. Which is fine because it has to, but let us say that I stoped the slidedown because I have decided to slide it back up again a bit prematurely. It would look something like this: $(this).slideDown(2000) //The below events is not in queue but will rather start execute almost simultaneously as the above line. (dont remember the exact syntax) $(this).delay(1000).stop().slideUp(2000) The above code might not make much sense, but the point is: After 1 second of sliding down the animation is stopped and it starts to slide back up. Works like a charm. BUT!!! And here is the problem. Once it it has slid back up the elements css properties are reset to the exact values it had 1000ms into the slideDown() animation (when stop() was called). If we now try to run the following: $(this).slideDown(2000) It will slide down to the very point the prior slideDown was aborted and not further at half the speed (since it uses the same time for approximately half the height). This is because the css properties were saved as I see it. But it is not especially wished for. Of course I want it to slide all the way down this time. Due to UI interaction that is hard to predict everything might soon break. The longer animations we use increases the risk of something like this happening. Is this to be considered a bug, or am I doing something wrong? Or maybe it's just a feature that is not supported? I guess I can use a callback function to reset the css properties, but depending on the animation used, different css properties are used to render it, and covering your back would result in quite a not-so-fancy solution.

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• Can't access Elements previously created by innerHTML with Javascript/Prototype

  - by Joe Hopfgartner

  I am setting the innerHTML variable of a div with contents from an ajax request: new Ajax.Request('/search/ajax/allakas/?ext_id='+extid, { method:'get', onSuccess: function(transport){ var response = transport.responseText || "no response text"; $('admincovers_content').innerHTML=response; }, onFailure: function(){ alert('Something went wrong...') } }); The response text cotains a form: <form id="akas-admin" method="post" action="/search/ajax/modifyakas/"> <input type="text" name="formfield" value="i am a form field"/> </form> Then I call a functiont that should submit that form: $('akas-admin').request({ onComplete: function(transport){ //alert('Form data saved! '+transport.responseText) $('admincovers_content').innerHTML=transport.responseText; } }); The problem is $('akas-admin) returns null , I tried to put the form with this id in the original document, which works. Question: Can I somehow "revalidate" the dom or access elements that have been inserted with innerHTML? Edit Info: document.getElementById("akas-admin").submit() works just fine, problem is i don't want to reload the whole page but post the form over ajax and get the response text in a callback function. Edit: Based on the answers provided, i replaced my function that does the request with the following observer: Event.observe(document.body, 'click', function(event) { var e = Event.element(event); if ('aka-savelink' == e.identify()) { alert('savelink clicked!'); if (el = e.findElement('#akas-admin')) { alert('found form to submit it has id: '+el.identify()); el.request({ onComplete: function(transport){ alert('Form data saved! '+transport.responseText) $('admincovers_content').innerHTML=transport.responseText; } }); } } }); problem is that i get as far as alert('savelink clicked!'); . findelement doesnt return the form. i tried to place the save link above and under the form. both doesnt work. i also think this approach is a bit clumsy and i am doing it wrong. could anyone point me in the right direction?

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• JQuery, Load() contents with plugins

  - by Galas

  I know this is not a completely new question, but none of the answers solved my problem... I have built a little menu that uses load() to load image galleries (as external html files) into a specified div ("content"). The said galleries make use of a JQuery plugin (SlideJS). Now I know that load() does not work for script tags and that I need to use $.getscript in the callback function in order to run the scripts, but it does not work. I have two .js files that need to be loaded: one is the plugin itself and another one is a smaller script with a preloader and the animations for the captions. I can't seem to merge them together; if I put them into the same document, the script won't run. So I tried just using $.getscript to load the two files. I tried using two callbacks as suggested in other answer (I know it's not ideal...): $("#proposal").click(function(){ $(this).addClass('selected'); $("a:not(:#proposal)").removeClass('selected'); $("#content").load("works/proposal/proposal.html", function(){ $.getScript("js/slide.js", function (){ $.getScript("js/slidepage.js"); }); }); }); and I tried a variable (read about it in some other faq, not sure if the syntax is correct) $("#proposal").click(function(){ $(this).addClass('selected'); $("a:not(:#proposal)").removeClass('selected'); $("#content").load("works/proposal/proposal.html", function(){ var scripts = ['js/slide.js','js/slidepage.js']; $.getScript(scripts); }); }); So none of these work. What am I doing wrong? I'm just starting on jquery and my js knowledge is very limited. Should I just merge the two .js files together using minify or something? One of them is already minified, but I've tried with a non-minified version and it does not work either. Can anyone suggest any other solution around this problem? I thought of just having the div embedded in the main document and just showing it on click, but I'll have at least 4 galleries with about 8 to 10 images each... its a lot of images to load in the main page, so I don't think its the best way. if you need me to post any more code, please ask! Thanks in advance for all your help!

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• Is this a good approach to dealing with tagging?

  - by Mel

  Can this code be optimized or re-factored? Is this an optimal approach to tagging? The following code is a callback in my posts model. It creates a record that associates a tag with a post in a QuestionsTags joiner table. When necessary, if a given tag does not already exist in the tags table, the function creates it, then uses its id to create the new record in the QuestionsTags table. The difficulty with this approach is the QuestionsTags table depends on data in the tags table which may or may not exist. The function assumes the following tables: tags(id, tagName), posts(tags) // Comma delimited list questionsTags(postId, tagId) The idea is to loop over a delimited list of tags submitted with a post and check to see if each tag already exists in the tags table If tag exists: Check to see if there's already a QuestionTag record for this post and this tag in the QuestionTags table. If yes, do nothing (the association already exists) If no, create a new QuestionTag record using the id of the existing tag and the postId If tag does not already exist: Create the new tag in the tags table Use its id to create a new QuestionsTags record Code /** * @hint Sets tags for a given question. **/ private function setTags() { // Loop over the comma and space delmited list of tags for (local.i = 1; local.i LTE ListLen(this.tags, ", "); local.i = (local.i + 1)) { // Check if the tag already exists in the database local.tag = model("tag").findOneByTagName(local.i); // If the tag exists, look for an existing association between the tag and the question in the QuestionTag table if (IsObject(local.tag)) { local.questionTag = model("questionTag").findOneByPostIdAndTagId(values="#this.postId#,#local.tag.id#"); // If no assciatione exists, create a new QuestionTag record using the tagId and the postId if (! IsObject(local.questionTag)) { local.newQuestionTag = model("questionTag").new(postId = this.id, tagId = local.tag.id); // Abort if the saving the new QuestionTag is unsuccesful if (! local.newQuestionTag.save()) { return false; } } } // If the tag does not exist create it else { local.newTag = model("tag").new(tagName = local.i, userId = this.ownerUserId); // Abort if the the new tag is not saved successfully if (! local.newTag.save()) { return false; } // Otherwise create a new association in the QuestionTags table using the id of the newly created tag and the postId local.newQuestionTag = model("questionTag").new(postId = this.id, tagId = local.newTag.id); // Abort if the new QuestionTag does not save correctly if (! local.newQuestionTag.save()) { return false; } } } } FYI: I'm using CFWheels in my application, which explains the ORM functions used.

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• Declare Ajax-webservicecall OnSuccess method anonymous.

  - by user333113

  I write a lot of ajax javascript code and have a little design problem which I'm not totally satisfied with. A lot of times I end up with writing something like this: var typeOfPopup; function RetrievePopupContent(_typeOfPopup) { switch (_typeOfPopup) { case Popup1: WebService.RetrievePopup1Content(param1, param2, DisplayPopup, OnError); break; case Popup2: WebService.RetrievePopup2Content(param1, param2, DisplayPopup, OnError); break; } typeOfPopup = _typeOfPopup; } function DisplayPopup(result) { switch (typeOfPopup) { case Popup1: $get('Popup1').innerHTML = result; break; case Popup2: $get('Popup2').innerHTML = result; break; } Allright. This is a simplified example of what I mean. Often I end up with a lot worse code I believe. What I don't like is the global state variabel outside the functions. One solution I wasn't thinking about when writing this code is to send a context object. I believe you could write something like this: function RetrievePopupContent(typeOfPopup) { switch (typeOfPopup) { case Popup1: WebService.RetrievePopup1Content(param1, param2, DisplayPopup, OnError, typeOfPopup); break; case Popup2: WebService.RetrievePopup2Content(param1, param2, DisplayPopup, OnError, typeOfPopup); break; } } function DisplayPopup(result, typeOfPopup) { switch (typeOfPopup) { case Popup1: $get('Popup1').innerHTML = result; break; case Popup2: $get('Popup2').innerHTML = result; break; } Is this the recommended way? What I also want to do is to be able to write something like this: function RetrievePopupContent(typeOfPopup) { switch (typeOfPopup) { case Popup1: WebService.RetrievePopup1Content(param1, param2, new function(result) { $get('Popup1').innerHTML = result; }, OnError); break; case Popup2: WebService.RetrievePopup2Content(param1, param2, new function(result) { $get('Popup2').innerHTML = result; }, OnError); break; } } Is this possible at all? To declare the callback function anonymous? I am grateful for all opinions on the two options I mentioned myself and also new alternatives to get rid of my global variables I have used this way.

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• SSH X11 not working

  - by azat

  I have a home and work computer, the home computer has a static IP address. If I ssh from my work computer to my home computer, the ssh connection works but X11 applications are not displayed. In my /etc/ssh/sshd_config at home: X11Forwarding yes X11DisplayOffset 10 X11UseLocalhost yes At work I have tried the following commands: xhost + home HOME_IP ssh -X home ssh -X HOME_IP ssh -Y home ssh -Y HOME_IP My /etc/ssh/ssh_config at work: Host * ForwardX11 yes ForwardX11Trusted yes My ~/.ssh/config at work: Host home HostName HOME_IP User azat PreferredAuthentications password ForwardX11 yes My ~/.Xauthority at work: -rw------- 1 azat azat 269 Jun 7 11:25 .Xauthority My ~/.Xauthority at home: -rw------- 1 azat azat 246 Jun 7 19:03 .Xauthority But it doesn't work After I make an ssh connection to home: $ echo $DISPLAY localhost:10.0 $ kate X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. X11 connection rejected because of wrong authentication. kate: cannot connect to X server localhost:10.0 I use iptables at home, but I've allowed port 22. According to what I've read that's all I need. UPD. With -vvv ... debug2: callback start debug2: x11_get_proto: /usr/bin/xauth list :0 2/dev/null debug1: Requesting X11 forwarding with authentication spoofing. debug2: channel 1: request x11-req confirm 1 debug2: client_session2_setup: id 1 debug2: fd 3 setting TCP_NODELAY debug2: channel 1: request pty-req confirm 1 ... When try to launch kate: debug1: client_input_channel_open: ctype x11 rchan 2 win 65536 max 16384 debug1: client_request_x11: request from 127.0.0.1 55486 debug2: fd 8 setting O_NONBLOCK debug3: fd 8 is O_NONBLOCK debug1: channel 2: new [x11] debug1: confirm x11 debug2: X11 connection uses different authentication protocol. X11 connection rejected because of wrong authentication. debug2: X11 rejected 2 i0/o0 debug2: channel 2: read failed debug2: channel 2: close_read debug2: channel 2: input open - drain debug2: channel 2: ibuf empty debug2: channel 2: send eof debug2: channel 2: input drain - closed debug2: channel 2: write failed debug2: channel 2: close_write debug2: channel 2: output open - closed debug2: X11 closed 2 i3/o3 debug2: channel 2: send close debug2: channel 2: rcvd close debug2: channel 2: is dead debug2: channel 2: garbage collecting debug1: channel 2: free: x11, nchannels 3 debug3: channel 2: status: The following connections are open: #1 client-session (t4 r0 i0/0 o0/0 fd 5/6 cc -1) #2 x11 (t7 r2 i3/0 o3/0 fd 8/8 cc -1) # The same as above repeate about 7 times kate: cannot connect to X server localhost:10.0 UPD2 Please provide your Linux distribution & version number. Are you using a default GNOME or KDE environment for X or something else you customized yourself? azat:~$ kded4 -version Qt: 4.7.4 KDE Development Platform: 4.6.5 (4.6.5) KDE Daemon: $Id$ Are you invoking ssh directly on a command line from a terminal window? What terminal are you using? xterm, gnome-terminal, or? How did you start the terminal running in the X environment? From a menu? Hotkey? or ? From terminal emulator `yakuake` Manualy press `Ctrl + N` and write commands Can you run xeyes from the same terminal window where the ssh -X fails? `xeyes` - is not installed But `kate` or another kde app is running Are you invoking the ssh command as the same user that you're logged into the X session as? From the same user UPD3 I also download ssh sources, and using debug2() write why it's report that version is different It see some cookies, and one of them is empty, another is MIT-MAGIC-COOKIE-1

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• Red Hat Yum not working out of the box?

  - by Tucker

  I have a server runnning Red Hat Enterprise Linux v5.6 in the cloud. My project constraints do not allow me to use another OS. When I created the cloud server, I was able to SSH into it and access the shell. I next ran the command: sudo yum update But the command failed. About a month ago I created another server with the same machine image and didn't have that error. Why is it failing now? The following is the terminal output sudo yum update Loaded plugins: security Repository rhel-server is listed more than once in the configuration Traceback (most recent call last): File "/usr/bin/yum", line 29, in ? yummain.user_main(sys.argv[1:], exit_code=True) File "/usr/share/yum-cli/yummain.py", line 309, in user_main errcode = main(args) File "/usr/share/yum-cli/yummain.py", line 178, in main result, resultmsgs = base.doCommands() File "/usr/share/yum-cli/cli.py", line 345, in doCommands self._getTs(needTsRemove) File "/usr/lib/python2.4/site-packages/yum/depsolve.py", line 101, in _getTs self._getTsInfo(remove_only) File "/usr/lib/python2.4/site-packages/yum/depsolve.py", line 112, in _getTsInfo pkgSack = self.pkgSack File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 662, in <lambda> pkgSack = property(fget=lambda self: self._getSacks(), File "/usr/lib/python2.4/site-packages/yum/__init__.py", line 502, in _getSacks self.repos.populateSack(which=repos) File "/usr/lib/python2.4/site-packages/yum/repos.py", line 260, in populateSack sack.populate(repo, mdtype, callback, cacheonly) File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 168, in populate if self._check_db_version(repo, mydbtype): File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 226, in _check_db_version return repo._check_db_version(mdtype) File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1233, in _check_db_version repoXML = self.repoXML File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1406, in <lambda> repoXML = property(fget=lambda self: self._getRepoXML(), File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1398, in _getRepoXML self._loadRepoXML(text=self) File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1388, in _loadRepoXML return self._groupLoadRepoXML(text, ["primary"]) File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1372, in _groupLoadRepoXML if self._commonLoadRepoXML(text): File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1208, in _commonLoadRepoXML result = self._getFileRepoXML(local, text) File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 989, in _getFileRepoXML cache=self.http_caching == 'all') File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 826, in _getFile http_headers=headers, File "/usr/lib/python2.4/site-packages/urlgrabber/mirror.py", line 412, in urlgrab return self._mirror_try(func, url, kw) File "/usr/lib/python2.4/site-packages/urlgrabber/mirror.py", line 398, in _mirror_try return func_ref( *(fullurl,), **kwargs ) File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 936, in urlgrab return self._retry(opts, retryfunc, url, filename) File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 854, in _retry r = apply(func, (opts,) + args, {}) File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 922, in retryfunc fo = URLGrabberFileObject(url, filename, opts) File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 1010, in __init__ self._do_open() File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 1093, in _do_open fo, hdr = self._make_request(req, opener) File "/usr/lib/python2.4/site-packages/urlgrabber/grabber.py", line 1202, in _make_request fo = opener.open(req) File "/usr/lib64/python2.4/urllib2.py", line 358, in open response = self._open(req, data) File "/usr/lib64/python2.4/urllib2.py", line 376, in _open '_open', req) File "/usr/lib64/python2.4/urllib2.py", line 337, in _call_chain result = func(*args) File "/usr/lib64/python2.4/site-packages/M2Crypto/m2urllib2.py", line 82, in https_open h.request(req.get_method(), req.get_selector(), req.data, headers) File "/usr/lib64/python2.4/httplib.py", line 810, in request self._send_request(method, url, body, headers) File "/usr/lib64/python2.4/httplib.py", line 833, in _send_request self.endheaders() File "/usr/lib64/python2.4/httplib.py", line 804, in endheaders self._send_output() File "/usr/lib64/python2.4/httplib.py", line 685, in _send_output self.send(msg) File "/usr/lib64/python2.4/httplib.py", line 652, in send self.connect() File "/usr/lib64/python2.4/site-packages/M2Crypto/httpslib.py", line 47, in connect self.sock.connect((self.host, self.port)) File "/usr/lib64/python2.4/site-packages/M2Crypto/SSL/Connection.py", line 174, in connect ret = self.connect_ssl() File "/usr/lib64/python2.4/site-packages/M2Crypto/SSL/Connection.py", line 167, in connect_ssl return m2.ssl_connect(self.ssl, self._timeout) M2Crypto.SSL.SSLError: certificate verify failed

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• Have I pushed the limits of my current VPS or is there room for optimization?

  - by JRameau

  I am currently on a mediatemple DV server (basic) 512mb dedicated ram, this is a CentOS based VPS with Plesk and Virtuozzo. My experience with it from day 1 has been bad and I only could sooth my server issues with several caching "Band-aids," but my sites are not as small as they were a year ago either so the issues have worsen. I have 3 Drupal installs running on separate (plesk) domains, 1 of those drupal installs is a multisite, that consists of 5-6 sites 2 of those sites are bringing in actual traffic. Those caching "Band-aids" I mentioned are APC, which seemed to help alot initially, and Drupal's Boost, which is considered a poorman's Varnish, it makes all my pages static for anonymous users. Last 30day combined estimate on Google Ananlytics: 90k visitors 260k pageviews. Issue: alot of downtime, I am continually checking if my sites are up, and lately I have been finding it down more than 3 times daily. Restarting Apache will bring it back up, for some time. I have google search every error message and looked up ways to optimize my DV server, and I am beyond stump what is my next move. Is this server bad, have I hit a impossibly low restriction such as the 12mb kernel memory barrier (kmemsize), is it on my end, do I need to optimize some more? *I have provided as much information as I can below, any help or suggestions given will be appreciated Common Error messages I see in the log: [error] (12)Cannot allocate memory: fork: Unable to fork new process [error] make_obcallback: could not import mod_python.apache.\n Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 21, in ? import traceback File "/usr/lib/python2.4/traceback.py", line 3, in ? import linecache ImportError: No module named linecache [error] python_handler: no interpreter callback found. [warn-phpd] mmap cache can't open /var/www/vhosts/***/httpdocs/*** - Too many open files in system (pid ***) [alert] Child 8125 returned a Fatal error... Apache is exiting! [emerg] (43)Identifier removed: couldn't grab the accept mutex [emerg] (22)Invalid argument: couldn't release the accept mutex cat /proc/user_beancounters: Version: 2.5 uid resource held maxheld barrier limit failcnt 41548: kmemsize 4582652 5306699 12288832 13517715 21105036 lockedpages 0 0 600 600 0 privvmpages 38151 42676 229036 249036 0 shmpages 16274 16274 17237 17237 2 dummy 0 0 0 0 0 numproc 43 46 300 300 0 physpages 27260 29528 0 2147483647 0 vmguarpages 0 0 131072 2147483647 0 oomguarpages 27270 29538 131072 2147483647 0 numtcpsock 21 29 300 300 0 numflock 8 8 480 528 0 numpty 1 1 30 30 0 numsiginfo 0 1 1024 1024 0 tcpsndbuf 648440 675272 2867477 4096277 1711499 tcprcvbuf 301620 359716 2867477 4096277 0 othersockbuf 4472 4472 1433738 2662538 0 dgramrcvbuf 0 0 1433738 1433738 0 numothersock 12 12 300 300 0 dcachesize 0 0 2684271 2764800 0 numfile 3447 3496 6300 6300 3872 dummy 0 0 0 0 0 dummy 0 0 0 0 0 dummy 0 0 0 0 0 numiptent 14 14 200 200 0 TOP: (In January the load avg was really high 3-10, I was able to bring it down where it is currently is by giving APC more memory play around with) top - 16:46:07 up 2:13, 1 user, load average: 0.34, 0.20, 0.20 Tasks: 40 total, 2 running, 37 sleeping, 0 stopped, 1 zombie Cpu(s): 0.3% us, 0.1% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si Mem: 916144k total, 156668k used, 759476k free, 0k buffers Swap: 0k total, 0k used, 0k free, 0k cached MySQLTuner: (after optimizing every table and repairing any table with overage I got the fragmented count down to 86) [--] Data in MyISAM tables: 285M (Tables: 1105) [!!] Total fragmented tables: 86 [--] Up for: 2h 44m 38s (409K q [41.421 qps], 6K conn, TX: 1B, RX: 174M) [--] Reads / Writes: 79% / 21% [--] Total buffers: 58.0M global + 2.7M per thread (100 max threads) [!!] Query cache prunes per day: 675307 [!!] Temporary tables created on disk: 35% (7K on disk / 20K total)

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• Capturing and Transforming ASP.NET Output with Response.Filter

  - by Rick Strahl

  During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Parallelism in .NET – Part 18, Task Continuations with Multiple Tasks

  - by Reed

  In my introduction to Task continuations I demonstrated how the Task class provides a more expressive alternative to traditional callbacks.  Task continuations provide a much cleaner syntax to traditional callbacks, but there are other reasons to switch to using continuations… Task continuations provide a clean syntax, and a very simple, elegant means of synchronizing asynchronous method results with the user interface.  In addition, continuations provide a very simple, elegant means of working with collections of tasks. Prior to .NET 4, working with multiple related asynchronous method calls was very tricky.  If, for example, we wanted to run two asynchronous operations, followed by a single method call which we wanted to run when the first two methods completed, we’d have to program all of the handling ourselves.  We would likely need to take some approach such as using a shared callback which synchronized against a common variable, or using a WaitHandle shared within the callbacks to allow one to wait for the second.  Although this could be accomplished easily enough, it requires manually placing this handling into every algorithm which requires this form of blocking.  This is error prone, difficult, and can easily lead to subtle bugs. Similar to how the Task class static methods providing a way to block until multiple tasks have completed, TaskFactory contains static methods which allow a continuation to be scheduled upon the completion of multiple tasks: TaskFactory.ContinueWhenAll. This allows you to easily specify a single delegate to run when a collection of tasks has completed.  For example, suppose we have a class which fetches data from the network.  This can be a long running operation, and potentially fail in certain situations, such as a server being down.  As a result, we have three separate servers which we will “query” for our information.  Now, suppose we want to grab data from all three servers, and verify that the results are the same from all three. With traditional asynchronous programming in .NET, this would require using three separate callbacks, and managing the synchronization between the various operations ourselves.  The Task and TaskFactory classes simplify this for us, allowing us to write: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAll( new[] {server1, server2, server3 }, (tasks) => { // Propogate exceptions (see below) Task.WaitAll(tasks); return this.CompareTaskResults( tasks[0].Result, tasks[1].Result, tasks[2].Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is clean, simple, and elegant.  The one complication is the Task.WaitAll(tasks); statement. Although the continuation will not complete until all three tasks (server1, server2, and server3) have completed, there is a potential snag.  If the networkClass.GetResults method fails, and raises an exception, we want to make sure to handle it cleanly.  By using Task.WaitAll, any exceptions raised within any of our original tasks will get wrapped into a single AggregateException by the WaitAll method, providing us a simplified means of handling the exceptions.  If we wait on the continuation, we can trap this AggregateException, and handle it cleanly.  Without this line, it’s possible that an exception could remain uncaught and unhandled by a task, which later might trigger a nasty UnobservedTaskException.  This would happen any time two of our original tasks failed. Just as we can schedule a continuation to occur when an entire collection of tasks has completed, we can just as easily setup a continuation to run when any single task within a collection completes.  If, for example, we didn’t need to compare the results of all three network locations, but only use one, we could still schedule three tasks.  We could then have our completion logic work on the first task which completed, and ignore the others.  This is done via TaskFactory.ContinueWhenAny: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAny( new[] {server1, server2, server3 }, (firstTask) => { return this.ProcessTaskResult(firstTask.Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, instead of working with all three tasks, we’re just using the first task which finishes.  This is very useful, as it allows us to easily work with results of multiple operations, and “throw away” the others.  However, you must take care when using ContinueWhenAny to properly handle exceptions.  At some point, you should always wait on each task (or use the Task.Result property) in order to propogate any exceptions raised from within the task.  Failing to do so can lead to an UnobservedTaskException.

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• Authenticating clients in the new WCF Http stack

  - by cibrax

  About this time last year, I wrote a couple of posts about how to use the “Interceptors” from the REST starker kit for implementing several authentication mechanisms like “SAML”, “Basic Authentication” or “OAuth” in the WCF Web programming model. The things have changed a lot since then, and Glenn finally put on our hands a new version of the Web programming model that deserves some attention and I believe will help us a lot to build more Http oriented services in the .NET stack. What you can get today from wcf.codeplex.com is a preview with some cool features like Http Processors (which I already discussed here), a new and improved version of the HttpClient library, Dependency injection and better TDD support among others. However, the framework still does not support an standard way of doing client authentication on the services (This is something planned for the upcoming releases I believe). For that reason, moving the existing authentication interceptors to this new programming model was one of the things I did in the last few days. In order to make authentication simple and easy to extend,  I first came up with a model based on what I called “Authentication Interceptors”. An authentication interceptor maps to an existing Http authentication mechanism and implements the following interface, public interface IAuthenticationInterceptor{ string Scheme { get; } bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal);} An authentication interceptors basically needs to returns the http authentication schema that implements in the property “Scheme”, and implements the authentication mechanism in the method “DoAuthentication”. As you can see, this last method “DoAuthentication” only relies on the HttpRequestMessage and HttpResponseMessage classes, making the testing of this interceptor very simple (There is no need to do some black magic with the WCF context or messages). After this, I implemented a couple of interceptors for supporting basic authentication and brokered authentication with SAML (using WIF) in my services. The following code illustrates how the basic authentication interceptors looks like. public class BasicAuthenticationInterceptor : IAuthenticationInterceptor{ Func<UsernameAndPassword, bool> userValidation; string realm;  public BasicAuthenticationInterceptor(Func<UsernameAndPassword, bool> userValidation, string realm) { if (userValidation == null) throw new ArgumentNullException("userValidation");  if (string.IsNullOrEmpty(realm)) throw new ArgumentNullException("realm");  this.userValidation = userValidation; this.realm = realm; }  public string Scheme { get { return "Basic"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { string[] credentials = ExtractCredentials(request); if (credentials.Length == 0 || !AuthenticateUser(credentials[0], credentials[1])) { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied"); response.Headers.WwwAuthenticate.Add(new AuthenticationHeaderValue("Basic", "realm=" + this.realm));  principal = null;  return false; } else { principal = new GenericPrincipal(new GenericIdentity(credentials[0]), new string[] {});  return true; } }  private string[] ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme.StartsWith("Basic")) { string encodedUserPass = request.Headers.Authorization.Parameter.Trim();  Encoding encoding = Encoding.GetEncoding("iso-8859-1"); string userPass = encoding.GetString(Convert.FromBase64String(encodedUserPass)); int separator = userPass.IndexOf(':');  string[] credentials = new string[2]; credentials[0] = userPass.Substring(0, separator); credentials[1] = userPass.Substring(separator + 1);  return credentials; }  return new string[] { }; }  private bool AuthenticateUser(string username, string password) { var usernameAndPassword = new UsernameAndPassword { Username = username, Password = password };  if (this.userValidation(usernameAndPassword)) { return true; }  return false; }} This interceptor receives in the constructor a callback in the form of a Func delegate for authenticating the user and the “realm”, which is required as part of the implementation. The rest is a general implementation of the basic authentication mechanism using standard http request and response messages. I also implemented another interceptor for authenticating a SAML token with WIF. public class SamlAuthenticationInterceptor : IAuthenticationInterceptor{ SecurityTokenHandlerCollection handlers = null;  public SamlAuthenticationInterceptor(SecurityTokenHandlerCollection handlers) { if (handlers == null) throw new ArgumentNullException("handlers");  this.handlers = handlers; }  public string Scheme { get { return "saml"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { SecurityToken token = ExtractCredentials(request);  if (token != null) { ClaimsIdentityCollection claims = handlers.ValidateToken(token);  principal = new ClaimsPrincipal(claims);  return true; } else { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied");  principal = null;  return false; } }  private SecurityToken ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme == "saml") { XmlTextReader xmlReader = new XmlTextReader(new StringReader(request.Headers.Authorization.Parameter));  var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection(); SecurityToken token = col.ReadToken(xmlReader);  return token; }  return null; }}This implementation receives a “SecurityTokenHandlerCollection” instance as part of the constructor. This class is part of WIF, and basically represents a collection of token managers to know how to handle specific xml authentication tokens (SAML is one of them). I also created a set of extension methods for injecting these interceptors as part of a service route when the service is initialized. var basicAuthentication = new BasicAuthenticationInterceptor((u) => true, "ContactManager");var samlAuthentication = new SamlAuthenticationInterceptor(serviceConfiguration.SecurityTokenHandlers); // use MEF for providing instancesvar catalog = new AssemblyCatalog(typeof(Global).Assembly);var container = new CompositionContainer(catalog);var configuration = new ContactManagerConfiguration(container); RouteTable.Routes.AddServiceRoute<ContactResource>("contact", configuration, basicAuthentication, samlAuthentication);RouteTable.Routes.AddServiceRoute<ContactsResource>("contacts", configuration, basicAuthentication, samlAuthentication); In the code above, I am injecting the basic authentication and saml authentication interceptors in the “contact” and “contacts” resource implementations that come as samples in the code preview. I will use another post to discuss more in detail how the brokered authentication with SAML model works with this new WCF Http bits. The code is available to download in this location.

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