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  • Fake ISAPI Handler to serve static files with extention that are rewritted by url rewriter

    - by developerit
    Introduction I often map html extention to the asp.net dll in order to use url rewritter with .html extentions. Recently, in the new version of www.nouvelair.ca, we renamed all urls to end with .html. This works great, but failed when we used FCK Editor. Static html files would not get serve because we mapped the html extension to the .NET Framework. We can we do to to use .html extension with our rewritter but still want to use IIS behavior with static html files. Analysis I thought that this could be resolve with a simple HTTP handler. We would map urls of static files in our rewriter to this handler that would read the static file and serve it, just as IIS would do. Implementation This is how I coded the class. Note that this may not be bullet proof. I only tested it once and I am sure that the logic behind IIS is more complicated that this. If you find errors or think of possible improvements, let me know. Imports System.Web Imports System.Web.Services ' Author: Nicolas Brassard ' For: Solutions Nitriques inc. http://www.nitriques.com ' Date Created: April 18, 2009 ' Last Modified: April 18, 2009 ' License: CPOL (http://www.codeproject.com/info/cpol10.aspx) ' Files: ISAPIDotNetHandler.ashx ' ISAPIDotNetHandler.ashx.vb ' Class: ISAPIDotNetHandler ' Description: Fake ISAPI handler to serve static files. ' Usefull when you want to serve static file that has a rewrited extention. ' Example: It often map html extention to the asp.net dll in order to use url rewritter with .html. ' If you want to still serve static html file, add a rewritter rule to redirect html files to this handler Public Class ISAPIDotNetHandler Implements System.Web.IHttpHandler Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest ' Since we are doing the job IIS normally does with html files, ' we set the content type to match html. ' You may want to customize this with your own logic, if you want to serve ' txt or xml or any other text file context.Response.ContentType = "text/html" ' We begin a try here. Any error that occurs will result in a 404 Page Not Found error. ' We replicate the behavior of IIS when it doesn't find the correspoding file. Try ' Declare a local variable containing the value of the query string Dim uri As String = context.Request("fileUri") ' If the value in the query string is null, ' throw an error to generate a 404 If String.IsNullOrEmpty(uri) Then Throw New ApplicationException("No fileUri") End If ' If the value in the query string doesn't end with .html, then block the acces ' This is a HUGE security hole since it could permit full read access to .aspx, .config, etc. If Not uri.ToLower.EndsWith(".html") Then ' throw an error to generate a 404 Throw New ApplicationException("Extention not allowed") End If ' Map the file on the server. ' If the file doesn't exists on the server, it will throw an exception and generate a 404. Dim fullPath As String = context.Server.MapPath(uri) ' Read the actual file Dim stream As IO.StreamReader = FileIO.FileSystem.OpenTextFileReader(fullPath) ' Write the file into the response context.Response.Output.Write(stream.ReadToEnd) ' Close and Dipose the stream stream.Close() stream.Dispose() stream = Nothing Catch ex As Exception ' Set the Status Code of the response context.Response.StatusCode = 404 'Page not found ' For testing and bebugging only ! This may cause a security leak ' context.Response.Output.Write(ex.Message) Finally ' In all cases, flush and end the response context.Response.Flush() context.Response.End() End Try End Sub ' Automaticly generated by Visual Studio ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable Get Return False End Get End Property End Class Conclusion As you see, with our static files map to this handler using query string (ex.: /ISAPIDotNetHandler.ashx?fileUri=index.html) you will have the same behavior as if you ask for the uri /index.html. Finally, test this only in IIS with the html extension map to aspnet_isapi.dll. Url rewritting will work in Casini (Internal Web Server shipped with Visual Studio) but it’s not the same as with IIS since EVERY request is handle by .NET. Versions First release

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  • Issues with signal handling [closed]

    - by user34790
    I am trying to actually study the signal handling behavior in multiprocess system. I have a system where there are three signal generating processes generating signals of type SIGUSR1 and SIGUSR1. I have two handler processes that handle a particular type of signal. I have another monitoring process that also receives the signals and then does its work. I have a certain issue. Whenever my signal handling processes generate a signal of a particular type, it is sent to the process group so it is received by the signal handling processes as well as the monitoring processes. Whenever the signal handlers of monitoring and signal handling processes are called, I have printed to indicate the signal handling. I was expecting a uniform series of calls for the signal handlers of the monitoring and handling processes. However, looking at the output I could see like at the beginning the monitoring and signal handling processes's signal handlers are called uniformly. However, after I could see like signal handler processes handlers being called in a burst followed by the signal handler of monitoring process being called in a burst. Here is my code and output #include <iostream> #include <sys/types.h> #include <sys/wait.h> #include <sys/time.h> #include <signal.h> #include <cstdio> #include <stdlib.h> #include <sys/ipc.h> #include <sys/shm.h> #define NUM_SENDER_PROCESSES 3 #define NUM_HANDLER_PROCESSES 4 #define NUM_SIGNAL_REPORT 10 #define MAX_SIGNAL_COUNT 100000 using namespace std; volatile int *usrsig1_handler_count; volatile int *usrsig2_handler_count; volatile int *usrsig1_sender_count; volatile int *usrsig2_sender_count; volatile int *lock_1; volatile int *lock_2; volatile int *lock_3; volatile int *lock_4; volatile int *lock_5; volatile int *lock_6; //Used only by the monitoring process volatile int monitor_count; volatile int usrsig1_monitor_count; volatile int usrsig2_monitor_count; double time_1[NUM_SIGNAL_REPORT]; double time_2[NUM_SIGNAL_REPORT]; //Used only by the main process int total_signal_count; //For shared memory int shmid; const int shareSize = sizeof(int) * (10); double timestamp() { struct timeval tp; gettimeofday(&tp, NULL); return (double)tp.tv_sec + tp.tv_usec / 1000000.; } pid_t senders[NUM_SENDER_PROCESSES]; pid_t handlers[NUM_HANDLER_PROCESSES]; pid_t reporter; void signal_catcher_1(int); void signal_catcher_2(int); void signal_catcher_int(int); void signal_catcher_monitor(int); void signal_catcher_main(int); void terminate_processes() { //Kill the child processes int status; cout << "Time up terminating the child processes" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); //Wait for the child processes to finish for(int i=0; i<NUM_SENDER_PROCESSES; i++) { waitpid(senders[i], &status, 0); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { waitpid(handlers[i], &status, 0); } waitpid(reporter, &status, 0); } int main(int argc, char *argv[]) { if(argc != 2) { cout << "Required parameters missing. " << endl; cout << "Option 1 = 1 which means run for 30 seconds" << endl; cout << "Option 2 = 2 which means run until 100000 signals" << endl; exit(0); } int option = atoi(argv[1]); pid_t pid; if(option == 2) { if(signal(SIGUSR1, signal_catcher_main) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, signal_catcher_main) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } if(signal(SIGINT, signal_catcher_int) == SIG_ERR) { perror("3"); exit(1); } /////////////////////////////////////////////////////////////////////////////////////// ////////////////////// Initializing the shared memory ///////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////// cout << "Initializing the shared memory" << endl; if ((shmid=shmget(IPC_PRIVATE,shareSize,IPC_CREAT|0660))< 0) { perror("shmget fail"); exit(1); } usrsig1_handler_count = (int *) shmat(shmid, NULL, 0); usrsig2_handler_count = usrsig1_handler_count + 1; usrsig1_sender_count = usrsig2_handler_count + 1; usrsig2_sender_count = usrsig1_sender_count + 1; lock_1 = usrsig2_sender_count + 1; lock_2 = lock_1 + 1; lock_3 = lock_2 + 1; lock_4 = lock_3 + 1; lock_5 = lock_4 + 1; lock_6 = lock_5 + 1; //Initialize them to be zero *usrsig1_handler_count = 0; *usrsig2_handler_count = 0; *usrsig1_sender_count = 0; *usrsig2_sender_count = 0; *lock_1 = 0; *lock_2 = 0; *lock_3 = 0; *lock_4 = 0; *lock_5 = 0; *lock_6 = 0; cout << "End of initializing the shared memory" << endl; ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////// End of initializing the shared memory /////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////Registering the signal handlers/////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal handlers" << endl; for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { if((pid = fork()) == 0) { if(i%2 == 0) { struct sigaction action; action.sa_handler = signal_catcher_1; sigset_t block_mask; action.sa_flags = 0; sigaction(SIGUSR1,&action,NULL); if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1 ,SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } struct sigaction action; action.sa_handler = signal_catcher_2; action.sa_flags = 0; sigaction(SIGUSR2,&action,NULL); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { //cout << "Registerd the handler " << pid << endl; handlers[i] = pid; } } cout << "End of registering the signal handlers" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////End of registering the signal handlers ////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////////Registering the monitoring process ////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the monitoring process" << endl; if((pid = fork()) == 0) { struct sigaction action; action.sa_handler = signal_catcher_monitor; sigemptyset(&action.sa_mask); sigset_t block_mask; sigemptyset(&block_mask); sigaddset(&block_mask,SIGUSR1); sigaddset(&block_mask,SIGUSR2); action.sa_flags = 0; action.sa_mask = block_mask; sigaction(SIGUSR1,&action,NULL); sigaction(SIGUSR2,&action,NULL); if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { cout << "Monitor's pid is " << pid << endl; reporter = pid; } cout << "End of registering the monitoring process" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////End of registering the monitoring process//////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Sleep to make sure that the monitor and handler processes are well initialized and ready to handle signals sleep(5); ////////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////Registering the signal generators/////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal generators" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { if((pid = fork()) == 0) { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } srand(i); while(true) { int signal_id = rand()%2 + 1; if(signal_id == 1) { killpg(getpgid(getpid()), SIGUSR1); while(__sync_lock_test_and_set(lock_4,1) != 0) { } (*usrsig1_sender_count)++; *lock_4 = 0; } else { killpg(getpgid(getpid()), SIGUSR2); while(__sync_lock_test_and_set(lock_5,1) != 0) { } (*usrsig2_sender_count)++; *lock_5=0; } int r = rand()%10 + 1; double s = (double)r/100; sleep(s); } exit(0); } else { //cout << "Registered the sender " << pid << endl; senders[i] = pid; } } //cout << "End of registering the signal generators" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////End of registering the signal generators/////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Either sleep for 30 seconds and terminate the program or if the number of signals generated reaches 10000, terminate the program if(option = 1) { sleep(90); terminate_processes(); } else { while(true) { if(total_signal_count >= MAX_SIGNAL_COUNT) { terminate_processes(); } else { sleep(0.001); } } } } void signal_catcher_1(int the_sig) { while(__sync_lock_test_and_set(lock_1,1) != 0) { } (*usrsig1_handler_count) = (*usrsig1_handler_count) + 1; cout << "Signal Handler 1 " << *usrsig1_handler_count << endl; __sync_lock_release(lock_1); } void signal_catcher_2(int the_sig) { while(__sync_lock_test_and_set(lock_2,1) != 0) { } (*usrsig2_handler_count) = (*usrsig2_handler_count) + 1; __sync_lock_release(lock_2); } void signal_catcher_main(int the_sig) { while(__sync_lock_test_and_set(lock_6,1) != 0) { } total_signal_count++; *lock_6 = 0; } void signal_catcher_int(int the_sig) { for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); exit(3); } void signal_catcher_monitor(int the_sig) { cout << "Monitoring process " << *usrsig1_handler_count << endl; } Here is the initial segment of output Monitoring process 0 Monitoring process 0 Monitoring process 0 Monitoring process 0 Signal Handler 1 1 Monitoring process 2 Signal Handler 1 2 Signal Handler 1 3 Signal Handler 1 4 Monitoring process 4 Monitoring process Signal Handler 1 6 Signal Handler 1 7 Monitoring process 7 Monitoring process 8 Monitoring process 8 Signal Handler 1 9 Monitoring process 9 Monitoring process 9 Monitoring process 10 Signal Handler 1 11 Monitoring process 11 Monitoring process 12 Signal Handler 1 13 Signal Handler 1 14 Signal Handler 1 15 Signal Handler 1 16 Signal Handler 1 17 Signal Handler 1 18 Monitoring process 19 Signal Handler 1 20 Monitoring process 20 Signal Handler 1 21 Monitoring process 21 Monitoring process 21 Monitoring process 22 Monitoring process 22 Monitoring process 23 Signal Handler 1 24 Signal Handler 1 25 Monitoring process 25 Signal Handler 1 27 Signal Handler 1 28 Signal Handler 1 29 Here is the segment when the signal handler processes signal handlers are called in a burst Signal Handler 1 456 Signal Handler 1 457 Signal Handler 1 458 Signal Handler 1 459 Signal Handler 1 460 Signal Handler 1 461 Signal Handler 1 462 Signal Handler 1 463 Signal Handler 1 464 Signal Handler 1 465 Signal Handler 1 466 Signal Handler 1 467 Signal Handler 1 468 Signal Handler 1 469 Signal Handler 1 470 Signal Handler 1 471 Signal Handler 1 472 Signal Handler 1 473 Signal Handler 1 474 Signal Handler 1 475 Signal Handler 1 476 Signal Handler 1 477 Signal Handler 1 478 Signal Handler 1 479 Signal Handler 1 480 Signal Handler 1 481 Signal Handler 1 482 Signal Handler 1 483 Signal Handler 1 484 Signal Handler 1 485 Signal Handler 1 486 Signal Handler 1 487 Signal Handler 1 488 Signal Handler 1 489 Signal Handler 1 490 Signal Handler 1 491 Signal Handler 1 492 Signal Handler 1 493 Signal Handler 1 494 Signal Handler 1 495 Signal Handler 1 496 Signal Handler 1 497 Signal Handler 1 498 Signal Handler 1 499 Signal Handler 1 500 Signal Handler 1 501 Signal Handler 1 502 Signal Handler 1 503 Signal Handler 1 504 Signal Handler 1 505 Signal Handler 1 506 Here is the segment when the monitoring processes signal handlers are called in a burst Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Why isn't it uniform afterwards. Why are they called in a burst?

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  • Subterranean IL: Exception handler semantics

    - by Simon Cooper
    In my blog posts on fault and filter exception handlers, I said that the same behaviour could be replicated using normal catch blocks. Well, that isn't entirely true... Changing the handler semantics Consider the following: .try { .try { .try { newobj instance void [mscorlib]System.Exception::.ctor() // IL for: // e.Data.Add("DictKey", true) throw } fault { ldstr "1: Fault handler" call void [mscorlib]System.Console::WriteLine(string) endfault } } filter { ldstr "2a: Filter logic" call void [mscorlib]System.Console::WriteLine(string) // IL for: // (bool)((Exception)e).Data["DictKey"] endfilter }{ ldstr "2b: Filter handler" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } } catch object { ldstr "3: Catch handler" call void [mscorlib]System.Console::WriteLine(string) leave.s Return } Return: // rest of method If the filter handler is engaged (true is inserted into the exception dictionary) then the filter handler gets engaged, and the following gets printed to the console: 2a: Filter logic 1: Fault handler 2b: Filter handler and if the filter handler isn't engaged, then the following is printed: 2a:Filter logic 1: Fault handler 3: Catch handler Filter handler execution The filter handler is executed first. Hmm, ok. Well, what happens if we replaced the fault block with the C# equivalent (with the exception dictionary value set to false)? .try { // throw exception } catch object { ldstr "1: Fault handler" call void [mscorlib]System.Console::WriteLine(string) rethrow } we get this: 1: Fault handler 2a: Filter logic 3: Catch handler The fault handler is executed first, instead of the filter block. Eh? This change in behaviour is due to the way the CLR searches for exception handlers. When an exception is thrown, the CLR stops execution of the thread, and searches up the stack for an exception handler that can handle the exception and stop it propagating further - catch or filter handlers. It checks the type clause of catch clauses, and executes the code in filter blocks to see if the filter can handle the exception. When the CLR finds a valid handler, it saves the handler's location, then goes back to where the exception was thrown and executes fault and finally blocks between there and the handler location, discarding stack frames in the process, until it reaches the handler. So? By replacing a fault with a catch, we have changed the semantics of when the filter code is executed; by using a rethrow instruction, we've split up the exception handler search into two - one search to find the first catch, then a second when the rethrow instruction is encountered. This is only really obvious when mixing C# exception handlers with fault or filter handlers, so this doesn't affect code written only in C#. However it could cause some subtle and hard-to-debug effects with object initialization and ordering when using and calling code written in a language that can compile fault and filter handlers.

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  • IIS7 Handler Mapping Migration from Sites Config to Server Config [migrated]

    - by Danomite
    We have a bunch of sites running with about 8 handler mappings in their web.config files. Unfortunately, they were getting copied site to site every time a new one was added. Now the time has come for me to get these out of all the web.config's and get them into the server's Handler Mappings. If I add the mapping to the the server while it still exists in the web.config, IIS throws an error when you browse to the site. I have a few dozen web.config's to edit here with about 10 mappings in each. Is there a way to add these mappings to the server without having to go in an edit each web.config file manually? Otherwise, every site will be down for a few minutes while I go into each file and remove the handlers. Thanks!

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  • Custom ASP.NET Routing to an HttpHandler

    - by Rick Strahl
    As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add  a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a  RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name,           new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){    RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}",                     new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) );     routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}",                     new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){    string parmString = routeData.Values[parameter.Name] as string;    adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes):   which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies.  (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  AJAX  HTTP  

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  • Override an IOCTL Handler in PQOAL

    - by Kate Moss' Big Fan
    When porting or creating a BSP to a new platform, we often need to make change to OEMIoControl or HAL IOCTL handler for more specific. Since Microsoft introduced PQOAL in CE 5.0 and more and more BSP today leverages PQOAL to simplify the OAL, we no longer define the OEMIoControl directly. It is somehow analogous to migrate from pure Windows SDK to MFC; people starts to define those MFC handlers and forgot the WinMain and the big message loop. If you ever take a look at the interface between OAL and Kernel, PUBLIC\COMMON\OAK\INC\oemglobal.h, the pfnOEMIoctl is still there just as the entry point of Windows Program is WinMain since day one. (For those may argue about pfnOEMIoctl is not OEMIoControl, I will encourage you to dig into PRIVATE\WINCEOS\COREOS\NK\OEMMAIN\oemglobal.c which initialized pfnOEMIoctl to OEMIoControl. The interface is just to split OAL and Kernel which no longer linked to one executable file in CE 6, all of the function signature is still identical) So let's trace into PQOAL to realize how it implements OEMIoControl and how can we override an IOCTL handler we interest. First thing to know is the entry point (just as finding the WinMain in MFC), OEMIoControl is defined in PLATFORM\COMMON\SRC\COMMON\IOCTL\ioctl.c. Basically, it does nothing special but scan a pre-defined IOCTL table, g_oalIoCtlTable, and then execute the handler. (The highlight part) Other than that is just for error handling and the use of critical section to serialize the function. BOOL OEMIoControl(     DWORD code, VOID *pInBuffer, DWORD inSize, VOID *pOutBuffer, DWORD outSize,     DWORD *pOutSize ) {     BOOL rc = FALSE;     UINT32 i; ...     // Search the IOCTL table for the requested code.     for (i = 0; g_oalIoCtlTable[i].pfnHandler != NULL; i++) {         if (g_oalIoCtlTable[i].code == code) break;     }     // Indicate unsupported code     if (g_oalIoCtlTable[i].pfnHandler == NULL) {         NKSetLastError(ERROR_NOT_SUPPORTED);         OALMSG(OAL_IOCTL, (             L"OEMIoControl: Unsupported Code 0x%x - device 0x%04x func %d\r\n",             code, code >> 16, (code >> 2)&0x0FFF         ));         goto cleanUp;     }            // Take critical section if required (after postinit & no flag)     if (         g_ioctlState.postInit &&         (g_oalIoCtlTable[i].flags & OAL_IOCTL_FLAG_NOCS) == 0     ) {         // Take critical section                    EnterCriticalSection(&g_ioctlState.cs);     }     // Execute the handler     rc = g_oalIoCtlTable[i].pfnHandler(         code, pInBuffer, inSize, pOutBuffer, outSize, pOutSize     );     // Release critical section if it was taken above     if (         g_ioctlState.postInit &&         (g_oalIoCtlTable[i].flags & OAL_IOCTL_FLAG_NOCS) == 0     ) {         // Release critical section                    LeaveCriticalSection(&g_ioctlState.cs);     } cleanUp:     OALMSG(OAL_IOCTL&&OAL_FUNC, (L"-OEMIoControl(rc = %d)\r\n", rc ));     return rc; }   Where is the g_oalIoCtlTable? It is defined in your BSP. Let's use DeviceEmulator BSP as an example. The PLATFORM\DEVICEEMULATOR\SRC\OAL\OALLIB\ioctl.c defines the table as const OAL_IOCTL_HANDLER g_oalIoCtlTable[] = { #include "ioctl_tab.h" }; And that leads to PLATFORM\DEVICEEMULATOR\SRC\INC\ioctl_tab.h which defined some of IOCTL handler but others are defined in oal_ioctl_tab.h which is under PLATFORM\COMMON\SRC\INC\. Finally, we got the full table body! (Just like tracing MFC, always jumping back and forth). The format of table is very straight forward, IOCTL code, Flags and Handler Function // IOCTL CODE,                          Flags   Handler Function //------------------------------------------------------------------------------ { IOCTL_HAL_INITREGISTRY,                   0,  OALIoCtlHalInitRegistry     }, { IOCTL_HAL_INIT_RTC,                       0,  OALIoCtlHalInitRTC          }, { IOCTL_HAL_REBOOT,                         0,  OALIoCtlHalReboot           }, The PQOAL scans through the table until it find a matched IOCTL code, then invokes the handler function. Since it scans the table from the top which means if we define TWO handler with same IOCTL code, the first one is always invoked with no exception. Now back to the PLATFORM\DEVICEEMULATOR\SRC\INC\ioctl_tab.h, with the following table { IOCTL_HAL_INITREGISTRY,                   0,  OALIoCtlDeviceEmulatorHalInitRegistry     }, ... #include <oal_ioctl_tab.h> Note the IOCTL_HAL_INITREGISTRY handler are defined in both BSP's local ioctl_tab.h and the common oal_ioctl_tab.h, but due to BSP's local handler comes before "#include <oal_ioctl_tab.h>" so we know the OALIoCtlDeviceEmulatorHalInitRegistry always get called. In this example, the DeviceEmulator BSP overrides the IOCTL_HAL_INITREGISTRY handler from OALIoCtlHalInitRegistry to OALIoCtlDeviceEmulatorHalInitRegistry by manipulating the g_oalIoCtlTable table. (In some point of view, it is similar to message map in MFC) Please be aware, when you override an IOCTL handler in PQOAL, you may want to clone the original implementation to your BSP and change to meet your need. It is recommended and save you the redundant works but remember to rename the handler function (Just like the DeviceEmulator it changes the name of OALIoCtlHalInitRegistry to OALIoCtlDeviceEmulatorHalInitRegistry). If you don't change the name, linker may not be happy (due to name conflict) and the more important is by using different handler name, you could always redirect the handler back to original one. (It is like the concept of OOP that calling a function in base class; still not so clear? I am goinf to show you soon!) The OALIoCtlDeviceEmulatorHalInitRegistry setups DeviceEmulator specific registry settings and in the end, if everything goes well, it calls the OALIoCtlHalInitRegistry (PLATFORM\COMMON\SRC\COMMON\IOCTL\reginit.c) to do the rest.     if(fOk) {         fOk = OALIoCtlHalInitRegistry(code, pInpBuffer, inpSize, pOutBuffer,             outSize, pOutSize);     } Now you got the picture, whenever you want to override an IOCTL hadnler that is implemented in PQOAL just Clone the handler function to your BSP as a template. Simple name change for the handler function, and a name change in the IOCTL table header file that maps the IOCTL with the function Implement your IOCTL handler and whenever you need to redirect it back just calling the original handler function. It is the standard way of implementing a custom IOCTL and most Microsoft developers prefer. The mapping of IOCTL routine to IOCTL code is platform specific - you control the header file that does that mapping.

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  • Update UI in the main activity through handler in a thread (Android)

    - by Hrk
    Hello, I try to make several connection in a class and update the multiple progressbar in the main screen. But I've got the following error trying to use thread in android : Code: 05-06 13:13:11.092: ERROR/ConnectionManager(22854): ERROR:Can't create handler inside thread that has not called Looper.prepare() Here is a small part of my code in the main Activity public class Act_Main extends ListActivity { private ConnectionManager cm; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Set up the window layout requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); setContentView(R.layout.main); getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title); } public void startConnection() { //open DB connection db = new DBAdapter(getApplicationContext()); db.open(); cm = new ConnectionManager(handler, db); showDialog(DIALOG_PROGRESS_LOGIN); } @Override public void onStart() { super.onStart(); startConnection(); } protected Dialog onCreateDialog(int id) { switch (id) { case DIALOG_PROGRESS_LOGIN: progressDialog = new ProgressDialog(Act_Main.this); progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); progressDialog.setMessage("Connecting.\nPlease wait..."); progressThreadLogin = new ProgressThreadLogin(); progressThreadLogin.start(); return progressDialog; case DIALOG_PROGRESS_NETWORK: [b]progressDialog = new ProgressDialog(Act_Main.this);[/b] progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); progressDialog.setMessage("Loading entire network.\nPlease wait..."); progressThreadNetwork = new ProgressThreadNetwork(); progressThreadNetwork.start(); return progressDialog; default: return null; } } // Define the Handler that receives messages from the thread and update the progress final Handler handler = new Handler() { public void handleMessage(Message msg) { int total = msg.getData().getInt("total"); int step = msg.getData().getInt("step"); Log.d(TAG, "handleMessage:PROCESSBAR:"+total); progressDialog.setProgress(total); if (total >= 100) { switch (step) { case UPDATE_NETWORK: dismissDialog(DIALOG_PROGRESS_LOGIN); showDialog(DIALOG_PROGRESS_NETWORK); cm.getNetwork(); break; .... default: break; } } } }; private class ProgressThreadLogin extends Thread { ProgressThreadLogin() { } public void run() { cm.login(); } } private class ProgressThreadNetwork extends Thread { ProgressThreadNetwork() { } public void run() { cm.getNetwork(); } } } And my connectionManager class: public class ConnectionManager { public ConnectionManager(Handler handler, DBAdapter db) { this.handler = handler; this.db = db; } public void updateProgressBar(int step, int value) { if (value == 0) total = total+1; else total = value ; Message msg = handler.obtainMessage(); Bundle b = new Bundle(); b.putInt("total", total); b.putInt("step", step); msg.setData(b); handler.handleMessage(msg); } public void login() { //DO MY LOGIN TASK updateProgressBar(Act_Main.UPDATE_NETWORK, 100); } } The crash errors occurs on the first line of "case DIALOG_PROGRESS_NETWORK:". My first progressbar is hidden but the second one is not displayed. I think I've done somthing wrong using the threads and handlers but I dont' know why. I was first using handler.sendMessage in place of handler.handleMessage but when I had several task in my connectionManager, the progressbar was updated only at the end of all tasks. Thank you in advance for your help

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  • what is need for a handler in general

    - by nish
    I have been searching for a definition for handler. basics i've understood that "A handler is a piece of code that is called when something happens, and usually takes some action, like generating a response." - (from http://stackoverflow.com/questions/3246200/what-is-an-handler ). But that can be a trigger or a callback. Also in specific an event handler on a low-level , often works by polling a device and waiting for a hardware response. So, what is the specific role of a handler ( that makes it unique from a trigger or a callback or any other such function ). Do all handlers have similar role ( event handler, file handler , exception handler, error handler )...

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  • ASP.NET Web Forms Extensibility: Handler Factories

    - by Ricardo Peres
    An handler factory is the class that implements IHttpHandlerFactory and is responsible for instantiating an handler (IHttpHandler) that will process the current request. This is true for all kinds of web requests, whether they are for ASPX pages, ASMX/SVC web services, ASHX/AXD handlers, or any other kind of file. Also used for restricting access for certain file types, such as Config, Csproj, etc. Handler factories are registered on the global Web.config file, normally located at %WINDIR%\Microsoft.NET\Framework<x64>\vXXXX\Config for a given path and request type (GET, POST, HEAD, etc). This goes on section <httpHandlers>. You would create a custom handler factory for a number of reasons, let me list just two: A centralized place for using dependency injection; Also a centralized place for invoking custom methods or performing some kind of validation on all pages. Let’s see an example using Unity for injecting dependencies into a page, suppose we have this on Global.asax.cs: 1: public class Global : HttpApplication 2: { 3: internal static readonly IUnityContainer Unity = new UnityContainer(); 4: 5: void Application_Start(Object sender, EventArgs e) 6: { 7: Unity.RegisterType<IFunctionality, ConcreteFunctionality>(); 8: } 9: } We instantiate Unity and register a concrete implementation for an interface, this could/should probably go in the Web.config file. Forget about its actual definition, it’s not important. Then, we create a custom handler factory: 1: public class UnityPageHandlerFactory : PageHandlerFactory 2: { 3: public override IHttpHandler GetHandler(HttpContext context, String requestType, String virtualPath, String path) 4: { 5: IHttpHandler handler = base.GetHandler(context, requestType, virtualPath, path); 6: 7: //one scenario: inject dependencies 8: Global.Unity.BuildUp(handler.GetType(), handler, String.Empty); 9:  10: return (handler); 11: } 12: } It inherits from PageHandlerFactory, which is .NET’s included factory for building regular ASPX pages. We override the GetHandler method and issue a call to the BuildUp method, which will inject required dependencies, if any exist. An example page with dependencies might be: 1: public class SomePage : Page 2: { 3: [Dependency] 4: public IFunctionality Functionality 5: { 6: get; 7: set; 8: } 9: } Notice the DependencyAttribute, it is used by Unity to identify properties that require dependency injection. When BuildUp is called, the Functionality property (or any other properties with the DependencyAttribute attribute) will receive the concrete implementation associated with it’s type, as registered on Unity. Another example, checking a page for authorization. Let’s define an interface first: 1: public interface IRestricted 2: { 3: Boolean Check(HttpContext ctx); 4: } An a page implementing that interface: 1: public class RestrictedPage : Page, IRestricted 2: { 3: public Boolean Check(HttpContext ctx) 4: { 5: //check the context and return a value 6: return ...; 7: } 8: } For this, we would use an handler factory such as this: 1: public class RestrictedPageHandlerFactory : PageHandlerFactory 2: { 3: private static readonly IHttpHandler forbidden = new UnauthorizedHandler(); 4:  5: public override IHttpHandler GetHandler(HttpContext context, String requestType, String virtualPath, String path) 6: { 7: IHttpHandler handler = base.GetHandler(context, requestType, virtualPath, path); 8: 9: if (handler is IRestricted) 10: { 11: if ((handler as IRestricted).Check(context) == false) 12: { 13: return (forbidden); 14: } 15: } 16:  17: return (handler); 18: } 19: } 20:  21: public class UnauthorizedHandler : IHttpHandler 22: { 23: #region IHttpHandler Members 24:  25: public Boolean IsReusable 26: { 27: get { return (true); } 28: } 29:  30: public void ProcessRequest(HttpContext context) 31: { 32: context.Response.StatusCode = (Int32) HttpStatusCode.Unauthorized; 33: context.Response.ContentType = "text/plain"; 34: context.Response.Write(context.Response.Status); 35: context.Response.Flush(); 36: context.Response.Close(); 37: context.ApplicationInstance.CompleteRequest(); 38: } 39:  40: #endregion 41: } The UnauthorizedHandler is an example of an IHttpHandler that merely returns an error code to the client, but does not cause redirection to the login page, it is included merely as an example. One thing we must keep in mind is, there can be only one handler factory registered for a given path/request type (verb) tuple. A typical registration would be: 1: <httpHandlers> 2: <remove path="*.aspx" verb="*"/> 3: <add path="*.aspx" verb="*" type="MyNamespace.MyHandlerFactory, MyAssembly"/> 4: </httpHandlers> First we remove the previous registration for ASPX files, and then we register our own. And that’s it. A very useful mechanism which I use lots of times.

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  • Python Tkinter - Edit external object within event handler?

    - by M3RPHY
    Hey all, As the title says, I'm grabbing the cursor location within a motion triggered event handler in Tkinter. I'd like to update an existing label widget with the location, however I cannot for the life of me figure out how to edit the label's text field (or any external object for that matter) within the event handler. From what I understand, event is the only argument passed to the handler, which means I can't pass the label object. How do I access objects outside of the handler? Apologize for the noobish question as I'm a C programmer new to Python. Thanks!

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  • IIS 6 ASP.NET default handler-mappings and virtual directories

    - by mlauter
    I'm having a problem with setting a default mapping in IIS 6. I want to secure *.HTML files with ASP.NET forms authentication. The problem seems to have something to do with using virtual directories to hold the html files. Here's how it's setup: sample directory tree c:/inetpub/ (nothing in here) d:/web_files/my_web_apps d:/web_files/my_web_apps/app1/ d:/web_files/my_web_apps/app2/ d:/web_files/my_web_apps/html_files/ app1 and app2 both access the same html_files directory, so html_files is set as a virtual directory in the web apps in IIS... sample web directory tree //app1/html_files/ (points to physical directory: d:/web_files/my_web_apps/html_files/) //app2/html_files/ (points to physical directory: d:/web_files/my_web_apps/html_files/) If I put a file called test.html in the root of //app1/ and then add the default mapping to the asp.net dll and setup my security on the root folder with deny="?", then accessing test.html works exactly as expected. If I'm not authenticated, it takes me to the login.aspx page, and if I am authenticated then it displays test.html. If I put the test.html file in the html_files directory I get a totally different behavior. Now the login.aspx page loads and I stuck some code in to check if I was still authenticated: <p>autheticated: <%=User.Identity.IsAuthenticated%></p> I figured it would say false because why else would it bother to load the login page? Nope, it says true - so it knows i'm authenticated, but it won't give me access to the test.html file. I've spent several hours on this and haven't been able to solve it. I'm going to spend some more time on google to see if I've missed something. Fingers crossed.

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  • IIS 6 ASP.NET default handler-mappings and virtual directories

    - by Mark Lauter
    I'm having a problem with setting a default mapping in IIS 6. I want to secure *.HTML files with ASP.NET forms authentication. The problem seems to have something to do with using virtual directories to hold the html files. Here's how it's setup: sample directory tree c:/inetpub/ (nothing in here) d:/web_files/my_web_apps d:/web_files/my_web_apps/app1/ d:/web_files/my_web_apps/app2/ d:/web_files/my_web_apps/html_files/ app1 and app2 both access the same html_files directory, so html_files is set as a virtual directory in the web apps in IIS... sample web directory tree //app1/html_files/ (points to physical directory: d:/web_files/my_web_apps/html_files/) //app2/html_files/ (points to physical directory: d:/web_files/my_web_apps/html_files/) If I put a file called test.html in the root of //app1/ and then add the default mapping to the asp.net dll and setup my security on the root folder with deny="?", then accessing test.html works exactly as expected. If I'm not authenticated, it takes me to the login.aspx page, and if I am authenticated then it displays test.html. If I put the test.html file in the html_files directory I get a totally different behavior. Now the login.aspx page loads and I stuck some code in to check if I was still authenticated: <p>autheticated: <%=User.Identity.IsAuthenticated%></p> I figured it would say false because why else would it bother to load the login page? Nope, it says true - so it knows i'm authenticated, but it won't give me access to the test.html file. I've spent several hours on this and haven't been able to solve it. I'm going to spend some more time on google to see if I've missed something. Fingers crossed.

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  • JAX-WS modifying handler chain programmatically? PortInfo?

    - by wuntee
    I have a JAX-WS client that needs to have a modified handler-chain. I am currently doing it by binding this XML when generated the WSDL stubs: <jaxws:bindings xmlns:jaxws="http://java.sun.com/xml/ns/jaxws"> <jws:handler-chains xmlns:jws="http://java.sun.com/xml/ns/javaee"> <jws:handler-chain> <jws:handler> <jws:handler-name>ServiceRequestServiceClientHandler</jws:handler-name> <jws:handler-class>blah.ServiceRequestServiceClientHandler</jws:handler-class> </jws:handler> </jws:handler-chain> </jws:handler-chains> </jaxws:bindings> I was looking that the ServiceRequestService_Service object, and it seems like this could be done programmatically (easier in my opinion - less configuration files). new ServiceRequestService_Service().getHandlerResolver().getHandlerChain(PORTINFO).add(HANDLER); But, I do not know what the PortInfo object is, or how to obtain it in relation to the specific service. Has anyone done this?

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  • GAE Simple Request Handler only run once

    - by Hiro
    Good day! https://developers.google.com/appengine/docs/python/gettingstarted/helloworld this is the hello world that I'm trying to run. I can seeing the Hello, world! Status: 500 message. however it will be turned to a "HTTP Error 500" after I hit the refresh. and... it seems that the appengine only shows me the good result once after I re-save either app.yaml or helloworld.py This is the trace for the good result Traceback (most recent call last): File "C:\Program Files\Google\google_appengine\google\appengine\runtime\wsgi.py", line 187, in Handle handler = _config_handle.add_wsgi_middleware(self._LoadHandler()) File "C:\Program Files\Google\google_appengine\google\appengine\runtime\wsgi.py", line 239, in _LoadHandler raise ImportError('%s has no attribute %s' % (handler, name)) ImportError: <module 'helloworld' from 'D:\work\[GAE] tests\helloworld\helloworld.pyc'> has no attribute app INFO 2012-06-23 01:47:28,522 dev_appserver.py:2891] "GET /hello HTTP/1.1" 200 - ERROR 2012-06-23 01:47:30,040 wsgi.py:189] and this is the trace for the Error 500 Traceback (most recent call last): File "C:\Program Files\Google\google_appengine\google\appengine\runtime\wsgi.py", line 187, in Handle handler = _config_handle.add_wsgi_middleware(self._LoadHandler()) File "C:\Program Files\Google\google_appengine\google\appengine\runtime\wsgi.py", line 239, in _LoadHandler raise ImportError('%s has no attribute %s' % (handler, name)) ImportError: <module 'helloworld' from 'D:\work\[GAE] tests\helloworld\helloworld.pyc'> has no attribute app INFO 2012-06-23 01:47:30,127 dev_appserver.py:2891] "GET /hello HTTP/1.1" 500 - here's my helloworld.py print 'Content-Type: text/plain' print '' print 'Hello, world!' my main.py. (app is used instead of application) import webapp2 class hello(webapp2.RequestHandler): def get(self): self.response.out.write('normal hello') app = webapp2.WSGIApplication([ ('/', hello), ], debug = True) and the app.yaml application: helloworld version: 1 runtime: python27 api_version: 1 threadsafe: true handlers: - url: /favicon\.ico static_files: favicon.ico upload: favicon\.ico - url: /hello script: helloworld.app - url: /.* script: main.app libraries: - name: webapp2 version: "2.5.1" any clue what's causing this? Regards,

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  • Android Handler postDelayed executes twice

    - by Ömer Baykal
    When I use Handler and its postDelayed method, the run() method executes twice. Below is part of my code. Handler deneme = new Handler(); deneme.postDelayed(new Runnable() { @Override public void run() { randomOyna(); } }, 1000); where randomOyna is the method public void randomOyna() { Log.v("sonOlarak", "çalisti"); } I monitor the LogCat and see that "çalisti" entry is written twice, so that randomOyna is called twice. The task is scheduled truely, but executes both after 1 sec and 2 secs. Can you help me???

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  • ScoreNinja causes java.lang.RuntimeException: Can't create handler inside thread that has not called

    - by sirconnorstack
    I'm trying to add ScoreNinja, the global high score system, to my Android game, and it works fine when I load it on my phone, but when I release it into the wild, I got crash reports saying: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() Here is part of the call stack: android.os.Handler.<init>(Handler.java:121) android.app.Dialog.<init>(Dialog.java:99) android.app.AlertDialog.<init>(AlertDialog.java:65) android.app.AlertDialog.<init>(AlertDialog.java:61) android.app.AlertDialog$Builder.create(AlertDialog.java:797) android.app.AlertDialog$Builder.show(AlertDialog.java:812) com.scoreninja.adapter.ScoreNinjaAdapter.show(ScoreNinjaAdapter.java:136) com.scoreninja.adapter.ScoreNinjaAdapter.show(ScoreNinjaAdapter.java:99) I thought the main thread had prepare() called automatically, and if not, why would it work fine for me but not anyone else?

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  • Javascript calling JSF handler method

    - by msharma
    Hi All, I am reading an xml file using javascript and then I need to submit my form so that it calls a particular method in my JSF handler. Usually this can be done on a jsp when user clicks a button by having an actionlistener like so: <h:commandLink styleClass="button" action="#{myHandler.outcome}" actionListener="#{myHandler.doNext}"> <span><h:outputText value="#{text.button_submit}" /></span> </h:commandLink> I am not sure how to call a method like 'doNext' above in the handler from javascript. I cannot do a simple: document.form.submit(); as it then repeats the processing i have already done. I want to read values from an xml file and then call a particular method in handler. Any ideas much appreciated.

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  • Event handler of Dropdownlist inside Gridview

    - by hotcoder
    I've added Dropdownlist in Gridview at RowDataBound event. The code is: if (e.Row.RowType == DataControlRowType.DataRow) { DropDownList ddlSeason = new DropDownList(); ddlSeason.DataSourceID = "odsRoomSeason"; ddlSeason.DataTextField = "SeasonTittle"; ddlSeason.DataValueField = "SeasonID"; ddlSeason.AutoPostBack = true; ddlSeason.SelectedIndexChanged += new EventHandler(ddlSeason_SelectedIndexChanged); TableCell tcSeason= new TableCell(); tcSeason.Controls.Add(ddlSeason); e.Row.Cells.AddAt(e.Row.Cells.Count, tcSeason); } The event handler I've added is: protected void ddlSeason_SelectedIndexChanged(object sender, EventArgs e) { // } But the problem is that the event handler function doesn't catch the event. Please tell me how to write the correct event handler, also I need to get the row from which the Dropdownlist's event has fired.

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  • Google app engine-php: script handler

    - by Eve
    I try to create php web app using GAE. In the GAE tutorial, "A script handler executes a PHP script to handle the request that matches the URL pattern. The mapping defines a URL pattern to match, and the script to be executed" Now I want to map the url with the file having same name in the folder, e.g. if the url is /hello.* , it will map the file name hello.php in the folder. And if it is /hello1.*, hello1.php in the folder will be responded to the server. I thought this should be done directly by mapping the name of the url with the name in the folder. But if I left empty for the handler in the app.yaml, I got an error. So I want to know how to set up the handler in app.yaml?

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  • Detecting when a handler couldn't be started when embedding Jetty

    - by scompt.com
    I'm embedding Jetty in a similar manner as described here. When the RequestLogHandler can't open the specified logfile, it throws an exception which is unfortunately caught by org.eclipse.jetty.server.Server and swallowed (but logged first, at least). This means that there's no obvious way for me to tell if the log handler was started correctly. Is there a way that I'm missing to detect when a handler couldn't start?

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  • Creating a KeyDown Event Handler for the Label Control

    - by j-t-s
    Hi All I'm sure you're all aware of the fact that the Label Control has no KeyDown handler (and why would it?)... Anyway, I'm in need of a KeyDown handler for the Label Control and would appreciate any pointers/suggestions to get me started. I've searched around but haven't found any info on creating my own Event Handlers for the Label Control. Can this be done is C#? Thanks

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  • sigsetjmp and siglongjmp inside signal handler

    - by EpsilonVector
    How do I: sigsetjmp inside the handler and then return from the handler such that the signal will be unmasked once I siglongjmp back to this point? In pseudo code this is sort of the function that I have: signal_handler(){ if(sigsetjmp(env[i++])) return; else siglongjmp(env[i]); } It's supposed to be the context switch code for user threads in Linux.

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  • Put an object in Handler message

    - by Tsimmi
    Hi! I need to download an image from the internet, in a different thread, and then send that image object in the handler message, to the UI thread. I already have this: ... Message msg = Message.obtain(); Bundle b = new Bundle(); b.putParcelable("MyObject", (Parcelable) object); msg.setData(b); handler.sendMessage(msg); And when I receive this message, I want to extract the object: ... public void handleMessage(Message msg) { super.handleMessage(msg); MyObject objectRcvd = (MyObject) msg.getData().getParcelable("IpTile"); addToCache(ipTile); mapView.invalidate(); } But this is giving me: ...java.lang.ClassCastException... Can anyone help? And by the way, is this the most efficient way to pass an object to the UI Thread? Thank you all!

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  • bind event handler on keydown listen function JavaScript jQuery

    - by user1644123
    I am trying to bind a handler to an event. The event is a keydown function. The handler will listen for hit variables to produce one of two conditions. The 1st condition (odd number of hits) will perform 1 function, the 2nd (even number of hits) will perform another function. To elaborate, the 1st function will scroll to one element, the 2nd will scroll to another element. My syntax may be the wrong approach, but it works for the 1st condition, but not the 2nd. I think I have the conditional statement in the wrong place. How can I rewrite this to work as intended? Thank you kindly, in advance! $(document).keydown(function(e) { switch (e.which) { case 37: break; case 38: break; case 39: break; case 40: //bottom arrow key var hits = 0; if (hits % 2 !== 0) { $('#wrap').animate({ scrollTop: $("#scrollToHere").offset().top }, 2800); } else { $('#wrap').animate({ scrollTop: $("#scroll2ToHere").offset().top }, 2800); } hits++; return false; break; } })? *I moved "var hits = 0;" to the top, but it only works! But is there a way I can reset the whole thing after every two hits? I want to reset because when there is a bug and if I press a 3rd time it scrolls to the very top of the page, where there is no element to make it scroll to the top. Why would it scroll to the top of the page if I never scripted it to do so?? *

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