Given an application pool that runs on integrated mode, the apppool is able to provide service to "Managed Handler Requests" (GET an aspx page) as well as "non-Managed Handler Requests" (GET a jpg file).
When processing a MHR request the app pool should consider all modules but for nonMHRs should not consider the modules marked with the Managed Handler precondition.
Has the app pool two different HttpAplication pipelines (one for MHRs and the other for nonMHRs) ?
Or he only has one pipeline and is able to decide which httpAplication event handlers are raised depending of the request?
I guess the app pool decides if the request is managed or not, before httpApplication starts the BeginRequest. At least before the AuthenticateRequest. Is that right?
Response in the link:
All resources served by IIS are mapped to a handler in configuration. If the configuration mapping does not exist, requests for the resource will receive a 404 HTTP status. In addition to the configuration mapping, which takes place before the pipeline begins, the handler mapping can be changed during request execution ...
The Init function of the modules are only executed once (maybe in the application pool startup) independently of the Managed Handler precondition?
I guess the apppool doesn't create the whole pipeline (registering httpaplication events and so) for each request.
Thanks in advance,
UPDATE1: After reading the link I still "see" two diferent pipelines given a single apppool.
By diferent pipelines I mean two diferent sets of event handlers registered in the IIS pipeline:
BEGIN_REQUEST
AUTHENTICATE_REQUEST
AUTHORIZE_REQUEST
RESOLVE_REQUEST_CACHE
MAP_REQUEST_HANDLER
ACQUIRE_REQUEST_STATE
PRE_EXECUTE_REQUEST_HANDLER
EXECUTE_REQUEST_HANDLER
RELEASE_REQUEST_STATE
UPDATE_REQUEST_CACHE
LOG_REQUEST
END_REQUEST
When an application pool in integrated mode starts, it can look up the modules section and can execute the Init function of each module (indepentdently of the precondition setting). The Init function of each module registers itself in some IIS pipeline stages. But at runtime when processing non-managed requests it should skip the event handlers of modules with precondition managed handler. How can do that?
UPDATE2:
From my understanding, an app pool (the windows process) host an ASP.Net runtime (httpRuntime in System.Web?). This runtime contains a pool of httpApplication objects. When app pool starts (or maybe until first request arrive) several httpApplications are instantiated. At this time the Init method of the httpModules (under modules in web.config) are called.
Until IIS7 integration mode appearance I thought all httpApplication objects would be clones, but because depending of the type of handler's request (managed or non managed) some httpModules should be considered or not, I deduce that the httpRutime contains two httpApplication pools or maybe a given httpApplication object is only able to process managed handler requests or non-managed hadler requests, but never the two...
I think you can read this one
http://blogs.msdn.com/b/tmarq/archive/2007/08/30/iis-7-0-asp-net-pipelines-modules-handlers-and-preconditions.aspx
In there you see that the IIS has only one pipeline. The "classic" way of serving asp.net requests begins in the IIS pipeline’s EXECUTE_REQUEST_HANDLER event. Think of ASP.NET in classic mode as a pipeline within the IIS pipeline.
With the integrated mode you can basically plug in managed code in the whole IIS pipeline series of events, like adding asp.net forms authentication to static files like .jpg
Related
I'm having a Web application that also integrates a Web API. Just today I've found myself surprised to see that the first REST request on the Web API re-triggers the execution of Application_Start (although it has been run already when starting the web page). After reading ASP.NET HttpApplication lifecycle and ASP.NET Application Life Cycle Overview, it seems that the REST request is spawning a new HttpApplication.
Further, on the MSDN it says:
The first time that an ASP.NET page or process is requested in an application, a new instance of the HttpApplication class is created. However, to maximize performance, HttpApplication instances might be reused for multiple requests.
This sounds to me that each request could potentially spawn a new HttpApplication and that thus, Application_Start must be written in a re-entrant or idempotent way. Is this conclusion right?
In my concrete case, I'm initializing a log writer in Application_Start which fails the second time because the file is already being used. I guess in the case of an application pool recycling this wouldn't be a problem, as the resources are freed in-between.
You can read further down on the provided link
The Application_Start and Application_End methods are special methods that do not represent HttpApplication events. ASP.NET calls them once for the lifetime of the application domain, not for each HttpApplication instance.
So there is no need to write Application_Start in a re-entrant or idempotent way.
Furthermore Application_Start is not called on the recycling of IIS. It gets called on the first request after recycling when the application is actually loaded by IIS.
As for your error, make sure you're disposing off your logger on Application_End so the file handle gets released.
I have a asp.net web app and few actions are performed using WCF.
My question is -
While my WCF method call is in progress, the application pool is reset due to:
1) Change in Web.Config
2) Some assembly is deployed in Bin Folder
3) IIS Crash
4) IIS Stops
What will happen to my method call?
Things I have tried:
1) Applied Thread.Sleep of 20 Secs in WCF method
2) While the WCF method is in progress, I changed the assembly in bin folder.
Result - Surprisingly, the Success Callback of WCF method is called and the WCF method is called successfully.
As per my expectation, it should go to the Failure Callback.
http://www.iis.net/learn/manage/provisioning-and-managing-iis/features-of-the-windows-process-activation-service-was
In the "Recycling" section
WAS does this by spawning up a new worker process parallel to the old one that is still handling requests. Once the new worker process is up it starts picking up requests from the request queue while the old worker process is instructed by WAS to stop picking up requests. Once the old worker process finishes all executing requests it shuts down. This feature is called "overlapping recycling". It ensures that no requests are lost during a recycle.
My ASP.NET Web Application serves on IIS 7.0 and .NET 4.0
I want to measure total duration for "any request to my web services methods (asmx)"
This log needs to include some custom data (for example ID, given by my application).
I am planning to follow these steps:
-- Run application in Integrated Pipeline mode
-- Implement custom http module and attach to BeginRequest and EndRequest events of HttpApplication.
-- In BeginRequest method, Start Stopwatch
-- In EndRequest method;
end Stopwatch; read custom ID data from context.Session;
write results to database or file log.
Do you think it is a good method?
What is the best way to achieve this, would you recommend other?
IIS will log time taken, and you can add any custom data that you wish.
You can even use ETW to read log objects instead of parsing the log files.
IIS logging:
http://msdn.microsoft.com/en-us/library/ms525410(v=vs.90).aspx
What "time taken" means:
http://support.microsoft.com/kb/944884/en-us
Writing custom data to IIS logs from your app:
http://msdn.microsoft.com/en-us/library/system.web.httpresponse.appendtolog.aspx
Optionally interfacing through ETW instead of reading the logs from the file system:
http://msdn.microsoft.com/en-us/library/windows/desktop/bb968803(v=vs.85).aspx
http://www.iis.net/learn/get-started/whats-new-in-iis-85/logging-to-etw-in-iis-85
I have a wcf service and i want to call a method automatically , immediately after the publishing in IIS. Like an initialization of the WCF service without having to call the method manually or from somewhere else. Where should i place my Initialize method in WCF Service in order to run exactly after the start of the application?
If you're hosting in IIS you can use the application_start event within the Global.asax of the web app that hosting tHE WCF service to do any application initialization. If you are trying to call one of your services when it is first installed then this is likely the wrong approach.
What is the motivation for running some code on start up of the web service? If you are trying to get around a slow initial call to the WCF service I suggest you would want to do some work on the WCF client-side rather than in the service...but Im just guessing at your motivation here
Initialization of the WCF service? So do you have singleton service or do you want to initialize some global state? Otherwise initialization doesn't make sense because service instances will be created for actual clients.
By default IIS starts application when it is accessed first time. If you place initialization in Application_Start (HttpApplication or Global.asax) the code will run when the application is first accessed. But accessing the service is not something that your application can initiate.
IIS 7.5 (Windows 2008 R2) has warm-up module which can run some code when pool is recycled or worker is restarted. If you use other version of IIS you have to use some external solution like custom application pinging your service in regular intervals.
I have some doubt over HttpModule and HttpHandler Please help me to clarify
1)In HttpModule I have noticed methods Init called only once . context_BeginRequest and context_EndRequest etc method calling for each request.
Is it guaranteed that for a module Init will call once for different users(or different request) and BeginRequest etc will call every time for different users (or different request) ?
2)Is there any possibility that Application_Start(global.asax) can run more than once because there may be more than one application object
3) Since application object can be different (from application pool) In this case how Application data is shared between different users?
4) In HttpHandler ProcessRequest method will call for each request (or for each user).
Thanks
Ritu
"Is it guaranteed that for a module Init will call once for different users(or different request) and BeginRequest etc will call every time for different users (or different request)?"
The init method will be called when the app pool starts / when the application is started for the first time. This is when the module is loaded.
The BeginRequest method is called every time the application starts handling a new HTTP request.
"2)Is there any possibility that Application_Start(global.asax) can run more than once because there may be more than one application object"
There is not more than one application in a particular folder. IIS doesn't work that way. Only one global.asax per application, and Application_Start will only be called once for each application unless the app pool is reset.
"3) Since application object can be different (from application pool) In this case how Application data is shared between different users?"
Depends where you're storing this application data and what you're using to retrieve it. I'm not sure what you mean about this. Session data should be scoped to an individual application (certainly for in-process session state server, and if properly configured also for out-of-process session state server)
"4) In HttpHandler ProcessRequest method will call for each request (or for each user)."
Yes, but only for requests which are mapped to your handler. Conversely, HttpModule can be called for ALL requests.