IIS hosted WCF blocks access to session object

Discussion in 'ASP .Net' started by mabra, Aug 3, 2009.

  1. mabra

    mabra Guest

    Hi !

    I have a WCF [hosted in IIS], that has two methods, which both will be
    called - one after the other - on a click by a ajax client. The first method
    a method with long duration, the second method is a method with short
    duration. Both calls terminate "at the same time". So, the call with the long
    duration blocks the short call. Only one request from the same client can be
    processed at the same time.

    This is completely inacceptable. I added the interface
    "IReadOnlySessionState" to the wcf service [no host declaration exists!!] and
    used "ServiceBehavior(ConcurrencyMode=ConcurrencyMode.Multiple,
    InstanceContextMode=InstanceContextMode.PerCall)". Nothing is of any help.

    So, my resume:WCF is a bad decision to use with ajax.

    If session handling on the asp(x) is disabled, everything works like
    expected. But I need the seeion handling, so I tried the readonly attribute.

    Or:Do I miss something????

    Thanks a lot.

    mabra, Aug 3, 2009
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  2. mabra

    Mr. Arnold Guest

    So why can't you use a async WCF Web service to make the calls to the
    methods, which would be independent from each other?

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    Mr. Arnold, Aug 3, 2009
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  3. mabra

    mabra Guest

    Hi !

    Much thanks for your reply! Sorry, I am late ....don't saw it
    before ...

    From your answer, I see, it might be, I have mis-described the

    The client has two buttons, each one calling one WCF method
    asynchronously, both are async ajax request.
    If the first called method is the long running method, both calls
    returns ~nearly at the same time. Means:One
    executing WCF method blocks executing the other one.

    I rewrote the WCF service as a webservice [asmx], deriving the service
    class from interface "IReadOnlySessionState", both calls are running
    parallel and so, the short calls returns immidiately.

    I tried to use "IReadOnlySessionState" on the WCF service also, but
    this has no effect.

    Do you possibly know a solution?
    I have not understand, what you meant with "async WCF" service!??

    Thanks a lot!


    mabra, Aug 12, 2009
  4. mabra

    Mr. Arnold Guest



    WCF also supports non-blocking (asynchronous) calls between client and
    service, via several mechanisms.

    You can go to the WCF WEB service reference on the client-side project,
    the Web Service itself.

    You right-click the Web service and select "Configure Service Reference".

    You check mark enable "Generate asynchronous Operations" and click the
    OK button.

    You recompile the client-side project.

    After the recompile of the project, it will generate the new methods for
    the client-side the WCF Web service reference for sync and async calls
    to the same methods of the service contract.

    var client = new wcfwebservice();

    client.DoSomething(); // sync call to the method.

    client.DoSomethingAsync(); // the async call to DoSomething()

    There is also a DoSomethingCompleted(), too.

    You may have to use IWCFservice, WCFservice.svc and WCFservice.svc.cs
    with [Operational Contract] attribute.
    Mr. Arnold, Aug 13, 2009
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