WCF client hangs on response - c#

I have a WCF client (running on Win7) pointing to a WebSphere service.
All is good from a test harness (a little test fixture outside my web app) but when my calls to the service originate from my web project one of the calls (and only that one) is extremely slow to deserialize (it takes minutes VS seconds) and not just the first time.
I can see from fiddler that the response comes back quickly but then the WCF client hangs on the response itself for more than a minute before the next line of code is hit by the debugger, almost if the client was having trouble deserializing. This happens only if in the response I have a given pdf string (the operation generates a pdf), base64 encoded chunked. If for example the service raises a fault (thus the pdf string is not there) then the response is deserialized immediately.
Again, If I send the exact same envelope through Soap-UI or from outside the web project all is good.
I am at loss - What should I be looking for and is there some config setting that might do the trick?
Any help appreciated!
EDIT:
I coded a stub against the same service contract. Using the exact same basicHttpBinding and returning the exact same pdf string there is no delay registered. I think this rules out the string and the binding as a possible cause. What's left?

Changing transferMode="Buffered" into transferMode="Streamed" on the binding did the trick!
So the payload was apparently being chunked in small bits the size of the buffer.
I thought the same could have been achieved by increasing the buffersize (maxBufferSize="1000000") but I had that in place already and it did not help.

I have had this bite me many times. Check in your WCF client configuration that you are not trying to use the windows web proxy, that step to check on the proxy (even if there is not one configured) will eat up a lot of time during your connection.

If the tips of the other users don't help, you might want to Enable WCF Tracing and open it in the Service Trace Viewer. The information is detailed, but it has enabled me to fix a number of hard-to-identity problems in the past.
More information on WCF Tracing can be found on MSDN.

Two thing you can try:
Adjust the readerQoutas settings for your client. See http://msdn.microsoft.com/en-us/library/ms731325.aspx
Disable "Just My Code" in debugging options. Tools -> Options -> Debugging -> General "Enable Just My Code (Managed only)" and see if you can catch interal WCF exceptions.
//huusom

I had the very same issue... The problem of WCF, IMO, is in the deserialization of the base64 string returned by the service into a byte[] client side.
The easiest to solve this if you may not change your service configuration (Ex.: use a transferMode="Streamed") is to adapt your DataContract/ServiceContract client side. Replace the type "byte[]" with "string" in the Response DataContract.
Next simply decode the returned string yourself with a piece of code such as:
byte[] file = Convert.FromBase64String(pdfBase64String);
To download a PDF of 70KB, it used to required ~6 sec. With the suggested change here above, it takes now < 1 sec.
V.
PS.: Regarding the transfer mode, I did try to only change the client side (transferMode="StreamedResponse") but without improvement...

First things to check:
Is the config the same in the web project and the test project?
When you test from SOAP UI are you doing it from the same server and in the same security context as when the code is running from the web project.
-Is there any spike in the memory when the pdf comes back?
Edit
From your comments the 1 min wait, appears that it is waiting for a timeout. You also mention transactions.
I am wondering if the problem is somewhere else. The call to the WCF service goes OK, but the call is inside a transaction, and there is no complete or dispose on the transaction (I am guessing here), then the transaction / code will hang for 1 min while it waits to timeout.
Edit 2
Next things to check:
Is there any difference in the code is the test and in the web project, on how the service is being called.
Is there any differnce in the framework version, for example is one 3.0 and the other 3.5

Can it be that client side is trying to analyse what type of content is coming from server side? Try to specify mime type of the service response explicitly on the server side, e.g. Response.ContentType = "application/pdf" EDIT: By client side I mean any possible mediator like a firewall or a security suite.

Related

WCF request returns wrong response

I have a c# application that the client uses wcf to talk to the server. In the background every X seconds the client calls a Ping method to the server (through WCF). The following error has reproduced a couple of times (for different method calls):
System.ServiceModel.ProtocolException: A reply message was received for operation 'MyMethodToServer' with action 'http://tempuri.org/IMyInterface/PingServerResponse'. However, your client code requires action 'http://tempuri.org/IMyInterface/MyMethodToServerResponse'.
MyMethodToServer is not consistent and it falls on different methods.
How can this happen that a request receives a different response?
I think you have a pretty mess problem with async communication, main suggestion (as your question isn't clear very well), is try to identify every request, catch the calls and waiting for them, do asyncronic communication and getting a several work with threading.
As you present it, is a typical architecture problem.
If you present more code, can I suggest some code fixing in my answer and I'll be glad to update my answer.
If this occurs randomly and not you consistently, you might be running in a load-balanced setup, and deployed an update to only one of the servers?
Wild guess: your client uses same connection to do two requests in parallel. So what happens is:
Thread 1 sends request ARequest
Thread 2 sends request BRequest
Server sends reply BReply
Thread 1 receives reply BReply while expecting AReply
If you have request logs on the server, it'll be easy to confirm - you'll likely see two requests coming with short delay from the client host experiencing the issue
I think MaxConcurrentCall and ConcurrencyMode may be relevant here (although I did not touch WCF for a long while)

.asmx request timeout when returning a very large string

We have a couple of .asmx soap web services that handle communication between our web gui and our backend app server. Recently we went from running our Visual Studio 2010 solution in the built in web server to running it through IIS 7.5. Right away we started experiencing very slow response times and started getting various exception that we weren't seeing before, like timeouts & serialization errors in our xml's.
We've tried to narrow the problem down to a minimum, but are short a solution so now we're throwing it "out there" to see if anyone have experienced the same or maybe have a solution.
PS. We know that .asmx web services are outdated, but we can't convert the services to WCF at this time. DS.
This code will reproduce the error:
[WebMethod]
public string DebugGetAuditTrail()
{
const string data = "Some random text that is not very interesting. ";
StringBuilder lotsOfData = new StringBuilder();
for(int counter=0; counter<100000; counter++)
{
lotsOfData.Append(data);
}
return lotsOfData.ToString();
}
Our web.config states:
<httpRuntime executionTimeout="600" requestValidationMode="2.0" maxRequestLength="1400000"/>
Thanks in advance!
Ideally it is not advisable to send huge amount of data using web-service. However, to deal with such situations, the best way is to break apart the data in small packets.
What you can do is, create a header which indexes the data packets. Once the header is received, configure the server to send the remaining part of data.

HttpModule ATL Server Service InputStream Failure

I'm trying to add some SOAP message logging capabilities to an old, old ATL Server web service that is running in integrated mode in IIS 7.5 on a Windows Server 2008 box, but running into a strange problem. For further background, I've added the assembly that contains the HttpModule to the modules element of the web.config for the ATL Server web service.
I've been following the answer provided here and the logging itself works great.
However, whenever I use this logging capability, the service responds with "SOAP Invalid Request", while the log file has the SOAP message as expected. I've done lots of fiddling around with it and figured out that this only happens if/when I access the request object's InputStream property in my handler for the BeginRequest event. It will fail if I even simply set a variable to the length of the InputStream like this:
private void OnBegin(object sender, EventArgs e)
{
var request = _application.Request;
//this will blow up
var foo = request.InputStream.Position;
}
If I don't touch the InputStream in my handler (which doesn't do much good when I'm only doing this to log the contents of the request, obviously), the request goes through perfectly.
I can access header values in the Request object and various other properties of the HttpApplication involved, but accessing the InputStream causes the service to choke.
Is there something intrinsic with ATL Server that will prevent me from doing this logging? Do I need to add some sort of locking or other safeguard in my BeginRequest handler to make sure this behaves? Is my handler hosing up the InputStream somehow causing it to be unusable for the service?
Another way of approaching this is to ask if there is a way to see the request as it gets to my service (i.e. after this HttpModule executes)?
It may also be worth noting that I am using SoapUI to test the service.
EDIT:
I've now done some failed request tracing in IIS and I get this error message:
ModuleName IsapiModule
Notification 128
HttpStatus 500
HttpReason Internal Server Error
HttpSubStatus 0
ErrorCode 0
ConfigExceptionInfo
Notification EXECUTE_REQUEST_HANDLER
ErrorCode The operation completed successfully. (0x0)
This comes in the handler for the ATL Server web service (i.e. the DLL for the service). Directly before that is the "GENERAL_READ_ENTITY_START" and "GENERAL_READ_ENTITY_END" messages, and the "END" has this message:
BytesReceived 0
ErrorCode 2147942438
ErrorCode Reached the end of the file. (0x80070026)
Does that mean what I think it means? That the handler isn't getting any data? Is this more evidence pointing towards my HttpModule messing with the Request's InputStream?
Are you sure your request object is valid? You're doing things slightly differently here from the sample you reference. They are extracting the stream from the sender argument whereas you obviously rely on a member variable.
So I finally determined that this wasn't a workable approach: I couldn't get the HttpModule to fire at all in IIS 6 (which I would need to have it to do for it to be an acceptable solution). I tried setting the Filter property on the Request object and all sorts of other crazy ideas, but none that led me to be able to both record the request body in the HttpModule and have the service still work.
So I did more digging and came upon this article on codeproject that talks about the inner workings of ATL Server, specifically the HandleRequest method in atlsoap.h. I mucked around in there for a while and figured out a way to get at the request body in there, and it was pretty simple to write it to a file manually from there.
For those curious, this is the final code I added to HandleRequest():
//****************************************REQUEST LOGGING**********************************************************
BYTE* bytes = pRequestInfo->pServerContext->GetAvailableData();
FILE* pFile;
pFile = fopen("C:\\IISLog\\ATL.txt", "a");
fwrite(bytes, 1, pRequestInfo->pServerContext->GetAvailableBytes(), pFile);
fclose(pFile);
//****************************************REQUEST LOGGING**********************************************************
I am going to still play around with it a bit more, but I have what appears to be a workable solution.

Java error Consuming WCF Service

I'm started to develop a Web Service with WCF and created a WCF Service poject. I let all as it was and imported the service in netbeans as JAX WS service. All seems to be fine.
Service1 test= new Service1();
CompositeType ct=new CompositeType();
ct.setBoolValue(Boolean.TRUE);
ObjectFactory factory=new ObjectFactory();
ct.setStringValue(factory.createString("StringValue"));
CompositeType result= test.getBasicHttpBindingIService1().getDataUsingDataContract(ct);
I can send the request. I can break in Visual studio and see the CompositeType object. But the object is not as it should be:
The bool value is set as expected to true.
The string value is still null.
When i manipulate the string value in the WCF Service and give the change object back the string is set correct and i can read it in java.
Why can't i post the CompositeType to java but can consume it?
It's hard to tell from just the detail you've provided.
Here is what I suggest:
Enable tracing on the service side, generate tracing logs, and analyze with SvcTraceViewer. To do this, follow the instructions at this MSDN article on using the service trace viewer. Notice what's different between the first and second time.
Turn on debug exceptions. This is done by turning in includeExceptionDetailInFaults, which you can do by following the instructions here. Notice what's different between the first and second time.
Use Fiddler to monitor the wire traffic on both the client side and the service side.
Generally, once you do this, you should plenty of more info on what's going funky at the service side and can diagnose the issue pretty quickly. Try it, and please report back! :)
I also lost 2 hours in this!
The problem is in java code :)
Instead of this
ct.setStringValue(factory.createString("StringValue"));
use this
ct.setStringValue(factory.createCompositeTypeStringValue("StringValue"));

CommunicationException with 'not recognized sequence' message in WCF

I get a CommunicationException while using WCF service. The message is:
The remote endpoint no longer recognizes this sequence. This is most likely due to an abort on the remote endpoint. The value of wsrm:Identifier is not a known Sequence identifier. The reliable session was faulted.
The exception is thrown in a moment after a contract method was called. Before calling contract method the channel state is Opened. I restore my service client after catching this exception and for some time it works fine. But then this error occures again. It seems like some timeout is exceeded, but I can't understand which one exactly.
I use wsHttpBinding with reliableSession enabled. The InactivityTimeout is set to half an hour and I'm sure it's not exceeded, because exception is thrown earlier.
I solved the problem. The reason was RecieveTimeout on a server side. It was set to 1 minute, so after having no requests during 1 minute server used to close a channel, and when client tried to call a contract, channel was already crashed due to the timeout.
I found the solution after reading this article:
http://msdn.microsoft.com/en-us/library/system.servicemodel.reliablesession.inactivitytimeout.aspx
I received this error while setting up a new WCF service which returned a list of objects.
My understanding is that WCF services can only pass very simple objects back n forth.
So objects with anything other than public properties will not be transferable.
The object had a read only property doing a bit of logic.
Once I got rid of this, rebuilt, and updated the web references, the error went away.
Tip:
If you're returning a object and it has properties check the gets and sets of each one.
We had a problem around it.
I have seen this happen when an application pool gets recycled.
Look at the very last section of this blog about service recycling .

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