WCF Chunking / Streaming

Question

Hi,

I'm using WCF and want to upload a large file from the client to the server. I have investigated and decided to follow the chunking approach outlined at http://msdn.microsoft.com/en-us/library/aa717050.aspx

However, this approach (just like streaming) restricts the contract to limited method signitures:

[OperationContract(IsOneWay=true)]
[ChunkingBehavior(ChunkingAppliesTo.InMessage)]
void UploadStream(Stream stream);

The sample uses the rather convenient example of uploading a file from a fixed path and saving it to a fixed path on the server. Therefore, my question is how do I pass additional parameters to specify things like filename, filepath etc.

eg. I would like something like:

[OperationContract(IsOneWay=true)]
[ChunkingBehavior(ChunkingAppliesTo.InMessage)]
void UploadStream(Stream stream, String filePath);

Thanks in advance, Mark.

Answer 1

You could make your service session-ful and have an initialization method in the contract with the IsInitiating property set to true. Something like:

[OperationContract(IsInitiating = true)]
void InitializeUploadService(string filename);

[OperationContract(IsOneWay = true, IsInitiating = false)]
[ChunkingBehavior(ChunkingAppliesTo.InMessage)]
void UploadStream(Stream stream);

I have never tried it with streaming services but it should basically make WCF enforce that InitializeUploadService is always called before UploadStream.

More documentation can be found here: http://msdn.microsoft.com/en-us/library/system.servicemodel.description.operationdescription.isinitiating.aspx

Answer 2

This article explains how to use the MessageHeader attribute to force things to be passed in the header, and therefore not count as a parameter. So, instead of passing a stream and other meta data, create a class that has the attribute MessageContract and mark all of the meta data as a MessageHeader. Then, mark the stream as a MessageBodyMember (which the article incorrect calls "MessageBody"). Have your UploadStream method take a single parameter whose type is that of the MessageContract class you've just created. I've done this successfully, but I haven't done it in tandem with chunking. Good luck.

Answer 3

Setting up the maxItemsInObjectGraph in the Client side and Server side worked for me.

(Dont forget the client side.) http://social.msdn.microsoft.com/Forums/en/wcf/thread/0af69654-2d89-44f3-857a-583b57844ca5