WCF - Streaming file upload over http - wcf

Question

I am trying to build a WCF service that will allow my WPF desktop clients to upload files to a server.
I adapted a code sample from The Code Project (WCF Streaming: Upload/Download Files Over HTTP) and I've looked at several SO posts as well, but can't seem to get this working.
When I execute the code, it fails with a null reference exception at the point that the server tries to read the stream that has been passed through the interface.
At this point, I am rather lost and don't know how to fix this up. Any suggestions are appreciated.
Code samples follow:
CustomerDocumentModel is the data element that I pass through the WCF interface with the stream to read the client side file:
[DataContract]
[KnownType(typeof(System.IO.FileStream))]
public class CustomerDocumentModel : IDisposable
{
public CustomerDocumentModel()
{
}
public CustomerDocumentModel(string documentName, string path)
{
DocumentName = documentName;
Path = path;
}
[DataMember]
public string DocumentName;
[DataMember]
public string Path;
[DataMember]
public System.IO.Stream FileByteStream;
public void Dispose()
{
if (FileByteStream != null)
{
FileByteStream.Close();
FileByteStream = null;
}
}
}
IBillingService is the interface definition for my WCF service:
[ServiceContract]
public interface IBillingService
{
// other methods redacted...
[OperationContract]
void UploadCustomerDocument(CustomerDocumentModel model);
}
The class BillingService implements the WCF service:
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class BillingService : IBillingService
{
// Other methods redacted ...
public void UploadCustomerDocument(CustomerDocumentModel model)
{
string path = HttpContext.Current.Server.MapPath(
String.Format("/Documents/{1}",
model.DocumentName));
using (FileStream stream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None))
{
const int bufferSize = 4096;
byte[] buffer = new byte[bufferSize];
int size = 0;
try
{
// The following Read() fails with a NullReferenceException
while ((size = model.FileByteStream.Read(buffer, 0, bufferSize)) > 0)
{
stream.Write(buffer, 0, size);
}
}
catch
{
throw;
}
finally
{
stream.Close();
model.FileByteStream.Close();
}
}
}
}
A few relevant bits from the web.config on my WCF web server:
<system.web>
<compilation debug="true" targetFramework="4.0" />
<httpRuntime maxRequestLength="2097151" useFullyQualifiedRedirectUrl="true" executionTimeout="360"/>
</system.web>
<system.serviceModel>
<serviceHostingEnvironment
aspNetCompatibilityEnabled="true"
multipleSiteBindingsEnabled="true" />
<bindings>
<basicHttpBinding>
<binding name="userHttps" transferMode="Streamed" maxReceivedMessageSize="2147483647" maxBufferSize="2147483647">
<readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" />
<security mode="None" />
</binding>
</basicHttpBinding>
</bindings>
<behaviors>
<serviceBehaviors>
<behavior name="">
<dataContractSerializer maxItemsInObjectGraph="2147483646"/>
<serviceDebug includeExceptionDetailInFaults="true" />
<serviceMetadata httpGetEnabled="true" />
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
The client is a WPF/MVVM app that creates a CustomerDocumentModel model, uses an OpenFileDialog to Open() the file stream and then passes the model to the UploadCustomerDocument method on WCF Service.
If I am missing any relevant details, please ask.

Answer 1

I know this rather very late reply for your question and I'm sure you must have resolved your problem as well. This could be helpful to someone else :-)
Use Messagecontract over Datacontract and only one MessageBodyMember with datatype Stream and rest all parameter are MessageHeader.
Here is the example:
[MessageContract]
public class CustomerDocumentModel : IDisposable
{
public CustomerDocumentModel(string documentName, string path)
{
DocumentName = documentName;
Path = path;
}
[MessageHeader]
public string DocumentName{get;set;}
[MessageHeader]
public string Path{get;set;}
[MessageBodyMember]
public System.IO.Stream FileByteStream{get;set;}
public void Dispose()
{
if (FileByteStream != null)
{
FileByteStream.Close();
FileByteStream = null;
}
}
}
Note: Make sure your in your configuration transfer mode is StreamedResponse, also you may want to change the MessageEncoding to MTOM for better performance.
public void UploadCustomerDocument(CustomerDocumentModel model)
{
var filename = //your file name and path;
using (var fs = new FileStream(filename, FileMode.Create))
{
model.FileByteStream.CopyTo(fs);
}
}

Answer 2

Your data type is what is making the streaming fail. This is documented on MSDN here: http://msdn.microsoft.com/en-us/library/ms731913.aspx
The relevant passage is:
Restrictions on Streamed Transfers
Using the streamed transfer mode causes the run time to enforce
additional restrictions.
Operations that occur across a streamed transport can have a contract
with at most one input or output parameter. That parameter corresponds
to the entire body of the message and must be a Message, a derived
type of Stream, or an IXmlSerializable implementation. Having a return
value for an operation is equivalent to having an output parameter.
Some WCF features, such as reliable messaging, transactions, and SOAP
message-level security, rely on buffering messages for transmissions.
Using these features may reduce or eliminate the performance benefits
gained by using streaming. To secure a streamed transport, use
transport-level security only or use transport-level security plus
authentication-only message security.
SOAP headers are always buffered, even when the transfer mode is set
to streamed. The headers for a message must not exceed the size of the
MaxBufferSize transport quota. For more information about this
setting, see Transport Quotas.