WCF Content-Length HTTP header on outbound message

Question

I'm in a tough situation in which a Java web service endpoint hosted on an IBM HTTP Server (IHS) requires a Content-Length header, although it supposedly conforms to HTTP/1.1. If I send the header, everything works. If I leave it off, I get a 500 error response informing me that my POST entity body was empty (even though it was not).

We've invested significant time into our WCF client for these services (developed by a third party) and I can't seem to find a good way to append a Content-Length header to the request. I am able to add arbitrary headers (i.e. X-Dan-Lynn-Header) to the request using an IClientMessageInspector as described in blog posts like this, but WCF seems to ignore a Content-Length header.

My options are:

a) figure out how to force WCF to append a Content-Length header to the HTTP POST request or,

b) find or write an extremely simple-yet-transparent HTTP proxy that decorates the request with a Content-Length header.

Thanks!

Sample IClientMessageInspector.BeforeSendRequest:

public object BeforeSendRequest(ref Message request, IClientChannel channel)
{
    var buffer = request.CreateBufferedCopy(Int32.MaxValue);
    var tempRequest = buffer.CreateMessage();


    HttpRequestMessageProperty httpRequest = GetHttpRequestProp(tempRequest);
    if (httpRequest != null)
    {
        if (string.IsNullOrEmpty(httpRequest.Headers[HttpRequestHeader.ContentLength]))
        {
            httpRequest.Headers.Add(HttpRequestHeader.ContentLength, GetMessageLength(buffer).ToString());
            httpRequest.Headers.Add("X-Dan-Lynn-Header", "abcdefghijk");
        }

    }

    request = tempRequest;
    request.Properties[HttpRequestMessageProperty.Name] = httpRequest;

    return null;
}

Sample request generated by WCF (and the preceding IClientMessageInspector):

POST /path/to/service HTTP/1.1
Content-Type: text/xml; charset=utf-8
X-Dan-Lynn-Header: abcdefghijk
SOAPAction: "http://tempuri.org/path/to/service/action"
Host: service.host.tld
Transfer-Encoding: chunked
Connection: Keep-Alive


<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"&gt;
    <s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
        .......body removed for clarity......

    </s:Body>
</s:Envelope>

Answer 1

I am not currently able to actually try to run the code to see what happens but something like

WCFClient client = new WCFClient();
using (OperationContextScope scope = new OperationContextScope(client.InnerChannel))    
{     
    HttpRequestMessageProperty req = new HttpRequestMessageProperty();            
    req.Headers.Add("Content-Length", "YOUR CONTENT LENGTH HERE");      
    OperationContext.Current.OutgoingMessageProperties[HttpRequestMessageProperty.Name] = req;      
}

see http://msdn.microsoft.com/en-us/library/aa395196.aspx for more information on how you can use the OperationContextScope object to include additional headers.

update: I do have to say I find this a strange issue. I wonder why the content length isn't being set. I wouldn't be surprissed if your actual problem is somewhere else.

Answer 2

Figured it out. Setting the binding to use transferMode="Streamed" was causing a Transfer-Encoding: chunked. We needed streamed transfers due to very large responses from the web service, so I was able to go with:

Bad:

transferMode="Streamed"

Good:

transferMode="StreamedResponse"

Changing the binding to this solved the problem:

<basicHttpBinding>
    <binding name="MyBinding" closeTimeout="00:30:00" openTimeout="00:30:00"
      receiveTimeout="00:30:00" sendTimeout="00:30:00" allowCookies="false"
      bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard"
      maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="16777216"
      messageEncoding="Text" textEncoding="utf-8" transferMode="StreamedResponse"
      useDefaultWebProxy="false">
      <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="65536"
        maxBytesPerRead="4096" maxNameTableCharCount="16384" />
      <security mode="None" />
    </binding>
  </basicHttpBinding>