WCF Custom Serializer to send FileStream over network - wcf

Question

I have been trying to understand WCF internals. I tried to create custom formatters and message inspectors (both at the client and the server by following some online links) but have been facing issues.
My operationcontract method at the server simply reads a file (which has "testing" text in it) and returns a filestream. A custom dispatch formatter then tries to serialize the the stream received as a message. Following is the definition of custom serializer method at server -
public System.ServiceModel.Channels.Message SerializeReply(System.ServiceModel.Channels.MessageVersion messageVersion, object[] parameters, object result)
{
string content;
using(var reader = new StreamReader(((FileStream)result), Encoding.ASCII))
{ content = reader.ReadToEnd(); }
Message message = Message.CreateMessage(messageVersion, "http://tempuri.org/IService1/GetStreamVideoResponse", new CustomBodyWriter(content));
return message;
}
CustomBodyWriter is implemented as -
class CustomBodyWriter : BodyWriter
{
string content;
public RawBodyWriter(string content)
: base(true)
{
this.content = content;
}
protected override void OnWriteBodyContents(XmlDictionaryWriter writer)
{
writer.WriteStartElement("GetStreamVideoResponse");
writer.WriteAttributeString("xmlns", "http://tempuri.org/");
writer.WriteStartElement("GetStreamVideoResult");
writer.WriteString(content);
writer.WriteEndElement();
}
}
I think the xmldictionarywriter overrides the envelop when i write xml in OnWriteBodyContents method in CustomBodyWriter. But then how can i insert the response elements properly..
When I hook in to custom Inspector just to print the reply sent in BeforeSendReply method, I see following output at the console (which has an ending envelop element missing)-
<s:Envelope xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:s="http://www.w
3.org/2003/05/soap-envelope">
<s:Header>
<a:Action s:mustUnderstand="1">http://tempuri.org/IService1/GetStreamVideoRe
sponse</a:Action>
<ActivityId CorrelationId="0e0a6aae-91fa-4f9d-94b2-8c390cb5493d" xmlns="http
://schemas.microsoft.com/2004/09/ServiceModel/Diagnostics">e452a645-e8c5-44bf-81
06-d821522b7883</ActivityId>
<a:RelatesTo>urn:uuid:72b789cb-cc0b-48ac-b73a-434040434ce1</a:RelatesTo>
</s:Header>
<s:Body>
<GetStreamVideoResponse xmlns="http://tempuri.org/">
<GetStreamVideoResult>**testing**</GetStreamVideoResult>
</GetStreamVideoResponse>
</s:Body>
At the client, i have created custom inspector which tries to deserialize message by simply reading the body part of message in a byte[] and creating a filestream over it which is then returned -
public object DeserializeReply(System.ServiceModel.Channels.Message message, object[] parameters)
{
var getBody = message.GetReaderAtBodyContents();
byte[] buffer = getBody.ReadContentAsBase64();
FileStream fs = new FileStream("c:\\test.txt", FileMode.OpenOrCreate);//not ideal but need for testing at present
fs.Write(buffer, 0, buffer.Length);
return fs;
}
how can i get the complete SOAP message that culminates with Envelop element.
Even the byte[] created at client has no value in it. What is wrong that I have been doing?
Thanks in anticipation..