Question

I have a WCF Rest Service project set up serving JSON datastructures. I have defined a contract in an interface file like:

[OperationContract]
[WebInvoke(Method = "GET",
    ResponseFormat = WebMessageFormat.Json,
    BodyStyle = WebMessageBodyStyle.Bare,
    UriTemplate = "location/{id}")]
Location GetLocation(string id);

Now the WebService needs to return multimedia (images, PDF documents) documents like a standard Web Server does. The WCF WebMessageFormat of the ResponseFormat only support JSON or XML. How do i define the method in the interface to return a file ?

Something like:

[OperationContract]
[WebInvoke(Method="GET",
    ResponseFormat = ?????
    BodyStyle = WebMessageBodyStyle.Bare,
    UriTemplate = "multimedia/{id}")]
???? GetMultimedia(string id);

So that: wget http://example.com/multimedia/10 returns the PDF document with id 10.

Answer 1

You can get a file from your RESTful service as shown below:

[WebGet(UriTemplate = "file")]
        public Stream GetFile()
        {
            WebOperationContext.Current.OutgoingResponse.ContentType = "application/txt";
            FileStream f = new FileStream("C:\\Test.txt", FileMode.Open);
            int length = (int)f.Length;
            WebOperationContext.Current.OutgoingResponse.ContentLength = length;
            byte[] buffer = new byte[length];
            int sum = 0;
            int count;
            while((count = f.Read(buffer, sum , length - sum)) > 0 )
            {
                sum += count;
            }
            f.Close();
            return new MemoryStream(buffer); 
        }

When you browse to the service in IE it should show a open save dialog for the response.

NOTE: You should set the appropriate content type of the file your service returns. In the above example it return a text file.