Question

I have successfully made an app that sends a request from my Windows Phone to a WCF api hosted in an azure web role. I am using a restful POST method to do this using RestSharp. It all works brilliantly and the images are appearing in storage but the images are not opening as normal image files.

Comparing them to other images I uploaded previously, in the metadata info it says the unviewable images have a contentMD5 field which is set to something like “AKEYWqGgulwi6/9/VY2KPg==” (whereas the others do not) could this be what is causing the problem with the files?

I have attached my RestSharp code, maybe I’m am adding something I shouldn’t be? The error I suspect must be coming from here as this is the only place where the imagestream is manipulated.

   public void SendRequest(Stream imageStream, string imageID)
    {
        var client = new RestClient();
        client.BaseUrl = apiAddress;
        var request = new RestRequest("agerecog/{imageName}", Method.POST);
        request.AddUrlSegment("imageName", imageID);

        //convert imagestream to byte array
        var byteArray = new byte[imageStream.Length];
        imageStream.Read(byteArray, 0, (int)imageStream.Length);

        //add byteArray to request
        request.AddFile("image/jpeg", byteArray, imageID);
        var url = client.BuildUri(request).ToString();
        client.ExecuteAsync<VizageResponse>(request, response =>
            {
                //request info. to be added here
            });
    }

EDIT #1
After some work I decided to change the addFile line to this:

  request.AddFile(null, byteArray, null);

Which changed the stream length and also made the contentMD5 field empty. However, the image is still not a valid image file. Given the fact the images I am comparing are both from the Windows Phone emulator they should both be an identical white page with a small black square in the corner – but there is a different in size between the file (5670 length for the valid image file, 6076 length for the original code and 6239 length using the second addFile above)

EDIT #2
Doing some more analysis, when the before the image Stream is sent its length property is 6116, when it arrives on the server, however it is 6370. 264 is being added from somewhere in the RestSharp method I believe or when the stream of data is interpreted on the server side. The code of the WCF service:

  [WebInvoke(UriTemplate = "/agerecog/{imageName}", Method = "POST")]
    VizageResult analyseFace(string imageName, Stream imageStream);

Answer 1

Problem Solved

I have finally solved the problem and an image is visible as the end result. What was happening was that the imageStream also contained data regarding the name of the file and this was causing it (when saved in Azure) to not appear as an image file.

I fixed this by using the MultipartParser class found here: http://multipartparser.codeplex.com/ on the server side to parse the request into the filename and filestream chunks. I then saved the image from this byte[] using the normal process.

My code to parse the webrequest data into its constituent parts is found below:

    MemoryStream imageStream = new MemoryStream();

     MultipartParser parser = new MultipartParser(dataStream);
        if (parser != null && parser.Success)
        {
            imageName = parser.Filename;
            imageStream.Write(parser.FileContents, 0, parser.FileContents.Length);
        }

When you use the memory stream remember to set its position back to 0 – a schoolboy mistake I made!