RESTful WCF service image upload problem

Question

1 namespace Uploader  
2 {  
3     using System;  
4     using System.IO;  
5     using System.ServiceModel;  
6     using System.ServiceModel.Description;  
7     using System.ServiceModel.Web;  
8     using System.Drawing;  
9     using System.Drawing.Imaging;  
10     using System.Net;  
11     using System.Xml;  
12   
13     [ServiceContract(Namespace = "http://Uploader")]  
14     public interface IUploaderService  
15     {  
16         [OperationContract, WebInvoke(Method = "POST",UriTemplate = "File/{fileName}")]  
17         bool UploadFile(string fileName, Stream fileContents);  
18     }  
19   
20     [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)]  
21     public class UploaderService : IUploaderService  
22     {  
23         public bool UploadFile(string fileName, Stream fileContents)  
24         {  
25             return true;  
26         }  
27     }  
28   
29     class Program  
30     {  
31         static void Main()  
32         {  
33             var host = new   
34                 ServiceHost(typeof (UploaderService),   
35                 new Uri("http://localhost:8080/Uploader"));  
36             host.AddServiceEndpoint("Uploader.IUploaderService",   
37                 new WebHttpBinding(), "").Behaviors.Add(new WebHttpBehavior());  
38             try  
39             {  
40                 host.Open();  
41                 Console.WriteLine(host.BaseAddresses[0].AbsoluteUri + " running.");  
42                 Console.WriteLine();  
43                 var uri = "http://localhost:8080/Uploader/file.jpg";  
44                 var req = WebRequest.Create(uri) as HttpWebRequest;  
45                 if (req != null)  
46                 {  
47                     req.Method = "POST";  
48                     req.ContentType = "image/jpeg";  
49                     var reqStream = req.GetRequestStream();  
50                   
51                     var imageStream = new MemoryStream();  
52                     using (var i = Image.FromFile(@"c:\photo.jpg"))   
53                         i.Save(imageStream, ImageFormat.Jpeg);  
54                       
55                     var imageArray = imageStream.ToArray();  
56                     reqStream.Write(imageArray, 0, imageArray.Length);  
57                     reqStream.Close();  
58                     var resp = (HttpWebResponse)req.GetResponse();  
59                     var r = new XmlTextReader(resp.GetResponseStream());  
60                     if (r.Read())  
61                     {  
62                         Console.WriteLine(r.ReadString());      
63                     }  
64                 }  
65                 Console.WriteLine("Press <ENTER> to quit.");  
66                 Console.ReadLine();  
67             }  
68             catch (Exception ex)  
69             {  
70                 Console.WriteLine(ex.Message);  
71                 Console.ReadKey();  
72             }  
73             finally  
74             {  
75                 if (host.State == CommunicationState.Faulted)  
76                     host.Abort();  
77                 else  
78                     host.Close();  
79             }  
80         }  
81     }  
82 }  
83   
84   

Hi, hope you can help....

I am creating a simple app(maybe webpage) that will have a simple UI and will upload files from an external device, the app/webpage will be started via autorun.inf when the user plugs a device into there PC. The webservice will perform the complex job of linking the file to the management system etc. This will enable the IT illiterate users that can't use file explore to submit files to the the management system...!

The problem I have is that my RESTful serivce is giving me a 400 error when the content type is a image/jpeg.. It works fine for text/plain or text/xml (see Blog Post)

Thanks J

Solution

You can try to override any content-type and upload all files as application/octet-stream, or text/plain using an IOperationBehavior.

public class WebContentTypeAttribute : Attribute, IOperationBehavior, IDispatchMessageFormatter
{
    private IDispatchMessageFormatter innerFormatter;
    public string ContentTypeOverride { get; set; }

    public WebContentTypeAttribute(string contentTypeOverride)
    {
        this.ContentTypeOverride = contentTypeOverride;
    }


    // IOperationBehavior
    public void Validate(OperationDescription operationDescription)
    {

    }

    public void ApplyDispatchBehavior(OperationDescription operationDescription, DispatchOperation dispatchOperation)
    {
        innerFormatter = dispatchOperation.Formatter;
        dispatchOperation.Formatter = this;
    }

    public void ApplyClientBehavior(OperationDescription operationDescription, ClientOperation clientOperation)
    {

    }

    public void AddBindingParameters(OperationDescription operationDescription, BindingParameterCollection bindingParameters)
    {

    }

    // IDispatchMessageFormatter
    public void DeserializeRequest(Message message, object[] parameters)
    {
        if (message == null)
            return;

        if (string.IsNullOrEmpty(ContentTypeOverride))
            return;

        var httpRequest = (HttpRequestMessageProperty)message.Properties[HttpRequestMessageProperty.Name];
        httpRequest.Headers["Content-Type"] = ContentTypeOverride;
    }

    public Message SerializeReply(MessageVersion messageVersion, object[] parameters, object result)
    {
        return innerFormatter.SerializeReply(messageVersion, parameters, result);
    }
}

And you would have to modify your Service contract to look like this one

[OperationContract]
[WebInvoke(Method = "POST",UriTemplate = "File/{fileName}")]
[WebContentType("application/octet-stream")]
bool UploadFile(string fileName, Stream fileContents);  

Although, if you are uploading from a webpage, wouldn't the data be posted in a multipart/form-data format?

Comments

[jaimie]

Just what I was after! Not sure about the the webpage upload yet, however I may use JavaScript to hook into the service, so I will need to make a JSON enabled version too. Cross that bridge when/if i reach it. The app is a small protoype at the mo.

[jaimie]

I'm really liking this RESTful WCF, it seems so much cleaner and thinner than the standard SOAP WS-* standards for interoperability. There is a great white paper on msdn: msdn.microsoft.com/en-us/library/dd203052.aspx for anyone who wants to know more. Thanks for your help Ben... J