Question

I’m in a need to send a HttpPostedFileBase to a wcf serivce for processing which runs at the server, from the front end of web page after user click “upload a file” button. I used HttpPostedFileBase in the service contract first, but it didn’t work. Then I tried to put HttpPostedFileBase into the data contract but it still didn’t work. I struggled two days to go through that problem. Now here is the approach:

In Service Contract:

[ServiceContract]
public interface IFileImportWcf
{
    [OperationContract]
    string FileImport(byte[] file);
}

And found these two methods to convert byte[] to stream and vice versa.

    public byte[] StreamToBytes(Stream stream)
    {
        byte[] bytes = new byte[stream.Length];
        stream.Read(bytes, 0, bytes.Length);
        stream.Seek(0, SeekOrigin.Begin);
        return bytes;
    }
    public Stream BytesToStream(byte[] bytes)
    {
        Stream stream = new MemoryStream(bytes);
        return stream;
    } 

In the controller:

[HttpPost]
public ActionResult Import(HttpPostedFileBase attachment)
{
    //convert HttpPostedFileBase to bytes[]
    var binReader = new BinaryReader(attachment.InputStream);
    var file = binReader.ReadBytes(attachment.ContentLength);
    //call wcf service
    var wcfClient = new ImportFileWcfClient();
    wcfClient.FileImport(file);
}

My question is: What’s the better way to send a HttpPostedFileBase to a wcf service?

Answer 1

You need to use WCF Data Streaming here.

As I understood from your question you have control over your WCF Service contract.

If you change contract to something like the following:

[ServiceContract]
public interface IFileImportWcf
{
    [OperationContract]
    string FileImport(Stream file);
}

Then you will be able to use it on client side:

[HttpPost]
public ActionResult Import(HttpPostedFileBase attachment)
{
    var wcfClient = new ImportFileWcfClient();
    wcfClient.FileImport(attachment.InputStream);
}

Please note that you need to enable streaming in configuration

<binding name="ExampleBinding" transferMode="Streamed"/>

(see link above for more details)