Transfer Files in WCF

I have seen those threads too. I don't understand the concept (I am used to doing things  the hard way..think VB6 :-) ). Can you explain, please?

Hi,

What concept do you want explained.

The articles show how to upload and download files using WCF.

Do you want the entire concept of WCF or how streaming works?

Darren

I get how it can call remote functions, and return values.

When we open a stream, there has to be an endpoint (a file handle). With WCF, am I opening a file directly on the remote machine for writing?

Hi again,

WCF is a communication tool built on top of the .NET framework. You are simply passing the file as a byte array, there is no file handle at this point, and the communication foundation (WCF) is taking care of sending the byte array from the client to the server using an endpoint so that it knows where to send it, and using a config file and binding so that it knows how you want it sent. Once the byte array reaches the server you must take care of creating the file handle and writing out the contents of the byte array to it.

This is C# but WCF has taken care of sending the data and then you must decide what to do with it...

http://www.google.ie/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLG_enIE327IE327&q=WCF+and+File+Streaming

Taken from the above article:

        string filePath = @"I:\Sabid\WCF\Downloads\" + fileName;
        FileStream fs = new FileStream(filePath, FileMode.Create, FileAccess.Write);
        fs.Write(data, 0, data.Length);
        fs.Close();

The endpoint is created so that the client knows where to send the byte array.

Let me know if you need more info,

Darren

So I loop through the file sending byte arrays until I reach the end of the file (just like as if I was sending it over a regular stream).

Is this what the function should look like on the server side?

    Public Sub RecieveFile(ByVal Buffer As Byte(), ByVal lOffset As Long)
        Dim fs As New FileStream("C:\temp\file.tmp", FileMode.Append)
        fs.Write(Buffer, lOffset, Buffer.Length)
 
    End Sub

                                              

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Hi,

Yes exactly. You create the file from the stream of bytes.

Darren

How does the server know that the file is done? That we've reached 100%? pass the file size every time?

What about this? It appears they are passing the actual stream object, which means I can loop through to the end of the stream on the server side.

http://www.codeproject.com/KB/WCF/wcffileserver.aspx

Is my interpretation correct?

Hi,

As the article says:
'The upload and download functions get special mention because they work with Stream objects, but as you can see, you don't do anything different with them than what you'd normally do when working with streams. You just have to create some sort of stream and pass it to the service; we have already configured our service for streamed mode, so the transfer of the data is handled appropriately for us.'

I don't see where in the article they are looping through the stream except for when it is being copied.

WCF takes care of the communication for you.

Darren

"I don't see where in the article they are looping through the stream except for when it is being copied."

...exactly. That's how I copy a file from client to server. Yes?