Difference between returning a Stream and writing to HTTP output stream

Question

What is the difference when returning files between

public Stream getFile(string filename){
    Stream s = _getFileStream(filename);
    Response.AddHeader( "Content-Disposition", "attachment;filename=" + filename+ ";" );
    return s;
}

and

public void getFile(string filename){
    byte[] b = _getFileBytes(filename);
    Response.AddHeader( "Content-Disposition", "attachment;filename=" + filename+ ";"  );
    Response.BinaryWrite(b)
}

and the method provided in the question here.

The problem I'm encountering is that sometimes parts of the image a user has uploaded appear scrambled. What's also odd is I cannot reproduce the problem locally - only when the application is on the www.

My thinking is that perhaps since my resources are local I wouldn't see the problem when streaming data and that the way I am streaming content back to the client isn't correct. So which is the "correct" (or recommended) way of returning the file?

First function does not write and data. 2nd returns undeclared variable `s` in a `void` function. — Magnus, May 08 '13 at 15:02
Whoops, I didn't proof-read. Both functions work for me. I just want to know if one is more better than the other and why. — spots, May 08 '13 at 15:06
If you're mixing WCF (I think, based on the tags in the question) with plain ASP.NET - you shouldn't do that. Either go full ASP.NET (and forget about `[ServiceContract]` and friends) where you can use the Response object, or go full WCF (where you return `Stream` but use the `WebOperationContext.Current.OutgoingResponse.Headers` to add the returning header. — carlosfigueira, May 08 '13 at 17:49
I am accessing the Response by HttpContext.Current.Response. I want to go the WCF route and avoid the ASP.net stuff. — spots, May 08 '13 at 18:28

score 0 · Accepted Answer · answered May 10 '13 at 16:06

I resolved my issue with two changes.

I took what carlosfiguera said and changed HttpContext.Current.Response.AddHeaders(...) to WebOperationContext.Current.OutgoingResponse.Add(...)
In my WebConfig I located the binding tag my service had it's bindingCOnfiguration set to and changed transferMode to "Streamed"

These two changes got my images showing up correctly.

Difference between returning a Stream and writing to HTTP output stream

1 Answers1