Chaudhry Mohsin Ali Chaudhry Mohsin Ali - 1 year ago 68
C# Question

Byte array different from an Web Api Method in C#?

So I have a web api which returns a byte array like this

public byte[] Validate()
byte[] buffer = licensePackage.ToByteArray();
return buffer;

The thing is when I get it on client it is different size and different byte array, I googled and found this link helpful

But can I know why this happens? Also, what is an alternate way to send back that file contents from the server?

Answer Source

With the given information I think it must have something to do with content negotiation. I can't tell about the reason, but what I'm sure it's that there is a different approach to serve files behind a Web Api.

var response = Request.CreateResponse(HttpStatusCode.OK);
var stream = new FileStream(pathToFile, FileMode.Open, FileAccess.Read);

response.Content = new StreamContent(stream);
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
return ResponseMessage(response);

With this solution, you serve the file contents returning an IHttpActionResult instance. And, returning a response with StreamContent you are conceptually returning an array of bytes that must not be modified by Web Api. Content negotiation is not going to alter anything.