Question

I am running a very simple Web application (Asp.Net MVC3) on Win 7 IIS.
I have a very simple HTTP GET API which returns hello world.

Calling:

http://localhost/helloworld

Returns:

Hello World!

This works perfectly over a browser.
But when I write an app which tries to pull this URL using a webclient, I get the following error:

{"Unable to read data from the transport connection: The connection was closed."}

My Code is as follows

WebClient web = new WebClient();
var response = web.DownloadString("http://localhost/helloworld");

My IIS Settings are as follows

What should I be looking at? I have been at this for hours and I have run out of options to try! Any help will be really appreciated!

Thanks.

Answer 1

I finally figured out what the issue was and instead of it being an IIS specific issue – which I was leaning towards, it turned out to be an issue with the code that I wrote.

Adding details here incase someone else runs into a similar problem.

I had the following method in my code which I was using to send the response of the request as a JSON object.

private void sendJsonResult(string result) {
    Response.StatusCode = 200;
    Response.Headers.Add("Content-Type", "application/json; charset=utf-8");
    Response.Flush();
    Response.Write(result);
    Response.End();
    Response.Close();    // <-- This is the problem statement
}

On digging around a bit, I found out that we should not be doing a Response.Close().

A better explanation of this is here.
Once I removed that line, it started working perfectly – both in my consuming app as well as the web browser, etc.

If you will read the link above, you will clearly understand why we should not be using a Response.Close() – so I will not go into that description. Learnt a new thing today.