CODEWITHSUNDEEP
visual-studio
EJS
EJS

Reputation: 1071

How can I set "Content-Length" for Visual Studio web performance test request?

I have created a web performance test in VS 2015, and am trying to set request headers. When setting headers such as "Referer" or "User-Agent" everything seems to work fine. I just set the header by right-clicking the request and adding a new header, and when I run the test and inspect the request I can see that the new header has been added. However if I try to add a new header named "Content-Length" and then run the test, this header is missing from the request. I'm getting an http error which I assume is because VS doesn't use the "Content-Length" header:

HTTP Error 411. The request must be chunked or have a content length.

Upvotes: 3

Views: 1638

Answers (1)

Tyler Nielsen
Tyler Nielsen

Reputation: 615

I ran into this problem as well. The consistent trend with these issues online seems to be when the content-length is 0. Otherwise VS seems to dynamically come up with the content-length header on it's own.

Explanation of Problem
Esentially, I don't think you can add it manually. VS wants to add this itself, so the real problem is why isn't VS adding this?

The problem comes from the request being simply a "Request" and not a "Web Service Request", the significant difference here being that the latter includes the "String Body" component. I'm assuming that VS does this because the content-length it recorded was 0. I recorded my workflow in Fiddler and got the same result. I would also assume that the reason adding the Content-Length header doesn't work is because this gets calculated by Visual Studio if the request has a body in the request.

The Workaround
Make the request a "Web Service Request" so that it includes the String Body component. In the test, right click and choose "Insert Web Service Request".

I got clued into this from the below post (which also includes an example for a coded UI test): https://social.msdn.microsoft.com/Forums/en-US/da492346-760e-4971-a666-8897ae7b35e3/length-required-error?forum=vstswebtest

Plugin Option
I couldn't find a way to just convert my existing request into a Web Service Request, so I created a WebTestRequestPlugin that can be added to a request to dynamically add a body to the request.

  1. Add the below to your project
  2. Change the namespace to match your project's name
  3. Build your solution.
  4. Right click on the problematic request and click "Add Request Plugin" and then select this plugin.
using Microsoft.VisualStudio.TestTools.WebTesting;
using System.ComponentModel;

namespace YourProjectName
{
    [DisplayName("Add Request Body")]
    [Description("If a request is intended to have a content-length of 0, the Web Test won't include an empty String Body and the Content-Length header won't " +
        "be added during test execution. This may result in a 411 - Length required error. This plugin can be added to that request to add a body to the request" +
        "during test execution.")]
    public class AddBodyToRequestPlugin : WebTestRequestPlugin
    {
        public AddBodyToRequestPlugin()
        {

        }

        public override void PreRequest(object sender, PreRequestEventArgs e)
        {
            // Add string body if it doesn't exist yet.
            if ( e.Request.Body == null )
            {
                e.Request.Body = new StringHttpBody();
            }
        }
    }
}

Upvotes: 2

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