How to dump ASP.NET Request headers to string

For those (like me) having troubles with the absence of AllKeys property in IHeaderDictionary implementation, this is the way I was able to serialize all headers in a string (inside a controller action).

using System;
using System.Text;

// ...

var builder = new StringBuilder(Environment.NewLine);
foreach (var header in Request.Headers)
{
    builder.AppendLine($"{header.Key}: {header.Value}");
}
var headersDump = builder.ToString();

I'm using ASP.NET Core 3.1.

You can use,

string headers = Request.Headers.ToString(); 

But It will return URL encoded string so to decode it use below code,

String headers = HttpUtility.UrlDecode(Request.Headers.ToString()) 

You could turn on tracing on the page to see headers, cookies, form variables, querystring etc painlessly:

Top line of the aspx starting:

<%@ Page Language="C#" Trace="true" 

Have a look at the Headers property in the Request object.

C#

string headers = Request.Headers.ToString();

Or, if you want it formatted in some other way:

string headers = String.Empty;
foreach (var key in Request.Headers.AllKeys)
  headers += key + "=" + Request.Headers[key] + Environment.NewLine;

VB.NET:

Dim headers = Request.Headers.ToString()

Or:

Dim headers As String = String.Empty
For Each key In Request.Headers.AllKeys
  headers &= key & "=" & Request.Headers(key) & Environment.NewLine
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