Why is HttpRequestMessage decoding my encoded string

Question

I am trying to make a Http request, like the following:

var category = Uri.EscapeDataString("Power Tools");

var request = new HttpRequestMessage(HttpMethod.Get, $"/api/Items/GetAll?category={category}");

category now equals: Power%20Tools

The request gets translated to:

request = {Method: GET, RequestUri: 'http://localhost/api/Items/GetAll?category=Power Tools', ...

Why is HttpRequestMessage decoding my encoded string?

Answer 1

I reproduce in Console app in .NET 5. I think, it's just the ToString that decode the url to be friendly on debug information. I don't find a information to this on the documentation, but .NET is now open source.

Generaly, the method ToString is used to generate debug information. See See the source code of HttpRequestMessage.ToString :

public override string ToString()
{
    StringBuilder sb = new StringBuilder();

    sb.Append("Method: ");
    sb.Append(method);

    sb.Append(", RequestUri: '");
    sb.Append(requestUri == null ? "<null>" : requestUri.ToString());
    ...
    return sb.ToString();
}

This just display requsetUri.ToString() and requestUri is type of Uri. From the official documentation of Uri.String:

The unescaped canonical representation of the Uri instance. All characters are unescaped except #, ?, and %.

// Create a new Uri from a string address.
Uri uriAddress = new Uri("HTTP://www.Contoso.com:80/thick%20and%20thin.htm");

// Write the new Uri to the console and note the difference in the two values.
// ToString() gives the canonical version.  OriginalString gives the orginal
// string that was passed to the constructor.

// The following outputs "http://www.contoso.com/thick and thin.htm".
Console.WriteLine(uriAddress.ToString());

// The following outputs "HTTP://www.Contoso.com:80/thick%20and%20thin.htm".
Console.WriteLine(uriAddress.OriginalString);