Add support for authenticated HTTP proxy in HTTPClient

[almusx]

Godot version

4.0.2

System information

Windows 10, Windows 11

Issue description

Godot has the option to manually add a proxy setting in editor preferences but we need support for authenticated proxy using
username and password. Its Basic proxy authentication TCP 8080 port.
Other softwares load proxy configuration from http_proxy variable and i had my cofiguration like this: http://username:password@proxy.com:8080

Steps to reproduce

Load GODOT, trying to load AssetLib, get error connection to assetlib. No internet connection.
Trying to do a custom android build i get error from gradle downloading...
i tried configuring the proxy in editor preferences like i do in my http_proxy variable: http://username:password@proxy.com:8080 but doesnt work.

Minimal reproduction project

N/A

[Calinou]

For reference, HTTP proxy support was added in #55747.

If proxy authentication information is sent as basic HTTP authentication, it should be easy to extract the username and password from the proxy URL and pass it as request headers to the proxy.

[almusx]

For reference, HTTP proxy support was added in #55747.

If proxy authentication information is sent as basic HTTP authentication, it should be easy to extract the username and password from the proxy URL and pass it as request headers to the proxy.

I know its http proxy using tcp, for the authentication the only information i have is "basic proxy authentication", but I don't know what that means.

[timothyqiu]

If you want to implement this, all you need is adding an Proxy-Authorization: Basic <Base64 of user:pass> header to the correct request.

• If the proxy server uses HTTP, add this header to all requests you want to send.

• If the proxy server uses HTTPS, add this header to the first CONNECT request.

[almusx]

A solution for anyone using Godot behind an authenticated proxy, i am using a small program "proxify", its a localhost proxy server that can be configured to connect to the "Real Proxy". You need to configure Godot to connect to proxify : 127.0.0.1:8888 and import TLS certificate generated by proxify, all connection made by Godot are sent to proxify and redirected to your proxy.