Update the Host field in the request header

[HaoweiCh]

This update checks for the 'Host' value in the request header, specifically assigning it to 'u.Host' if no value is found. This same logic is applied to 'cfg.ServerName'. The aim of this change is to ensure a correct 'Host' value is used throughout, addressing a bug related to setting the 'Host' field of the header.

What type of PR is this? (check all applicable)

• Refactor
• Feature
• Bug Fix
• Optimization
• Documentation Update
• Go Version Update
• Dependency Update

Description

Related Tickets & Documents

• Related Issue #
• Closes #

Added/updated tests?

• Yes
• No, and this is why: please replace this line with details on why tests
  have not been included
• I need help with writing tests

Run verifications and test

• make verify is passing
• make test is passing

[HaoweiCh]

When it comes to dealing with dynamic servers that the application controls, the ability to send data through a Content Delivery Network (CDN) is a big deal for me. It becomes especially important when I have to forward WebSocket connections. This feature allows me to use DNS over HTTPS (DoH) to look up and specifically choose the server's IP address. Particularly with Cloudflare CDN, I can even customize and select specific IP addresses for Cloudflare's edge nodes. To put it simply, this gives me the flexibility and control I need to ensure smooth communication between the application and the server.

[ghost]

Is this a correct statement of the problem: specify the sever address separate from the host used in the request header and when negotiating TLS.

If the statement of the problem is correct, then use the net dial function:

 addr := "example1.com:80" // server address
 url := "wss://example2.com/ws"  // use example2.com in host header and for TLS

 wsd := websocket.Dialer{
     NetDialContext: func(ctx context.Context, network, urlAddr string) (net.Conn, error) {
          // urlAddr is the address taken from the request
         // URL. We ignore that address when dialing the 
         // underlying network connection.
         var nd net.Dialer        
         return nd.DialContext(ctx, network, addr)
    },
}
ws, _, err := wsd.DialContext(ctx, url, nil)

[HaoweiCh]

curl 1.2.3.4 -H "Host: example.com".
to be honestly, I think the custom header setting should has higher priority, same logic like curl command.
and I think this should be inside framework. :)

[ghost]

This package should follow the design of the net/http package, not curl. The net/http package ignores the application specified Host header (start here to view the code).

This package solves your underlying problem using the net dial function. Whether the package should add additional ways to solve the problem is up to the package maintainers.

If the maintainers do decide to proceed forward with this PR, then the PR should be updated to include:

• Documentation for the new feature.
• A test for the new feature.
• A PR comment analyzing what happens to existing applications that set the Host header. Does this PR break those applications, or were the applications flawed to begin with?

I am not asking you to do any of the items above. That's up to the maintainers.