templates: Add dummy RemoteAddr to httpInclude request, proxy compatibility (#5845)

* Enhancement: Allow X-Forwarded-For Header in httpInclude Virtual Requests

The goal of this enhancement is to modify the funcHTTPInclude function in the Caddy codebase to include the X-Forwarded-For header in the virtual request. This change will enable reverse proxies to set the X-Forwarded-For header, ensuring that the client's IP address is correctly provided to the target endpoint. This modification is essential for applications that depend on the X-Forwarded-For header for various functionalities, such as authentication, logging, or content customization.

* Updated tplcontext.go - set `virtReq.RemoteAddr = "127.0.0.1"`

i have made the suggested changes

* Apply suggestions from code review

* Update modules/caddyhttp/templates/tplcontext.go

---------

Co-authored-by: Francis Lavoie <[email protected]>

Author: ThanmayNath

modules/caddyhttp/templates/tplcontext.go

@@ -188,6 +188,7 @@ func (c TemplateContext) funcHTTPInclude(uri string) (string, error) {
 		return "", err
 	}
 	virtReq.Host = c.Req.Host
+	virtReq.RemoteAddr = "127.0.0.1:10000" // https://github.com/caddyserver/caddy/issues/5835
 	virtReq.Header = c.Req.Header.Clone()
 	virtReq.Header.Set("Accept-Encoding", "identity") // https://github.com/caddyserver/caddy/issues/4352
 	virtReq.Trailer = c.Req.Trailer.Clone()