获取当前请求URL的方案

Question

In Ruby/Rack, I'm able to get the scheme of the current request URL from scheme#request. However, in Go, http.Request.URL.Scheme returns an empty string:

package main

import (
    "fmt"
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", handler)
    log.Fatal(http.ListenAndServe(":8080", nil))
}

func handler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "%#v
", r.URL.Scheme) // Always shows empty string
}

How do I get scheme of the current request URL?

Answer 1

It is because, you're accessing the HTTP server so:

GET / HTTP/1.1
Host: localhost:8080

in this cases, based on parsing what you get is raw URL from Go's http.Request.URL. why you are getting this is because you are accessing the URL from a relative path, hence the lack of a Host or Scheme in the URL object.

If you do want to get the HTTP host, you may have to access the Host attribute of the http.Request struct. See http://golang.org/pkg/http/#Request

as it is not directly available, but you can still be able to assemble it:

u := r.URL

// The scheme can be http/https because that's depends on protocol your server handles.
u.Scheme = "http"