title: Why are request.URL.Host and Scheme blank in the development server?
body: <p>I'm very new to Go. Tried this first <a href="http://code.google.com/appengine/docs/go/gettingstarted/helloworld.html">hello, world</a> from the documentation, and wanted to read the Host and Scheme from the request:</p>
  
  <pre><code>package hello
  
  import (
      "fmt"
      "http"
  )
  
  func init() {
      http.HandleFunc("/", handler)
  }
  
  func handler(w http.ResponseWriter, r *http.Request) {
      fmt.Fprint(w, "Host: " + r.URL.Host + " Scheme: " + r.URL.Scheme)
  }
  </code></pre>
  
  <p>But their values are both blank. Why?</p>