GO: How to POST data into datastore?

1)Rendered a Login Page through template method.
Ex.: this is index.html

{{ define "title" }}Guestbook{{ end }}
    
    {{ define "content" }}
    	<form action="/login" method="post">
          <div><label>UserName : </label><input name="username" type="text" /></div>
          <div><label>Password : </label><input name="password" type="password" /></div>
          <div><input type="submit" value="login"></div>
        </form>
    	
    {{ end }}

2. hello.go file:

   package main

   import (
   "fmt"
   "html/template"
   "net/http"
   )

   var index = template.Must(template.ParseFiles(
   "templates/base.html",
   "templates/index.html",
   ))
   type UserLogin struct{
   UserName string
   PassWord string
   }

   func handler(w http.ResponseWriter, r *http.Request) {
   index.Execute(w, nil)
   }

   /*func login(w http.ResponseWriter, r http.Request) {
   remPartOfURL := r.URL.Path[len("/login/"):]
   if r.Method == "POST" {
   fmt.Fprintf(w, "after",r.FormValue("username"))
   }
   fmt.Fprintf(w, "Hello %s!", remPartOfURL)
   }/
   func login(w http.ResponseWriter, r *http.Request) {
   fmt.Fprint(w, "login : ", "\n")
   remPartOfURL := r.URL.Path[len("/login/"):]
   if r.Method == "POST" {
   g := UserLogin{
   UserName: r.FormValue("username"),
   PassWord: r.FormValue("password"),
   }
   fmt.Fprint(w, "&g : ", &g,"\n")
   }
   fmt.Fprintf(w, "Hello %s!", remPartOfURL)
   }

   func init() {
   http.HandleFunc("/", handler)
   http.HandleFunc("/login/", login)
   }

Question: After clicked on Login button: &g should print username and password values but it is showing empty: &g : &{ }
What can be done?

One thing you might try is replacing the fmt.Fprintf statements with http.Error statements.

For example replace:

fmt.Fprintf(w, "after",r.FormValue("username"))

with:

http.Error(w, fmt.Sprintf("after %s", r.FormValue("username")), http.StatusOK)

You're writing directly to the http.ResponseWriter which can cause problems.