前往：如何在数据存储中“放置” r.FormValue，以及如何从数据存储中“获取”？

Example:
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",
))
//UserLogin struct is created
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" {          
    http.Error(w, fmt.Sprintf("First Name: %s", r.FormValue("username")), http.StatusOK)           
    http.Error(w, fmt.Sprintf("Password: %s", r.FormValue("password")), http.StatusOK)          
    }           
}

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

In this Example in login(): Able to print the r.FormValue("username") and r.FormValue("password") but how to "put" in datastore and how to "get" from datastore.

Reference : https://github.com/stephenlewis/eveningwithgo/blob/master/datastore/datastore/datastore.go

Answer :

package main

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

var index = template.Must(template.ParseFiles(
  "templates/base.html",
  "templates/index.html",
))

type cUserLogin struct{
    UserName string
    PassWord string
}

func handler(w http.ResponseWriter, r *http.Request) {  
    index.Execute(w, nil)
    fmt.Fprint(w, "handler : ", "
")
    c := appengine.NewContext(r)
    q := datastore.NewQuery("cUserLogin")
        w.Header().Add("Content-Type", "text/plain")
        for t := q.Run(c); ; {
            var getuser cUserLogin
            key, err := t.Next(&getuser)
            if err == datastore.Done {
                break
            }
            fmt.Fprintf(w, "%v: %s %s
", key, getuser.UserName, getuser.PassWord)
        }

}

func login(w http.ResponseWriter, r *http.Request) {  
        remPartOfURL := r.URL.Path[len("/login/"):] 
        c := appengine.NewContext(r)
        if r.Method == "POST" {            
            http.Error(w, fmt.Sprintf("First Name: %s", r.FormValue("username")), http.StatusOK)           
            http.Error(w, fmt.Sprintf("Password: %s", r.FormValue("password")), http.StatusOK)
            g := cUserLogin{
                UserName: r.FormValue("username"),
                PassWord: r.FormValue("password"),
            }
            key, err := datastore.Put(c, datastore.NewIncompleteKey(c, "cUserLogin", nil), &g)
            if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
            }
            fmt.Fprintf(w, "Written with key %v
", key)            
        }       

        fmt.Fprintf(w, "Hello %s!", remPartOfURL)
    }


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