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// Copyright 2011 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
// This example only works on App Engine "flexible environment".
// +build !appengine
package main
import (
"html/template"
"net/http"
"time"
"golang.org/x/net/context"
"google.golang.org/appengine"
"google.golang.org/appengine/datastore"
"google.golang.org/appengine/log"
"google.golang.org/appengine/user"
)
var initTime time.Time
type Greeting struct {
Author string
Content string
Date time.Time
}
func main() {
http.HandleFunc("/", handleMainPage)
http.HandleFunc("/sign", handleSign)
appengine.Main()
}
// guestbookKey returns the key used for all guestbook entries.
func guestbookKey(ctx context.Context) *datastore.Key {
// The string "default_guestbook" here could be varied to have multiple guestbooks.
return datastore.NewKey(ctx, "Guestbook", "default_guestbook", 0, nil)
}
var tpl = template.Must(template.ParseGlob("templates/*.html"))
func handleMainPage(w http.ResponseWriter, r *http.Request) {
if r.Method != "GET" {
http.Error(w, "GET requests only", http.StatusMethodNotAllowed)
return
}
if r.URL.Path != "/" {
http.NotFound(w, r)
return
}
ctx := appengine.NewContext(r)
tic := time.Now()
q := datastore.NewQuery("Greeting").Ancestor(guestbookKey(ctx)).Order("-Date").Limit(10)
var gg []*Greeting
if _, err := q.GetAll(ctx, &gg); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
log.Errorf(ctx, "GetAll: %v", err)
return
}
log.Infof(ctx, "Datastore lookup took %s", time.Since(tic).String())
log.Infof(ctx, "Rendering %d greetings", len(gg))
var email, logout, login string
if u := user.Current(ctx); u != nil {
logout, _ = user.LogoutURL(ctx, "/")
email = u.Email
} else {
login, _ = user.LoginURL(ctx, "/")
}
data := struct {
Greetings []*Greeting
Login, Logout, Email string
}{
Greetings: gg,
Login: login,
Logout: logout,
Email: email,
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
if err := tpl.ExecuteTemplate(w, "guestbook.html", data); err != nil {
log.Errorf(ctx, "%v", err)
}
}
func handleSign(w http.ResponseWriter, r *http.Request) {
if r.Method != "POST" {
http.Error(w, "POST requests only", http.StatusMethodNotAllowed)
return
}
ctx := appengine.NewContext(r)
g := &Greeting{
Content: r.FormValue("content"),
Date: time.Now(),
}
if u := user.Current(ctx); u != nil {
g.Author = u.String()
}
key := datastore.NewIncompleteKey(ctx, "Greeting", guestbookKey(ctx))
if _, err := datastore.Put(ctx, key, g); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// Redirect with 303 which causes the subsequent request to use GET.
http.Redirect(w, r, "/", http.StatusSeeOther)
}
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