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