blog.go
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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.
package guestbook
import (
"io"
"net/http"
"text/template"
"time"
"appengine"
"appengine/datastore"
"appengine/user"
)
type Greeting struct {
Author string
Content string
Date time.Time
}
func serve404(w http.ResponseWriter) {
w.WriteHeader(http.StatusNotFound)
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
io.WriteString(w, "Not Found")
}
func serveError(c appengine.Context, w http.ResponseWriter, err error) {
w.WriteHeader(http.StatusInternalServerError)
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
io.WriteString(w, "Internal Server Error")
c.Errorf("%v", err)
}
var mainPage = template.Must(template.New("guestbook").Parse(
`<html><body>
{{range .}}
{{with .Author}}<b>{{.|html}}</b>{{else}}An anonymous person{{end}}
on <em>{{.Date.Format "3:04pm, Mon 2 Jan"}}</em>
wrote <blockquote>{{.Content|html}}</blockquote>
{{end}}
<form action="/sign" method="post">
<div><textarea name="content" rows="3" cols="60"></textarea></div>
<div><input type="submit" value="Sign Guestbook"></div>
</form></body></html>
`))
func handleMainPage(w http.ResponseWriter, r *http.Request) {
if r.Method != "GET" || r.URL.Path != "/" {
serve404(w)
return
}
c := appengine.NewContext(r)
q := datastore.NewQuery("Greeting").Order("-Date").Limit(10)
var gg []*Greeting
_, err := q.GetAll(c, &gg)
if err != nil {
serveError(c, w, err)
return
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
if err := mainPage.Execute(w, gg); err != nil {
c.Errorf("%v", err)
}
}
func handleSign(w http.ResponseWriter, r *http.Request) {
if r.Method != "POST" {
serve404(w)
return
}
c := appengine.NewContext(r)
if err := r.ParseForm(); err != nil {
serveError(c, w, err)
return
}
g := &Greeting{
Content: r.FormValue("content"),
Date: time.Now(),
}
if u := user.Current(c); u != nil {
g.Author = u.String()
}
if _, err := datastore.Put(c, datastore.NewIncompleteKey(c, "Greeting", nil), g); err != nil {
serveError(c, w, err)
return
}
http.Redirect(w, r, "/", http.StatusFound)
}
func init() {
http.HandleFunc("/", handleMainPage)
http.HandleFunc("/sign", handleSign)
}