// mainHandler tracks how many times each user has visited this page.
func mainHandler(w http.ResponseWriter, r *http.Request) *appError {
if r.URL.Path != "/" {
http.NotFound(w, r)
return nil
}
ctx := appengine.NewContext(r)
u := user.Current(ctx)
if u == nil {
login, err := user.LoginURL(ctx, r.URL.String())
if err != nil {
return &appError{err, "Error finding login URL", http.StatusInternalServerError}
}
http.Redirect(w, r, login, http.StatusFound)
return nil
}
logoutURL, err := user.LogoutURL(ctx, "/")
if err != nil {
return &appError{err, "Error finding logout URL", http.StatusInternalServerError}
}
// Display hello page.
tbl := client.Open(tableName)
rmw := bigtable.NewReadModifyWrite()
rmw.Increment(familyName, u.Email, 1)
row, err := tbl.ApplyReadModifyWrite(ctx, u.Email, rmw)
if err != nil {
return &appError{err, "Error applying ReadModifyWrite to row: " + u.Email, http.StatusInternalServerError}
}
data := struct {
Username, Logout string
Visits uint64
}{
Username: u.Email,
// Retrieve the most recently edited column.
Visits: binary.BigEndian.Uint64(row[familyName][0].Value),
Logout: logoutURL,
}
var buf bytes.Buffer
if err := tmpl.Execute(&buf, data); err != nil {
return &appError{err, "Error writing template", http.StatusInternalServerError}
}
buf.WriteTo(w)
return nil
}
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)
}
}