Add /bug redirects to the home page AppEngine app

doc/appengine/main.go

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 13 matching lines @@
         "net/url"
         "path"
         "strings"
         "time"
 
         "google.golang.org/appengine"
         "google.golang.org/appengine/memcache"
         "google.golang.org/appengine/urlfetch"
 )
 
-const baseURL = "https://chromium.googlesource.com/crashpad/crashpad/+/doc/doc/generated/?format=TEXT"
-
 func init() {
         http.HandleFunc("/", handler)
 }
 
 func handler(w http.ResponseWriter, r *http.Request) {
+        const (
+                baseURL    = "https://chromium.googlesource.com/crashpad/crashpad/+/doc/doc/generated/?format=TEXT"
+                bugBaseURL = "https://bugs.chromium.org/p/crashpad/"
+        )
+
         ctx := appengine.NewContext(r)
         client := urlfetch.Client(ctx)
 
         // Don’t show dotfiles.
         if strings.HasPrefix(path.Base(r.URL.Path), ".") {
                 http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
                 return
         }
 
+        if r.URL.Path == "/bug" || r.URL.Path == "/bug/" {
+                http.Redirect(w, r, bugBaseURL, http.StatusFound)
+                return
+        } else if r.URL.Path == "/bug/new" {
+                http.Redirect(w, r, bugBaseURL+"issues/entry", http.StatusFound)
+                return
+        } else if strings.HasPrefix(r.URL.Path, "/bug/") {
+                http.Redirect(w, r, bugBaseURL+"issues/detail?id="+r.URL.Path[5:], http.StatusFound)
+                return
+        }
+
         u, err := url.Parse(baseURL)
         if err != nil {
                 http.Error(w, err.Error(), http.StatusInternalServerError)
                 return
         }
 
         u.Path = path.Join(u.Path, r.URL.Path)
         urlStr := u.String()
 
         item, err := memcache.Get(ctx, urlStr)
@@ skipping 53 matching lines @@
                 ".png":  "image/png",
                 ".ico":  "image/x-icon",
         }
         for suffix, typ := range contentTypes {
                 if strings.HasSuffix(file, suffix) {
                         return typ
                 }
         }
         return "text/plain; charset=UTF-8"
 }