[som] Add revision range exapansion.

go/src/infra/appengine/sheriff-o-matic/main.go

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Package som implements HTTP server that handles requests to default module.
 package som
 
 import (
         "crypto/sha1"
         "encoding/json"
@@ skipping 422 matching lines @@
         bytes, err := json.Marshal(res)
         if err != nil {
                 errStatus(w, http.StatusInternalServerError, err.Error())
                 return
         }
 
         w.Header().Set("Content-Type", "application/json")
         w.Write(bytes)
 }
 
+func getCrRevJSON(c context.Context, pos string) (map[string]string, error) {
+        c = client.UseServiceAccountTransport(c, nil, nil)
+
+        hc := &http.Client{Transport: urlfetch.Get(c)}
+
+        resp, err := hc.Get(fmt.Sprintf("https://cr-rev.appspot.com/_ah/api/crrev/v1/redirect/%s", pos))
+        if err != nil {
+                return nil, err
+        }
+
+        defer resp.Body.Close()
+        body, err := ioutil.ReadAll(resp.Body)
+        if err != nil {
+                return nil, err
+        }
+
+        m := map[string]string{}
+        err = json.Unmarshal(body, &m)
+        if err != nil {
+                return nil, err
+        }
+
+        return m, nil
+}
+
+func getRevRangeHandler(c context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) {
+        start := p.ByName("start")
+        end := p.ByName("end")
+        if start == "" || end == "" {
+                errStatus(w, http.StatusBadRequest, "Start and end parameters must be set.")
+                return
+        }
+
+        startRev, err := getCrRevJSON(c, start)
+        if err != nil {
+                errStatus(w, http.StatusInternalServerError, err.Error())
+                return
+        }
+
+        endRev, err := getCrRevJSON(c, end)
+        if err != nil {
+                errStatus(w, http.StatusInternalServerError, err.Error())
+                return
+        }
+
+        // TODO(seanmccullough): some sanity checking of the rev json (same repo etc)
+
+        gitilesURL := fmt.Sprintf("https://chromium.googlesource.com/chromium/src/+log/%s^..%s?format=JSON",
+                startRev["git_sha"], endRev["git_sha"])
+
+        http.Redirect(w, r, gitilesURL, 301)
+}
+
 // base is the root of the middleware chain.
 func base(h middleware.Handler) httprouter.Handle {
         methods := auth.Authenticator{
                 &server.OAuth2Method{Scopes: []string{server.EmailScope}},
                 server.CookieAuth,
                 &server.InboundAppIDAuthMethod{},
         }
         h = auth.Use(h, methods)
         if !appengine.IsDevAppServer() {
                 h = middleware.WithPanicCatcher(h)
         }
         return gaemiddleware.BaseProd(h)
 }
 
 //// Routes.
 func init() {
         settings.RegisterUIPage(settingsKey, settingsUIPage{})
 
         router := httprouter.New()
         gaemiddleware.InstallHandlers(router, base)
         router.GET("/api/v1/trees/", base(auth.Authenticate(getTreesHandler)))
         router.GET("/api/v1/alerts/:tree", base(auth.Authenticate(getAlertsHandler)))
         router.POST("/api/v1/alerts/:tree", base(auth.Authenticate(postAlertsHandler)))
         router.GET("/api/v1/annotations/", base(auth.Authenticate(getAnnotationsHandler)))
         router.POST("/api/v1/annotations/:annKey/:action", base(auth.Authenticate(postAnnotationsHandler)))
         router.GET("/api/v1/bugqueue/:tree", base(auth.Authenticate(getBugQueueHandler)))
+        router.GET("/api/v1/revrange/:start/:end", base(getRevRangeHandler))
 
         rootRouter := httprouter.New()
         rootRouter.GET("/*path", base(auth.Authenticate(indexPage)))
 
         http.DefaultServeMux.Handle("/api/", router)
         http.DefaultServeMux.Handle("/admin/", router)
         http.DefaultServeMux.Handle("/auth/", router)
         http.DefaultServeMux.Handle("/_ah/", router)
         http.DefaultServeMux.Handle("/", rootRouter)
 }