Build correct URL for cacheinvalidation endpoint.

sync/notifier/gcm_network_channel.cc

Index: sync/notifier/gcm_network_channel.cc
diff --git a/sync/notifier/gcm_network_channel.cc b/sync/notifier/gcm_network_channel.cc
index c6fbd0239dc60cd1fb2574793dbeb19a3c3224e8..99ad6242e507db69c3b67fb0bec82c3cd53d2689 100644
--- a/sync/notifier/gcm_network_channel.cc
+++ b/sync/notifier/gcm_network_channel.cc
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/base64.h"
+#include "google/cacheinvalidation/android_channel.pb.h"
+#include "google/cacheinvalidation/channel_common.pb.h"
 #include "google_apis/gaia/google_service_auth_error.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
@@ -13,6 +16,10 @@ namespace syncer {
 
 namespace {
 
+const char kCacheInvalidationEndpointUrl[] =
+    "https://clients4.google.com/invalidation/android/request/";
+const char kCacheInvalidationPackageName[] = "com.google.chrome.invalidations";
+
 // Register backoff policy.
 const net::BackoffEntry::Policy kRegisterBackoffPolicy = {
   // Number of initial errors (in sequence) to ignore before applying
@@ -142,9 +149,8 @@ void GCMNetworkChannel::OnGetTokenComplete(
   access_token_ = token;
 
   DVLOG(2) << "Got access token, sending message";
-
-  fetcher_.reset(net::URLFetcher::Create(BuildUrl(), net::URLFetcher::POST,
-                                         this));
+  fetcher_.reset(net::URLFetcher::Create(
+      BuildUrl(registration_id_), net::URLFetcher::POST, this));
   fetcher_->SetRequestContext(request_context_getter_);
   const std::string auth_header("Authorization: Bearer " + access_token_);
   fetcher_->AddExtraRequestHeader(auth_header);
@@ -174,13 +180,30 @@ void GCMNetworkChannel::OnURLFetchComplete(const net::URLFetcher* source) {
   DVLOG(2) << "URLFetcher success";
 }
 
-GURL GCMNetworkChannel::BuildUrl() {
-  DCHECK(!registration_id_.empty());
-  // Prepare NetworkEndpointId using registration_id
-  // Serialize NetworkEndpointId into byte array and base64 encode.
-  // Format url using encoded NetworkEndpointId.
-  // TODO(pavely): implement all of the above.
-  return GURL("http://invalid.url.com");
+GURL GCMNetworkChannel::BuildUrl(const std::string& registration_id) {
+  DCHECK(!registration_id.empty());
+  std::string buffer;
+
+  ipc::invalidation::EndpointId endpoint_id;
+  endpoint_id.set_c2dm_registration_id(registration_id);
+  endpoint_id.set_client_key(std::string());
+  endpoint_id.set_package_name(kCacheInvalidationPackageName);
+  endpoint_id.mutable_channel_version()->set_major_version(
+      ipc::invalidation::INITIAL);
+  endpoint_id.SerializeToString(&buffer);
+
+  ipc::invalidation::NetworkEndpointId network_endpoint_id;
+  network_endpoint_id.set_network_address(
+      ipc::invalidation::NetworkEndpointId_NetworkAddress_ANDROID);
+  network_endpoint_id.set_client_address(buffer);

[rlarocque, 2014/02/26 22:55:46]

Couldn't you get the same serialized result by making the client_address an
embedded message protobuf of type EndpointId?

I'm guessing these are not your protos, so there's not much you could do to
change it.  I'm curious to know if there's any justification for it.

[pavely, 2014/02/26 23:11:13]

If network_address is not NetworkAddress::ANDROID then client_address will have
different protobuf serialized into it. It is the way how server decodes address.

+  network_endpoint_id.SerializeToString(&buffer);

[rlarocque, 2014/02/26 22:55:46]

I'd prefer to see a different buffer for this serialization.  As it is, it's
hard to tell whether or not this overwrite is intentional.

[pavely, 2014/02/26 23:11:13]

Done.

+
+  std::string base64URLPiece;
+  base::Base64Encode(buffer, &base64URLPiece);
+
+  std::string url(kCacheInvalidationEndpointUrl);
+  url += base64URLPiece;
+  return GURL(url);
 }
 
 }  // namespace syncer