[Offline Prefetch] Prefetch request fetcher

components/offline_pages/core/prefetch/prefetch_request_fetcher.cc

+// Copyright 2017 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.
+
+#include "components/offline_pages/core/prefetch/prefetch_request_fetcher.h"
+
+#include "base/logging.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_status_code.h"
+#include "net/traffic_annotation/network_traffic_annotation.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_context_getter.h"
+#include "net/url_request/url_request_status.h"
+#include "url/gurl.h"
+
+namespace offline_prefetch {
+
+namespace {
+const char kRequestContentType[] = "application/x-protobuf";
+}  // namespace
+
+PrefetchRequestFetcher::PrefetchRequestFetcher(
+    const GURL& url,
+    const std::string& message,
+    scoped_refptr<net::URLRequestContextGetter> request_context_getter,
+    const FinishedCallback& callback)
+    : request_context_getter_(request_context_getter), callback_(callback) {
+  net::NetworkTrafficAnnotationTag traffic_annotation =
+      net::DefineNetworkTrafficAnnotation("offline_prefetch", R"(
+        semantics {
+          sender: "Offline Prefetch"
+          description:
+            "Chromium interacts with Offline Page Service to prefetch "
+            "suggested website resources."
+          trigger:
+            "When there are suggested website resources to fetch."
+          data:
+            "URLs of the suggested website resources to fetch."
+          destination: GOOGLE_OWNED_SERVICE
+        }
+        policy {
+          cookies_allowed: false
+          setting:
+            "Users can enable or disable the offline prefetch by toggling"
+            "chrome://flags#offline-prefetch in Chromium on Android."
+          policy_exception_justification:
+            "Not implemented, considered not useful."
+        })");
+  url_fetcher_ = net::URLFetcher::Create(url, net::URLFetcher::POST, this,
+                                         traffic_annotation);
+  url_fetcher_->SetRequestContext(request_context_getter_.get());
+  url_fetcher_->SetAutomaticallyRetryOn5xx(false);
+  url_fetcher_->SetAutomaticallyRetryOnNetworkChanges(0);
+  url_fetcher_->SetUploadData(kRequestContentType, message);
+  url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                             net::LOAD_DO_NOT_SAVE_COOKIES);
+  url_fetcher_->Start();
+}
+
+PrefetchRequestFetcher::~PrefetchRequestFetcher() {}
+
+void PrefetchRequestFetcher::OnURLFetchComplete(const net::URLFetcher* source) {
+  std::string data;
+  Status status = ParseResponse(source, &data);
+
+  // TODO(jianli): Report UMA.
+
+  callback_.Run(status, data);
+}
+
+PrefetchRequestFetcher::Status PrefetchRequestFetcher::ParseResponse(
+    const net::URLFetcher* source,
+    std::string* data) {
+  if (!source->GetStatus().is_success()) {
+    net::Error net_error = source->GetStatus().ToNetError();
+    DVLOG(1) << "Net error: " << net_error;
+    return (net_error == net::ERR_BLOCKED_BY_ADMINISTRATOR)
+               ? Status::SHOULD_SUSPEND
+               : Status::SHOULD_RETRY_WITHOUT_BACKOFF;
+  }
+
+  net::HttpStatusCode response_status =
+      static_cast<net::HttpStatusCode>(source->GetResponseCode());
+  if (response_status != net::HTTP_OK) {
+    DVLOG(1) << "HTTP status: " << response_status;
+    return (response_status == net::HTTP_NOT_IMPLEMENTED)
+               ? Status::SHOULD_SUSPEND
+               : Status::SHOULD_RETRY_WITH_BACKOFF;
+  }
+
+  if (!source->GetResponseAsString(data) || data->empty()) {
+    DVLOG(1) << "Failed to get response or empty response";
+    return Status::SHOULD_RETRY_WITH_BACKOFF;
+  }
+
+  return Status::SUCCESS;
+}
+
+}  // offline_prefetch