components/google/core/browser/google_url_tracker.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/google/core/browser/google_url_tracker.h"
   6
   7 #include "base/bind.h"
   8 #include "base/command_line.h"
   9 #include "base/location.h"
  10 #include "base/prefs/pref_service.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/thread_task_runner_handle.h"
  14 #include "components/google/core/browser/google_pref_names.h"
  15 #include "components/google/core/browser/google_switches.h"
  16 #include "components/google/core/browser/google_util.h"
  17 #include "components/pref_registry/pref_registry_syncable.h"
  18 #include "net/base/load_flags.h"
  19 #include "net/url_request/url_fetcher.h"
  20 #include "net/url_request/url_request_status.h"
  21
  22
  23 const char GoogleURLTracker::kDefaultGoogleHomepage[] =
  24     "https://www.google.com/";
  25 const char GoogleURLTracker::kSearchDomainCheckURL[] =
  26     "https://www.google.com/searchdomaincheck?format=domain&type=chrome";
  27
  28 GoogleURLTracker::GoogleURLTracker(scoped_ptr<GoogleURLTrackerClient> client,
  29                                    Mode mode)
  30     : client_(client.Pass()),
  31       google_url_(mode == UNIT_TEST_MODE ?
  32           kDefaultGoogleHomepage :
  33           client_->GetPrefs()->GetString(prefs::kLastKnownGoogleURL)),
  34       fetcher_id_(0),
  35       in_startup_sleep_(true),
  36       already_fetched_(false),
  37       need_to_fetch_(false),
  38       weak_ptr_factory_(this) {
  39   net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
  40   client_->set_google_url_tracker(this);
  41
  42   // Because this function can be called during startup, when kicking off a URL
  43   // fetch can eat up 20 ms of time, we delay five seconds, which is hopefully
  44   // long enough to be after startup, but still get results back quickly.
  45   // Ideally, instead of this timer, we'd do something like "check if the
  46   // browser is starting up, and if so, come back later", but there is currently
  47   // no function to do this.
  48   //
  49   // In UNIT_TEST_MODE, where we want to explicitly control when the tracker
  50   // "wakes up", we do nothing at all.
  51   if (mode == NORMAL_MODE) {
  52     static const int kStartFetchDelayMS = 5000;
  53     base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
  54         FROM_HERE, base::Bind(&GoogleURLTracker::FinishSleep,
  55                               weak_ptr_factory_.GetWeakPtr()),
  56         base::TimeDelta::FromMilliseconds(kStartFetchDelayMS));
  57   }
  58 }
  59
  60 GoogleURLTracker::~GoogleURLTracker() {
  61 }
  62
  63 // static
  64 void GoogleURLTracker::RegisterProfilePrefs(
  65     user_prefs::PrefRegistrySyncable* registry) {
  66   registry->RegisterStringPref(prefs::kLastKnownGoogleURL,
  67                                GoogleURLTracker::kDefaultGoogleHomepage);
  68   registry->RegisterStringPref(prefs::kLastPromptedGoogleURL, std::string());
  69 }
  70
  71 void GoogleURLTracker::RequestServerCheck(bool force) {
  72   // If this instance already has a fetcher, SetNeedToFetch() is unnecessary,
  73   // and changing |already_fetched_| is wrong.
  74   if (!fetcher_) {
  75     if (force)
  76       already_fetched_ = false;
  77     SetNeedToFetch();
  78   }
  79 }
  80
  81 scoped_ptr<GoogleURLTracker::Subscription> GoogleURLTracker::RegisterCallback(
  82     const OnGoogleURLUpdatedCallback& cb) {
  83   return callback_list_.Add(cb);
  84 }
  85
  86 void GoogleURLTracker::OnURLFetchComplete(const net::URLFetcher* source) {
  87   // Delete the fetcher on this function's exit.
  88   scoped_ptr<net::URLFetcher> clean_up_fetcher(fetcher_.release());
  89
  90   // Don't update the URL if the request didn't succeed.
  91   if (!source->GetStatus().is_success() || (source->GetResponseCode() != 200)) {
  92     already_fetched_ = false;
  93     return;
  94   }
  95
  96   // See if the response data was valid.  It should be ".google.<TLD>".
  97   std::string url_str;
  98   source->GetResponseAsString(&url_str);
  99   base::TrimWhitespace(url_str, base::TRIM_ALL, &url_str);
 100   if (!base::StartsWith(url_str, ".google.",
 101                         base::CompareCase::INSENSITIVE_ASCII))
 102     return;
 103   GURL url("https://www" + url_str);
 104   if (!url.is_valid() || (url.path().length() > 1) || url.has_query() ||
 105       url.has_ref() ||
 106       !google_util::IsGoogleDomainUrl(url, google_util::DISALLOW_SUBDOMAIN,
 107                                       google_util::DISALLOW_NON_STANDARD_PORTS))
 108     return;
 109
 110   if (url != google_url_) {
 111     google_url_ = url;
 112     client_->GetPrefs()->SetString(prefs::kLastKnownGoogleURL,
 113                                    google_url_.spec());
 114     callback_list_.Notify();
 115   }
 116 }
 117
 118 void GoogleURLTracker::OnNetworkChanged(
 119     net::NetworkChangeNotifier::ConnectionType type) {
 120   // Ignore destructive signals.
 121   if (type == net::NetworkChangeNotifier::CONNECTION_NONE)
 122     return;
 123   already_fetched_ = false;
 124   StartFetchIfDesirable();
 125 }
 126
 127 void GoogleURLTracker::Shutdown() {
 128   client_.reset();
 129   fetcher_.reset();
 130   weak_ptr_factory_.InvalidateWeakPtrs();
 131   net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
 132 }
 133
 134 void GoogleURLTracker::SetNeedToFetch() {
 135   need_to_fetch_ = true;
 136   StartFetchIfDesirable();
 137 }
 138
 139 void GoogleURLTracker::FinishSleep() {
 140   in_startup_sleep_ = false;
 141   StartFetchIfDesirable();
 142 }
 143
 144 void GoogleURLTracker::StartFetchIfDesirable() {
 145   // Bail if a fetch isn't appropriate right now.  This function will be called
 146   // again each time one of the preconditions changes, so we'll fetch
 147   // immediately once all of them are met.
 148   //
 149   // See comments in header on the class, on RequestServerCheck(), and on the
 150   // various members here for more detail on exactly what the conditions are.
 151   if (in_startup_sleep_ || already_fetched_ || !need_to_fetch_)
 152     return;
 153
 154   // Some switches should disable the Google URL tracker entirely.  If we can't
 155   // do background networking, we can't do the necessary fetch, and if the user
 156   // specified a Google base URL manually, we shouldn't bother to look up any
 157   // alternatives or offer to switch to them.
 158   if (!client_->IsBackgroundNetworkingEnabled() ||
 159       base::CommandLine::ForCurrentProcess()->HasSwitch(
 160           switches::kGoogleBaseURL))
 161     return;
 162
 163   already_fetched_ = true;
 164   fetcher_ = net::URLFetcher::Create(fetcher_id_, GURL(kSearchDomainCheckURL),
 165                                      net::URLFetcher::GET, this);
 166   ++fetcher_id_;
 167   // We don't want this fetch to set new entries in the cache or cookies, lest
 168   // we alarm the user.
 169   fetcher_->SetLoadFlags(net::LOAD_DISABLE_CACHE |
 170                          net::LOAD_DO_NOT_SAVE_COOKIES);
 171   fetcher_->SetRequestContext(client_->GetRequestContext());
 172
 173   // Configure to retry at most kMaxRetries times for 5xx errors.
 174   static const int kMaxRetries = 5;
 175   fetcher_->SetMaxRetriesOn5xx(kMaxRetries);
 176
 177   // Also retry kMaxRetries times on network change errors. A network change can
 178   // propagate through Chrome in various stages, so it's possible for this code
 179   // to be reached via OnNetworkChanged(), and then have the fetch we kick off
 180   // be canceled due to e.g. the DNS server changing at a later time. In general
 181   // it's not possible to ensure that by the time we reach here any requests we
 182   // start won't be canceled in this fashion, so retrying is the best we can do.
 183   fetcher_->SetAutomaticallyRetryOnNetworkChanges(kMaxRetries);
 184
 185   fetcher_->Start();
 186 }