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