chrome/browser/web_resource/web_resource_service.cc

   1 // Copyright (c) 2012 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 "chrome/browser/web_resource/web_resource_service.h"
   6
   7 #include "base/bind.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/prefs/pref_service.h"
  10 #include "base/strings/string_number_conversions.h"
  11 #include "base/strings/string_util.h"
  12 #include "base/strings/utf_string_conversions.h"
  13 #include "base/time/time.h"
  14 #include "base/values.h"
  15 #include "chrome/browser/browser_process.h"
  16 #include "chrome/browser/google/google_util.h"
  17 #include "net/base/load_flags.h"
  18 #include "net/url_request/url_fetcher.h"
  19 #include "net/url_request/url_request_status.h"
  20 #include "url/gurl.h"
  21
  22 WebResourceService::WebResourceService(
  23     PrefService* prefs,
  24     const GURL& web_resource_server,
  25     bool apply_locale_to_url,
  26     const char* last_update_time_pref_name,
  27     int start_fetch_delay_ms,
  28     int cache_update_delay_ms)
  29     : prefs_(prefs),
  30       json_unpacker_(NULL),
  31       in_fetch_(false),
  32       web_resource_server_(web_resource_server),
  33       apply_locale_to_url_(apply_locale_to_url),
  34       last_update_time_pref_name_(last_update_time_pref_name),
  35       start_fetch_delay_ms_(start_fetch_delay_ms),
  36       cache_update_delay_ms_(cache_update_delay_ms),
  37       weak_ptr_factory_(this) {
  38   resource_request_allowed_notifier_.Init(this);
  39   DCHECK(prefs);
  40 }
  41
  42 WebResourceService::~WebResourceService() {
  43   if (in_fetch_)
  44     EndFetch();
  45 }
  46
  47 void WebResourceService::OnUnpackFinished(
  48     const base::DictionaryValue& parsed_json) {
  49   Unpack(parsed_json);
  50   EndFetch();
  51 }
  52
  53 void WebResourceService::OnUnpackError(const std::string& error_message) {
  54   LOG(ERROR) << error_message;
  55   EndFetch();
  56 }
  57
  58 void WebResourceService::EndFetch() {
  59   if (json_unpacker_) {
  60     json_unpacker_->ClearDelegate();
  61     json_unpacker_ = NULL;
  62   }
  63   in_fetch_ = false;
  64 }
  65
  66 void WebResourceService::StartAfterDelay() {
  67   // If resource requests are not allowed, we'll get a callback when they are.
  68   if (resource_request_allowed_notifier_.ResourceRequestsAllowed())
  69     OnResourceRequestsAllowed();
  70 }
  71
  72 void WebResourceService::OnResourceRequestsAllowed() {
  73   int64 delay = start_fetch_delay_ms_;
  74   // Check whether we have ever put a value in the web resource cache;
  75   // if so, pull it out and see if it's time to update again.
  76   if (prefs_->HasPrefPath(last_update_time_pref_name_)) {
  77     std::string last_update_pref =
  78         prefs_->GetString(last_update_time_pref_name_);
  79     if (!last_update_pref.empty()) {
  80       double last_update_value;
  81       base::StringToDouble(last_update_pref, &last_update_value);
  82       int64 ms_until_update = cache_update_delay_ms_ -
  83           static_cast<int64>((base::Time::Now() - base::Time::FromDoubleT(
  84           last_update_value)).InMilliseconds());
  85       // Wait at least |start_fetch_delay_ms_|.
  86       if (ms_until_update > start_fetch_delay_ms_)
  87         delay = ms_until_update;
  88     }
  89   }
  90   // Start fetch and wait for UpdateResourceCache.
  91   ScheduleFetch(delay);
  92 }
  93
  94 // Delay initial load of resource data into cache so as not to interfere
  95 // with startup time.
  96 void WebResourceService::ScheduleFetch(int64 delay_ms) {
  97   base::MessageLoop::current()->PostDelayedTask(
  98       FROM_HERE,
  99       base::Bind(&WebResourceService::StartFetch,
 100                  weak_ptr_factory_.GetWeakPtr()),
 101       base::TimeDelta::FromMilliseconds(delay_ms));
 102 }
 103
 104 // Initializes the fetching of data from the resource server.  Data
 105 // load calls OnURLFetchComplete.
 106 void WebResourceService::StartFetch() {
 107   // First, put our next cache load on the MessageLoop.
 108   ScheduleFetch(cache_update_delay_ms_);
 109
 110   // Set cache update time in preferences.
 111   prefs_->SetString(last_update_time_pref_name_,
 112       base::DoubleToString(base::Time::Now().ToDoubleT()));
 113
 114   // If we are still fetching data, exit.
 115   if (in_fetch_)
 116     return;
 117   in_fetch_ = true;
 118
 119   // Balanced in OnURLFetchComplete.
 120   AddRef();
 121
 122   GURL web_resource_server = apply_locale_to_url_ ?
 123       google_util::AppendGoogleLocaleParam(web_resource_server_) :
 124       web_resource_server_;
 125
 126   DVLOG(1) << "WebResourceService StartFetch " << web_resource_server;
 127   url_fetcher_.reset(net::URLFetcher::Create(
 128       web_resource_server, net::URLFetcher::GET, this));
 129   // Do not let url fetcher affect existing state in system context
 130   // (by setting cookies, for example).
 131   url_fetcher_->SetLoadFlags(net::LOAD_DISABLE_CACHE |
 132                              net::LOAD_DO_NOT_SEND_COOKIES |
 133                              net::LOAD_DO_NOT_SAVE_COOKIES);
 134   net::URLRequestContextGetter* url_request_context_getter =
 135       g_browser_process->system_request_context();
 136   url_fetcher_->SetRequestContext(url_request_context_getter);
 137   url_fetcher_->Start();
 138 }
 139
 140 void WebResourceService::OnURLFetchComplete(const net::URLFetcher* source) {
 141   // Delete the URLFetcher when this function exits.
 142   scoped_ptr<net::URLFetcher> clean_up_fetcher(url_fetcher_.release());
 143
 144   if (source->GetStatus().is_success() && source->GetResponseCode() == 200) {
 145     std::string data;
 146     source->GetResponseAsString(&data);
 147
 148     // UnpackerClient calls EndFetch and releases itself on completion.
 149     json_unpacker_ = JSONAsynchronousUnpacker::Create(this);
 150     json_unpacker_->Start(data);
 151   } else {
 152     // Don't parse data if attempt to download was unsuccessful.
 153     // Stop loading new web resource data, and silently exit.
 154     // We do not call UnpackerClient, so we need to call EndFetch ourselves.
 155     EndFetch();
 156   }
 157
 158   Release();
 159 }