components/web_resource/web_resource_service.h

   1 // Copyright 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 #ifndef COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
   6 #define COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
   7
   8 #include <string>
   9
  10 #include "base/callback_forward.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "components/web_resource/resource_request_allowed_notifier.h"
  15 #include "net/url_request/url_fetcher_delegate.h"
  16 #include "url/gurl.h"
  17
  18 class PrefService;
  19
  20 namespace base {
  21 class DictionaryValue;
  22 class Value;
  23 }
  24
  25 namespace net {
  26 class URLFetcher;
  27 class URLRequestContextGetter;
  28 }
  29
  30 namespace web_resource {
  31
  32 // A WebResourceService fetches JSON data from a web server and periodically
  33 // refreshes it.
  34 class WebResourceService
  35     : public net::URLFetcherDelegate,
  36       public ResourceRequestAllowedNotifier::Observer {
  37  public:
  38   // Callbacks for JSON parsing.
  39   using SuccessCallback = base::Callback<void(scoped_ptr<base::Value>)>;
  40   using ErrorCallback = base::Callback<void(const std::string&)>;
  41   using ParseJSONCallback = base::Callback<
  42       void(const std::string&, const SuccessCallback&, const ErrorCallback&)>;
  43
  44   // Creates a new WebResourceService.
  45   // If |application_locale| is not empty, it will be appended as a locale
  46   // parameter to the resource URL.
  47   WebResourceService(PrefService* prefs,
  48                      const GURL& web_resource_server,
  49                      const std::string& application_locale,  // May be empty
  50                      const char* last_update_time_pref_name,
  51                      int start_fetch_delay_ms,
  52                      int cache_update_delay_ms,
  53                      net::URLRequestContextGetter* request_context,
  54                      const char* disable_network_switch,
  55                      const ParseJSONCallback& parse_json_callback);
  56
  57   ~WebResourceService() override;
  58
  59   // Sleep until cache needs to be updated, but always for at least
  60   // |start_fetch_delay_ms| so we don't interfere with startup.
  61   // Then begin updating resources.
  62   void StartAfterDelay();
  63
  64  protected:
  65   PrefService* prefs_;
  66
  67  private:
  68   // For the subclasses to process the result of a fetch.
  69   virtual void Unpack(const base::DictionaryValue& parsed_json) = 0;
  70
  71   // net::URLFetcherDelegate implementation:
  72   void OnURLFetchComplete(const net::URLFetcher* source) override;
  73
  74   // Schedules a fetch after |delay_ms| milliseconds.
  75   void ScheduleFetch(int64 delay_ms);
  76
  77   // Starts fetching data from the server.
  78   void StartFetch();
  79
  80   // Set |in_fetch_| to false, clean up temp directories (in the future).
  81   void EndFetch();
  82
  83   // Callbacks from the JSON parser.
  84   void OnUnpackFinished(scoped_ptr<base::Value> value);
  85   void OnUnpackError(const std::string& error_message);
  86
  87   // Implements ResourceRequestAllowedNotifier::Observer.
  88   void OnResourceRequestsAllowed() override;
  89
  90   // Helper class used to tell this service if it's allowed to make network
  91   // resource requests.
  92   ResourceRequestAllowedNotifier resource_request_allowed_notifier_;
  93
  94   // The tool that fetches the url data from the server.
  95   scoped_ptr<net::URLFetcher> url_fetcher_;
  96
  97   // True if we are currently fetching or unpacking data. If we are asked to
  98   // start a fetch when we are still fetching resource data, schedule another
  99   // one in |cache_update_delay_ms_| time, and silently exit.
 100   bool in_fetch_;
 101
 102   // URL that hosts the web resource.
 103   GURL web_resource_server_;
 104
 105   // Application locale, appended to the URL if not empty.
 106   std::string application_locale_;
 107
 108   // Pref name to store the last update's time.
 109   const char* last_update_time_pref_name_;
 110
 111   // Delay on first fetch so we don't interfere with startup.
 112   int start_fetch_delay_ms_;
 113
 114   // Delay between calls to update the web resource cache. This delay may be
 115   // different for different builds of Chrome.
 116   int cache_update_delay_ms_;
 117
 118   // The request context for the resource fetch.
 119   scoped_refptr<net::URLRequestContextGetter> request_context_;
 120
 121   // Callback used to parse JSON.
 122   ParseJSONCallback parse_json_callback_;
 123
 124   // So that we can delay our start so as not to affect start-up time; also,
 125   // so that we can schedule future cache updates.
 126   base::WeakPtrFactory<WebResourceService> weak_ptr_factory_;
 127
 128   DISALLOW_COPY_AND_ASSIGN(WebResourceService);
 129 };
 130
 131 }  // namespace web_resource
 132
 133 #endif  // COMPONENTS_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_