xunjieli | 413a6878 | 2015-06-16 17:15:43 | [diff] [blame^] | 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 | #ifndef EXTENSIONS_BROWSER_EXTENSION_THROTTLE_MANAGER_H_ |
| 6 | #define EXTENSIONS_BROWSER_EXTENSION_THROTTLE_MANAGER_H_ |
| 7 | |
| 8 | #include <map> |
| 9 | #include <string> |
| 10 | |
| 11 | #include "base/basictypes.h" |
| 12 | #include "base/memory/ref_counted.h" |
| 13 | #include "base/memory/scoped_ptr.h" |
| 14 | #include "base/threading/non_thread_safe.h" |
| 15 | #include "base/threading/platform_thread.h" |
| 16 | #include "extensions/browser/extension_throttle_entry.h" |
| 17 | #include "net/base/net_export.h" |
| 18 | #include "net/base/network_change_notifier.h" |
| 19 | #include "url/gurl.h" |
| 20 | |
| 21 | namespace content { |
| 22 | class ResourceThrottle; |
| 23 | } |
| 24 | |
| 25 | namespace net { |
| 26 | class BoundNetLog; |
| 27 | class NetLog; |
| 28 | } |
| 29 | |
| 30 | namespace extensions { |
| 31 | |
| 32 | // Class that registers URL request throttler entries for URLs being accessed |
| 33 | // in order to supervise traffic. URL requests for HTTP contents should |
| 34 | // register their URLs in this manager on each request. |
| 35 | // |
| 36 | // ExtensionThrottleManager maintains a map of URL IDs to URL request |
| 37 | // throttler entries. It creates URL request throttler entries when new URLs |
| 38 | // are registered, and does garbage collection from time to time in order to |
| 39 | // clean out outdated entries. URL ID consists of lowercased scheme, host, port |
| 40 | // and path. All URLs converted to the same ID will share the same entry. |
| 41 | class ExtensionThrottleManager |
| 42 | : NON_EXPORTED_BASE(public base::NonThreadSafe), |
| 43 | public net::NetworkChangeNotifier::IPAddressObserver, |
| 44 | public net::NetworkChangeNotifier::ConnectionTypeObserver { |
| 45 | public: |
| 46 | ExtensionThrottleManager(); |
| 47 | ~ExtensionThrottleManager() override; |
| 48 | |
| 49 | // Creates a content::ResourceThrottle for |request| to prevent extensions |
| 50 | // from requesting a URL too often, if such a throttle is needed. |
| 51 | scoped_ptr<content::ResourceThrottle> MaybeCreateThrottle( |
| 52 | const net::URLRequest* request); |
| 53 | |
| 54 | // TODO(xunjieli): Remove this method and replace with |
| 55 | // ShouldRejectRequest(request) and UpdateWithResponse(request, status_code), |
| 56 | // which will also allow ExtensionThrottleEntry to no longer be reference |
| 57 | // counted, and ExtensionThrottleEntryInterface to be removed. |
| 58 | |
| 59 | // Must be called for every request, returns the URL request throttler entry |
| 60 | // associated with the URL. The caller must inform this entry of some events. |
| 61 | // Please refer to extension_throttle_entry_interface.h for further |
| 62 | // informations. |
| 63 | scoped_refptr<ExtensionThrottleEntryInterface> RegisterRequestUrl( |
| 64 | const GURL& url); |
| 65 | |
| 66 | // Registers a new entry in this service and overrides the existing entry (if |
| 67 | // any) for the URL. The service will hold a reference to the entry. |
| 68 | // It is only used by unit tests. |
| 69 | void OverrideEntryForTests(const GURL& url, ExtensionThrottleEntry* entry); |
| 70 | |
| 71 | // Explicitly erases an entry. |
| 72 | // This is useful to remove those entries which have got infinite lifetime and |
| 73 | // thus won't be garbage collected. |
| 74 | // It is only used by unit tests. |
| 75 | void EraseEntryForTests(const GURL& url); |
| 76 | |
| 77 | // Sets whether to ignore net::LOAD_MAYBE_USER_GESTURE of the request for |
| 78 | // testing. Otherwise, requests will not be throttled when they may have been |
| 79 | // throttled in response to a recent user gesture, though they're still |
| 80 | // counted for the purpose of throttling other requests. |
| 81 | void SetIgnoreUserGestureLoadFlagForTests( |
| 82 | bool ignore_user_gesture_load_flag_for_tests); |
| 83 | |
| 84 | // Turns threading model verification on or off. Any code that correctly |
| 85 | // uses the network stack should preferably call this function to enable |
| 86 | // verification of correct adherence to the network stack threading model. |
| 87 | void set_enable_thread_checks(bool enable); |
| 88 | bool enable_thread_checks() const; |
| 89 | |
| 90 | // Whether throttling is enabled or not. |
| 91 | void set_enforce_throttling(bool enforce); |
| 92 | bool enforce_throttling(); |
| 93 | |
| 94 | // Sets the net::NetLog instance to use. |
| 95 | void set_net_log(net::NetLog* net_log); |
| 96 | net::NetLog* net_log() const; |
| 97 | |
| 98 | // IPAddressObserver interface. |
| 99 | void OnIPAddressChanged() override; |
| 100 | |
| 101 | // ConnectionTypeObserver interface. |
| 102 | void OnConnectionTypeChanged( |
| 103 | net::NetworkChangeNotifier::ConnectionType type) override; |
| 104 | |
| 105 | // Method that allows us to transform a URL into an ID that can be used in our |
| 106 | // map. Resulting IDs will be lowercase and consist of the scheme, host, port |
| 107 | // and path (without query string, fragment, etc.). |
| 108 | // If the URL is invalid, the invalid spec will be returned, without any |
| 109 | // transformation. |
| 110 | std::string GetIdFromUrl(const GURL& url) const; |
| 111 | |
| 112 | // Method that ensures the map gets cleaned from time to time. The period at |
| 113 | // which garbage collecting happens is adjustable with the |
| 114 | // kRequestBetweenCollecting constant. |
| 115 | void GarbageCollectEntriesIfNecessary(); |
| 116 | |
| 117 | // Method that does the actual work of garbage collecting. |
| 118 | void GarbageCollectEntries(); |
| 119 | |
| 120 | // When we switch from online to offline or change IP addresses, we |
| 121 | // clear all back-off history. This is a precaution in case the change in |
| 122 | // online state now lets us communicate without error with servers that |
| 123 | // we were previously getting 500 or 503 responses from (perhaps the |
| 124 | // responses are from a badly-written proxy that should have returned a |
| 125 | // 502 or 504 because it's upstream connection was down or it had no route |
| 126 | // to the server). |
| 127 | void OnNetworkChange(); |
| 128 | |
| 129 | // Used by tests. |
| 130 | int GetNumberOfEntriesForTests() const { return url_entries_.size(); } |
| 131 | |
| 132 | private: |
| 133 | // From each URL we generate an ID composed of the scheme, host, port and path |
| 134 | // that allows us to uniquely map an entry to it. |
| 135 | typedef std::map<std::string, scoped_refptr<ExtensionThrottleEntry>> |
| 136 | UrlEntryMap; |
| 137 | |
| 138 | // Maximum number of entries that we are willing to collect in our map. |
| 139 | static const unsigned int kMaximumNumberOfEntries; |
| 140 | // Number of requests that will be made between garbage collection. |
| 141 | static const unsigned int kRequestsBetweenCollecting; |
| 142 | |
| 143 | // Map that contains a list of URL ID and their matching |
| 144 | // ExtensionThrottleEntry. |
| 145 | UrlEntryMap url_entries_; |
| 146 | |
| 147 | // This keeps track of how many requests have been made. Used with |
| 148 | // GarbageCollectEntries. |
| 149 | unsigned int requests_since_last_gc_; |
| 150 | |
| 151 | // Valid after construction. |
| 152 | GURL::Replacements url_id_replacements_; |
| 153 | |
| 154 | // Certain tests do not obey the net component's threading policy, so we |
| 155 | // keep track of whether we're being used by tests, and turn off certain |
| 156 | // checks. |
| 157 | // |
| 158 | // TODO(joi): See if we can fix the offending unit tests and remove this |
| 159 | // workaround. |
| 160 | bool enable_thread_checks_; |
| 161 | |
| 162 | // Initially false, switches to true once we have logged because of back-off |
| 163 | // being disabled for localhost. |
| 164 | bool logged_for_localhost_disabled_; |
| 165 | |
| 166 | // net::NetLog to use, if configured. |
| 167 | net::BoundNetLog net_log_; |
| 168 | |
| 169 | // Valid once we've registered for network notifications. |
| 170 | base::PlatformThreadId registered_from_thread_; |
| 171 | |
| 172 | bool ignore_user_gesture_load_flag_for_tests_; |
| 173 | |
| 174 | DISALLOW_COPY_AND_ASSIGN(ExtensionThrottleManager); |
| 175 | }; |
| 176 | |
| 177 | } // namespace extensions |
| 178 | |
| 179 | #endif // EXTENSIONS_BROWSER_EXTENSION_THROTTLE_MANAGER_H_ |