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entries when new URLs 32 // are registered, and does garbage collection from time to time in order to 33 // clean out outdated entries.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