1 // Copyright (c) 2011 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 #pragma once 8 9 #include <map> 10 #include <set> 11 #include <string> 12 13 #include "base/basictypes.h" 14 #include "base/memory/scoped_ptr.h" 15 #include "base/memory/singleton.h" 16 #include "base/threading/non_thread_safe.h" 17 #include "googleurl/src/gurl.h" 18 #include "net/url_request/url_request_throttler_entry.h" 19 20 namespace net { 21 22 // Class that registers URL request throttler entries for URLs being accessed 23 // in order to supervise traffic. URL requests for HTTP contents should 24 // register their URLs in this manager on each request. 25 // 26 // URLRequestThrottlerManager maintains a map of URL IDs to URL request 27 // throttler entries. It creates URL request throttler entries when new URLs 28 // are registered, and does garbage collection from time to time in order to 29 // clean out outdated entries. URL ID consists of lowercased scheme, host, port 30 // and path. All URLs converted to the same ID will share the same entry. 31 // 32 // NOTE: All usage of this singleton object must be on the same thread, 33 // although to allow it to be used as a singleton, construction and destruction 34 // can occur on a separate thread. 35 class URLRequestThrottlerManager : public base::NonThreadSafe { 36 public: 37 static URLRequestThrottlerManager* GetInstance(); 38 39 // Must be called for every request, returns the URL request throttler entry 40 // associated with the URL. The caller must inform this entry of some events. 41 // Please refer to url_request_throttler_entry_interface.h for further 42 // informations. 43 scoped_refptr<URLRequestThrottlerEntryInterface> RegisterRequestUrl( 44 const GURL& url); 45 46 // Adds the given host to a list of sites for which exponential back-off 47 // throttling will be disabled. Subdomains are not included, so they 48 // must be added separately. 49 void AddToOptOutList(const std::string& host); 50 51 // Registers a new entry in this service and overrides the existing entry (if 52 // any) for the URL. The service will hold a reference to the entry. 53 // It is only used by unit tests. 54 void OverrideEntryForTests(const GURL& url, URLRequestThrottlerEntry* entry); 55 56 // Explicitly erases an entry. 57 // This is useful to remove those entries which have got infinite lifetime and 58 // thus won't be garbage collected. 59 // It is only used by unit tests. 60 void EraseEntryForTests(const GURL& url); 61 62 // Turns threading model verification on or off. Any code that correctly 63 // uses the network stack should preferably call this function to enable 64 // verification of correct adherence to the network stack threading model. 65 void set_enable_thread_checks(bool enable); 66 bool enable_thread_checks() const; 67 68 // Whether throttling is enabled or not. 69 void set_enforce_throttling(bool enforce); 70 bool enforce_throttling(); 71 72 protected: 73 URLRequestThrottlerManager(); 74 ~URLRequestThrottlerManager(); 75 76 // Method that allows us to transform a URL into an ID that can be used in our 77 // map. Resulting IDs will be lowercase and consist of the scheme, host, port 78 // and path (without query string, fragment, etc.). 79 // If the URL is invalid, the invalid spec will be returned, without any 80 // transformation. 81 std::string GetIdFromUrl(const GURL& url) const; 82 83 // Method that ensures the map gets cleaned from time to time. The period at 84 // which garbage collecting happens is adjustable with the 85 // kRequestBetweenCollecting constant. 86 void GarbageCollectEntriesIfNecessary(); 87 88 // Method that does the actual work of garbage collecting. 89 void GarbageCollectEntries(); 90 91 // Used by tests. 92 int GetNumberOfEntriesForTests() const { return url_entries_.size(); } 93 94 private: 95 friend struct DefaultSingletonTraits<URLRequestThrottlerManager>; 96 97 // From each URL we generate an ID composed of the scheme, host, port and path 98 // that allows us to uniquely map an entry to it. 99 typedef std::map<std::string, scoped_refptr<URLRequestThrottlerEntry> > 100 UrlEntryMap; 101 102 // We maintain a set of hosts that have opted out of exponential 103 // back-off throttling. 104 typedef std::set<std::string> OptOutHosts; 105 106 // Maximum number of entries that we are willing to collect in our map. 107 static const unsigned int kMaximumNumberOfEntries; 108 // Number of requests that will be made between garbage collection. 109 static const unsigned int kRequestsBetweenCollecting; 110 111 // Map that contains a list of URL ID and their matching 112 // URLRequestThrottlerEntry. 113 UrlEntryMap url_entries_; 114 115 // Set of hosts that have opted out. 116 OptOutHosts opt_out_hosts_; 117 118 // This keeps track of how many requests have been made. Used with 119 // GarbageCollectEntries. 120 unsigned int requests_since_last_gc_; 121 122 // Valid after construction. 123 GURL::Replacements url_id_replacements_; 124 125 // Whether we would like to reject outgoing HTTP requests during the back-off 126 // period. 127 bool enforce_throttling_; 128 129 // Certain tests do not obey the net component's threading policy, so we 130 // keep track of whether we're being used by tests, and turn off certain 131 // checks. 132 // 133 // TODO(joi): See if we can fix the offending unit tests and remove this 134 // workaround. 135 bool enable_thread_checks_; 136 137 DISALLOW_COPY_AND_ASSIGN(URLRequestThrottlerManager); 138 }; 139 140 } // namespace net 141 142 #endif // NET_URL_REQUEST_URL_REQUEST_THROTTLER_MANAGER_H_ 143
