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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33 // clean out outdated entries.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 ~URLRequestThrottlerManager() override; | |
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 void OnIPAddressChanged() override; | |
82 | |
83 // ConnectionTypeObserver interface. | |
84 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_ | |
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