net/url_request/url_request_backoff_manager.cc

   1 // Copyright 2015 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 #include "net/url_request/url_request_backoff_manager.h"
   6
   7 #include "base/logging.h"
   8 #include "base/strings/string_number_conversions.h"
   9 #include "base/strings/string_piece.h"
  10 #include "base/strings/string_util.h"
  11 #include "net/http/http_response_headers.h"
  12
  13 namespace net {
  14
  15 const uint16 URLRequestBackoffManager::kMinimumBackoffInSeconds = 1;
  16 const uint16 URLRequestBackoffManager::kMaximumBackoffInSeconds = 50000;
  17 const uint16 URLRequestBackoffManager::kNewEntriesBetweenCollecting = 200;
  18
  19 URLRequestBackoffManager::URLRequestBackoffManager()
  20     : new_entries_since_last_gc_(0) {
  21   url_id_replacements_.ClearPassword();
  22   url_id_replacements_.ClearUsername();
  23   url_id_replacements_.ClearQuery();
  24   url_id_replacements_.ClearRef();
  25
  26   NetworkChangeNotifier::AddIPAddressObserver(this);
  27   NetworkChangeNotifier::AddConnectionTypeObserver(this);
  28 }
  29
  30 URLRequestBackoffManager::~URLRequestBackoffManager() {
  31   NetworkChangeNotifier::RemoveIPAddressObserver(this);
  32   NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
  33   for (UrlEntryMap::iterator it = url_entries_.begin();
  34        it != url_entries_.end(); ++it) {
  35     delete it->second;
  36   }
  37   url_entries_.clear();
  38 }
  39
  40 void URLRequestBackoffManager::UpdateWithResponse(
  41     const GURL& url,
  42     HttpResponseHeaders* headers,
  43     const base::Time& response_time) {
  44   CalledOnValidThread();
  45   base::TimeDelta result;
  46   if (GetBackoffTime(headers, &result)) {
  47     new_entries_since_last_gc_++;
  48     std::string url_id = GetIdFromUrl(url);
  49     url_entries_[url_id] =
  50         new Entry(response_time + result, response_time + result * 1.1);
  51     GarbageCollectEntriesIfNecessary();
  52   }
  53 }
  54
  55 bool URLRequestBackoffManager::ShouldRejectRequest(
  56     const GURL& url,
  57     const base::Time& request_time) {
  58   CalledOnValidThread();
  59   std::string url_id = GetIdFromUrl(url);
  60   UrlEntryMap::iterator it = url_entries_.find(url_id);
  61   if (it == url_entries_.end())
  62     return false;
  63   Entry* entry = it->second;
  64   if (request_time < entry->throttled_time)
  65     return true;
  66   // Allow one request between throttled_time and release_time.
  67   if (request_time >= entry->throttled_time &&
  68       request_time < entry->release_time) {
  69     if (entry->used)
  70       return true;
  71     entry->used = true;
  72   }
  73   return false;
  74 }
  75
  76 void URLRequestBackoffManager::OnIPAddressChanged() {
  77   OnNetworkChange();
  78 }
  79
  80 void URLRequestBackoffManager::OnConnectionTypeChanged(
  81     NetworkChangeNotifier::ConnectionType type) {
  82   OnNetworkChange();
  83 }
  84
  85 int URLRequestBackoffManager::GetNumberOfEntriesForTests() const {
  86   return url_entries_.size();
  87 }
  88
  89 void URLRequestBackoffManager::GarbageCollectEntriesIfNecessary() {
  90   CalledOnValidThread();
  91   if (new_entries_since_last_gc_ < kNewEntriesBetweenCollecting)
  92     return;
  93
  94   new_entries_since_last_gc_ = 0;
  95   UrlEntryMap::iterator it = url_entries_.begin();
  96   while (it != url_entries_.end()) {
  97     Entry* entry = it->second;
  98     if (entry->IsOutDated()) {
  99       url_entries_.erase(it++);
 100       delete entry;
 101     } else {
 102       ++it;
 103     }
 104   }
 105 }
 106
 107 bool URLRequestBackoffManager::GetBackoffTime(HttpResponseHeaders* headers,
 108                                               base::TimeDelta* result) const {
 109   base::StringPiece name("Backoff");
 110   std::string value;
 111   void* iter = NULL;
 112   while (headers->EnumerateHeader(&iter, name, &value)) {
 113     int64 seconds;
 114     base::StringToInt64(value, &seconds);
 115     if (seconds >= kMinimumBackoffInSeconds &&
 116         seconds <= kMaximumBackoffInSeconds) {
 117       *result = base::TimeDelta::FromSeconds(seconds);
 118       return true;
 119     }
 120   }
 121   return false;
 122 }
 123
 124 std::string URLRequestBackoffManager::GetIdFromUrl(const GURL& url) const {
 125   if (!url.is_valid())
 126     return url.possibly_invalid_spec();
 127
 128   GURL id = url.ReplaceComponents(url_id_replacements_);
 129   return base::StringToLowerASCII(id.spec()).c_str();
 130 }
 131
 132 void URLRequestBackoffManager::OnNetworkChange() {
 133   CalledOnValidThread();
 134
 135   new_entries_since_last_gc_ = 0;
 136   // Remove all entries.
 137   for (UrlEntryMap::iterator it = url_entries_.begin();
 138        it != url_entries_.end(); ++it) {
 139     delete it->second;
 140   }
 141   url_entries_.clear();
 142 }
 143
 144 }  // namespace net