src/chrome/browser/net/connect_interceptor.cc

   1 // Copyright (c) 2013 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 "chrome/browser/net/connect_interceptor.h"
   6
   7 #include "chrome/browser/net/predictor.h"
   8 #include "net/base/load_flags.h"
   9 #include "net/url_request/url_request.h"
  10
  11 namespace chrome_browser_net {
  12
  13 ConnectInterceptor::ConnectInterceptor(Predictor* predictor)
  14     : timed_cache_(base::TimeDelta::FromSeconds(
  15           Predictor::kMaxUnusedSocketLifetimeSecondsWithoutAGet)),
  16       predictor_(predictor) {
  17   DCHECK(predictor);
  18 }
  19
  20 ConnectInterceptor::~ConnectInterceptor() {
  21 }
  22
  23 void ConnectInterceptor::WitnessURLRequest(net::URLRequest* request) {
  24   GURL request_scheme_host(Predictor::CanonicalizeUrl(request->url()));
  25   if (request_scheme_host == GURL::EmptyGURL())
  26     return;
  27
  28   // Learn what URLs are likely to be needed during next startup.
  29   predictor_->LearnAboutInitialNavigation(request_scheme_host);
  30
  31   bool redirected_host = false;
  32   bool is_subresource = !(request->load_flags() & net::LOAD_MAIN_FRAME);
  33   if (request->referrer().empty()) {
  34     if (request->url() != request->original_url()) {
  35       // This request was completed with a redirect.
  36       GURL original_scheme_host(request->original_url().GetWithEmptyPath());
  37       if (request_scheme_host != original_scheme_host) {
  38         redirected_host = true;
  39         // Don't learn from redirects that take path as an argument, but do
  40         // learn from short-hand typing entries, such as "cnn.com" redirects to
  41         // "www.cnn.com".  We can't just check for has_path(), as a mere "/"
  42         // will count as a path, so we check that the path is at most a "/"
  43         // (1 character long) to decide the redirect is "definitive" and has no
  44         // significant path.
  45         // TODO(jar): It may be ok to learn from all redirects, as the adaptive
  46         // system will not respond until several identical redirects have taken
  47         // place.  Hence a use of a path (that changes) wouldn't really be
  48         // learned from anyway.
  49         if (request->original_url().path().length() <= 1 &&
  50             timed_cache_.WasRecentlySeen(original_scheme_host)) {
  51           // TODO(jar): These definite redirects could be learned much faster.
  52           predictor_->LearnFromNavigation(original_scheme_host,
  53                                           request_scheme_host);
  54         }
  55       }
  56     }
  57   } else {
  58     GURL referring_scheme_host = GURL(request->referrer()).GetWithEmptyPath();
  59     // Learn about our referring URL, for use in the future.
  60     if (is_subresource && timed_cache_.WasRecentlySeen(referring_scheme_host))
  61       predictor_->LearnFromNavigation(referring_scheme_host,
  62                                       request_scheme_host);
  63     if (referring_scheme_host == request_scheme_host) {
  64       // We've already made any/all predictions when we navigated to the
  65       // referring host, so we can bail out here.
  66       // We don't update the RecentlySeen() time because any preconnections
  67       // need to be made at the first navigation (i.e., when referer was loaded)
  68       // and wouldn't have waited for this current request navigation.
  69       return;
  70     }
  71   }
  72   timed_cache_.SetRecentlySeen(request_scheme_host);
  73
  74   predictor_->RecordPreconnectNavigationStat(request->url_chain(),
  75                                              is_subresource);
  76
  77   // Subresources for main frames usually get predicted when we detected the
  78   // main frame request - way back in RenderViewHost::Navigate.  So only handle
  79   // predictions now for subresources or for redirected hosts.
  80   if ((request->load_flags() & net::LOAD_SUB_FRAME) || redirected_host)
  81     predictor_->PredictFrameSubresources(request_scheme_host,
  82                                          request->first_party_for_cookies());
  83   return;
  84 }
  85
  86 }  // namespace chrome_browser_net