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      1 // Copyright 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/spdyproxy/proxy_advisor.h"
      6 
      7 #include "base/command_line.h"
      8 #include "base/logging.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "base/prefs/pref_service.h"
     11 #include "base/stl_util.h"
     12 #include "chrome/common/chrome_switches.h"
     13 #include "chrome/common/pref_names.h"
     14 #include "components/data_reduction_proxy/browser/data_reduction_proxy_params.h"
     15 #include "components/data_reduction_proxy/browser/data_reduction_proxy_settings.h"
     16 #include "content/public/browser/browser_thread.h"
     17 #include "net/base/load_flags.h"
     18 #include "net/base/request_priority.h"
     19 #include "net/http/http_status_code.h"
     20 #include "net/proxy/proxy_info.h"
     21 #include "net/proxy/proxy_service.h"
     22 #include "net/url_request/url_request_context.h"
     23 #include "net/url_request/url_request_context_getter.h"
     24 
     25 // TODO(marq): Remove this class because it is not being used.
     26 
     27 // Ensure data reduction features are available.
     28 #if !defined(OS_ANDROID) && !defined(OS_IOS)
     29 #error proxy_advisor should only be included in Android or iOS builds.
     30 #endif
     31 
     32 using content::BrowserThread;
     33 using data_reduction_proxy::DataReductionProxySettings;
     34 
     35 namespace {
     36 const char kOmniboxMotivation[] = "omnibox";
     37 const char kLowThresholdOmniboxMotivation[] = "low_threshold_omnibox";
     38 const char kStartupDNSMotivation[] = "startup_dns";
     39 const char kEarlyLoadMotivation[] = "early_load";
     40 const char kLearnedReferralMotivation[] = "learned_referral";
     41 const char kLowThresholdLearnedReferralMotivation[] =
     42     "low_threshold_learned_referral";
     43 const char kSelfReferralMotivation[] = "self_referral";
     44 const char kPageScanMotivation[] = "page_scan";
     45 
     46 // Maps a ResolutionMotivation to a string for use in the advisory HEAD
     47 // request.
     48 const char* MotivationName(
     49     chrome_browser_net::UrlInfo::ResolutionMotivation motivation,
     50     bool is_preconnect) {
     51   switch (motivation) {
     52     case chrome_browser_net::UrlInfo::OMNIBOX_MOTIVATED:
     53       return
     54           is_preconnect ? kOmniboxMotivation : kLowThresholdOmniboxMotivation;
     55     case chrome_browser_net::UrlInfo::STARTUP_LIST_MOTIVATED:
     56       return kStartupDNSMotivation;
     57     case chrome_browser_net::UrlInfo::EARLY_LOAD_MOTIVATED:
     58       return kEarlyLoadMotivation;
     59     case chrome_browser_net::UrlInfo::LEARNED_REFERAL_MOTIVATED:
     60       return is_preconnect ?
     61           kLearnedReferralMotivation : kLowThresholdLearnedReferralMotivation;
     62     case chrome_browser_net::UrlInfo::SELF_REFERAL_MOTIVATED:
     63       return kSelfReferralMotivation;
     64     case chrome_browser_net::UrlInfo::PAGE_SCAN_MOTIVATED:
     65       return kPageScanMotivation;
     66     default:
     67       // Other motivations should never be passed to here.
     68       NOTREACHED();
     69       break;
     70   }
     71   NOTREACHED();
     72   return "";
     73 }
     74 
     75 }  // namespace
     76 
     77 ProxyAdvisor::ProxyAdvisor(PrefService* pref_service,
     78                            net::URLRequestContextGetter* context_getter)
     79     : context_getter_(context_getter) {
     80   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     81 
     82   // pref_service may be null in mock test subclasses.
     83   if (pref_service) {
     84     proxy_pref_member_.Init(
     85         data_reduction_proxy::prefs::kDataReductionProxyEnabled,
     86         pref_service,
     87         base::Bind(&ProxyAdvisor::UpdateProxyState, base::Unretained(this)));
     88     proxy_pref_member_.MoveToThread(
     89         BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
     90   }
     91 }
     92 
     93 ProxyAdvisor::~ProxyAdvisor() {
     94   STLDeleteElements(&inflight_requests_);
     95 }
     96 
     97 void ProxyAdvisor::OnResponseStarted(net::URLRequest* request) {
     98   const net::URLRequestStatus& status(request->status());
     99   if (!status.is_success()) {
    100     DLOG(WARNING) << "Proxy advisory failed "
    101         << "status:" << status.status()
    102         << " error:" << status.error();
    103   } else if (request->GetResponseCode() != net::HTTP_OK) {
    104     DLOG(WARNING) << "Proxy advisory status: " << request->GetResponseCode();
    105   }
    106   RequestComplete(request);
    107 }
    108 
    109 void ProxyAdvisor::OnReadCompleted(net::URLRequest* request, int bytes_read) {
    110   // No-op for now, as we don't care yet.
    111 }
    112 
    113 void ProxyAdvisor::Advise(
    114     const GURL& url,
    115     chrome_browser_net::UrlInfo::ResolutionMotivation motivation,
    116     bool is_preconnect) {
    117   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    118 
    119   if (!WouldProxyURL(url))
    120     return;
    121 
    122   std::string motivation_name(MotivationName(motivation, is_preconnect));
    123   std::string header_value = motivation_name + " " + url.spec();
    124   net::URLRequestContext* context = context_getter_->GetURLRequestContext();
    125   data_reduction_proxy::DataReductionProxyParams params(
    126       data_reduction_proxy::DataReductionProxyParams::kAllowed |
    127       data_reduction_proxy::DataReductionProxyParams::kFallbackAllowed |
    128       data_reduction_proxy::DataReductionProxyParams::kPromoAllowed);
    129   std::string endpoint =
    130       params.origin().spec() + "preconnect";
    131   scoped_ptr<net::URLRequest> request = context->CreateRequest(
    132       GURL(endpoint), net::DEFAULT_PRIORITY, this, NULL);
    133   request->set_method("HEAD");
    134   request->SetExtraRequestHeaderByName(
    135       "Proxy-Host-Advisory", header_value, false);
    136   request->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
    137                         net::LOAD_DO_NOT_SAVE_COOKIES |
    138                         net::LOAD_BYPASS_PROXY |
    139                         net::LOAD_DISABLE_CACHE);
    140   net::URLRequest* raw_request = request.get();
    141   inflight_requests_.insert(request.release());
    142   raw_request->Start();
    143 }
    144 
    145 // TODO(marq): Move this into DataReductionProxySettings, and add support for
    146 // inspecting the current proxy configs -- if ResolveProxy on |url| can be
    147 // done synchronously, then this is no longer an approximation.
    148 bool ProxyAdvisor::WouldProxyURL(const GURL& url)  {
    149   if (!proxy_pref_member_.GetValue())
    150     return false;
    151 
    152   if (url.SchemeIsSecure())
    153     return false;
    154 
    155   return true;
    156 }
    157 
    158 void ProxyAdvisor::RequestComplete(net::URLRequest* request) {
    159   DCHECK_EQ(1u, inflight_requests_.count(request));
    160   scoped_ptr<net::URLRequest> scoped_request_for_deletion(request);
    161   inflight_requests_.erase(request);
    162   // |scoped_request_for_deletion| will delete |request|
    163 }
    164 
    165 void ProxyAdvisor::UpdateProxyState() {
    166   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    167   // Delete all inflight requests. Each request's destructor will call Cancel().
    168   STLDeleteElements(&inflight_requests_);
    169 }
    170