chrome/browser/net/spdyproxy/proxy_advisor.h

   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 #ifndef CHROME_BROWSER_NET_SPDYPROXY_PROXY_ADVISOR_H_
   6 #define CHROME_BROWSER_NET_SPDYPROXY_PROXY_ADVISOR_H_
   7
   8 #include <set>
   9
  10 #include "base/prefs/pref_member.h"
  11 #include "chrome/browser/net/url_info.h"
  12 #include "net/url_request/url_request.h"
  13
  14 namespace net {
  15 class URLRequestContextGetter;
  16 }
  17
  18 class PrefService;
  19
  20 // Accessory class for net/preconnect to be used in conjunction with the
  21 // data reduction proxy. An instance of this class will accept Advise()
  22 // calls and will send HEAD requests to an endpoint URL on the proxy
  23 // which notify the proxy of preconnection opportunities.
  24 // The HEAD requests have a header of the form:
  25 //   Proxy-Host-Advisory: <motivation> <url>
  26 // Where <motivation> is a string describing what is motivating the
  27 // preconnection ('learned_referral', 'omnibox', etc.).
  28 //
  29 // The ProxyAdvisor owns the HEAD requests. Since we don't care about any
  30 // responses from the requests, they are deleted as soon as a response
  31 // code is received.
  32 //
  33 // ProxyAdvisor monitors the state of the proxy preference; if it is
  34 // disabled, all in-flight requests are canceled.
  35 //
  36 // ProxyAdvisor instances should be created on the UI thread.
  37 class ProxyAdvisor : public net::URLRequest::Delegate {
  38  public:
  39   ProxyAdvisor(PrefService* pref_service,
  40                net::URLRequestContextGetter* context_getter);
  41   virtual ~ProxyAdvisor();
  42
  43   // net::URLRequest::Delegate callbacks.
  44   virtual void OnResponseStarted(net::URLRequest* request) OVERRIDE;
  45   virtual void OnReadCompleted(net::URLRequest* request,
  46                                int bytes_read) OVERRIDE;
  47
  48   // Tell the advisor that |url| is being preconnected or pre-resolved and why.
  49   // If |url| would be proxied (according to WouldProxyURL()), the ProxyAdvisor
  50   // will send a HEAD request to the proxy, giving it an opportunity to
  51   // preconnect or pre-resolve hostnames prior to the browser sending actual
  52   // requests.
  53   // If WouldProxyURL returns a false positive, then Advise() will send an
  54   // advisory HEAD request to the proxy, but |url| will be fetched by the
  55   // browser directly.
  56   // |motivation| and |is_preconnect| are used to determine a motivation string
  57   // that is passed as part of the request (if |is_preconnect| is false, the
  58   // advisory is interprered as being of lower priority).
  59   // Advise() may only be called on the IO thread.
  60   virtual void Advise(const GURL& url,
  61               chrome_browser_net::UrlInfo::ResolutionMotivation motivation,
  62               bool is_preconnect);
  63
  64   // Returns true if, under the current proxy settings, |url| is likely to be
  65   // proxied. This is quick and dirty, rather that doing full proxy resolution
  66   // (which may involve PAC file execution and checking bad proxy lists).
  67   // TODO(marq): Make this method part of DataReductionProxySettings.
  68   virtual bool WouldProxyURL(const GURL& url);
  69
  70  private:
  71   // Removes |request| from |inflight_requests_|.
  72   void RequestComplete(net::URLRequest* request);
  73
  74   // Checks prefs::kSpdyProxyAuthEnabled and updates |proxy_enabled_|
  75   // accordingly. If the proxy has turned off, cancels all inflight requests.
  76   void UpdateProxyState();
  77
  78   scoped_refptr<net::URLRequestContextGetter> context_getter_;
  79
  80   BooleanPrefMember proxy_pref_member_;
  81
  82   std::set<net::URLRequest*> inflight_requests_;
  83 };
  84
  85 #endif  // CHROME_BROWSER_NET_SPDYPROXY_PROXY_ADVISOR_H_
  86