chrome/browser/metrics/variations/variations_http_header_provider.h

   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 CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_
   6 #define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_
   7
   8 #include <set>
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "base/gtest_prod_util.h"
  13 #include "base/metrics/field_trial.h"
  14 #include "base/synchronization/lock.h"
  15 #include "components/variations/variations_associated_data.h"
  16
  17 namespace content {
  18 class ResourceContext;
  19 }
  20
  21 namespace net {
  22 class HttpRequestHeaders;
  23 }
  24
  25 class GURL;
  26 class Profile;
  27 class ProfileIOData;
  28
  29 template <typename T> struct DefaultSingletonTraits;
  30
  31 namespace chrome_variations {
  32
  33 // A helper class for maintaining Chrome experiments and metrics state
  34 // transmitted in custom HTTP request headers.
  35 // This class is a thread-safe singleton.
  36 class VariationsHttpHeaderProvider : base::FieldTrialList::Observer {
  37  public:
  38   static VariationsHttpHeaderProvider* GetInstance();
  39
  40   // Adds Chrome experiment and metrics state as custom headers to |headers|.
  41   // Some headers may not be set given the |incognito| mode or whether
  42   // the user has |uma_enabled|.  Also, we never transmit headers to non-Google
  43   // sites, which is checked based on the destination |url|.
  44   void AppendHeaders(const GURL& url,
  45                      bool incognito,
  46                      bool uma_enabled,
  47                      net::HttpRequestHeaders* headers);
  48
  49   // Sets *additional* variation ids to be encoded in the X-Client-Data
  50   // request header.  This is intended for development use to force a server
  51   // side experiment id.  |variation_ids| should be a comma-separated string of
  52   // numeric experiment ids.
  53   bool SetDefaultVariationIds(const std::string& variation_ids);
  54
  55  private:
  56   friend struct DefaultSingletonTraits<VariationsHttpHeaderProvider>;
  57
  58   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
  59                            ShouldAppendHeaders);
  60   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
  61                            SetDefaultVariationIds_Valid);
  62   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
  63                            SetDefaultVariationIds_Invalid);
  64
  65   VariationsHttpHeaderProvider();
  66   virtual ~VariationsHttpHeaderProvider();
  67
  68   // base::FieldTrialList::Observer implementation.
  69   // This will add the variation ID associated with |trial_name| and
  70   // |group_name| to the variation ID cache.
  71   virtual void OnFieldTrialGroupFinalized(
  72       const std::string& trial_name,
  73       const std::string& group_name) OVERRIDE;
  74
  75   // Prepares the variation IDs cache with initial values if not already done.
  76   // This method also registers the caller with the FieldTrialList to receive
  77   // new variation IDs.
  78   void InitVariationIDsCacheIfNeeded();
  79
  80   // Takes whatever is currently in |variation_ids_set_| and recreates
  81   // |variation_ids_header_| with it.  Assumes the the |lock_| is currently
  82   // held.
  83   void UpdateVariationIDsHeaderValue();
  84
  85   // Checks whether variation headers should be appended to requests to the
  86   // specified |url|. Returns true for google.<TLD> and youtube.<TLD> URLs.
  87   static bool ShouldAppendHeaders(const GURL& url);
  88
  89   // Guards |variation_ids_cache_initialized_|, |variation_ids_set_| and
  90   // |variation_ids_header_|.
  91   base::Lock lock_;
  92
  93   // Whether or not we've initialized the cache.
  94   bool variation_ids_cache_initialized_;
  95
  96   // Keep a cache of variation IDs that are transmitted in headers to Google.
  97   // This consists of a list of valid IDs, and the actual transmitted header.
  98   std::set<chrome_variations::VariationID> variation_ids_set_;
  99
 100   // Provides the google experiment ids forced from command line.
 101   std::set<chrome_variations::VariationID> default_variation_ids_set_;
 102   std::string variation_ids_header_;
 103
 104   DISALLOW_COPY_AND_ASSIGN(VariationsHttpHeaderProvider);
 105 };
 106
 107 }  // namespace chrome_variations
 108
 109 #endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_