blob: 2386a5f3fd12ea09d94d4fa2c00d0e8a8324790e [file] [log] [blame]
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <set>
#include <string>
#include "base/basictypes.h"
#include "base/gtest_prod_util.h"
#include "base/metrics/field_trial.h"
#include "base/synchronization/lock.h"
#include "components/variations/variations_associated_data.h"
namespace content {
class ResourceContext;
namespace net {
class HttpRequestHeaders;
class GURL;
template <typename T> struct DefaultSingletonTraits;
namespace variations {
// A helper class for maintaining client experiments and metrics state
// transmitted in custom HTTP request headers.
// This class is a thread-safe singleton.
class VariationsHttpHeaderProvider : base::FieldTrialList::Observer {
static VariationsHttpHeaderProvider* GetInstance();
// Adds Chrome experiment and metrics state as custom headers to |headers|.
// Some headers may not be set given the |incognito| mode or whether
// the user has |uma_enabled|. Also, we never transmit headers to non-Google
// sites, which is checked based on the destination |url|.
void AppendHeaders(const GURL& url,
bool incognito,
bool uma_enabled,
net::HttpRequestHeaders* headers);
// Sets *additional* variation ids and trigger variation ids to be encoded in
// the X-Client-Data request header. This is intended for development use to
// force a server side experiment id. |variation_ids| should be a
// comma-separated string of numeric experiment ids. If an id is prefixed
// with "t" it will be treated as a trigger experiment id.
bool SetDefaultVariationIds(const std::string& variation_ids);
friend struct DefaultSingletonTraits<VariationsHttpHeaderProvider>;
virtual ~VariationsHttpHeaderProvider();
// base::FieldTrialList::Observer implementation.
// This will add the variation ID associated with |trial_name| and
// |group_name| to the variation ID cache.
virtual void OnFieldTrialGroupFinalized(
const std::string& trial_name,
const std::string& group_name) OVERRIDE;
// Prepares the variation IDs cache with initial values if not already done.
// This method also registers the caller with the FieldTrialList to receive
// new variation IDs.
void InitVariationIDsCacheIfNeeded();
// Takes whatever is currently in |variation_ids_set_| and recreates
// |variation_ids_header_| with it. Assumes the the |lock_| is currently
// held.
void UpdateVariationIDsHeaderValue();
// Checks whether variation headers should be appended to requests to the
// specified |url|. Returns true for google.<TLD> and youtube.<TLD> URLs.
static bool ShouldAppendHeaders(const GURL& url);
// Guards |variation_ids_cache_initialized_|, |variation_ids_set_| and
// |variation_ids_header_|.
base::Lock lock_;
// Whether or not we've initialized the cache.
bool variation_ids_cache_initialized_;
// Keep a cache of variation IDs that are transmitted in headers to Google.
// This consists of a list of valid IDs, and the actual transmitted header.
std::set<VariationID> variation_ids_set_;
std::set<VariationID> variation_trigger_ids_set_;
// Provides the google experiment ids forced from command line.
std::set<VariationID> default_variation_ids_set_;
std::set<VariationID> default_trigger_id_set_;
std::string variation_ids_header_;
} // namespace variations