NTP: Extract JSON requests from Fetcher.

components/ntp_snippets/remote/ntp_snippets_json_request.cc

Index: components/ntp_snippets/remote/ntp_snippets_json_request.cc
diff --git a/components/ntp_snippets/remote/ntp_snippets_json_request.cc b/components/ntp_snippets/remote/ntp_snippets_json_request.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4d50f652efadf52d21daadaa22541a4d47ae1be2
--- /dev/null
+++ b/components/ntp_snippets/remote/ntp_snippets_json_request.cc
@@ -0,0 +1,524 @@
+// Copyright 2016 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 "components/ntp_snippets/remote/ntp_snippets_json_request.h"
+
+#include <algorithm>
+#include <utility>
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/json/json_writer.h"
+#include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/strings/stringprintf.h"
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
+#include "base/values.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
+#include "components/ntp_snippets/category_info.h"
+#include "components/ntp_snippets/features.h"
+#include "components/ntp_snippets/remote/ntp_snippets_request_params.h"
+#include "components/ntp_snippets/user_classifier.h"
+#include "components/signin/core/browser/profile_oauth2_token_service.h"
+#include "components/signin/core/browser/signin_manager.h"
+#include "components/signin/core/browser/signin_manager_base.h"
+#include "components/variations/net/variations_http_headers.h"
+#include "components/variations/variations_associated_data.h"
+#include "grit/components_strings.h"
+#include "net/base/load_flags.h"
+#include "net/http/http_response_headers.h"
+#include "net/http/http_status_code.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_request_context_getter.h"
+#include "third_party/icu/source/common/unicode/uloc.h"
+#include "third_party/icu/source/common/unicode/utypes.h"
+#include "ui/base/l10n/l10n_util.h"
+
+using net::URLFetcher;
+using net::URLRequestContextGetter;
+using net::HttpRequestHeaders;
+using net::URLRequestStatus;
+using translate::LanguageModel;
+
+namespace ntp_snippets {
+
+namespace internal {
+
+namespace {
+
+// Variation parameter for disabling the retry.
+const char kBackground5xxRetriesName[] = "background_5xx_retries_count";
+
+const int kMaxExcludedIds = 100;
+
+// Variation parameter for sending LanguageModel info to the server.
+const char kSendTopLanguagesName[] = "send_top_languages";
+
+// Variation parameter for sending UserClassifier info to the server.
+const char kSendUserClassName[] = "send_user_class";
+
+int Get5xxRetryCount(bool interactive_request) {
+  if (interactive_request) {
+    return 2;
+  }
+  return std::max(0, variations::GetVariationParamByFeatureAsInt(
+                         ntp_snippets::kArticleSuggestionsFeature,
+                         kBackground5xxRetriesName, 0));
+}
+
+bool IsSendingTopLanguagesEnabled() {
+  return variations::GetVariationParamByFeatureAsBool(
+      ntp_snippets::kArticleSuggestionsFeature, kSendTopLanguagesName,
+      /*default_value=*/false);
+}
+
+bool IsSendingUserClassEnabled() {
+  return variations::GetVariationParamByFeatureAsBool(
+      ntp_snippets::kArticleSuggestionsFeature, kSendUserClassName,
+      /*default_value=*/false);
+}
+
+// Translate the BCP 47 |language_code| into a posix locale string.
+std::string PosixLocaleFromBCP47Language(const std::string& language_code) {
+  char locale[ULOC_FULLNAME_CAPACITY];
+  UErrorCode error = U_ZERO_ERROR;
+  // Translate the input to a posix locale.
+  uloc_forLanguageTag(language_code.c_str(), locale, ULOC_FULLNAME_CAPACITY,
+                      nullptr, &error);
+  if (error != U_ZERO_ERROR) {
+    DLOG(WARNING) << "Error in translating language code to a locale string: "
+                  << error;
+    return std::string();
+  }
+  return locale;
+}
+
+std::string ISO639FromPosixLocale(const std::string& locale) {
+  char language[ULOC_LANG_CAPACITY];
+  UErrorCode error = U_ZERO_ERROR;
+  uloc_getLanguage(locale.c_str(), language, ULOC_LANG_CAPACITY, &error);
+  if (error != U_ZERO_ERROR) {
+    DLOG(WARNING)
+        << "Error in translating locale string to a ISO639 language code: "
+        << error;
+    return std::string();
+  }
+  return language;
+}
+
+void AppendLanguageInfoToList(base::ListValue* list,
+                              const LanguageModel::LanguageInfo& info) {
+  auto lang = base::MakeUnique<base::DictionaryValue>();
+  lang->SetString("language", info.language_code);
+  lang->SetDouble("frequency", info.frequency);
+  list->Append(std::move(lang));
+}
+
+std::string GetUserClassString(UserClassifier::UserClass user_class) {
+  switch (user_class) {
+    case UserClassifier::UserClass::RARE_NTP_USER:
+      return "RARE_NTP_USER";
+    case UserClassifier::UserClass::ACTIVE_NTP_USER:
+      return "ACTIVE_NTP_USER";
+    case UserClassifier::UserClass::ACTIVE_SUGGESTIONS_CONSUMER:
+      return "ACTIVE_SUGGESTIONS_CONSUMER";
+  }
+  NOTREACHED();
+  return std::string();
+}
+
+}  // namespace
+
+CategoryInfo BuildArticleCategoryInfo(
+    const base::Optional<base::string16>& title) {
+  return CategoryInfo(
+      title.has_value() ? title.value()
+                        : l10n_util::GetStringUTF16(
+                              IDS_NTP_ARTICLE_SUGGESTIONS_SECTION_HEADER),
+      ContentSuggestionsCardLayout::FULL_CARD,
+      // TODO(dgn): merge has_more_action and has_reload_action when we remove
+      // the kFetchMoreFeature flag. See https://crbug.com/667752
+      /*has_more_action=*/base::FeatureList::IsEnabled(kFetchMoreFeature),
+      /*has_reload_action=*/true,
+      /*has_view_all_action=*/false,
+      /*show_if_empty=*/true,
+      l10n_util::GetStringUTF16(IDS_NTP_ARTICLE_SUGGESTIONS_SECTION_EMPTY));
+}
+
+CategoryInfo BuildRemoteCategoryInfo(const base::string16& title,
+                                     bool allow_fetching_more_results) {
+  return CategoryInfo(
+      title, ContentSuggestionsCardLayout::FULL_CARD,
+      // TODO(dgn): merge has_more_action and has_reload_action when we remove
+      // the kFetchMoreFeature flag. See https://crbug.com/667752
+      /*has_more_action=*/allow_fetching_more_results &&
+          base::FeatureList::IsEnabled(kFetchMoreFeature),
+      /*has_reload_action=*/allow_fetching_more_results,
+      /*has_view_all_action=*/false,
+      /*show_if_empty=*/false,
+      // TODO(tschumann): The message for no-articles is likely wrong
+      // and needs to be added to the stubby protocol if we want to
+      // support it.
+      l10n_util::GetStringUTF16(IDS_NTP_ARTICLE_SUGGESTIONS_SECTION_EMPTY));
+}
+
+NTPSnippetsJsonRequest::NTPSnippetsJsonRequest(
+    base::Optional<Category> exclusive_category,
+    base::TickClock* tick_clock,  // Needed until destruction of the request.
+    const ParseJSONCallback& callback)
+    : exclusive_category_(exclusive_category),
+      tick_clock_(tick_clock),
+      parse_json_callback_(callback),
+      weak_ptr_factory_(this) {
+  creation_time_ = tick_clock_->NowTicks();
+}
+
+NTPSnippetsJsonRequest::~NTPSnippetsJsonRequest() {
+  LOG_IF(DFATAL, !request_completed_callback_.is_null())
+      << "The CompletionCallback was never called!";
+}
+
+void NTPSnippetsJsonRequest::Start(CompletedCallback callback) {
+  request_completed_callback_ = std::move(callback);
+  url_fetcher_->Start();
+}
+
+base::TimeDelta NTPSnippetsJsonRequest::GetFetchDuration() const {
+  return tick_clock_->NowTicks() - creation_time_;
+}
+
+std::string NTPSnippetsJsonRequest::GetResponseString() const {
+  std::string response;
+  url_fetcher_->GetResponseAsString(&response);
+  return response;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// URLFetcherDelegate overrides
+void NTPSnippetsJsonRequest::OnURLFetchComplete(const net::URLFetcher* source) {
+  DCHECK_EQ(url_fetcher_.get(), source);
+  const URLRequestStatus& status = url_fetcher_->GetStatus();
+  int response = url_fetcher_->GetResponseCode();
+  UMA_HISTOGRAM_SPARSE_SLOWLY(
+      "NewTabPage.Snippets.FetchHttpResponseOrErrorCode",
+      status.is_success() ? response : status.error());
+
+  if (!status.is_success()) {
+    std::move(request_completed_callback_)
+        .Run(/*result=*/nullptr, FetchResult::URL_REQUEST_STATUS_ERROR,
+             /*error_details=*/base::StringPrintf(" %d", status.error()));
+  } else if (response != net::HTTP_OK) {
+    // TODO(jkrcal): https://crbug.com/609084
+    // We need to deal with the edge case again where the auth
+    // token expires just before we send the request (in which case we need to
+    // fetch a new auth token). We should extract that into a common class
+    // instead of adding it to every single class that uses auth tokens.
+    std::move(request_completed_callback_)
+        .Run(/*result=*/nullptr, FetchResult::HTTP_ERROR,
+             /*error_details=*/base::StringPrintf(" %d", response));
+  } else {
+    ParseJsonResponse();
+  }
+}
+
+void NTPSnippetsJsonRequest::ParseJsonResponse() {
+  std::string json_string;
+  bool stores_result_to_string =
+      url_fetcher_->GetResponseAsString(&json_string);
+  DCHECK(stores_result_to_string);
+
+  parse_json_callback_.Run(json_string,
+                           base::Bind(&NTPSnippetsJsonRequest::OnJsonParsed,
+                                      weak_ptr_factory_.GetWeakPtr()),
+                           base::Bind(&NTPSnippetsJsonRequest::OnJsonError,
+                                      weak_ptr_factory_.GetWeakPtr()));
+}
+
+void NTPSnippetsJsonRequest::OnJsonParsed(std::unique_ptr<base::Value> result) {
+  std::move(request_completed_callback_)
+      .Run(std::move(result), FetchResult::SUCCESS,
+           /*error_details=*/std::string());
+}
+
+void NTPSnippetsJsonRequest::OnJsonError(const std::string& error) {
+  std::string json_string;
+  url_fetcher_->GetResponseAsString(&json_string);
+  LOG(WARNING) << "Received invalid JSON (" << error << "): " << json_string;
+  std::move(request_completed_callback_)
+      .Run(/*result=*/nullptr, FetchResult::JSON_PARSE_ERROR,
+           /*error_details=*/base::StringPrintf(" (error %s)", error.c_str()));
+}
+
+NTPSnippetsJsonRequest::Builder::Builder()
+    : fetch_api_(CHROME_READER_API),
+      personalization_(Personalization::kBoth),
+      language_model_(nullptr) {}
+NTPSnippetsJsonRequest::Builder::Builder(NTPSnippetsJsonRequest::Builder&&) =
+    default;
+NTPSnippetsJsonRequest::Builder::~Builder() = default;
+
+std::unique_ptr<NTPSnippetsJsonRequest> NTPSnippetsJsonRequest::Builder::Build()
+    const {
+  DCHECK(!url_.is_empty());
+  DCHECK(url_request_context_getter_);
+  DCHECK(tick_clock_);
+  auto request = base::MakeUnique<NTPSnippetsJsonRequest>(
+      params_.exclusive_category, tick_clock_, parse_json_callback_);
+  std::string body = BuildBody();
+  std::string headers = BuildHeaders();
+  request->url_fetcher_ = BuildURLFetcher(request.get(), headers, body);
+
+  // Log the request for debugging network issues.
+  VLOG(1) << "Sending a NTP snippets request to " << url_ << ":\n"
+          << headers << "\n"
+          << body;
+
+  return request;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetAuthentication(
+    const std::string& account_id,
+    const std::string& auth_header) {
+  obfuscated_gaia_id_ = account_id;
+  auth_header_ = auth_header;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder& NTPSnippetsJsonRequest::Builder::SetFetchAPI(
+    FetchAPI fetch_api) {
+  fetch_api_ = fetch_api;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetLanguageModel(
+    const translate::LanguageModel* language_model) {
+  language_model_ = language_model;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder& NTPSnippetsJsonRequest::Builder::SetParams(
+    const NTPSnippetsRequestParams& params) {
+  params_ = params;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetParseJsonCallback(
+    ParseJSONCallback callback) {
+  parse_json_callback_ = callback;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetPersonalization(
+    Personalization personalization) {
+  personalization_ = personalization;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder& NTPSnippetsJsonRequest::Builder::SetTickClock(
+    base::TickClock* tick_clock) {
+  tick_clock_ = tick_clock;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder& NTPSnippetsJsonRequest::Builder::SetUrl(
+    const GURL& url) {
+  url_ = url;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetUrlRequestContextGetter(
+    const scoped_refptr<net::URLRequestContextGetter>& context_getter) {
+  url_request_context_getter_ = context_getter;
+  return *this;
+}
+
+NTPSnippetsJsonRequest::Builder&
+NTPSnippetsJsonRequest::Builder::SetUserClassifier(
+    const UserClassifier& user_classifier) {
+  if (IsSendingUserClassEnabled()) {
+    user_class_ = GetUserClassString(user_classifier.GetUserClass());
+  }
+  return *this;
+}
+
+std::string NTPSnippetsJsonRequest::Builder::BuildHeaders() const {
+  net::HttpRequestHeaders headers;
+  headers.SetHeader("Content-Type", "application/json; charset=UTF-8");
+  if (!auth_header_.empty()) {
+    headers.SetHeader("Authorization", auth_header_);
+  }
+  // Add X-Client-Data header with experiment IDs from field trials.
+  // Note: It's fine to pass in |is_signed_in| false, which does not affect
+  // transmission of experiment ids coming from the variations server.
+  bool is_signed_in = false;
+  variations::AppendVariationHeaders(url_,
+                                     false,  // incognito
+                                     false,  // uma_enabled
+                                     is_signed_in, &headers);
+  return headers.ToString();
+}
+
+std::string NTPSnippetsJsonRequest::Builder::BuildBody() const {
+  auto request = base::MakeUnique<base::DictionaryValue>();
+  std::string user_locale = PosixLocaleFromBCP47Language(params_.language_code);
+  switch (fetch_api_) {
+    case CHROME_READER_API: {
+      auto content_params = base::MakeUnique<base::DictionaryValue>();
+      content_params->SetBoolean("only_return_personalized_results",
+                                 ReturnOnlyPersonalizedResults());
+
+      auto content_restricts = base::MakeUnique<base::ListValue>();
+      for (const auto* metadata : {"TITLE", "SNIPPET", "THUMBNAIL"}) {
+        auto entry = base::MakeUnique<base::DictionaryValue>();
+        entry->SetString("type", "METADATA");
+        entry->SetString("value", metadata);
+        content_restricts->Append(std::move(entry));
+      }
+
+      auto local_scoring_params = base::MakeUnique<base::DictionaryValue>();
+      local_scoring_params->Set("content_params", std::move(content_params));
+      local_scoring_params->Set("content_restricts",
+                                std::move(content_restricts));
+
+      auto global_scoring_params = base::MakeUnique<base::DictionaryValue>();
+      global_scoring_params->SetInteger("num_to_return",
+                                        params_.count_to_fetch);
+      global_scoring_params->SetInteger("sort_type", 1);
+
+      auto advanced = base::MakeUnique<base::DictionaryValue>();
+      advanced->Set("local_scoring_params", std::move(local_scoring_params));
+      advanced->Set("global_scoring_params", std::move(global_scoring_params));
+
+      request->SetString("response_detail_level", "STANDARD");
+      request->Set("advanced_options", std::move(advanced));
+      if (!obfuscated_gaia_id_.empty()) {
+        request->SetString("obfuscated_gaia_id", obfuscated_gaia_id_);
+      }
+      if (!user_locale.empty()) {
+        request->SetString("user_locale", user_locale);
+      }
+      break;
+    }
+
+    case CHROME_CONTENT_SUGGESTIONS_API: {
+      if (!user_locale.empty()) {
+        request->SetString("uiLanguage", user_locale);
+      }
+
+      request->SetString("priority", params_.interactive_request
+                                         ? "USER_ACTION"
+                                         : "BACKGROUND_PREFETCH");
+
+      auto excluded = base::MakeUnique<base::ListValue>();
+      for (const auto& id : params_.excluded_ids) {
+        excluded->AppendString(id);
+        if (excluded->GetSize() >= kMaxExcludedIds) {
+          break;
+        }
+      }
+      request->Set("excludedSuggestionIds", std::move(excluded));
+
+      if (!user_class_.empty()) {
+        request->SetString("userActivenessClass", user_class_);
+      }
+
+      translate::LanguageModel::LanguageInfo ui_language;
+      translate::LanguageModel::LanguageInfo other_top_language;
+      PrepareLanguages(&ui_language, &other_top_language);
+
+      if (ui_language.frequency == 0 && other_top_language.frequency == 0) {
+        break;
+      }
+
+      auto language_list = base::MakeUnique<base::ListValue>();
+      if (ui_language.frequency > 0) {
+        AppendLanguageInfoToList(language_list.get(), ui_language);
+      }
+      if (other_top_language.frequency > 0) {
+        AppendLanguageInfoToList(language_list.get(), other_top_language);
+      }
+      request->Set("topLanguages", std::move(language_list));
+
+      // TODO(sfiera): Support only_return_personalized_results.
+      // TODO(sfiera): Support count_to_fetch.
+      break;
+    }
+  }
+
+  std::string request_json;
+  bool success = base::JSONWriter::WriteWithOptions(
+      *request, base::JSONWriter::OPTIONS_PRETTY_PRINT, &request_json);
+  DCHECK(success);
+  return request_json;
+}
+
+std::unique_ptr<net::URLFetcher>
+NTPSnippetsJsonRequest::Builder::BuildURLFetcher(
+    net::URLFetcherDelegate* delegate,
+    const std::string& headers,
+    const std::string& body) const {
+  std::unique_ptr<net::URLFetcher> url_fetcher =
+      net::URLFetcher::Create(url_, net::URLFetcher::POST, delegate);
+  url_fetcher->SetRequestContext(url_request_context_getter_.get());
+  url_fetcher->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
+                            net::LOAD_DO_NOT_SAVE_COOKIES);
+  data_use_measurement::DataUseUserData::AttachToFetcher(
+      url_fetcher.get(), data_use_measurement::DataUseUserData::NTP_SNIPPETS);
+
+  url_fetcher->SetExtraRequestHeaders(headers);
+  url_fetcher->SetUploadData("application/json", body);
+
+  // Fetchers are sometimes cancelled because a network change was detected.
+  url_fetcher->SetAutomaticallyRetryOnNetworkChanges(3);
+  url_fetcher->SetMaxRetriesOn5xx(
+      Get5xxRetryCount(params_.interactive_request));
+  return url_fetcher;
+}
+
+void NTPSnippetsJsonRequest::Builder::PrepareLanguages(
+    translate::LanguageModel::LanguageInfo* ui_language,
+    translate::LanguageModel::LanguageInfo* other_top_language) const {
+  // TODO(jkrcal): Add language model factory for iOS and add fakes to tests so
+  // that |language_model| is never nullptr. Remove this check and add a DCHECK
+  // into the constructor.
+  if (!language_model_ || !IsSendingTopLanguagesEnabled()) {
+    return;
+  }
+
+  // TODO(jkrcal): Is this back-and-forth converting necessary?
+  ui_language->language_code = ISO639FromPosixLocale(
+      PosixLocaleFromBCP47Language(params_.language_code));
+  ui_language->frequency =
+      language_model_->GetLanguageFrequency(ui_language->language_code);
+
+  std::vector<LanguageModel::LanguageInfo> top_languages =
+      language_model_->GetTopLanguages();
+  for (const LanguageModel::LanguageInfo& info : top_languages) {
+    if (info.language_code != ui_language->language_code) {
+      *other_top_language = info;
+
+      // Report to UMA how important the UI language is.
+      DCHECK_GT(other_top_language->frequency, 0)
+          << "GetTopLanguages() should not return languages with 0 frequency";
+      float ratio_ui_in_both_languages =
+          ui_language->frequency /
+          (ui_language->frequency + other_top_language->frequency);
+      UMA_HISTOGRAM_PERCENTAGE(
+          "NewTabPage.Languages.UILanguageRatioInTwoTopLanguages",
+          ratio_ui_in_both_languages * 100);
+      break;
+    }
+  }
+}
+
+}  // namespace internal
+
+}  // namespace ntp_snippets