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ios/chrome/browser/ui/contextual_search/contextual_search_delegate.cc

Index: ios/chrome/browser/ui/contextual_search/contextual_search_delegate.cc
diff --git a/ios/chrome/browser/ui/contextual_search/contextual_search_delegate.cc b/ios/chrome/browser/ui/contextual_search/contextual_search_delegate.cc
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index 0000000000000000000000000000000000000000..3acaf6243c6bcf438fdbfdfa8efe1a4fa0fb8e00
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+++ b/ios/chrome/browser/ui/contextual_search/contextual_search_delegate.cc
@@ -0,0 +1,333 @@
+// 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 "ios/chrome/browser/ui/contextual_search/contextual_search_delegate.h"
+
+#include <algorithm>
+#include <utility>
+
+#include "base/base64.h"
+#include "base/command_line.h"
+#include "base/json/json_string_value_serializer.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/google/core/browser/google_util.h"
+#include "components/search_engines/template_url_service.h"
+#include "components/search_engines/util.h"
+#include "components/variations/net/variations_http_headers.h"
+#include "components/variations/variations_associated_data.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/search_engines/template_url_service_factory.h"
+#include "ios/chrome/browser/ui/contextual_search/protos/client_discourse_context.pb.h"
+#include "ios/web/public/web_thread.h"
+#include "net/base/escape.h"
+#include "net/base/url_util.h"
+#include "net/url_request/url_fetcher.h"
+#include "url/gurl.h"
+
+namespace {
+
+const char kContextualSearchFieldTrialName[] = "ContextualSearch";
+const char kContextualSearchPreventPreload[] = "prevent_preload";
+const char kContextualSearchResolverUrl[] = "contextual-search-resolver-url";
+const char kContextualSearchResolverURLParamName[] = "resolver_url";
+const char kContextualSearchResponseDisplayTextParam[] = "display_text";
+const char kContextualSearchResponseMentionsParam[] = "mentions";
+const char kContextualSearchResponseResolvedTermParam[] = "resolved_term";
+const char kContextualSearchResponseSelectedTextParam[] = "selected_text";
+const char kContextualSearchResponseSearchTermParam[] = "search_term";
+const int kContextualSearchRequestVersion = 2;
+const char kContextualSearchServerEndpoint[] = "_/contextualsearch?";
+const char kDiscourseContextHeaderPrefix[] = "X-Additional-Discourse-Context: ";
+const char kDoPreventPreloadValue[] = "1";
+const char kXssiEscape[] = ")]}'\n";
+
+const double kMinimumDelayBetweenRequestSeconds = 1;
+
+// Decodes the given response from the search term resolution request and sets
+// the value of the given search-term and display_text parameters.
+void DecodeSearchTermsFromJsonResponse(const std::string& response,
+                                       std::string* search_term,
+                                       std::string* display_text,
+                                       std::string* alternate_term,
+                                       std::string* prevent_preload,
+                                       int& start_offset,
+                                       int& end_offset) {
+  bool contains_xssi_escape = response.find(kXssiEscape) == 0;
+  const std::string& proper_json =
+      contains_xssi_escape ? response.substr(strlen(kXssiEscape)) : response;
+  JSONStringValueDeserializer deserializer(proper_json);
+  std::unique_ptr<base::Value> root(deserializer.Deserialize(NULL, NULL));
+
+  if (root.get() != NULL && root->IsType(base::Value::Type::DICTIONARY)) {
+    base::DictionaryValue* dict =
+        static_cast<base::DictionaryValue*>(root.get());
+    dict->GetString(kContextualSearchPreventPreload, prevent_preload);
+    dict->GetString(kContextualSearchResponseSearchTermParam, search_term);
+    // For the display_text, if not present fall back to the "search_term".
+    if (!dict->GetString(kContextualSearchResponseDisplayTextParam,
+                         display_text)) {
+      *display_text = *search_term;
+    }
+    // If either the selected text or the resolved term is not the search term,
+    // use it as the alternate term.
+    std::string selected_text;
+    dict->GetString(kContextualSearchResponseSelectedTextParam, &selected_text);
+
+    const base::ListValue* mentionsList;
+    if (dict->GetList(kContextualSearchResponseMentionsParam, &mentionsList)) {
+      DCHECK(mentionsList->GetSize() == 2);
+      mentionsList->GetInteger(0, &start_offset);
+      mentionsList->GetInteger(1, &end_offset);
+    }
+
+    if (selected_text != *search_term) {
+      *alternate_term = selected_text;
+    } else {
+      std::string resolved_term;
+      dict->GetString(kContextualSearchResponseResolvedTermParam,
+                      &resolved_term);
+      if (resolved_term != *search_term) {
+        *alternate_term = resolved_term;
+      }
+    }
+  }
+}
+
+}  // namespace
+
+// URLFetcher ID, only used for tests: we only have one kind of fetcher.
+const int ContextualSearchDelegate::kContextualSearchURLFetcherID = 1;
+
+// Handles tasks for the ContextualSearchManager in a separable, testable way.
+ContextualSearchDelegate::ContextualSearchDelegate(
+    ios::ChromeBrowserState* browser_state,
+    const ContextualSearchDelegate::SearchTermResolutionCallback&
+        search_term_callback)
+    : template_url_service_(
+          ios::TemplateURLServiceFactory::GetForBrowserState(browser_state)),
+      browser_state_(browser_state),
+      search_term_callback_(search_term_callback),
+      weak_ptr_factory_(this) {}
+
+ContextualSearchDelegate::~ContextualSearchDelegate() {}
+
+void ContextualSearchDelegate::PostSearchTermRequest(
+    std::shared_ptr<ContextualSearchContext> context) {
+  context_ = context;
+  if (request_pending_) {
+    return;
+  }
+  request_pending_ = true;
+
+  base::TimeDelta interval =
+      base::TimeDelta::FromSecondsD(kMinimumDelayBetweenRequestSeconds);
+  base::Time now = base::Time::Now();
+  if (now > last_request_startup_time_ + interval) {
+    StartPendingSearchTermRequest();
+  } else {
+    base::TimeDelta delay = last_request_startup_time_ + interval - now;
+    web::WebThread::PostDelayedTask(
+        web::WebThread::UI, FROM_HERE,
+        base::Bind(&ContextualSearchDelegate::StartPendingSearchTermRequest,
+                   weak_ptr_factory_.GetWeakPtr()),
+        delay);
+  }
+}
+
+void ContextualSearchDelegate::StartPendingSearchTermRequest() {
+  if (!request_pending_ || !context_)
+    return;
+  request_pending_ = false;
+  last_request_startup_time_ = base::Time::Now();
+  if (context_->HasSurroundingText()) {
+    RequestServerSearchTerm();
+  } else {
+    RequestLocalSearchTerm();
+  }
+}
+
+void ContextualSearchDelegate::RequestLocalSearchTerm() {
+  SearchResolution resolution;
+  resolution.is_invalid = false;
+  resolution.response_code = 200;  // HTTP success.
+  resolution.search_term = context_->selected_text;
+  resolution.display_text = context_->selected_text;
+  resolution.alternate_term = context_->selected_text;
+  resolution.prevent_preload = false;
+  resolution.start_offset = -1;
+  resolution.end_offset = -1;
+  search_term_callback_.Run(resolution);
+}
+
+void ContextualSearchDelegate::RequestServerSearchTerm() {
+  GURL request_url(BuildRequestUrl());
+  DCHECK(request_url.is_valid());
+
+  // Reset will delete any previous fetcher, and we won't get any callback.
+  search_term_fetcher_ = net::URLFetcher::Create(
+      kContextualSearchURLFetcherID, request_url, net::URLFetcher::GET, this);
+  search_term_fetcher_->SetRequestContext(browser_state_->GetRequestContext());
+
+  // Add Chrome experiment state to the request headers.
+  net::HttpRequestHeaders headers;
+  // 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(search_term_fetcher_->GetOriginalURL(),
+                                     browser_state_->IsOffTheRecord(), false,
+                                     is_signed_in, &headers);
+  search_term_fetcher_->SetExtraRequestHeaders(headers.ToString());
+
+  SetDiscourseContextAndAddToHeader(*context_);
+
+  search_term_fetcher_->Start();
+}
+
+void ContextualSearchDelegate::CancelSearchTermRequest() {
+  search_term_fetcher_.reset();
+  context_.reset();
+}
+
+// Adapted from /chrome/browser/search_engines/template_url_service_android.cc
+GURL ContextualSearchDelegate::GetURLForResolvedSearch(
+    SearchResolution resolution,
+    bool should_prefetch) {
+  GURL url;
+  if (!resolution.search_term.empty()) {
+    url = GetDefaultSearchURLForSearchTerms(
+        template_url_service_, base::UTF8ToUTF16(resolution.search_term));
+    if (google_util::IsGoogleSearchUrl(url)) {
+      url = net::AppendQueryParameter(url, "ctxs", "2");
+      if (should_prefetch) {
+        // Indicate that the search page is being prefetched.
+        url = net::AppendQueryParameter(url, "pf", "c");
+      }
+
+      if (!resolution.alternate_term.empty()) {
+        url = net::AppendQueryParameter(url, "ctxsl_alternate_term",
+                                        resolution.alternate_term);
+      }
+    }
+  }
+  return url;
+}
+
+void ContextualSearchDelegate::OnURLFetchComplete(
+    const net::URLFetcher* source) {
+  DCHECK(source == search_term_fetcher_.get());
+  SearchResolution resolution;
+  std::string prevent_preload;
+  resolution.response_code = source->GetResponseCode();
+  if (source->GetStatus().is_success() && resolution.response_code == 200) {
+    std::string response;
+    bool has_string_response = source->GetResponseAsString(&response);
+    DCHECK(has_string_response);
+    if (has_string_response) {
+      resolution.start_offset = -1;
+      resolution.end_offset = -1;
+      DecodeSearchTermsFromJsonResponse(
+          response, &resolution.search_term, &resolution.display_text,
+          &resolution.alternate_term, &prevent_preload, resolution.start_offset,
+          resolution.end_offset);
+    }
+  }
+  resolution.is_invalid =
+      resolution.response_code == net::URLFetcher::RESPONSE_CODE_INVALID;
+  resolution.prevent_preload = prevent_preload == kDoPreventPreloadValue;
+
+  search_term_callback_.Run(resolution);
+}
+
+// TODO(donnd): use HTTP headers for the context instead of CGI params in GET.
+// See https://code.google.com/p/chromium/issues/detail?id=341762
+GURL ContextualSearchDelegate::BuildRequestUrl() {
+  // TODO(jeremycho): Confirm this is the right way to handle TemplateURL fails.
+  if (!template_url_service_ ||
+      !template_url_service_->GetDefaultSearchProvider()) {
+    return GURL();
+  }
+
+  std::string selected_text_escaped(
+      net::EscapeQueryParamValue(context_->selected_text, true));
+  std::string base_page_url = context_->page_url.spec();
+  bool use_resolved_search_term = context_->use_resolved_search_term;
+
+  std::string request = GetSearchTermResolutionUrlString(
+      selected_text_escaped, base_page_url, use_resolved_search_term);
+
+  return GURL(request);
+}
+
+std::string ContextualSearchDelegate::GetSearchTermResolutionUrlString(
+    const std::string& selected_text,
+    const std::string& base_page_url,
+    const bool use_resolved_search_term) {
+  TemplateURL* template_url = template_url_service_->GetDefaultSearchProvider();
+
+  TemplateURLRef::SearchTermsArgs search_terms_args =
+      TemplateURLRef::SearchTermsArgs(base::string16());
+
+  TemplateURLRef::SearchTermsArgs::ContextualSearchParams params(
+      kContextualSearchRequestVersion, selected_text, base_page_url,
+      use_resolved_search_term);
+
+  search_terms_args.contextual_search_params = params;
+
+  std::string request(
+      template_url->contextual_search_url_ref().ReplaceSearchTerms(
+          search_terms_args, template_url_service_->search_terms_data(), NULL));
+
+  // The switch/param should be the URL up to and including the endpoint.
+  std::string replacement_url;
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          kContextualSearchResolverUrl)) {
+    replacement_url =
+        base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+            kContextualSearchResolverUrl);
+  } else {
+    std::string param_value = variations::GetVariationParamValue(
+        kContextualSearchFieldTrialName, kContextualSearchResolverURLParamName);
+    if (!param_value.empty())
+      replacement_url = param_value;
+  }
+
+  // If a replacement URL was specified above, do the substitution.
+  if (!replacement_url.empty()) {
+    size_t pos = request.find(kContextualSearchServerEndpoint);
+    if (pos != std::string::npos) {
+      request.replace(0, pos + strlen(kContextualSearchServerEndpoint),
+                      replacement_url);
+    }
+  }
+  return request;
+}
+
+void ContextualSearchDelegate::SetDiscourseContextAndAddToHeader(
+    const ContextualSearchContext& context) {
+  discourse_context::ClientDiscourseContext proto;
+  discourse_context::Display* display = proto.add_display();
+  display->set_uri(context.page_url.spec());
+
+  discourse_context::Media* media = display->mutable_media();
+  media->set_mime_type(context.encoding);
+
+  discourse_context::Selection* selection = display->mutable_selection();
+  selection->set_content(
+      net::EscapeQueryParamValue(UTF16ToUTF8(context.surrounding_text), true));
+  selection->set_start(context.start_offset);
+  selection->set_end(context.end_offset);
+
+  std::string serialized;
+  proto.SerializeToString(&serialized);
+
+  std::string encoded_context;
+  base::Base64Encode(serialized, &encoded_context);
+  // The server memoizer expects a web-safe encoding.
+  std::replace(encoded_context.begin(), encoded_context.end(), '+', '-');
+  std::replace(encoded_context.begin(), encoded_context.end(), '/', '_');
+  search_term_fetcher_->AddExtraRequestHeader(kDiscourseContextHeaderPrefix +
+                                              encoded_context);
+}