content/browser/speech/google_one_shot_remote_engine.cc

   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 #include "content/browser/speech/google_one_shot_remote_engine.h"
   6
   7 #include <vector>
   8
   9 #include "base/json/json_reader.h"
  10 #include "base/strings/string_number_conversions.h"
  11 #include "base/strings/string_util.h"
  12 #include "base/values.h"
  13 #include "content/browser/speech/audio_buffer.h"
  14 #include "content/public/common/speech_recognition_error.h"
  15 #include "content/public/common/speech_recognition_result.h"
  16 #include "google_apis/google_api_keys.h"
  17 #include "net/base/escape.h"
  18 #include "net/base/load_flags.h"
  19 #include "net/url_request/url_fetcher.h"
  20 #include "net/url_request/url_request_context.h"
  21 #include "net/url_request/url_request_context_getter.h"
  22 #include "net/url_request/url_request_status.h"
  23
  24 namespace content {
  25 namespace {
  26
  27 const char* const kDefaultSpeechRecognitionUrl =
  28     "https://www.google.com/speech-api/v1/recognize?xjerr=1&client=chromium&";
  29 const char* const kStatusString = "status";
  30 const char* const kHypothesesString = "hypotheses";
  31 const char* const kUtteranceString = "utterance";
  32 const char* const kConfidenceString = "confidence";
  33 const int kWebServiceStatusNoError = 0;
  34 const int kWebServiceStatusNoSpeech = 4;
  35 const int kWebServiceStatusNoMatch = 5;
  36 const AudioEncoder::Codec kDefaultAudioCodec = AudioEncoder::CODEC_FLAC;
  37
  38 bool ParseServerResponse(const std::string& response_body,
  39                          SpeechRecognitionResult* result,
  40                          SpeechRecognitionError* error) {
  41   if (response_body.empty()) {
  42     LOG(WARNING) << "ParseServerResponse: Response was empty.";
  43     return false;
  44   }
  45   DVLOG(1) << "ParseServerResponse: Parsing response " << response_body;
  46
  47   // Parse the response, ignoring comments.
  48   std::string error_msg;
  49   scoped_ptr<base::Value> response_value(base::JSONReader::ReadAndReturnError(
  50       response_body, base::JSON_PARSE_RFC, NULL, &error_msg));
  51   if (response_value == NULL) {
  52     LOG(WARNING) << "ParseServerResponse: JSONReader failed : " << error_msg;
  53     return false;
  54   }
  55
  56   if (!response_value->IsType(base::Value::TYPE_DICTIONARY)) {
  57     VLOG(1) << "ParseServerResponse: Unexpected response type "
  58             << response_value->GetType();
  59     return false;
  60   }
  61   const base::DictionaryValue* response_object =
  62       static_cast<const base::DictionaryValue*>(response_value.get());
  63
  64   // Get the status.
  65   int status;
  66   if (!response_object->GetInteger(kStatusString, &status)) {
  67     VLOG(1) << "ParseServerResponse: " << kStatusString
  68             << " is not a valid integer value.";
  69     return false;
  70   }
  71
  72   // Process the status.
  73   switch (status) {
  74     case kWebServiceStatusNoError:
  75       break;
  76     case kWebServiceStatusNoSpeech:
  77       error->code = SPEECH_RECOGNITION_ERROR_NO_SPEECH;
  78       return false;
  79     case kWebServiceStatusNoMatch:
  80       error->code = SPEECH_RECOGNITION_ERROR_NO_MATCH;
  81       return false;
  82     default:
  83       error->code = SPEECH_RECOGNITION_ERROR_NETWORK;
  84       // Other status codes should not be returned by the server.
  85       VLOG(1) << "ParseServerResponse: unexpected status code " << status;
  86       return false;
  87   }
  88
  89   // Get the hypotheses.
  90   const base::Value* hypotheses_value = NULL;
  91   if (!response_object->Get(kHypothesesString, &hypotheses_value)) {
  92     VLOG(1) << "ParseServerResponse: Missing hypotheses attribute.";
  93     return false;
  94   }
  95
  96   DCHECK(hypotheses_value);
  97   if (!hypotheses_value->IsType(base::Value::TYPE_LIST)) {
  98     VLOG(1) << "ParseServerResponse: Unexpected hypotheses type "
  99             << hypotheses_value->GetType();
 100     return false;
 101   }
 102
 103   const base::ListValue* hypotheses_list =
 104       static_cast<const base::ListValue*>(hypotheses_value);
 105
 106   // For now we support only single shot recognition, so we are giving only a
 107   // final result, consisting of one fragment (with one or more hypotheses).
 108   size_t index = 0;
 109   for (; index < hypotheses_list->GetSize(); ++index) {
 110     const base::Value* hypothesis = NULL;
 111     if (!hypotheses_list->Get(index, &hypothesis)) {
 112       LOG(WARNING) << "ParseServerResponse: Unable to read hypothesis value.";
 113       break;
 114     }
 115     DCHECK(hypothesis);
 116     if (!hypothesis->IsType(base::Value::TYPE_DICTIONARY)) {
 117       LOG(WARNING) << "ParseServerResponse: Unexpected value type "
 118                    << hypothesis->GetType();
 119       break;
 120     }
 121
 122     const base::DictionaryValue* hypothesis_value =
 123         static_cast<const base::DictionaryValue*>(hypothesis);
 124     string16 utterance;
 125
 126     if (!hypothesis_value->GetString(kUtteranceString, &utterance)) {
 127       LOG(WARNING) << "ParseServerResponse: Missing utterance value.";
 128       break;
 129     }
 130
 131     // It is not an error if the 'confidence' field is missing.
 132     double confidence = 0.0;
 133     hypothesis_value->GetDouble(kConfidenceString, &confidence);
 134     result->hypotheses.push_back(SpeechRecognitionHypothesis(utterance,
 135                                                              confidence));
 136   }
 137
 138   if (index < hypotheses_list->GetSize()) {
 139     result->hypotheses.clear();
 140     return false;
 141   }
 142   return true;
 143 }
 144
 145 }  // namespace
 146
 147 const int GoogleOneShotRemoteEngine::kAudioPacketIntervalMs = 100;
 148 int GoogleOneShotRemoteEngine::url_fetcher_id_for_tests = 0;
 149
 150 GoogleOneShotRemoteEngine::GoogleOneShotRemoteEngine(
 151     net::URLRequestContextGetter* context)
 152     : url_context_(context) {
 153 }
 154
 155 GoogleOneShotRemoteEngine::~GoogleOneShotRemoteEngine() {}
 156
 157 void GoogleOneShotRemoteEngine::SetConfig(
 158     const SpeechRecognitionEngineConfig& config) {
 159   config_ = config;
 160 }
 161
 162 void GoogleOneShotRemoteEngine::StartRecognition() {
 163   DCHECK(delegate());
 164   DCHECK(!url_fetcher_.get());
 165   std::string lang_param = config_.language;
 166
 167   if (lang_param.empty() && url_context_.get()) {
 168     // If no language is provided then we use the first from the accepted
 169     // language list. If this list is empty then it defaults to "en-US".
 170     // Example of the contents of this list: "es,en-GB;q=0.8", ""
 171     net::URLRequestContext* request_context =
 172         url_context_->GetURLRequestContext();
 173     DCHECK(request_context);
 174     // TODO(pauljensen): GoogleOneShotRemoteEngine should be constructed with
 175     // a reference to the HttpUserAgentSettings rather than accessing the
 176     // accept language through the URLRequestContext.
 177     std::string accepted_language_list = request_context->GetAcceptLanguage();
 178     size_t separator = accepted_language_list.find_first_of(",;");
 179     lang_param = accepted_language_list.substr(0, separator);
 180   }
 181
 182   if (lang_param.empty())
 183     lang_param = "en-US";
 184
 185   std::vector<std::string> parts;
 186   parts.push_back("lang=" + net::EscapeQueryParamValue(lang_param, true));
 187
 188   if (!config_.grammars.empty()) {
 189     DCHECK_EQ(config_.grammars.size(), 1U);
 190     parts.push_back("lm=" + net::EscapeQueryParamValue(config_.grammars[0].url,
 191                                                        true));
 192   }
 193
 194   if (!config_.hardware_info.empty())
 195     parts.push_back("xhw=" + net::EscapeQueryParamValue(config_.hardware_info,
 196                                                         true));
 197   parts.push_back("maxresults=" + base::UintToString(config_.max_hypotheses));
 198   parts.push_back(config_.filter_profanities ? "pfilter=2" : "pfilter=0");
 199
 200   std::string api_key = google_apis::GetAPIKey();
 201   parts.push_back("key=" + net::EscapeQueryParamValue(api_key, true));
 202
 203   GURL url(std::string(kDefaultSpeechRecognitionUrl) + JoinString(parts, '&'));
 204
 205   encoder_.reset(AudioEncoder::Create(kDefaultAudioCodec,
 206                                       config_.audio_sample_rate,
 207                                       config_.audio_num_bits_per_sample));
 208   DCHECK(encoder_.get());
 209   url_fetcher_.reset(net::URLFetcher::Create(url_fetcher_id_for_tests,
 210                                              url,
 211                                              net::URLFetcher::POST,
 212                                              this));
 213   url_fetcher_->SetChunkedUpload(encoder_->mime_type());
 214   url_fetcher_->SetRequestContext(url_context_.get());
 215   url_fetcher_->SetReferrer(config_.origin_url);
 216
 217   // The speech recognition API does not require user identification as part
 218   // of requests, so we don't send cookies or auth data for these requests to
 219   // prevent any accidental connection between users who are logged into the
 220   // domain for other services (e.g. bookmark sync) with the speech requests.
 221   url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SAVE_COOKIES |
 222                              net::LOAD_DO_NOT_SEND_COOKIES |
 223                              net::LOAD_DO_NOT_SEND_AUTH_DATA);
 224   url_fetcher_->Start();
 225 }
 226
 227 void GoogleOneShotRemoteEngine::EndRecognition() {
 228   url_fetcher_.reset();
 229 }
 230
 231 void GoogleOneShotRemoteEngine::TakeAudioChunk(const AudioChunk& data) {
 232   DCHECK(url_fetcher_.get());
 233   DCHECK(encoder_.get());
 234   DCHECK_EQ(data.bytes_per_sample(), config_.audio_num_bits_per_sample / 8);
 235   encoder_->Encode(data);
 236   scoped_refptr<AudioChunk> encoded_data(encoder_->GetEncodedDataAndClear());
 237   url_fetcher_->AppendChunkToUpload(encoded_data->AsString(), false);
 238 }
 239
 240 void GoogleOneShotRemoteEngine::AudioChunksEnded() {
 241   DCHECK(url_fetcher_.get());
 242   DCHECK(encoder_.get());
 243
 244   // UploadAudioChunk requires a non-empty final buffer. So we encode a packet
 245   // of silence in case encoder had no data already.
 246   std::vector<int16> samples(
 247       config_.audio_sample_rate * kAudioPacketIntervalMs / 1000);
 248   scoped_refptr<AudioChunk> dummy_chunk(
 249       new AudioChunk(reinterpret_cast<uint8*>(&samples[0]),
 250                      samples.size() * sizeof(int16),
 251                      encoder_->bits_per_sample() / 8));
 252   encoder_->Encode(*dummy_chunk.get());
 253   encoder_->Flush();
 254   scoped_refptr<AudioChunk> encoded_dummy_data(
 255       encoder_->GetEncodedDataAndClear());
 256   DCHECK(!encoded_dummy_data->IsEmpty());
 257   encoder_.reset();
 258
 259   url_fetcher_->AppendChunkToUpload(encoded_dummy_data->AsString(), true);
 260 }
 261
 262 void GoogleOneShotRemoteEngine::OnURLFetchComplete(
 263     const net::URLFetcher* source) {
 264   DCHECK_EQ(url_fetcher_.get(), source);
 265   SpeechRecognitionResults results;
 266   results.push_back(SpeechRecognitionResult());
 267   SpeechRecognitionResult& result = results.back();
 268   SpeechRecognitionError error(SPEECH_RECOGNITION_ERROR_NETWORK);
 269   std::string data;
 270
 271   // The default error code in case of parse errors is NETWORK_FAILURE, however
 272   // ParseServerResponse can change the error to a more appropriate one.
 273   bool error_occurred = (!source->GetStatus().is_success() ||
 274                         source->GetResponseCode() != 200 ||
 275                         !source->GetResponseAsString(&data) ||
 276                         !ParseServerResponse(data, &result, &error));
 277   url_fetcher_.reset();
 278   if (error_occurred) {
 279     DVLOG(1) << "GoogleOneShotRemoteEngine: Network Error " << error.code;
 280     delegate()->OnSpeechRecognitionEngineError(error);
 281   } else {
 282     DVLOG(1) << "GoogleOneShotRemoteEngine: Invoking delegate with result.";
 283     delegate()->OnSpeechRecognitionEngineResults(results);
 284   }
 285 }
 286
 287 bool GoogleOneShotRemoteEngine::IsRecognitionPending() const {
 288   return url_fetcher_ != NULL;
 289 }
 290
 291 int GoogleOneShotRemoteEngine::GetDesiredAudioChunkDurationMs() const {
 292   return kAudioPacketIntervalMs;
 293 }
 294
 295 }  // namespace content