chromeos/timezone/timezone_request.cc

   1 // Copyright 2014 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 "chromeos/timezone/timezone_request.h"
   6
   7 #include <string>
   8
   9 #include "base/json/json_reader.h"
  10 #include "base/metrics/histogram.h"
  11 #include "base/metrics/sparse_histogram.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "base/time/time.h"
  15 #include "base/values.h"
  16 #include "chromeos/geolocation/geoposition.h"
  17 #include "google_apis/google_api_keys.h"
  18 #include "net/base/escape.h"
  19 #include "net/base/load_flags.h"
  20 #include "net/http/http_status_code.h"
  21 #include "net/url_request/url_fetcher.h"
  22 #include "net/url_request/url_request_context_getter.h"
  23 #include "net/url_request/url_request_status.h"
  24
  25 namespace chromeos {
  26
  27 namespace {
  28
  29 const char kDefaultTimezoneProviderUrl[] =
  30     "https://maps.googleapis.com/maps/api/timezone/json?";
  31
  32 const char kKeyString[] = "key";
  33 // Language parameter is unsupported for now.
  34 // const char kLanguageString[] = "language";
  35 const char kLocationString[] = "location";
  36 const char kSensorString[] = "sensor";
  37 const char kTimestampString[] = "timestamp";
  38
  39 const char kDstOffsetString[] = "dstOffset";
  40 const char kRawOffsetString[] = "rawOffset";
  41 const char kTimeZoneIdString[] = "timeZoneId";
  42 const char kTimeZoneNameString[] = "timeZoneName";
  43 const char kStatusString[] = "status";
  44 const char kErrorMessageString[] = "error_message";
  45
  46 // Sleep between timezone request retry on HTTP error.
  47 const unsigned int kResolveTimeZoneRetrySleepOnServerErrorSeconds = 5;
  48
  49 // Sleep between timezone request retry on bad server response.
  50 const unsigned int kResolveTimeZoneRetrySleepBadResponseSeconds = 10;
  51
  52 struct StatusString2Enum {
  53   const char* string;
  54   TimeZoneResponseData::Status value;
  55 };
  56
  57 const StatusString2Enum statusString2Enum[] = {
  58     {"OK", TimeZoneResponseData::OK},
  59     {"INVALID_REQUEST", TimeZoneResponseData::INVALID_REQUEST},
  60     {"OVER_QUERY_LIMIT", TimeZoneResponseData::OVER_QUERY_LIMIT},
  61     {"REQUEST_DENIED", TimeZoneResponseData::REQUEST_DENIED},
  62     {"UNKNOWN_ERROR", TimeZoneResponseData::UNKNOWN_ERROR},
  63     {"ZERO_RESULTS", TimeZoneResponseData::ZERO_RESULTS}, };
  64
  65 enum TimeZoneRequestEvent {
  66   // NOTE: Do not renumber these as that would confuse interpretation of
  67   // previously logged data. When making changes, also update the enum list
  68   // in tools/metrics/histograms/histograms.xml to keep it in sync.
  69   TIMEZONE_REQUEST_EVENT_REQUEST_START = 0,
  70   TIMEZONE_REQUEST_EVENT_RESPONSE_SUCCESS = 1,
  71   TIMEZONE_REQUEST_EVENT_RESPONSE_NOT_OK = 2,
  72   TIMEZONE_REQUEST_EVENT_RESPONSE_EMPTY = 3,
  73   TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED = 4,
  74
  75   // NOTE: Add entries only immediately above this line.
  76   TIMEZONE_REQUEST_EVENT_COUNT = 5
  77 };
  78
  79 enum TimeZoneRequestResult {
  80   // NOTE: Do not renumber these as that would confuse interpretation of
  81   // previously logged data. When making changes, also update the enum list
  82   // in tools/metrics/histograms/histograms.xml to keep it in sync.
  83   TIMEZONE_REQUEST_RESULT_SUCCESS = 0,
  84   TIMEZONE_REQUEST_RESULT_FAILURE = 1,
  85   TIMEZONE_REQUEST_RESULT_SERVER_ERROR = 2,
  86   TIMEZONE_REQUEST_RESULT_CANCELLED = 3,
  87
  88   // NOTE: Add entries only immediately above this line.
  89   TIMEZONE_REQUEST_RESULT_COUNT = 4
  90 };
  91
  92 // Too many requests (more than 1) mean there is a problem in implementation.
  93 void RecordUmaEvent(TimeZoneRequestEvent event) {
  94   UMA_HISTOGRAM_ENUMERATION(
  95       "TimeZone.TimeZoneRequest.Event", event, TIMEZONE_REQUEST_EVENT_COUNT);
  96 }
  97
  98 void RecordUmaResponseCode(int code) {
  99   UMA_HISTOGRAM_SPARSE_SLOWLY("TimeZone.TimeZoneRequest.ResponseCode", code);
 100 }
 101
 102 // Slow timezone resolve leads to bad user experience.
 103 void RecordUmaResponseTime(base::TimeDelta elapsed, bool success) {
 104   if (success) {
 105     UMA_HISTOGRAM_TIMES("TimeZone.TimeZoneRequest.ResponseSuccessTime",
 106                         elapsed);
 107   } else {
 108     UMA_HISTOGRAM_TIMES("TimeZone.TimeZoneRequest.ResponseFailureTime",
 109                         elapsed);
 110   }
 111 }
 112
 113 void RecordUmaResult(TimeZoneRequestResult result, unsigned retries) {
 114   UMA_HISTOGRAM_ENUMERATION(
 115       "TimeZone.TimeZoneRequest.Result", result, TIMEZONE_REQUEST_RESULT_COUNT);
 116   UMA_HISTOGRAM_SPARSE_SLOWLY("TimeZone.TimeZoneRequest.Retries", retries);
 117 }
 118
 119 // Creates the request url to send to the server.
 120 GURL TimeZoneRequestURL(const GURL& url,
 121                         const Geoposition& geoposition,
 122                         bool sensor) {
 123   std::string query(url.query());
 124   query += base::StringPrintf(
 125       "%s=%f,%f", kLocationString, geoposition.latitude, geoposition.longitude);
 126   if (url == DefaultTimezoneProviderURL()) {
 127     std::string api_key = google_apis::GetAPIKey();
 128     if (!api_key.empty()) {
 129       query += "&";
 130       query += kKeyString;
 131       query += "=";
 132       query += net::EscapeQueryParamValue(api_key, true);
 133     }
 134   }
 135   if (!geoposition.timestamp.is_null()) {
 136     query += base::StringPrintf(
 137         "&%s=%ld", kTimestampString, geoposition.timestamp.ToTimeT());
 138   }
 139   query += "&";
 140   query += kSensorString;
 141   query += "=";
 142   query += (sensor ? "true" : "false");
 143
 144   GURL::Replacements replacements;
 145   replacements.SetQueryStr(query);
 146   return url.ReplaceComponents(replacements);
 147 }
 148
 149 void PrintTimeZoneError(const GURL& server_url,
 150                         const std::string& message,
 151                         TimeZoneResponseData* timezone) {
 152   timezone->status = TimeZoneResponseData::REQUEST_ERROR;
 153   timezone->error_message =
 154       base::StringPrintf("TimeZone provider at '%s' : %s.",
 155                          server_url.GetOrigin().spec().c_str(),
 156                          message.c_str());
 157   LOG(WARNING) << "TimeZoneRequest::GetTimeZoneFromResponse() : "
 158                << timezone->error_message;
 159 }
 160
 161 // Parses the server response body. Returns true if parsing was successful.
 162 // Sets |*timezone| to the parsed TimeZone if a valid timezone was received,
 163 // otherwise leaves it unchanged.
 164 bool ParseServerResponse(const GURL& server_url,
 165                          const std::string& response_body,
 166                          TimeZoneResponseData* timezone) {
 167   DCHECK(timezone);
 168
 169   if (response_body.empty()) {
 170     PrintTimeZoneError(server_url, "Server returned empty response", timezone);
 171     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_EMPTY);
 172     return false;
 173   }
 174   VLOG(1) << "TimeZoneRequest::ParseServerResponse() : Parsing response "
 175           << response_body;
 176
 177   // Parse the response, ignoring comments.
 178   std::string error_msg;
 179   scoped_ptr<base::Value> response_value(base::JSONReader::ReadAndReturnError(
 180       response_body, base::JSON_PARSE_RFC, NULL, &error_msg));
 181   if (response_value == NULL) {
 182     PrintTimeZoneError(server_url, "JSONReader failed: " + error_msg, timezone);
 183     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 184     return false;
 185   }
 186
 187   const base::DictionaryValue* response_object = NULL;
 188   if (!response_value->GetAsDictionary(&response_object)) {
 189     PrintTimeZoneError(server_url,
 190                        "Unexpected response type : " +
 191                            base::StringPrintf("%u", response_value->GetType()),
 192                        timezone);
 193     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 194     return false;
 195   }
 196
 197   std::string status;
 198
 199   if (!response_object->GetStringWithoutPathExpansion(kStatusString, &status)) {
 200     PrintTimeZoneError(server_url, "Missing status attribute.", timezone);
 201     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 202     return false;
 203   }
 204
 205   bool found = false;
 206   for (size_t i = 0; i < arraysize(statusString2Enum); ++i) {
 207     if (status != statusString2Enum[i].string)
 208       continue;
 209
 210     timezone->status = statusString2Enum[i].value;
 211     found = true;
 212     break;
 213   }
 214
 215   if (!found) {
 216     PrintTimeZoneError(
 217         server_url, "Bad status attribute value: '" + status + "'", timezone);
 218     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 219     return false;
 220   }
 221
 222   const bool status_ok = (timezone->status == TimeZoneResponseData::OK);
 223
 224   if (!response_object->GetDoubleWithoutPathExpansion(kDstOffsetString,
 225                                                       &timezone->dstOffset) &&
 226       status_ok) {
 227     PrintTimeZoneError(server_url, "Missing dstOffset attribute.", timezone);
 228     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 229     return false;
 230   }
 231
 232   if (!response_object->GetDoubleWithoutPathExpansion(kRawOffsetString,
 233                                                       &timezone->rawOffset) &&
 234       status_ok) {
 235     PrintTimeZoneError(server_url, "Missing rawOffset attribute.", timezone);
 236     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 237     return false;
 238   }
 239
 240   if (!response_object->GetStringWithoutPathExpansion(kTimeZoneIdString,
 241                                                       &timezone->timeZoneId) &&
 242       status_ok) {
 243     PrintTimeZoneError(server_url, "Missing timeZoneId attribute.", timezone);
 244     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 245     return false;
 246   }
 247
 248   if (!response_object->GetStringWithoutPathExpansion(
 249           kTimeZoneNameString, &timezone->timeZoneName) &&
 250       status_ok) {
 251     PrintTimeZoneError(server_url, "Missing timeZoneName attribute.", timezone);
 252     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_MALFORMED);
 253     return false;
 254   }
 255
 256   // "error_message" field is optional. Ignore result.
 257   response_object->GetStringWithoutPathExpansion(kErrorMessageString,
 258                                                  &timezone->error_message);
 259
 260   return true;
 261 }
 262
 263 // Attempts to extract a position from the response. Detects and indicates
 264 // various failure cases.
 265 scoped_ptr<TimeZoneResponseData> GetTimeZoneFromResponse(
 266     bool http_success,
 267     int status_code,
 268     const std::string& response_body,
 269     const GURL& server_url) {
 270   scoped_ptr<TimeZoneResponseData> timezone(new TimeZoneResponseData);
 271
 272   // HttpPost can fail for a number of reasons. Most likely this is because
 273   // we're offline, or there was no response.
 274   if (!http_success) {
 275     PrintTimeZoneError(server_url, "No response received", timezone.get());
 276     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_EMPTY);
 277     return timezone.Pass();
 278   }
 279   if (status_code != net::HTTP_OK) {
 280     std::string message = "Returned error code ";
 281     message += base::IntToString(status_code);
 282     PrintTimeZoneError(server_url, message, timezone.get());
 283     RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_NOT_OK);
 284     return timezone.Pass();
 285   }
 286
 287   if (!ParseServerResponse(server_url, response_body, timezone.get()))
 288     return timezone.Pass();
 289
 290   RecordUmaEvent(TIMEZONE_REQUEST_EVENT_RESPONSE_SUCCESS);
 291   return timezone.Pass();
 292 }
 293
 294 }  // namespace
 295
 296 TimeZoneResponseData::TimeZoneResponseData()
 297     : dstOffset(0), rawOffset(0), status(ZERO_RESULTS) {
 298 }
 299
 300 GURL DefaultTimezoneProviderURL() {
 301   return GURL(kDefaultTimezoneProviderUrl);
 302 }
 303
 304 TimeZoneRequest::TimeZoneRequest(
 305     net::URLRequestContextGetter* url_context_getter,
 306     const GURL& service_url,
 307     const Geoposition& geoposition,
 308     bool sensor,
 309     base::TimeDelta retry_timeout)
 310     : url_context_getter_(url_context_getter),
 311       service_url_(service_url),
 312       geoposition_(geoposition),
 313       sensor_(sensor),
 314       retry_timeout_abs_(base::Time::Now() + retry_timeout),
 315       retry_sleep_on_server_error_(base::TimeDelta::FromSeconds(
 316           kResolveTimeZoneRetrySleepOnServerErrorSeconds)),
 317       retry_sleep_on_bad_response_(base::TimeDelta::FromSeconds(
 318           kResolveTimeZoneRetrySleepBadResponseSeconds)),
 319       retries_(0) {
 320 }
 321
 322 TimeZoneRequest::~TimeZoneRequest() {
 323   DCHECK(thread_checker_.CalledOnValidThread());
 324
 325   // If callback is not empty, request is cancelled.
 326   if (!callback_.is_null()) {
 327     RecordUmaResponseTime(base::Time::Now() - request_started_at_, false);
 328     RecordUmaResult(TIMEZONE_REQUEST_RESULT_CANCELLED, retries_);
 329   }
 330 }
 331
 332 void TimeZoneRequest::StartRequest() {
 333   DCHECK(thread_checker_.CalledOnValidThread());
 334   RecordUmaEvent(TIMEZONE_REQUEST_EVENT_REQUEST_START);
 335   request_started_at_ = base::Time::Now();
 336   ++retries_;
 337
 338   url_fetcher_.reset(
 339       net::URLFetcher::Create(request_url_, net::URLFetcher::GET, this));
 340   url_fetcher_->SetRequestContext(url_context_getter_.get());
 341   url_fetcher_->SetLoadFlags(net::LOAD_BYPASS_CACHE |
 342                              net::LOAD_DISABLE_CACHE |
 343                              net::LOAD_DO_NOT_SAVE_COOKIES |
 344                              net::LOAD_DO_NOT_SEND_COOKIES |
 345                              net::LOAD_DO_NOT_SEND_AUTH_DATA);
 346   url_fetcher_->Start();
 347 }
 348
 349 void TimeZoneRequest::MakeRequest(TimeZoneResponseCallback callback) {
 350   callback_ = callback;
 351   request_url_ =
 352       TimeZoneRequestURL(service_url_, geoposition_, false /* sensor */);
 353   StartRequest();
 354 }
 355
 356 void TimeZoneRequest::Retry(bool server_error) {
 357   const base::TimeDelta delay(server_error ? retry_sleep_on_server_error_
 358                                            : retry_sleep_on_bad_response_);
 359   timezone_request_scheduled_.Start(
 360       FROM_HERE, delay, this, &TimeZoneRequest::StartRequest);
 361 }
 362
 363 void TimeZoneRequest::OnURLFetchComplete(const net::URLFetcher* source) {
 364   DCHECK_EQ(url_fetcher_.get(), source);
 365
 366   net::URLRequestStatus status = source->GetStatus();
 367   int response_code = source->GetResponseCode();
 368   RecordUmaResponseCode(response_code);
 369
 370   std::string data;
 371   source->GetResponseAsString(&data);
 372   scoped_ptr<TimeZoneResponseData> timezone = GetTimeZoneFromResponse(
 373       status.is_success(), response_code, data, source->GetURL());
 374   const bool server_error =
 375       !status.is_success() || (response_code >= 500 && response_code < 600);
 376   url_fetcher_.reset();
 377
 378   DVLOG(1) << "TimeZoneRequest::OnURLFetchComplete(): timezone={"
 379            << timezone->ToStringForDebug() << "}";
 380
 381   const base::Time now = base::Time::Now();
 382   const bool retry_timeout = (now >= retry_timeout_abs_);
 383
 384   const bool success = (timezone->status == TimeZoneResponseData::OK);
 385   if (!success && !retry_timeout) {
 386     Retry(server_error);
 387     return;
 388   }
 389   RecordUmaResponseTime(base::Time::Now() - request_started_at_, success);
 390
 391   const TimeZoneRequestResult result =
 392       (server_error ? TIMEZONE_REQUEST_RESULT_SERVER_ERROR
 393                     : (success ? TIMEZONE_REQUEST_RESULT_SUCCESS
 394                                : TIMEZONE_REQUEST_RESULT_FAILURE));
 395   RecordUmaResult(result, retries_);
 396
 397   TimeZoneResponseCallback callback = callback_;
 398
 399   // Empty callback is used to identify "completed or not yet started request".
 400   callback_.Reset();
 401
 402   // callback.Run() usually destroys TimeZoneRequest, because this is the way
 403   // callback is implemented in TimeZoneProvider.
 404   callback.Run(timezone.Pass(), server_error);
 405   // "this" is already destroyed here.
 406 }
 407
 408 std::string TimeZoneResponseData::ToStringForDebug() const {
 409   static const char* const status2string[] = {
 410       "OK",
 411       "INVALID_REQUEST",
 412       "OVER_QUERY_LIMIT",
 413       "REQUEST_DENIED",
 414       "UNKNOWN_ERROR",
 415       "ZERO_RESULTS",
 416       "REQUEST_ERROR"
 417   };
 418
 419   return base::StringPrintf(
 420       "dstOffset=%f, rawOffset=%f, timeZoneId='%s', timeZoneName='%s', "
 421       "error_message='%s', status=%u (%s)",
 422       dstOffset,
 423       rawOffset,
 424       timeZoneId.c_str(),
 425       timeZoneName.c_str(),
 426       error_message.c_str(),
 427       (unsigned)status,
 428       (status < arraysize(status2string) ? status2string[status] : "unknown"));
 429 }
 430
 431 }  // namespace chromeos