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