google_apis/gaia/oauth2_access_token_fetcher.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 "google_apis/gaia/oauth2_access_token_fetcher.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/json/json_reader.h"
  12 #include "base/string_util.h"
  13 #include "base/stringprintf.h"
  14 #include "base/time.h"
  15 #include "base/values.h"
  16 #include "google_apis/gaia/gaia_urls.h"
  17 #include "google_apis/gaia/google_service_auth_error.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 using net::ResponseCookies;
  26 using net::URLFetcher;
  27 using net::URLFetcherDelegate;
  28 using net::URLRequestContextGetter;
  29 using net::URLRequestStatus;
  30
  31 namespace {
  32 static const char kGetAccessTokenBodyFormat[] =
  33     "client_id=%s&"
  34     "client_secret=%s&"
  35     "grant_type=refresh_token&"
  36     "refresh_token=%s";
  37
  38 static const char kGetAccessTokenBodyWithScopeFormat[] =
  39     "client_id=%s&"
  40     "client_secret=%s&"
  41     "grant_type=refresh_token&"
  42     "refresh_token=%s&"
  43     "scope=%s";
  44
  45 static const char kAccessTokenKey[] = "access_token";
  46 static const char kExpiresInKey[] = "expires_in";
  47
  48 static GoogleServiceAuthError CreateAuthError(URLRequestStatus status) {
  49   CHECK(!status.is_success());
  50   if (status.status() == URLRequestStatus::CANCELED) {
  51     return GoogleServiceAuthError(GoogleServiceAuthError::REQUEST_CANCELED);
  52   } else {
  53     DLOG(WARNING) << "Could not reach Google Accounts servers: errno "
  54                   << status.error();
  55     return GoogleServiceAuthError::FromConnectionError(status.error());
  56   }
  57 }
  58
  59 static URLFetcher* CreateFetcher(URLRequestContextGetter* getter,
  60                                  const GURL& url,
  61                                  const std::string& body,
  62                                  URLFetcherDelegate* delegate) {
  63   bool empty_body = body.empty();
  64   URLFetcher* result = net::URLFetcher::Create(
  65       0, url,
  66       empty_body ? URLFetcher::GET : URLFetcher::POST,
  67       delegate);
  68
  69   result->SetRequestContext(getter);
  70   result->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
  71                        net::LOAD_DO_NOT_SAVE_COOKIES);
  72   // Fetchers are sometimes cancelled because a network change was detected,
  73   // especially at startup and after sign-in on ChromeOS. Retrying once should
  74   // be enough in those cases; let the fetcher retry up to 3 times just in case.
  75   // http://crbug.com/163710
  76   result->SetAutomaticallyRetryOnNetworkChanges(3);
  77
  78   if (!empty_body)
  79     result->SetUploadData("application/x-www-form-urlencoded", body);
  80
  81   return result;
  82 }
  83 }  // namespace
  84
  85 OAuth2AccessTokenFetcher::OAuth2AccessTokenFetcher(
  86     OAuth2AccessTokenConsumer* consumer,
  87     URLRequestContextGetter* getter)
  88     : consumer_(consumer),
  89       getter_(getter),
  90       state_(INITIAL) { }
  91
  92 OAuth2AccessTokenFetcher::~OAuth2AccessTokenFetcher() { }
  93
  94 void OAuth2AccessTokenFetcher::CancelRequest() {
  95   fetcher_.reset();
  96 }
  97
  98 void OAuth2AccessTokenFetcher::Start(const std::string& client_id,
  99                                      const std::string& client_secret,
 100                                      const std::string& refresh_token,
 101                                      const std::vector<std::string>& scopes) {
 102   client_id_ = client_id;
 103   client_secret_ = client_secret;
 104   refresh_token_ = refresh_token;
 105   scopes_ = scopes;
 106   StartGetAccessToken();
 107 }
 108
 109 void OAuth2AccessTokenFetcher::StartGetAccessToken() {
 110   CHECK_EQ(INITIAL, state_);
 111   state_ = GET_ACCESS_TOKEN_STARTED;
 112   fetcher_.reset(CreateFetcher(
 113       getter_,
 114       MakeGetAccessTokenUrl(),
 115       MakeGetAccessTokenBody(
 116           client_id_, client_secret_, refresh_token_, scopes_),
 117       this));
 118   fetcher_->Start();  // OnURLFetchComplete will be called.
 119 }
 120
 121 void OAuth2AccessTokenFetcher::EndGetAccessToken(
 122     const net::URLFetcher* source) {
 123   CHECK_EQ(GET_ACCESS_TOKEN_STARTED, state_);
 124   state_ = GET_ACCESS_TOKEN_DONE;
 125
 126   URLRequestStatus status = source->GetStatus();
 127   if (!status.is_success()) {
 128     OnGetTokenFailure(CreateAuthError(status));
 129     return;
 130   }
 131
 132   // HTTP_FORBIDDEN (403) is treated as temporary error, because it may be
 133   // '403 Rate Limit Exeeded.'
 134   if (source->GetResponseCode() == net::HTTP_FORBIDDEN) {
 135     OnGetTokenFailure(GoogleServiceAuthError(
 136         GoogleServiceAuthError::SERVICE_UNAVAILABLE));
 137     return;
 138   }
 139
 140   // The other errors are treated as permanent error.
 141   if (source->GetResponseCode() != net::HTTP_OK) {
 142     OnGetTokenFailure(GoogleServiceAuthError(
 143         GoogleServiceAuthError::INVALID_GAIA_CREDENTIALS));
 144     return;
 145   }
 146
 147   // The request was successfully fetched and it returned OK.
 148   // Parse out the access token and the expiration time.
 149   std::string access_token;
 150   int expires_in;
 151   if (!ParseGetAccessTokenResponse(source, &access_token, &expires_in)) {
 152     DLOG(WARNING) << "Response doesn't match expected format";
 153     OnGetTokenFailure(
 154         GoogleServiceAuthError(GoogleServiceAuthError::SERVICE_UNAVAILABLE));
 155     return;
 156   }
 157   // The token will expire in |expires_in| seconds. Take a 10% error margin to
 158   // prevent reusing a token too close to its expiration date.
 159   OnGetTokenSuccess(
 160       access_token,
 161       base::Time::Now() + base::TimeDelta::FromSeconds(9 * expires_in / 10));
 162 }
 163
 164 void OAuth2AccessTokenFetcher::OnGetTokenSuccess(
 165     const std::string& access_token,
 166     const base::Time& expiration_time) {
 167   consumer_->OnGetTokenSuccess(access_token, expiration_time);
 168 }
 169
 170 void OAuth2AccessTokenFetcher::OnGetTokenFailure(
 171     const GoogleServiceAuthError& error) {
 172   state_ = ERROR_STATE;
 173   consumer_->OnGetTokenFailure(error);
 174 }
 175
 176 void OAuth2AccessTokenFetcher::OnURLFetchComplete(
 177     const net::URLFetcher* source) {
 178   CHECK(source);
 179   CHECK(state_ == GET_ACCESS_TOKEN_STARTED);
 180   EndGetAccessToken(source);
 181 }
 182
 183 // static
 184 GURL OAuth2AccessTokenFetcher::MakeGetAccessTokenUrl() {
 185   return GURL(GaiaUrls::GetInstance()->oauth2_token_url());
 186 }
 187
 188 // static
 189 std::string OAuth2AccessTokenFetcher::MakeGetAccessTokenBody(
 190     const std::string& client_id,
 191     const std::string& client_secret,
 192     const std::string& refresh_token,
 193     const std::vector<std::string>& scopes) {
 194   std::string enc_client_id = net::EscapeUrlEncodedData(client_id, true);
 195   std::string enc_client_secret =
 196       net::EscapeUrlEncodedData(client_secret, true);
 197   std::string enc_refresh_token =
 198       net::EscapeUrlEncodedData(refresh_token, true);
 199   if (scopes.empty()) {
 200     return base::StringPrintf(
 201         kGetAccessTokenBodyFormat,
 202         enc_client_id.c_str(),
 203         enc_client_secret.c_str(),
 204         enc_refresh_token.c_str());
 205   } else {
 206     std::string scopes_string = JoinString(scopes, ' ');
 207     return base::StringPrintf(
 208         kGetAccessTokenBodyWithScopeFormat,
 209         enc_client_id.c_str(),
 210         enc_client_secret.c_str(),
 211         enc_refresh_token.c_str(),
 212         net::EscapeUrlEncodedData(scopes_string, true).c_str());
 213   }
 214 }
 215
 216 // static
 217 bool OAuth2AccessTokenFetcher::ParseGetAccessTokenResponse(
 218     const net::URLFetcher* source,
 219     std::string* access_token,
 220     int* expires_in) {
 221   CHECK(source);
 222   CHECK(access_token);
 223   std::string data;
 224   source->GetResponseAsString(&data);
 225   scoped_ptr<base::Value> value(base::JSONReader::Read(data));
 226   if (!value.get() || value->GetType() != base::Value::TYPE_DICTIONARY)
 227     return false;
 228
 229   DictionaryValue* dict = static_cast<DictionaryValue*>(value.get());
 230   return dict->GetString(kAccessTokenKey, access_token) &&
 231       dict->GetInteger(kExpiresInKey, expires_in);
 232 }