xref: /external/chromium_org/chrome/browser/resources/print_preview/cloud_print_interface.js

// Copyright (c) 2012 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.

cr.define('cloudprint', function() {
  'use strict';

  /**
   * API to the Google Cloud Print service.
   * @param {string} baseUrl Base part of the Google Cloud Print service URL
   *     with no trailing slash. For example,
   *     'https://www.google.com/cloudprint'.
   * @param {!print_preview.NativeLayer} nativeLayer Native layer used to get
   *     Auth2 tokens.
   * @param {!print_preview.UserInfo} userInfo User information repository.
   * @param {boolean} isInAppKioskMode Whether the print preview is in App
   *     Kiosk mode.
   * @constructor
   * @extends {cr.EventTarget}
   */
  function CloudPrintInterface(
      baseUrl, nativeLayer, userInfo, isInAppKioskMode) {
    /**
     * The base URL of the Google Cloud Print API.
     * @type {string}
     * @private
     */
    this.baseUrl_ = baseUrl;

    /**
     * Used to get Auth2 tokens.
     * @type {!print_preview.NativeLayer}
     * @private
     */
    this.nativeLayer_ = nativeLayer;

    /**
     * User information repository.
     * @type {!print_preview.UserInfo}
     * @private
     */
    this.userInfo_ = userInfo;

    /**
     * Whether Print Preview is in App Kiosk mode, basically, use only printers
     * available for the device.
     * @type {boolean}
     * @private
     */
    this.isInAppKioskMode_ = isInAppKioskMode;

    /**
     * Currently logged in users (identified by email) mapped to the Google
     * session index.
     * @type {!Object.<string, number>}
     * @private
     */
    this.userSessionIndex_ = {};

    /**
     * Stores last received XSRF tokens for each user account. Sent as
     * a parameter with every request.
     * @type {!Object.<string, string>}
     * @private
     */
    this.xsrfTokens_ = {};

    /**
     * Pending requests delayed until we get access token.
     * @type {!Array.<!CloudPrintRequest>}
     * @private
     */
    this.requestQueue_ = [];

    /**
     * Outstanding cloud destination search requests.
     * @type {!Array.<!CloudPrintRequest>}
     * @private
     */
    this.outstandingCloudSearchRequests_ = [];

    /**
     * Event tracker used to keep track of native layer events.
     * @type {!EventTracker}
     * @private
     */
    this.tracker_ = new EventTracker();

    this.addEventListeners_();
  };

  /**
   * Event types dispatched by the interface.
   * @enum {string}
   */
  CloudPrintInterface.EventType = {
    INVITES_DONE: 'cloudprint.CloudPrintInterface.INVITES_DONE',
    INVITES_FAILED: 'cloudprint.CloudPrintInterface.INVITES_FAILED',
    PRINTER_DONE: 'cloudprint.CloudPrintInterface.PRINTER_DONE',
    PRINTER_FAILED: 'cloudprint.CloudPrintInterface.PRINTER_FAILED',
    PROCESS_INVITE_DONE: 'cloudprint.CloudPrintInterface.PROCESS_INVITE_DONE',
    PROCESS_INVITE_FAILED:
        'cloudprint.CloudPrintInterface.PROCESS_INVITE_FAILED',
    SEARCH_DONE: 'cloudprint.CloudPrintInterface.SEARCH_DONE',
    SEARCH_FAILED: 'cloudprint.CloudPrintInterface.SEARCH_FAILED',
    SUBMIT_DONE: 'cloudprint.CloudPrintInterface.SUBMIT_DONE',
    SUBMIT_FAILED: 'cloudprint.CloudPrintInterface.SUBMIT_FAILED',
    UPDATE_PRINTER_TOS_ACCEPTANCE_FAILED:
        'cloudprint.CloudPrintInterface.UPDATE_PRINTER_TOS_ACCEPTANCE_FAILED'
  };

  /**
   * Content type header value for a URL encoded HTTP request.
   * @type {string}
   * @const
   * @private
   */
  CloudPrintInterface.URL_ENCODED_CONTENT_TYPE_ =
      'application/x-www-form-urlencoded';

  /**
   * Multi-part POST request boundary used in communication with Google
   * Cloud Print.
   * @type {string}
   * @const
   * @private
   */
  CloudPrintInterface.MULTIPART_BOUNDARY_ =
      '----CloudPrintFormBoundaryjc9wuprokl8i';

  /**
   * Content type header value for a multipart HTTP request.
   * @type {string}
   * @const
   * @private
   */
  CloudPrintInterface.MULTIPART_CONTENT_TYPE_ =
      'multipart/form-data; boundary=' +
      CloudPrintInterface.MULTIPART_BOUNDARY_;

  /**
   * Regex that extracts Chrome's version from the user-agent string.
   * @type {!RegExp}
   * @const
   * @private
   */
  CloudPrintInterface.VERSION_REGEXP_ = /.*Chrome\/([\d\.]+)/i;

  /**
   * Enumeration of JSON response fields from Google Cloud Print API.
   * @enum {string}
   * @private
   */
  CloudPrintInterface.JsonFields_ = {
    PRINTER: 'printer'
  };

  /**
   * Could Print origins used to search printers.
   * @type {!Array.<!print_preview.Destination.Origin>}
   * @const
   * @private
   */
  CloudPrintInterface.CLOUD_ORIGINS_ = [
      print_preview.Destination.Origin.COOKIES,
      print_preview.Destination.Origin.DEVICE
      // TODO(vitalybuka): Enable when implemented.
      // ready print_preview.Destination.Origin.PROFILE
  ];

  CloudPrintInterface.prototype = {
    __proto__: cr.EventTarget.prototype,

    /** @return {string} Base URL of the Google Cloud Print service. */
    get baseUrl() {
      return this.baseUrl_;
    },

    /**
     * @return {boolean} Whether a search for cloud destinations is in progress.
     */
    get isCloudDestinationSearchInProgress() {
      return this.outstandingCloudSearchRequests_.length > 0;
    },

    /**
     * Sends Google Cloud Print search API request.
     * @param {string=} opt_account Account the search is sent for. When
     *      omitted, the search is done on behalf of the primary user.
     * @param {print_preview.Destination.Origin=} opt_origin When specified,
     *     searches destinations for {@code opt_origin} only, otherwise starts
     *     searches for all origins.
     */
    search: function(opt_account, opt_origin) {
      var account = opt_account || '';
      var origins =
          opt_origin && [opt_origin] || CloudPrintInterface.CLOUD_ORIGINS_;
      if (this.isInAppKioskMode_) {
        origins = origins.filter(function(origin) {
          return origin != print_preview.Destination.Origin.COOKIES;
        });
      }
      this.abortSearchRequests_(origins);
      this.search_(true, account, origins);
      this.search_(false, account, origins);
    },

    /**
     * Sends Google Cloud Print search API requests.
     * @param {boolean} isRecent Whether to search for only recently used
     *     printers.
     * @param {string} account Account the search is sent for. It matters for
     *     COOKIES origin only, and can be empty (sent on behalf of the primary
     *     user in this case).
     * @param {!Array.<!print_preview.Destination.Origin>} origins Origins to
     *     search printers for.
     * @private
     */
    search_: function(isRecent, account, origins) {
      var params = [
        new HttpParam('connection_status', 'ALL'),
        new HttpParam('client', 'chrome'),
        new HttpParam('use_cdd', 'true')
      ];
      if (isRecent) {
        params.push(new HttpParam('q', '^recent'));
      }
      origins.forEach(function(origin) {
        var cpRequest = this.buildRequest_(
            'GET',
            'search',
            params,
            origin,
            account,
            this.onSearchDone_.bind(this, isRecent));
        this.outstandingCloudSearchRequests_.push(cpRequest);
        this.sendOrQueueRequest_(cpRequest);
      }, this);
    },

    /**
     * Sends Google Cloud Print printer sharing invitations API requests.
     * @param {string} account Account the request is sent for.
     */
    invites: function(account) {
      var params = [
        new HttpParam('client', 'chrome'),
      ];
      this.sendOrQueueRequest_(this.buildRequest_(
          'GET',
          'invites',
          params,
          print_preview.Destination.Origin.COOKIES,
          account,
          this.onInvitesDone_.bind(this)));
    },

    /**
     * Accepts or rejects printer sharing invitation.
     * @param {!print_preview.Invitation} invitation Invitation to process.
     * @param {boolean} accept Whether to accept this invitation.
     */
    processInvite: function(invitation, accept) {
      var params = [
        new HttpParam('printerid', invitation.destination.id),
        new HttpParam('email', invitation.scopeId),
        new HttpParam('accept', accept),
        new HttpParam('use_cdd', true),
      ];
      this.sendOrQueueRequest_(this.buildRequest_(
          'POST',
          'processinvite',
          params,
          invitation.destination.origin,
          invitation.destination.account,
          this.onProcessInviteDone_.bind(this, invitation, accept)));
    },

    /**
     * Sends a Google Cloud Print submit API request.
     * @param {!print_preview.Destination} destination Cloud destination to
     *     print to.
     * @param {!print_preview.PrintTicketStore} printTicketStore Contains the
     *     print ticket to print.
     * @param {!print_preview.DocumentInfo} documentInfo Document data model.
     * @param {string} data Base64 encoded data of the document.
     */
    submit: function(destination, printTicketStore, documentInfo, data) {
      var result =
          CloudPrintInterface.VERSION_REGEXP_.exec(navigator.userAgent);
      var chromeVersion = 'unknown';
      if (result && result.length == 2) {
        chromeVersion = result[1];
      }
      var params = [
        new HttpParam('printerid', destination.id),
        new HttpParam('contentType', 'dataUrl'),
        new HttpParam('title', documentInfo.title),
        new HttpParam('ticket',
                      printTicketStore.createPrintTicket(destination)),
        new HttpParam('content', 'data:application/pdf;base64,' + data),
        new HttpParam('tag',
                      '__google__chrome_version=' + chromeVersion),
        new HttpParam('tag', '__google__os=' + navigator.platform)
      ];
      var cpRequest = this.buildRequest_(
          'POST',
          'submit',
          params,
          destination.origin,
          destination.account,
          this.onSubmitDone_.bind(this));
      this.sendOrQueueRequest_(cpRequest);
    },

    /**
     * Sends a Google Cloud Print printer API request.
     * @param {string} printerId ID of the printer to lookup.
     * @param {!print_preview.Destination.Origin} origin Origin of the printer.
     * @param {string=} account Account this printer is registered for. When
     *     provided for COOKIES {@code origin}, and users sessions are still not
     *     known, will be checked against the response (both success and failure
     *     to get printer) and, if the active user account is not the one
     *     requested, {@code account} is activated and printer request reissued.
     */
    printer: function(printerId, origin, account) {
      var params = [
        new HttpParam('printerid', printerId),
        new HttpParam('use_cdd', 'true'),
        new HttpParam('printer_connection_status', 'true')
      ];
      this.sendOrQueueRequest_(this.buildRequest_(
          'GET',
          'printer',
          params,
          origin,
          account,
          this.onPrinterDone_.bind(this, printerId)));
    },

    /**
     * Sends a Google Cloud Print update API request to accept (or reject) the
     * terms-of-service of the given printer.
     * @param {!print_preview.Destination} destination Destination to accept ToS
     *     for.
     * @param {boolean} isAccepted Whether the user accepted ToS or not.
     */
    updatePrinterTosAcceptance: function(destination, isAccepted) {
      var params = [
        new HttpParam('printerid', destination.id),
        new HttpParam('is_tos_accepted', isAccepted)
      ];
      this.sendOrQueueRequest_(this.buildRequest_(
          'POST',
          'update',
          params,
          destination.origin,
          destination.account,
          this.onUpdatePrinterTosAcceptanceDone_.bind(this)));
    },

    /**
     * Adds event listeners to relevant events.
     * @private
     */
    addEventListeners_: function() {
      this.tracker_.add(
          this.nativeLayer_,
          print_preview.NativeLayer.EventType.ACCESS_TOKEN_READY,
          this.onAccessTokenReady_.bind(this));
    },

    /**
     * Builds request to the Google Cloud Print API.
     * @param {string} method HTTP method of the request.
     * @param {string} action Google Cloud Print action to perform.
     * @param {Array.<!HttpParam>} params HTTP parameters to include in the
     *     request.
     * @param {!print_preview.Destination.Origin} origin Origin for destination.
     * @param {?string} account Account the request is sent for. Can be
     *     {@code null} or empty string if the request is not cookie bound or
     *     is sent on behalf of the primary user.
     * @param {function(number, Object, !print_preview.Destination.Origin)}
     *     callback Callback to invoke when request completes.
     * @return {!CloudPrintRequest} Partially prepared request.
     * @private
     */
    buildRequest_: function(method, action, params, origin, account, callback) {
      var url = this.baseUrl_ + '/' + action + '?xsrf=';
      if (origin == print_preview.Destination.Origin.COOKIES) {
        var xsrfToken = this.xsrfTokens_[account];
        if (!xsrfToken) {
          // TODO(rltoscano): Should throw an error if not a read-only action or
          // issue an xsrf token request.
        } else {
          url = url + xsrfToken;
        }
        if (account) {
          var index = this.userSessionIndex_[account] || 0;
          if (index > 0) {
            url += '&user=' + index;
          }
        }
      }
      var body = null;
      if (params) {
        if (method == 'GET') {
          url = params.reduce(function(partialUrl, param) {
            return partialUrl + '&' + param.name + '=' +
                encodeURIComponent(param.value);
          }, url);
        } else if (method == 'POST') {
          body = params.reduce(function(partialBody, param) {
            return partialBody + 'Content-Disposition: form-data; name=\"' +
                param.name + '\"\r\n\r\n' + param.value + '\r\n--' +
                CloudPrintInterface.MULTIPART_BOUNDARY_ + '\r\n';
          }, '--' + CloudPrintInterface.MULTIPART_BOUNDARY_ + '\r\n');
        }
      }

      var headers = {};
      headers['X-CloudPrint-Proxy'] = 'ChromePrintPreview';
      if (method == 'GET') {
        headers['Content-Type'] = CloudPrintInterface.URL_ENCODED_CONTENT_TYPE_;
      } else if (method == 'POST') {
        headers['Content-Type'] = CloudPrintInterface.MULTIPART_CONTENT_TYPE_;
      }

      var xhr = new XMLHttpRequest();
      xhr.open(method, url, true);
      xhr.withCredentials =
          (origin == print_preview.Destination.Origin.COOKIES);
      for (var header in headers) {
        xhr.setRequestHeader(header, headers[header]);
      }

      return new CloudPrintRequest(xhr, body, origin, account, callback);
    },

    /**
     * Sends a request to the Google Cloud Print API or queues if it needs to
     *     wait OAuth2 access token.
     * @param {!CloudPrintRequest} request Request to send or queue.
     * @private
     */
    sendOrQueueRequest_: function(request) {
      if (request.origin == print_preview.Destination.Origin.COOKIES) {
        return this.sendRequest_(request);
      } else {
        this.requestQueue_.push(request);
        this.nativeLayer_.startGetAccessToken(request.origin);
      }
    },

    /**
     * Sends a request to the Google Cloud Print API.
     * @param {!CloudPrintRequest} request Request to send.
     * @private
     */
    sendRequest_: function(request) {
      request.xhr.onreadystatechange =
          this.onReadyStateChange_.bind(this, request);
      request.xhr.send(request.body);
    },

    /**
     * Creates a Google Cloud Print interface error that is ready to dispatch.
     * @param {!CloudPrintInterface.EventType} type Type of the error.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @return {!Event} Google Cloud Print interface error event.
     * @private
     */
    createErrorEvent_: function(type, request) {
      var errorEvent = new Event(type);
      errorEvent.status = request.xhr.status;
      if (request.xhr.status == 200) {
        errorEvent.errorCode = request.result['errorCode'];
        errorEvent.message = request.result['message'];
      } else {
        errorEvent.errorCode = 0;
        errorEvent.message = '';
      }
      errorEvent.origin = request.origin;
      return errorEvent;
    },

    /**
     * Updates user info and session index from the {@code request} response.
     * @param {!CloudPrintRequest} request Request to extract user info from.
     * @private
     */
    setUsers_: function(request) {
      if (request.origin == print_preview.Destination.Origin.COOKIES) {
        var users = request.result['request']['users'] || [];
        this.userSessionIndex_ = {};
        for (var i = 0; i < users.length; i++) {
          this.userSessionIndex_[users[i]] = i;
        }
        this.userInfo_.setUsers(request.result['request']['user'], users);
      }
    },

    /**
     * Terminates search requests for requested {@code origins}.
     * @param {!Array.<print_preview.Destination.Origin>} origins Origins
     *     to terminate search requests for.
     * @private
     */
    abortSearchRequests_: function(origins) {
      this.outstandingCloudSearchRequests_ =
          this.outstandingCloudSearchRequests_.filter(function(request) {
            if (origins.indexOf(request.origin) >= 0) {
              request.xhr.abort();
              return false;
            }
            return true;
          });
    },

    /**
     * Called when a native layer receives access token.
     * @param {Event} event Contains the authentication type and access token.
     * @private
     */
    onAccessTokenReady_: function(event) {
      // TODO(vitalybuka): remove when other Origins implemented.
      assert(event.authType == print_preview.Destination.Origin.DEVICE);
      this.requestQueue_ = this.requestQueue_.filter(function(request) {
        assert(request.origin == print_preview.Destination.Origin.DEVICE);
        if (request.origin != event.authType) {
          return true;
        }
        if (event.accessToken) {
          request.xhr.setRequestHeader('Authorization',
                                       'Bearer ' + event.accessToken);
          this.sendRequest_(request);
        } else {  // No valid token.
          // Without abort status does not exist.
          request.xhr.abort();
          request.callback(request);
        }
        return false;
      }, this);
    },

    /**
     * Called when the ready-state of a XML http request changes.
     * Calls the successCallback with the result or dispatches an ERROR event.
     * @param {!CloudPrintRequest} request Request that was changed.
     * @private
     */
    onReadyStateChange_: function(request) {
      if (request.xhr.readyState == 4) {
        if (request.xhr.status == 200) {
          request.result = JSON.parse(request.xhr.responseText);
          if (request.origin == print_preview.Destination.Origin.COOKIES &&
              request.result['success']) {
            this.xsrfTokens_[request.result['request']['user']] =
                request.result['xsrf_token'];
          }
        }
        request.status = request.xhr.status;
        request.callback(request);
      }
    },

    /**
     * Called when the search request completes.
     * @param {boolean} isRecent Whether the search request was for recent
     *     destinations.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onSearchDone_: function(isRecent, request) {
      var lastRequestForThisOrigin = true;
      this.outstandingCloudSearchRequests_ =
          this.outstandingCloudSearchRequests_.filter(function(item) {
            if (item != request && item.origin == request.origin) {
              lastRequestForThisOrigin = false;
            }
            return item != request;
          });
      var activeUser = '';
      if (request.origin == print_preview.Destination.Origin.COOKIES) {
        activeUser =
            request.result &&
            request.result['request'] &&
            request.result['request']['user'];
      }
      var event = null;
      if (request.xhr.status == 200 && request.result['success']) {
        // Extract printers.
        var printerListJson = request.result['printers'] || [];
        var printerList = [];
        printerListJson.forEach(function(printerJson) {
          try {
            printerList.push(cloudprint.CloudDestinationParser.parse(
                printerJson, request.origin, activeUser));
          } catch (err) {
            console.error('Unable to parse cloud print destination: ' + err);
          }
        });
        // Extract and store users.
        this.setUsers_(request);
        // Dispatch SEARCH_DONE event.
        event = new Event(CloudPrintInterface.EventType.SEARCH_DONE);
        event.origin = request.origin;
        event.printers = printerList;
        event.isRecent = isRecent;
      } else {
        event = this.createErrorEvent_(
            CloudPrintInterface.EventType.SEARCH_FAILED,
            request);
      }
      event.user = activeUser;
      event.searchDone = lastRequestForThisOrigin;
      this.dispatchEvent(event);
    },

    /**
     * Called when invitations search request completes.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onInvitesDone_: function(request) {
      var event = null;
      var activeUser =
          (request.result &&
           request.result['request'] &&
           request.result['request']['user']) || '';
      if (request.xhr.status == 200 && request.result['success']) {
        // Extract invitations.
        var invitationListJson = request.result['invites'] || [];
        var invitationList = [];
        invitationListJson.forEach(function(invitationJson) {
          try {
            invitationList.push(cloudprint.InvitationParser.parse(
                invitationJson, activeUser));
          } catch (e) {
            console.error('Unable to parse invitation: ' + e);
          }
        });
        // Dispatch INVITES_DONE event.
        event = new Event(CloudPrintInterface.EventType.INVITES_DONE);
        event.invitations = invitationList;
      } else {
        event = this.createErrorEvent_(
            CloudPrintInterface.EventType.INVITES_FAILED, request);
      }
      event.user = activeUser;
      this.dispatchEvent(event);
    },

    /**
     * Called when invitation processing request completes.
     * @param {!print_preview.Invitation} invitation Processed invitation.
     * @param {boolean} accept Whether this invitation was accepted or rejected.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onProcessInviteDone_: function(invitation, accept, request) {
      var event = null;
      var activeUser =
          (request.result &&
           request.result['request'] &&
           request.result['request']['user']) || '';
      if (request.xhr.status == 200 && request.result['success']) {
        event = new Event(CloudPrintInterface.EventType.PROCESS_INVITE_DONE);
        if (accept) {
          try {
            event.printer = cloudprint.CloudDestinationParser.parse(
                request.result['printer'], request.origin, activeUser);
          } catch (e) {
            console.error('Failed to parse cloud print destination: ' + e);
          }
        }
      } else {
        event = this.createErrorEvent_(
            CloudPrintInterface.EventType.PROCESS_INVITE_FAILED, request);
      }
      event.invitation = invitation;
      event.accept = accept;
      event.user = activeUser;
      this.dispatchEvent(event);
    },

    /**
     * Called when the submit request completes.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onSubmitDone_: function(request) {
      if (request.xhr.status == 200 && request.result['success']) {
        var submitDoneEvent = new Event(
            CloudPrintInterface.EventType.SUBMIT_DONE);
        submitDoneEvent.jobId = request.result['job']['id'];
        this.dispatchEvent(submitDoneEvent);
      } else {
        var errorEvent = this.createErrorEvent_(
            CloudPrintInterface.EventType.SUBMIT_FAILED, request);
        this.dispatchEvent(errorEvent);
      }
    },

    /**
     * Called when the printer request completes.
     * @param {string} destinationId ID of the destination that was looked up.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onPrinterDone_: function(destinationId, request) {
      // Special handling of the first printer request. It does not matter at
      // this point, whether printer was found or not.
      if (request.origin == print_preview.Destination.Origin.COOKIES &&
          request.result &&
          request.account &&
          request.result['request']['user'] &&
          request.result['request']['users'] &&
          request.account != request.result['request']['user']) {
        this.setUsers_(request);
        // In case the user account is known, but not the primary one,
        // activate it.
        if (this.userSessionIndex_[request.account] > 0) {
          this.userInfo_.activeUser = request.account;
          // Repeat the request for the newly activated account.
          this.printer(
              request.result['request']['params']['printerid'],
              request.origin,
              request.account);
          // Stop processing this request, wait for the new response.
          return;
        }
      }
      // Process response.
      if (request.xhr.status == 200 && request.result['success']) {
        var activeUser = '';
        if (request.origin == print_preview.Destination.Origin.COOKIES) {
          activeUser = request.result['request']['user'];
        }
        var printerJson = request.result['printers'][0];
        var printer;
        try {
          printer = cloudprint.CloudDestinationParser.parse(
              printerJson, request.origin, activeUser);
        } catch (err) {
          console.error('Failed to parse cloud print destination: ' +
              JSON.stringify(printerJson));
          return;
        }
        var printerDoneEvent =
            new Event(CloudPrintInterface.EventType.PRINTER_DONE);
        printerDoneEvent.printer = printer;
        this.dispatchEvent(printerDoneEvent);
      } else {
        var errorEvent = this.createErrorEvent_(
            CloudPrintInterface.EventType.PRINTER_FAILED, request);
        errorEvent.destinationId = destinationId;
        errorEvent.destinationOrigin = request.origin;
        this.dispatchEvent(errorEvent, request.origin);
      }
    },

    /**
     * Called when the update printer TOS acceptance request completes.
     * @param {!CloudPrintRequest} request Request that has been completed.
     * @private
     */
    onUpdatePrinterTosAcceptanceDone_: function(request) {
      if (request.xhr.status == 200 && request.result['success']) {
        // Do nothing.
      } else {
        var errorEvent = this.createErrorEvent_(
            CloudPrintInterface.EventType.SUBMIT_FAILED, request);
        this.dispatchEvent(errorEvent);
      }
    }
  };

  /**
   * Data structure that holds data for Cloud Print requests.
   * @param {!XMLHttpRequest} xhr Partially prepared http request.
   * @param {string} body Data to send with POST requests.
   * @param {!print_preview.Destination.Origin} origin Origin for destination.
   * @param {?string} account Account the request is sent for. Can be
   *     {@code null} or empty string if the request is not cookie bound or
   *     is sent on behalf of the primary user.
   * @param {function(!CloudPrintRequest)} callback Callback to invoke when
   *     request completes.
   * @constructor
   */
  function CloudPrintRequest(xhr, body, origin, account, callback) {
    /**
     * Partially prepared http request.
     * @type {!XMLHttpRequest}
     */
    this.xhr = xhr;

    /**
     * Data to send with POST requests.
     * @type {string}
     */
    this.body = body;

    /**
     * Origin for destination.
     * @type {!print_preview.Destination.Origin}
     */
    this.origin = origin;

    /**
     * User account this request is expected to be executed for.
     * @type {?string}
     */
    this.account = account;

    /**
     * Callback to invoke when request completes.
     * @type {function(!CloudPrintRequest)}
     */
    this.callback = callback;

    /**
     * Result for requests.
     * @type {Object} JSON response.
     */
    this.result = null;
  };

  /**
   * Data structure that represents an HTTP parameter.
   * @param {string} name Name of the parameter.
   * @param {string} value Value of the parameter.
   * @constructor
   */
  function HttpParam(name, value) {
    /**
     * Name of the parameter.
     * @type {string}
     */
    this.name = name;

    /**
     * Name of the value.
     * @type {string}
     */
    this.value = value;
  };

  // Export
  return {
    CloudPrintInterface: CloudPrintInterface
  };
});