RestWrite.js

// A RestWrite encapsulates everything we need to run an operation
// that writes to the database.
// This could be either a "create" or an "update".

var SchemaController = require('./Controllers/SchemaController');
var deepcopy = require('deepcopy');

const Auth = require('./Auth');
var cryptoUtils = require('./cryptoUtils');
var passwordCrypto = require('./password');
var Parse = require('parse/node');
var triggers = require('./triggers');
var ClientSDK = require('./ClientSDK');
import RestQuery from './RestQuery';
import _ from 'lodash';
import logger from './logger';

// query and data are both provided in REST API format. So data
// types are encoded by plain old objects.
// If query is null, this is a "create" and the data in data should be
// created.
// Otherwise this is an "update" - the object matching the query
// should get updated with data.
// RestWrite will handle objectId, createdAt, and updatedAt for
// everything. It also knows to use triggers and special modifications
// for the _User class.
function RestWrite(
  config,
  auth,
  className,
  query,
  data,
  originalData,
  clientSDK
) {
  if (auth.isReadOnly) {
    throw new Parse.Error(
      Parse.Error.OPERATION_FORBIDDEN,
      'Cannot perform a write operation when using readOnlyMasterKey'
    );
  }
  this.config = config;
  this.auth = auth;
  this.className = className;
  this.clientSDK = clientSDK;
  this.storage = {};
  this.runOptions = {};
  this.context = {};
  if (!query && data.objectId) {
    throw new Parse.Error(
      Parse.Error.INVALID_KEY_NAME,
      'objectId is an invalid field name.'
    );
  }
  if (!query && data.id) {
    throw new Parse.Error(
      Parse.Error.INVALID_KEY_NAME,
      'id is an invalid field name.'
    );
  }

  // When the operation is complete, this.response may have several
  // fields.
  // response: the actual data to be returned
  // status: the http status code. if not present, treated like a 200
  // location: the location header. if not present, no location header
  this.response = null;

  // Processing this operation may mutate our data, so we operate on a
  // copy
  this.query = deepcopy(query);
  this.data = deepcopy(data);
  // We never change originalData, so we do not need a deep copy
  this.originalData = originalData;

  // The timestamp we'll use for this whole operation
  this.updatedAt = Parse._encode(new Date()).iso;

  // Shared SchemaController to be reused to reduce the number of loadSchema() calls per request
  // Once set the schemaData should be immutable
  this.validSchemaController = null;
}

// A convenient method to perform all the steps of processing the
// write, in order.
// Returns a promise for a {response, status, location} object.
// status and location are optional.
RestWrite.prototype.execute = function() {
  return Promise.resolve()
    .then(() => {
      return this.getUserAndRoleACL();
    })
    .then(() => {
      return this.validateClientClassCreation();
    })
    .then(() => {
      return this.handleInstallation();
    })
    .then(() => {
      return this.handleSession();
    })
    .then(() => {
      return this.validateAuthData();
    })
    .then(() => {
      return this.runBeforeSaveTrigger();
    })
    .then(() => {
      return this.deleteEmailResetTokenIfNeeded();
    })
    .then(() => {
      return this.validateSchema();
    })
    .then(schemaController => {
      this.validSchemaController = schemaController;
      return this.setRequiredFieldsIfNeeded();
    })
    .then(() => {
      return this.transformUser();
    })
    .then(() => {
      return this.expandFilesForExistingObjects();
    })
    .then(() => {
      return this.destroyDuplicatedSessions();
    })
    .then(() => {
      return this.runDatabaseOperation();
    })
    .then(() => {
      return this.createSessionTokenIfNeeded();
    })
    .then(() => {
      return this.handleFollowup();
    })
    .then(() => {
      return this.runAfterSaveTrigger();
    })
    .then(() => {
      return this.cleanUserAuthData();
    })
    .then(() => {
      return this.response;
    });
};

// Uses the Auth object to get the list of roles, adds the user id
RestWrite.prototype.getUserAndRoleACL = function() {
  if (this.auth.isMaster) {
    return Promise.resolve();
  }

  this.runOptions.acl = ['*'];

  if (this.auth.user) {
    return this.auth.getUserRoles().then(roles => {
      this.runOptions.acl = this.runOptions.acl.concat(roles, [
        this.auth.user.id,
      ]);
      return;
    });
  } else {
    return Promise.resolve();
  }
};

// Validates this operation against the allowClientClassCreation config.
RestWrite.prototype.validateClientClassCreation = function() {
  if (
    this.config.allowClientClassCreation === false &&
    !this.auth.isMaster &&
    SchemaController.systemClasses.indexOf(this.className) === -1
  ) {
    return this.config.database
      .loadSchema()
      .then(schemaController => schemaController.hasClass(this.className))
      .then(hasClass => {
        if (hasClass !== true) {
          throw new Parse.Error(
            Parse.Error.OPERATION_FORBIDDEN,
            'This user is not allowed to access ' +
              'non-existent class: ' +
              this.className
          );
        }
      });
  } else {
    return Promise.resolve();
  }
};

// Validates this operation against the schema.
RestWrite.prototype.validateSchema = function() {
  return this.config.database.validateObject(
    this.className,
    this.data,
    this.query,
    this.runOptions
  );
};

// Runs any beforeSave triggers against this operation.
// Any change leads to our data being mutated.
RestWrite.prototype.runBeforeSaveTrigger = function() {
  if (this.response) {
    return;
  }

  // Avoid doing any setup for triggers if there is no 'beforeSave' trigger for this class.
  if (
    !triggers.triggerExists(
      this.className,
      triggers.Types.beforeSave,
      this.config.applicationId
    )
  ) {
    return Promise.resolve();
  }

  // Cloud code gets a bit of extra data for its objects
  var extraData = { className: this.className };
  if (this.query && this.query.objectId) {
    extraData.objectId = this.query.objectId;
  }

  let originalObject = null;
  const updatedObject = this.buildUpdatedObject(extraData);
  if (this.query && this.query.objectId) {
    // This is an update for existing object.
    originalObject = triggers.inflate(extraData, this.originalData);
  }

  return Promise.resolve()
    .then(() => {
      // Before calling the trigger, validate the permissions for the save operation
      let databasePromise = null;
      if (this.query) {
        // Validate for updating
        databasePromise = this.config.database.update(
          this.className,
          this.query,
          this.data,
          this.runOptions,
          false,
          true
        );
      } else {
        // Validate for creating
        databasePromise = this.config.database.create(
          this.className,
          this.data,
          this.runOptions,
          true
        );
      }
      // In the case that there is no permission for the operation, it throws an error
      return databasePromise.then(result => {
        if (!result || result.length <= 0) {
          throw new Parse.Error(
            Parse.Error.OBJECT_NOT_FOUND,
            'Object not found.'
          );
        }
      });
    })
    .then(() => {
      return triggers.maybeRunTrigger(
        triggers.Types.beforeSave,
        this.auth,
        updatedObject,
        originalObject,
        this.config,
        this.context
      );
    })
    .then(response => {
      if (response && response.object) {
        this.storage.fieldsChangedByTrigger = _.reduce(
          response.object,
          (result, value, key) => {
            if (!_.isEqual(this.data[key], value)) {
              result.push(key);
            }
            return result;
          },
          []
        );
        this.data = response.object;
        // We should delete the objectId for an update write
        if (this.query && this.query.objectId) {
          delete this.data.objectId;
        }
      }
    });
};

RestWrite.prototype.runBeforeLoginTrigger = async function(userData) {
  // Avoid doing any setup for triggers if there is no 'beforeLogin' trigger
  if (
    !triggers.triggerExists(
      this.className,
      triggers.Types.beforeLogin,
      this.config.applicationId
    )
  ) {
    return;
  }

  // Cloud code gets a bit of extra data for its objects
  const extraData = { className: this.className };
  const user = triggers.inflate(extraData, userData);

  // no need to return a response
  await triggers.maybeRunTrigger(
    triggers.Types.beforeLogin,
    this.auth,
    user,
    null,
    this.config,
    this.context
  );
};

RestWrite.prototype.setRequiredFieldsIfNeeded = function() {
  if (this.data) {
    return this.validSchemaController.getAllClasses().then(allClasses => {
      const schema = allClasses.find(
        oneClass => oneClass.className === this.className
      );
      const setRequiredFieldIfNeeded = (fieldName, setDefault) => {
        if (
          this.data[fieldName] === undefined ||
          this.data[fieldName] === null ||
          this.data[fieldName] === '' ||
          (typeof this.data[fieldName] === 'object' &&
            this.data[fieldName].__op === 'Delete')
        ) {
          if (
            setDefault &&
            schema.fields[fieldName] &&
            schema.fields[fieldName].defaultValue !== null &&
            schema.fields[fieldName].defaultValue !== undefined &&
            (this.data[fieldName] === undefined ||
              (typeof this.data[fieldName] === 'object' &&
                this.data[fieldName].__op === 'Delete'))
          ) {
            this.data[fieldName] = schema.fields[fieldName].defaultValue;
            this.storage.fieldsChangedByTrigger =
              this.storage.fieldsChangedByTrigger || [];
            if (this.storage.fieldsChangedByTrigger.indexOf(fieldName) < 0) {
              this.storage.fieldsChangedByTrigger.push(fieldName);
            }
          } else if (
            schema.fields[fieldName] &&
            schema.fields[fieldName].required === true
          ) {
            throw new Parse.Error(
              Parse.Error.VALIDATION_ERROR,
              `${fieldName} is required`
            );
          }
        }
      };

      // Add default fields
      this.data.updatedAt = this.updatedAt;
      if (!this.query) {
        this.data.createdAt = this.updatedAt;

        // Only assign new objectId if we are creating new object
        if (!this.data.objectId) {
          this.data.objectId = cryptoUtils.newObjectId(
            this.config.objectIdSize
          );
        }
        if (schema) {
          Object.keys(schema.fields).forEach(fieldName => {
            setRequiredFieldIfNeeded(fieldName, true);
          });
        }
      } else if (schema) {
        Object.keys(this.data).forEach(fieldName => {
          setRequiredFieldIfNeeded(fieldName, false);
        });
      }
    });
  }
  return Promise.resolve();
};

// Transforms auth data for a user object.
// Does nothing if this isn't a user object.
// Returns a promise for when we're done if it can't finish this tick.
RestWrite.prototype.validateAuthData = function() {
  if (this.className !== '_User') {
    return;
  }

  if (!this.query && !this.data.authData) {
    if (
      typeof this.data.username !== 'string' ||
      _.isEmpty(this.data.username)
    ) {
      throw new Parse.Error(
        Parse.Error.USERNAME_MISSING,
        'bad or missing username'
      );
    }
    if (
      typeof this.data.password !== 'string' ||
      _.isEmpty(this.data.password)
    ) {
      throw new Parse.Error(
        Parse.Error.PASSWORD_MISSING,
        'password is required'
      );
    }
  }

  if (!this.data.authData || !Object.keys(this.data.authData).length) {
    return;
  }

  var authData = this.data.authData;
  var providers = Object.keys(authData);
  if (providers.length > 0) {
    const canHandleAuthData = providers.reduce((canHandle, provider) => {
      var providerAuthData = authData[provider];
      var hasToken = providerAuthData && providerAuthData.id;
      return canHandle && (hasToken || providerAuthData == null);
    }, true);
    if (canHandleAuthData) {
      return this.handleAuthData(authData);
    }
  }
  throw new Parse.Error(
    Parse.Error.UNSUPPORTED_SERVICE,
    'This authentication method is unsupported.'
  );
};

RestWrite.prototype.handleAuthDataValidation = function(authData) {
  const validations = Object.keys(authData).map(provider => {
    if (authData[provider] === null) {
      return Promise.resolve();
    }
    const validateAuthData = this.config.authDataManager.getValidatorForProvider(
      provider
    );
    if (!validateAuthData) {
      throw new Parse.Error(
        Parse.Error.UNSUPPORTED_SERVICE,
        'This authentication method is unsupported.'
      );
    }
    return validateAuthData(authData[provider]);
  });
  return Promise.all(validations);
};

RestWrite.prototype.findUsersWithAuthData = function(authData) {
  const providers = Object.keys(authData);
  const query = providers
    .reduce((memo, provider) => {
      if (!authData[provider]) {
        return memo;
      }
      const queryKey = `authData.${provider}.id`;
      const query = {};
      query[queryKey] = authData[provider].id;
      memo.push(query);
      return memo;
    }, [])
    .filter(q => {
      return typeof q !== 'undefined';
    });

  let findPromise = Promise.resolve([]);
  if (query.length > 0) {
    findPromise = this.config.database.find(this.className, { $or: query }, {});
  }

  return findPromise;
};

RestWrite.prototype.filteredObjectsByACL = function(objects) {
  if (this.auth.isMaster) {
    return objects;
  }
  return objects.filter(object => {
    if (!object.ACL) {
      return true; // legacy users that have no ACL field on them
    }
    // Regular users that have been locked out.
    return object.ACL && Object.keys(object.ACL).length > 0;
  });
};

RestWrite.prototype.handleAuthData = function(authData) {
  let results;
  return this.findUsersWithAuthData(authData).then(async r => {
    results = this.filteredObjectsByACL(r);

    if (results.length == 1) {
      this.storage['authProvider'] = Object.keys(authData).join(',');

      const userResult = results[0];
      const mutatedAuthData = {};
      Object.keys(authData).forEach(provider => {
        const providerData = authData[provider];
        const userAuthData = userResult.authData[provider];
        if (!_.isEqual(providerData, userAuthData)) {
          mutatedAuthData[provider] = providerData;
        }
      });
      const hasMutatedAuthData = Object.keys(mutatedAuthData).length !== 0;
      let userId;
      if (this.query && this.query.objectId) {
        userId = this.query.objectId;
      } else if (this.auth && this.auth.user && this.auth.user.id) {
        userId = this.auth.user.id;
      }
      if (!userId || userId === userResult.objectId) {
        // no user making the call
        // OR the user making the call is the right one
        // Login with auth data
        delete results[0].password;

        // need to set the objectId first otherwise location has trailing undefined
        this.data.objectId = userResult.objectId;

        if (!this.query || !this.query.objectId) {
          // this a login call, no userId passed
          this.response = {
            response: userResult,
            location: this.location(),
          };
          // Run beforeLogin hook before storing any updates
          // to authData on the db; changes to userResult
          // will be ignored.
          await this.runBeforeLoginTrigger(deepcopy(userResult));
        }

        // If we didn't change the auth data, just keep going
        if (!hasMutatedAuthData) {
          return;
        }
        // We have authData that is updated on login
        // that can happen when token are refreshed,
        // We should update the token and let the user in
        // We should only check the mutated keys
        return this.handleAuthDataValidation(mutatedAuthData).then(async () => {
          // IF we have a response, we'll skip the database operation / beforeSave / afterSave etc...
          // we need to set it up there.
          // We are supposed to have a response only on LOGIN with authData, so we skip those
          // If we're not logging in, but just updating the current user, we can safely skip that part
          if (this.response) {
            // Assign the new authData in the response
            Object.keys(mutatedAuthData).forEach(provider => {
              this.response.response.authData[provider] =
                mutatedAuthData[provider];
            });

            // Run the DB update directly, as 'master'
            // Just update the authData part
            // Then we're good for the user, early exit of sorts
            return this.config.database.update(
              this.className,
              { objectId: this.data.objectId },
              { authData: mutatedAuthData },
              {}
            );
          }
        });
      } else if (userId) {
        // Trying to update auth data but users
        // are different
        if (userResult.objectId !== userId) {
          throw new Parse.Error(
            Parse.Error.ACCOUNT_ALREADY_LINKED,
            'this auth is already used'
          );
        }
        // No auth data was mutated, just keep going
        if (!hasMutatedAuthData) {
          return;
        }
      }
    }
    return this.handleAuthDataValidation(authData).then(() => {
      if (results.length > 1) {
        // More than 1 user with the passed id's
        throw new Parse.Error(
          Parse.Error.ACCOUNT_ALREADY_LINKED,
          'this auth is already used'
        );
      }
    });
  });
};

// The non-third-party parts of User transformation
RestWrite.prototype.transformUser = function() {
  var promise = Promise.resolve();

  if (this.className !== '_User') {
    return promise;
  }

  if (!this.auth.isMaster && 'emailVerified' in this.data) {
    const error = `Clients aren't allowed to manually update email verification.`;
    throw new Parse.Error(Parse.Error.OPERATION_FORBIDDEN, error);
  }

  // Do not cleanup session if objectId is not set
  if (this.query && this.objectId()) {
    // If we're updating a _User object, we need to clear out the cache for that user. Find all their
    // session tokens, and remove them from the cache.
    promise = new RestQuery(this.config, Auth.master(this.config), '_Session', {
      user: {
        __type: 'Pointer',
        className: '_User',
        objectId: this.objectId(),
      },
    })
      .execute()
      .then(results => {
        results.results.forEach(session =>
          this.config.cacheController.user.del(session.sessionToken)
        );
      });
  }

  return promise
    .then(() => {
      // Transform the password
      if (this.data.password === undefined) {
        // ignore only if undefined. should proceed if empty ('')
        return Promise.resolve();
      }

      if (this.query) {
        this.storage['clearSessions'] = true;
        // Generate a new session only if the user requested
        if (!this.auth.isMaster) {
          this.storage['generateNewSession'] = true;
        }
      }

      return this._validatePasswordPolicy().then(() => {
        return passwordCrypto.hash(this.data.password).then(hashedPassword => {
          this.data._hashed_password = hashedPassword;
          delete this.data.password;
        });
      });
    })
    .then(() => {
      return this._validateUserName();
    })
    .then(() => {
      return this._validateEmail();
    });
};

RestWrite.prototype._validateUserName = function() {
  // Check for username uniqueness
  if (!this.data.username) {
    if (!this.query) {
      this.data.username = cryptoUtils.randomString(25);
      this.responseShouldHaveUsername = true;
    }
    return Promise.resolve();
  }
  // We need to a find to check for duplicate username in case they are missing the unique index on usernames
  // TODO: Check if there is a unique index, and if so, skip this query.
  return this.config.database
    .find(
      this.className,
      { username: this.data.username, objectId: { $ne: this.objectId() } },
      { limit: 1 },
      {},
      this.validSchemaController
    )
    .then(results => {
      if (results.length > 0) {
        throw new Parse.Error(
          Parse.Error.USERNAME_TAKEN,
          'Account already exists for this username.'
        );
      }
      return;
    });
};

RestWrite.prototype._validateEmail = function() {
  if (!this.data.email || this.data.email.__op === 'Delete') {
    return Promise.resolve();
  }
  // Validate basic email address format
  if (!this.data.email.match(/^.+@.+$/)) {
    return Promise.reject(
      new Parse.Error(
        Parse.Error.INVALID_EMAIL_ADDRESS,
        'Email address format is invalid.'
      )
    );
  }
  // Same problem for email as above for username
  return this.config.database
    .find(
      this.className,
      { email: this.data.email, objectId: { $ne: this.objectId() } },
      { limit: 1 },
      {},
      this.validSchemaController
    )
    .then(results => {
      if (results.length > 0) {
        throw new Parse.Error(
          Parse.Error.EMAIL_TAKEN,
          'Account already exists for this email address.'
        );
      }
      if (
        !this.data.authData ||
        !Object.keys(this.data.authData).length ||
        (Object.keys(this.data.authData).length === 1 &&
          Object.keys(this.data.authData)[0] === 'anonymous')
      ) {
        // We updated the email, send a new validation
        this.storage['sendVerificationEmail'] = true;
        this.config.userController.setEmailVerifyToken(this.data);
      }
    });
};

RestWrite.prototype._validatePasswordPolicy = function() {
  if (!this.config.passwordPolicy) return Promise.resolve();
  return this._validatePasswordRequirements().then(() => {
    return this._validatePasswordHistory();
  });
};

RestWrite.prototype._validatePasswordRequirements = function() {
  // check if the password conforms to the defined password policy if configured
  // If we specified a custom error in our configuration use it.
  // Example: "Passwords must include a Capital Letter, Lowercase Letter, and a number."
  //
  // This is especially useful on the generic "password reset" page,
  // as it allows the programmer to communicate specific requirements instead of:
  // a. making the user guess whats wrong
  // b. making a custom password reset page that shows the requirements
  const policyError = this.config.passwordPolicy.validationError
    ? this.config.passwordPolicy.validationError
    : 'Password does not meet the Password Policy requirements.';
  const containsUsernameError = 'Password cannot contain your username.';

  // check whether the password meets the password strength requirements
  if (
    (this.config.passwordPolicy.patternValidator &&
      !this.config.passwordPolicy.patternValidator(this.data.password)) ||
    (this.config.passwordPolicy.validatorCallback &&
      !this.config.passwordPolicy.validatorCallback(this.data.password))
  ) {
    return Promise.reject(
      new Parse.Error(Parse.Error.VALIDATION_ERROR, policyError)
    );
  }

  // check whether password contain username
  if (this.config.passwordPolicy.doNotAllowUsername === true) {
    if (this.data.username) {
      // username is not passed during password reset
      if (this.data.password.indexOf(this.data.username) >= 0)
        return Promise.reject(
          new Parse.Error(Parse.Error.VALIDATION_ERROR, containsUsernameError)
        );
    } else {
      // retrieve the User object using objectId during password reset
      return this.config.database
        .find('_User', { objectId: this.objectId() })
        .then(results => {
          if (results.length != 1) {
            throw undefined;
          }
          if (this.data.password.indexOf(results[0].username) >= 0)
            return Promise.reject(
              new Parse.Error(
                Parse.Error.VALIDATION_ERROR,
                containsUsernameError
              )
            );
          return Promise.resolve();
        });
    }
  }
  return Promise.resolve();
};

RestWrite.prototype._validatePasswordHistory = function() {
  // check whether password is repeating from specified history
  if (this.query && this.config.passwordPolicy.maxPasswordHistory) {
    return this.config.database
      .find(
        '_User',
        { objectId: this.objectId() },
        { keys: ['_password_history', '_hashed_password'] }
      )
      .then(results => {
        if (results.length != 1) {
          throw undefined;
        }
        const user = results[0];
        let oldPasswords = [];
        if (user._password_history)
          oldPasswords = _.take(
            user._password_history,
            this.config.passwordPolicy.maxPasswordHistory - 1
          );
        oldPasswords.push(user.password);
        const newPassword = this.data.password;
        // compare the new password hash with all old password hashes
        const promises = oldPasswords.map(function(hash) {
          return passwordCrypto.compare(newPassword, hash).then(result => {
            if (result)
              // reject if there is a match
              return Promise.reject('REPEAT_PASSWORD');
            return Promise.resolve();
          });
        });
        // wait for all comparisons to complete
        return Promise.all(promises)
          .then(() => {
            return Promise.resolve();
          })
          .catch(err => {
            if (err === 'REPEAT_PASSWORD')
              // a match was found
              return Promise.reject(
                new Parse.Error(
                  Parse.Error.VALIDATION_ERROR,
                  `New password should not be the same as last ${this.config.passwordPolicy.maxPasswordHistory} passwords.`
                )
              );
            throw err;
          });
      });
  }
  return Promise.resolve();
};

RestWrite.prototype.createSessionTokenIfNeeded = function() {
  if (this.className !== '_User') {
    return;
  }
  // Don't generate session for updating user (this.query is set) unless authData exists
  if (this.query && !this.data.authData) {
    return;
  }
  // Don't generate new sessionToken if linking via sessionToken
  if (this.auth.user && this.data.authData) {
    return;
  }
  if (
    !this.storage['authProvider'] && // signup call, with
    this.config.preventLoginWithUnverifiedEmail && // no login without verification
    this.config.verifyUserEmails
  ) {
    // verification is on
    return; // do not create the session token in that case!
  }
  return this.createSessionToken();
};

RestWrite.prototype.createSessionToken = async function() {
  // cloud installationId from Cloud Code,
  // never create session tokens from there.
  if (this.auth.installationId && this.auth.installationId === 'cloud') {
    return;
  }

  const { sessionData, createSession } = Auth.createSession(this.config, {
    userId: this.objectId(),
    createdWith: {
      action: this.storage['authProvider'] ? 'login' : 'signup',
      authProvider: this.storage['authProvider'] || 'password',
    },
    installationId: this.auth.installationId,
  });

  if (this.response && this.response.response) {
    this.response.response.sessionToken = sessionData.sessionToken;
  }

  return createSession();
};

// Delete email reset tokens if user is changing password or email.
RestWrite.prototype.deleteEmailResetTokenIfNeeded = function() {
  if (this.className !== '_User' || this.query === null) {
    // null query means create
    return;
  }

  if ('password' in this.data || 'email' in this.data) {
    const addOps = {
      _perishable_token: { __op: 'Delete' },
      _perishable_token_expires_at: { __op: 'Delete' },
    };
    this.data = Object.assign(this.data, addOps);
  }
};

RestWrite.prototype.destroyDuplicatedSessions = function() {
  // Only for _Session, and at creation time
  if (this.className != '_Session' || this.query) {
    return;
  }
  // Destroy the sessions in 'Background'
  const { user, installationId, sessionToken } = this.data;
  if (!user || !installationId) {
    return;
  }
  if (!user.objectId) {
    return;
  }
  this.config.database.destroy(
    '_Session',
    {
      user,
      installationId,
      sessionToken: { $ne: sessionToken },
    },
    {},
    this.validSchemaController
  );
};

// Handles any followup logic
RestWrite.prototype.handleFollowup = function() {
  if (
    this.storage &&
    this.storage['clearSessions'] &&
    this.config.revokeSessionOnPasswordReset
  ) {
    var sessionQuery = {
      user: {
        __type: 'Pointer',
        className: '_User',
        objectId: this.objectId(),
      },
    };
    delete this.storage['clearSessions'];
    return this.config.database
      .destroy('_Session', sessionQuery)
      .then(this.handleFollowup.bind(this));
  }

  if (this.storage && this.storage['generateNewSession']) {
    delete this.storage['generateNewSession'];
    return this.createSessionToken().then(this.handleFollowup.bind(this));
  }

  if (this.storage && this.storage['sendVerificationEmail']) {
    delete this.storage['sendVerificationEmail'];
    // Fire and forget!
    this.config.userController.sendVerificationEmail(this.data);
    return this.handleFollowup.bind(this);
  }
};

// Handles the _Session class specialness.
// Does nothing if this isn't an _Session object.
RestWrite.prototype.handleSession = function() {
  if (this.response || this.className !== '_Session') {
    return;
  }

  if (!this.auth.user && !this.auth.isMaster) {
    throw new Parse.Error(
      Parse.Error.INVALID_SESSION_TOKEN,
      'Session token required.'
    );
  }

  // TODO: Verify proper error to throw
  if (this.data.ACL) {
    throw new Parse.Error(
      Parse.Error.INVALID_KEY_NAME,
      'Cannot set ' + 'ACL on a Session.'
    );
  }

  if (this.query) {
    if (
      this.data.user &&
      !this.auth.isMaster &&
      this.data.user.objectId != this.auth.user.id
    ) {
      throw new Parse.Error(Parse.Error.INVALID_KEY_NAME);