@mysql/xdevapi/lib/Protocol/InboundHandlers/BaseHandler.js

MySQL Connector/Node.js - A Node.js driver for MySQL using the X Protocol and X DevAPI.

/*
 * Copyright (c) 2020, 2021, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0, as
 * published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an
 * additional permission to link the program and your derivative works
 * with the separately licensed software that they have included with
 * MySQL.
 *
 * Without limiting anything contained in the foregoing, this file,
 * which is part of MySQL Connector/Node.js, is also subject to the
 * Universal FOSS Exception, version 1.0, a copy of which can be found at
 * http://oss.oracle.com/licenses/universal-foss-exception.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */

'use strict';

const error = require('../Wrappers/Messages/Error');
const errors = require('../../constants/errors');
const notice = require('../Wrappers/Messages/Notice/Frame');
const logger = require('../../logger');
const util = require('util');

const log = logger('protocol:inbound:Mysqlx');

/**
 * Abstract prototype for a InboundHandler
 *
 * Each inherited object should add methods for the messages they want to handle. Common utility functions
 * are provided from here.
 *
 * @private
 * @constructor
 */
function BaseHandler () {
    this._resolve = null;
    this._fail = null;
    this._notices = [];
}

/**
 * Directly send a message to the server, without adding to the queue or returning a promise.
 *
 * @param stream {Stream}
 * @param buffer {Buffer} Ready packet, will be sent as is
 */
BaseHandler.prototype.sendDirect = function (stream, buffer) {
    stream.write(buffer);
};

/**
 * Quese the handler, creates our promise and sends the message
 * @param queue {WorkQueue}
 * @param stream {Stream}
 * @param buffer {Buffer} Ready packet, will be sent as is
 * @returns {Promise}
 */
BaseHandler.prototype.sendMessage = function (queue, stream, buffer) {
    const self = this;

    return new Promise((resolve, reject) => {
        self._resolve = resolve;
        self._fail = reject;

        const entry = function (message, queueDone) {
            if (message.id === error.SERVER_GONE) {
                // TODO: This needs a way better handling approach for this, probably the Queue has to learn about this
                queueDone();
                return reject(new Error(errors.MESSAGES.ER_DEVAPI_SERVER_GONE_AWAY));
            }

            if (!self[message.id]) {
                queueDone();
                return reject(new Error(util.format(errors.ER_X_CLIENT_UNEXPECTED_PROTOCOL_MESSAGE, message.id)));
            }

            self[message.id](message.payload, queueDone);
        };

        queue.push(entry);
        self.sendDirect(stream, buffer);
    });
};

BaseHandler.prototype[notice.MESSAGE_ID] = function (payload) {
    const inboundNotice = notice.deserialize(payload);
    log.info('Notice.Frame', inboundNotice);

    this._notices.push(inboundNotice);
};

/**
 * Common handler for errors.
 *
 * If a handler wants to handle these differently they can do by overriding
 *
 * @param message
 */
BaseHandler.prototype[error.MESSAGE_ID] = function (payload, queueDone) {
    queueDone();

    const inboundError = error.deserialize(payload);
    log.info('Error', inboundError);

    const data = inboundError.toObject();
    const err = new Error(data.msg);
    err.info = data;

    this._fail(err);
};

module.exports = BaseHandler;