github.com/mdaxf/iac@v0.0.0-20240519030858-58a061660378/integration/messagebus/glue/client/src/ajaxsocket.js

/*
 *  Glue - Robust Go and Javascript Socket Library
 *  Copyright (C) 2015  Roland Singer <roland.singer[at]desertbit.com>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  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 for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *  This code lives inside the glue function.
 */


var newAjaxSocket = function () {
    /*
     * Constants
     */

    var ajaxHost = host + options.baseURL + "ajax",
        sendTimeout = 8000,
        pollTimeout = 45000;

    var PollCommands = {
        Timeout:    "t",
        Closed:     "c"
    };

    var Commands = {
        Delimiter:  "&",
        Init:       "i",
        Push:       "u",
        Poll:       "o"
    };



    /*
     * Variables
     */

    var s = {},
        uid, pollToken,
        pollXhr = false,
        sendXhr = false,
        poll;



    /*
     * Methods
     */

    var stopRequests = function() {
        // Set the poll function to a dummy function.
        // This will prevent further poll calls.
        poll = function() {};

        // Kill the ajax requests.
        if (pollXhr) {
            pollXhr.abort();
        }
        if (sendXhr) {
            sendXhr.abort();
        }
    };

    var postAjax = function(url, timeout, data, success, error) {
        var xhr = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");

        xhr.onload = function() {
          success(xhr.response);
        };

        xhr.onerror = function() {
          error();
        };

        xhr.ontimeout = function() {
          error("timeout");
        };

        xhr.open('POST', url, true);
        xhr.responseType = "text";
        xhr.timeout = timeout;
        xhr.send(data);

        return xhr;
    };

    var triggerClosed = function() {
        // Stop the ajax requests.
        stopRequests();

        // Trigger the event.
        s.onClose();
    };

    var triggerError = function(msg) {
        // Stop the ajax requests.
        stopRequests();

        // Create the error message.
        if (msg) {
            msg = "the ajax socket closed the connection with the error: " + msg;
        }
        else {
            msg = "the ajax socket closed the connection with an error.";
        }

        // Trigger the event.
        s.onError(msg);
    };

    var send = function (data, callback) {
        sendXhr = postAjax(ajaxHost, sendTimeout, data, function (data) {
            sendXhr = false;

            if (callback) {
                callback(data);
            }
        }, function (msg) {
            sendXhr = false;
            triggerError(msg);
        });
    };

    poll = function () {
        var data = Commands.Poll + uid + Commands.Delimiter + pollToken;

        pollXhr = postAjax(ajaxHost, pollTimeout, data, function (data) {
          pollXhr = false;

          // Check if this jax request has reached the server's timeout.
          if (data == PollCommands.Timeout) {
              // Just start the next poll request.
              poll();
              return;
          }

          // Check if this ajax connection was closed.
          if (data == PollCommands.Closed) {
              // Trigger the closed event.
              triggerClosed();
              return;
          }

          // Split the new token from the rest of the data.
          var i = data.indexOf(Commands.Delimiter);
          if (i < 0) {
              triggerError("ajax socket: failed to split poll token from data!");
              return;
          }

          // Set the new token and the data variable.
          pollToken = data.substring(0, i);
          data = data.substr(i + 1);

          // Start the next poll request.
          poll();

          // Call the event.
          s.onMessage(data);
        }, function (msg) {
            pollXhr = false;
            triggerError(msg);
        });
    };



    /*
     * Socket layer implementation.
     */

    s.open = function () {
        // Initialize the ajax socket session
        send(Commands.Init, function (data) {
            // Get the uid and token string
            var i = data.indexOf(Commands.Delimiter);
            if (i < 0) {
                triggerError("ajax socket: failed to split uid and poll token from data!");
                return;
            }

            // Set the uid and token.
            uid = data.substring(0, i);
            pollToken = data.substr(i + 1);

            // Start the long polling process.
            poll();

            // Trigger the event.
            s.onOpen();
        });
    };

    s.send = function (data) {
        // Always prepend the command with the uid to the data.
        send(Commands.Push + uid + Commands.Delimiter + data);
    };

	s.reset = function() {
        // Stop the ajax requests.
        stopRequests();
    };

	return s;
};