x-http-client/lib/jsonp/addEventListeners.js

An http client to make it easier to send requests (including JSONP requests) to the server.

var isFunction = require('x-common-utils/isFunction');
var JSONPResponse = require('../class/JSONPResponse');
var fireCallbacks = require('../shared/fireCallbacks');
var noop = require('../shared/noop');
var constants = require('../shared/constants');
var ERR_CANCELLED = constants.ERR_CANCELLED;
var ERR_NETWORK   = constants.ERR_NETWORK;
var ERR_RESPONSE  = constants.ERR_RESPONSE;
var ERR_TIMEOUT   = constants.ERR_TIMEOUT;

/**
 * Add event listeners to JSONP request.
 *
 * @param {JSONPRequest} request The JSONP request.
 * @param {string} callbackName The callback name used to define the global JSONP callback.
 */
function addEventListeners(request, callbackName) {
    var script = request.script;
    var options = request.options;
    var requestType = request.requestType;
    var isResponseOk = options.isResponseOk;
    var response = new JSONPResponse(request);
    var timeout = parseInt(options.timeout || 0, 10);
    var timeoutId = null;

    /**
     * The function finish the request.
     *
     * @param {string} code The error code on error. If no error occured, the code is `null`.
     */
    var finish = function (code) {
        // Set finish to the no operation function.
        finish = noop;

        // Mark this request as finished.
        request.finished = true;

        // Clear listeners.
        window[callbackName] = noop;
        script.onerror = null;

        // Clear timeout.
        if (timeoutId !== null) {
            clearTimeout(timeoutId);
            timeoutId = null;
        }

        // Fire callbacks.
        fireCallbacks(code, response);
    };

    // Define the callback function.
    window[callbackName] = function (responseJSON) {
        request.responseJSON = responseJSON;
        if (isFunction(isResponseOk)) {
            if (isResponseOk(requestType, response)) {
                finish(null);
            } else {
                finish(ERR_RESPONSE);
            }
        } else {
            finish(null);
        }
    };

    // Catch the error.
    script.onerror = function () {
        finish(ERR_NETWORK);
    };

    /**
     * Cancel the request.
     */
    request.cancel = function () {
        finish(ERR_CANCELLED);
    };

    // Add timeout listener
    if (!isNaN(timeout) && timeout > 0) {
        timeoutId = setTimeout(function () {
            finish(ERR_TIMEOUT);
        }, timeout);
    }
}

module.exports = addEventListeners;