* This programming interface lets a JavaScript client application use the MQTT V3.1 or * V3.1.1 protocol to connect to an MQTT-supporting messaging server. * * The function supported includes: *
* The API consists of two main objects: *
* The programming interface validates parameters passed to it, and will throw * an Error containing an error message intended for developer use, if it detects * an error with any parameter. *
* Example:
*
*
var client = new Paho.MQTT.Client(location.hostname, Number(location.port), "clientId");
client.onConnectionLost = onConnectionLost;
client.onMessageArrived = onMessageArrived;
client.connect({onSuccess:onConnect});
function onConnect() {
// Once a connection has been made, make a subscription and send a message.
console.log("onConnect");
client.subscribe("/World");
var message = new Paho.MQTT.Message("Hello");
message.destinationName = "/World";
client.send(message);
};
function onConnectionLost(responseObject) {
if (responseObject.errorCode !== 0)
console.log("onConnectionLost:"+responseObject.errorMessage);
};
function onMessageArrived(message) {
console.log("onMessageArrived:"+message.payloadString);
client.disconnect();
};
*
* Most applications will create just one Client object and then call its connect() method, * however applications can create more than one Client object if they wish. * In this case the combination of host, port and clientId attributes must be different for each Client object. *
* The send, subscribe and unsubscribe methods are implemented as asynchronous JavaScript methods * (even though the underlying protocol exchange might be synchronous in nature). * This means they signal their completion by calling back to the application, * via Success or Failure callback functions provided by the application on the method in question. * Such callbacks are called at most once per method invocation and do not persist beyond the lifetime * of the script that made the invocation. *
* In contrast there are some callback functions, most notably onMessageArrived, * that are defined on the {@link Paho.Client} object. * These may get called multiple times, and aren't directly related to specific method invocations made by the client. * * @name Paho.Client * * @constructor * * @param {string} host - the address of the messaging server, as a fully qualified WebSocket URI, as a DNS name or dotted decimal IP address. * @param {number} port - the port number to connect to - only required if host is not a URI * @param {string} path - the path on the host to connect to - only used if host is not a URI. Default: '/mqtt'. * @param {string} clientId - the Messaging client identifier, between 1 and 23 characters in length. * * @property {string} host - read only the server's DNS hostname or dotted decimal IP address. * @property {number} port - read only the server's port. * @property {string} path - read only the server's path. * @property {string} clientId - read only used when connecting to the server. * @property {function} onConnectionLost - called when a connection has been lost. * after a connect() method has succeeded. * Establish the call back used when a connection has been lost. The connection may be * lost because the client initiates a disconnect or because the server or network * cause the client to be disconnected. The disconnect call back may be called without * the connectionComplete call back being invoked if, for example the client fails to * connect. * A single response object parameter is passed to the onConnectionLost callback containing the following fields: *
* All attributes may be null, which implies the default values. * * @name Paho.Message * @constructor * @param {String|ArrayBuffer} payload The message data to be sent. *
* @property {string} payloadString read only The payload as a string if the payload consists of valid UTF-8 characters. * @property {ArrayBuffer} payloadBytes read only The payload as an ArrayBuffer. *
* @property {string} destinationName mandatory The name of the destination to which the message is to be sent * (for messages about to be sent) or the name of the destination from which the message has been received. * (for messages received by the onMessage function). *
* @property {number} qos The Quality of Service used to deliver the message. *
* @property {Boolean} retained If true, the message is to be retained by the server and delivered * to both current and future subscriptions. * If false the server only delivers the message to current subscribers, this is the default for new Messages. * A received message has the retained boolean set to true if the message was published * with the retained boolean set to true * and the subscrption was made after the message has been published. *
* @property {Boolean} duplicate read only If true, this message might be a duplicate of one which has already been received. * This is only set on messages received from the server. * */ var Message = function (newPayload) { var payload; if ( typeof newPayload === 'string' || newPayload instanceof ArrayBuffer || (ArrayBuffer.isView(newPayload) && !(newPayload instanceof DataView)) ) { payload = newPayload; } else { throw format(ERROR.INVALID_ARGUMENT, [newPayload, 'newPayload']); } var destinationName; var qos = 0; var retained = false; var duplicate = false; Object.defineProperties(this, { payloadString: { enumerable: true, get: function () { if (typeof payload === 'string') return payload; else return parseUTF8(payload, 0, payload.length); }, }, payloadBytes: { enumerable: true, get: function () { if (typeof payload === 'string') { var buffer = new ArrayBuffer(UTF8Length(payload)); var byteStream = new Uint8Array(buffer); stringToUTF8(payload, byteStream, 0); return byteStream; } else { return payload; } }, }, destinationName: { enumerable: true, get: function () { return destinationName; }, set: function (newDestinationName) { if (typeof newDestinationName === 'string') destinationName = newDestinationName; else throw new Error( format(ERROR.INVALID_ARGUMENT, [ newDestinationName, 'newDestinationName', ]), ); }, }, qos: { enumerable: true, get: function () { return qos; }, set: function (newQos) { if (newQos === 0 || newQos === 1 || newQos === 2) qos = newQos; else throw new Error('Invalid argument:' + newQos); }, }, retained: { enumerable: true, get: function () { return retained; }, set: function (newRetained) { if (typeof newRetained === 'boolean') retained = newRetained; else throw new Error( format(ERROR.INVALID_ARGUMENT, [newRetained, 'newRetained']), ); }, }, topic: { enumerable: true, get: function () { return destinationName; }, set: function (newTopic) { destinationName = newTopic; }, }, duplicate: { enumerable: true, get: function () { return duplicate; }, set: function (newDuplicate) { duplicate = newDuplicate; }, }, }); }; // Module contents. return { Client: Client, Message: Message, }; // eslint-disable-next-line no-nested-ternary })( typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : typeof window !== 'undefined' ? window : {}, ); return PahoMQTT; });