diffusion/src/events/fetch-stream.js

Diffusion JavaScript client

var _interface = require('util/interface')._interface;
var Stream = require('./stream');

/**
 * Provides a stream of topic values for a given fetch request.
 * <P>
 * FetchStream inherits all functions defined on {@link Stream}.
 * <P>
 * <br/>
 *
 * @example
 * // Handle all events from stream
 * session.fetch("foo").on({
 *     open : function() {
 *         // Fetch stream has opened, values will be emitted after this event.
 *     },
 *     value : function(value, topicPath) {
 *         // Received topic value
 *     },
 *     error : function(err) {
 *         // Encountered an error
 *     },
 *     close : function() {
 *         // Fetch stream closed; no more values will be received
 *     }
 * });
 *
 * @class FetchStream
 *
 * @fires Stream#error
 * @fires Stream#close
 * @fires FetchStream#open
 * @fires FetchStream#value
 *
 * @augments Stream
 */
module.exports = _interface('FetchStream', Stream, [
    /**
     * Emitted when the fetch stream is initially opened. This will only be fired once.
     *
     * @event FetchStream#open
     */

    /**
     * Emitted when a topic that is selected by the fetch request's topic selector has returned its value. By default,
     * values are provided as <code>Buffer</code> instances. The topic path specifies which topic this value is for.
     *
     * @event FetchStream#value
     * @property {Buffer} value - the new value of the topic
     * @property {String} topicPath - the path to the topic to which the value update applies
     */
]);