149 lines
2.6 KiB
JavaScript
149 lines
2.6 KiB
JavaScript
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/**
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* Module dependencies.
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*/
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var debug = require('debug')('axon:sub');
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var escape = require('escape-string-regexp');
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var Message = require('amp-message');
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var Socket = require('./sock');
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/**
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* Expose `SubSocket`.
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*/
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module.exports = SubSocket;
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/**
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* Initialize a new `SubSocket`.
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*
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* @api private
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*/
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function SubSocket() {
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Socket.call(this);
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this.subscriptions = [];
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}
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/**
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* Inherits from `Socket.prototype`.
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*/
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SubSocket.prototype.__proto__ = Socket.prototype;
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/**
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* Check if this socket has subscriptions.
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*
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* @return {Boolean}
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* @api public
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*/
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SubSocket.prototype.hasSubscriptions = function(){
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return !! this.subscriptions.length;
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};
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/**
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* Check if any subscriptions match `topic`.
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*
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* @param {String} topic
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* @return {Boolean}
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* @api public
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*/
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SubSocket.prototype.matches = function(topic){
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for (var i = 0; i < this.subscriptions.length; ++i) {
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if (this.subscriptions[i].test(topic)) {
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return true;
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}
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}
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return false;
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};
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/**
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* Message handler.
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*
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* @param {net.Socket} sock
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* @return {Function} closure(msg, mulitpart)
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* @api private
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*/
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SubSocket.prototype.onmessage = function(sock){
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var subs = this.hasSubscriptions();
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var self = this;
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return function(buf){
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var msg = new Message(buf);
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if (subs) {
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var topic = msg.args[0];
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if (!self.matches(topic)) return debug('not subscribed to "%s"', topic);
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}
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self.emit.apply(self, ['message'].concat(msg.args).concat(sock));
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};
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};
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/**
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* Subscribe with the given `re`.
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*
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* @param {RegExp|String} re
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* @return {RegExp}
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* @api public
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*/
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SubSocket.prototype.subscribe = function(re){
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debug('subscribe to "%s"', re);
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this.subscriptions.push(re = toRegExp(re));
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return re;
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};
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/**
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* Unsubscribe with the given `re`.
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*
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* @param {RegExp|String} re
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* @api public
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*/
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SubSocket.prototype.unsubscribe = function(re){
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debug('unsubscribe from "%s"', re);
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re = toRegExp(re);
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for (var i = 0; i < this.subscriptions.length; ++i) {
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if (this.subscriptions[i].toString() === re.toString()) {
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this.subscriptions.splice(i--, 1);
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}
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}
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};
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/**
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* Clear current subscriptions.
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*
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* @api public
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*/
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SubSocket.prototype.clearSubscriptions = function(){
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this.subscriptions = [];
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};
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/**
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* Subscribers should not send messages.
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*/
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SubSocket.prototype.send = function(){
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throw new Error('subscribers cannot send messages');
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};
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/**
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* Convert `str` to a `RegExp`.
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*
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* @param {String} str
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* @return {RegExp}
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* @api private
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*/
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function toRegExp(str) {
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if (str instanceof RegExp) return str;
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str = escape(str);
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str = str.replace(/\\\*/g, '(.+)');
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return new RegExp('^' + str + '$');
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}
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