postal.js/lib/basic/postal.basic.js

/**
 * postal - Pub/Sub library providing wildcard subscriptions, complex message handling, etc.  Works server and client-side.
 * Author: Jim Cowart (http://freshbrewedcode.com/jimcowart)
 * Version: v0.8.11
 * Url: http://github.com/postaljs/postal.js
 * License(s): MIT, GPL
 */
(function (root, factory) {
    if (typeof module === "object" && module.exports) {
        // Node, or CommonJS-Like environments
        module.exports = factory(require("underscore"), this);
    } else if (typeof define === "function" && define.amd) {
        // AMD. Register as an anonymous module.
        define(["underscore"], function (_) {
            return factory(_, root);
        });
    } else {
        // Browser globals
        root.postal = factory(root._, root);
    }
}(this, function (_, global, undefined) {
    var _postal;
    var prevPostal = global.postal;
    var ChannelDefinition = function (channelName) {
        this.channel = channelName || _postal.configuration.DEFAULT_CHANNEL;
        this.initialize();
    };
    ChannelDefinition.prototype.initialize = function () {};
    ChannelDefinition.prototype.subscribe = function () {
        return _postal.subscribe({
            channel: this.channel,
            topic: (arguments.length === 1 ? arguments[0].topic : arguments[0]),
            callback: (arguments.length === 1 ? arguments[0].callback : arguments[1])
        });
    };
    ChannelDefinition.prototype.publish = function () {
        var envelope = arguments.length === 1 ? (Object.prototype.toString.call(arguments[0]) === "[object String]" ? {
            topic: arguments[0]
        } : arguments[0]) : {
            topic: arguments[0],
            data: arguments[1]
        };
        envelope.channel = this.channel;
        _postal.publish(envelope);
    };
    var SubscriptionDefinition = function (channel, topic, callback) {
        if (arguments.length !== 3) {
            throw new Error("You must provide a channel, topic and callback when creating a SubscriptionDefinition instance.");
        }
        if (topic.length === 0) {
            throw new Error("Topics cannot be empty");
        }
        this.channel = channel;
        this.topic = topic;
        this.subscribe(callback);
    };
    SubscriptionDefinition.prototype = {
        unsubscribe: function () {
            if (!this.inactive) {
                this.inactive = true;
                _postal.unsubscribe(this);
            }
        },
        subscribe: function (callback) {
            this.callback = callback;
            return this;
        },
        withContext: function (context) {
            this.context = context;
            return this;
        }
    };
    var bindingsResolver = {
        cache: {},
        regex: {},
        compare: function (binding, topic) {
            var pattern, rgx, prevSegment, result = (this.cache[topic] && this.cache[topic][binding]);
            if (typeof result !== "undefined") {
                return result;
            }
            if (!(rgx = this.regex[binding])) {
                pattern = "^" + _.map(binding.split("."), function (segment) {
                    var res = "";
                    if ( !! prevSegment) {
                        res = prevSegment !== "#" ? "\\.\\b" : "\\b";
                    }
                    if (segment === "#") {
                        res += "[\\s\\S]*";
                    } else if (segment === "*") {
                        res += "[^.]+";
                    } else {
                        res += segment;
                    }
                    prevSegment = segment;
                    return res;
                }).join("") + "$";
                rgx = this.regex[binding] = new RegExp(pattern);
            }
            this.cache[topic] = this.cache[topic] || {};
            this.cache[topic][binding] = result = rgx.test(topic);
            return result;
        },
        reset: function () {
            this.cache = {};
            this.regex = {};
        }
    };
    var fireSub = function (subDef, envelope) {
        if (!subDef.inactive && _postal.configuration.resolver.compare(subDef.topic, envelope.topic)) {
            subDef.callback.call(subDef.context || this, envelope.data, envelope);
        }
    };
    var pubInProgress = 0;
    var unSubQueue = [];
    var clearUnSubQueue = function () {
        while (unSubQueue.length) {
            _postal.unsubscribe(unSubQueue.shift());
        }
    };
    _postal = {
        configuration: {
            resolver: bindingsResolver,
            DEFAULT_CHANNEL: "/",
            SYSTEM_CHANNEL: "postal"
        },
        subscriptions: {},
        wireTaps: [],
        ChannelDefinition: ChannelDefinition,
        SubscriptionDefinition: SubscriptionDefinition,
        channel: function (channelName) {
            return new ChannelDefinition(channelName);
        },
        subscribe: function (options) {
            var subDef = new SubscriptionDefinition(options.channel || this.configuration.DEFAULT_CHANNEL, options.topic, options.callback);
            var channel = this.subscriptions[subDef.channel];
            var subs;
            this.publish({
                channel: this.configuration.SYSTEM_CHANNEL,
                topic: "subscription.created",
                data: {
                    event: "subscription.created",
                    channel: subDef.channel,
                    topic: subDef.topic
                }
            });
            if (!channel) {
                channel = this.subscriptions[subDef.channel] = {};
            }
            subs = this.subscriptions[subDef.channel][subDef.topic];
            if (!subs) {
                subs = this.subscriptions[subDef.channel][subDef.topic] = [];
            }
            subs.push(subDef);
            return subDef;
        },
        publish: function (envelope) {
            ++pubInProgress;
            envelope.channel = envelope.channel || this.configuration.DEFAULT_CHANNEL;
            envelope.timeStamp = new Date();
            _.each(this.wireTaps, function (tap) {
                tap(envelope.data, envelope);
            });
            if (this.subscriptions[envelope.channel]) {
                _.each(this.subscriptions[envelope.channel], function (subscribers) {
                    var idx = 0,
                        len = subscribers.length,
                        subDef;
                    while (idx < len) {
                        if (subDef = subscribers[idx++]) {
                            fireSub(subDef, envelope);
                        }
                    }
                });
            }
            if (--pubInProgress === 0) {
                clearUnSubQueue();
            }
        },
        unsubscribe: function (subDef) {
            if (pubInProgress) {
                unSubQueue.push(subDef);
                return;
            }
            if (this.subscriptions[subDef.channel] && this.subscriptions[subDef.channel][subDef.topic]) {
                var len = this.subscriptions[subDef.channel][subDef.topic].length,
                    idx = 0;
                while (idx < len) {
                    if (this.subscriptions[subDef.channel][subDef.topic][idx] === subDef) {
                        this.subscriptions[subDef.channel][subDef.topic].splice(idx, 1);
                        break;
                    }
                    idx += 1;
                }
            }
            this.publish({
                channel: this.configuration.SYSTEM_CHANNEL,
                topic: "subscription.removed",
                data: {
                    event: "subscription.removed",
                    channel: subDef.channel,
                    topic: subDef.topic
                }
            });
        },
        addWireTap: function (callback) {
            var self = this;
            self.wireTaps.push(callback);
            return function () {
                var idx = self.wireTaps.indexOf(callback);
                if (idx !== -1) {
                    self.wireTaps.splice(idx, 1);
                }
            };
        },
        linkChannels: function (sources, destinations) {
            var result = [],
                self = this;
            sources = !_.isArray(sources) ? [sources] : sources;
            destinations = !_.isArray(destinations) ? [destinations] : destinations;
            _.each(sources, function (source) {
                var sourceTopic = source.topic || "#";
                _.each(destinations, function (destination) {
                    var destChannel = destination.channel || self.configuration.DEFAULT_CHANNEL;
                    result.push(
                    self.subscribe({
                        channel: source.channel || self.configuration.DEFAULT_CHANNEL,
                        topic: sourceTopic,
                        callback: function (data, env) {
                            var newEnv = _.clone(env);
                            newEnv.topic = _.isFunction(destination.topic) ? destination.topic(env.topic) : destination.topic || env.topic;
                            newEnv.channel = destChannel;
                            newEnv.data = data;
                            self.publish(newEnv);
                        }
                    }));
                });
            });
            return result;
        },
        noConflict: function () {
            if (typeof window === "undefined") {
                throw new Error("noConflict can only be used in browser clients which aren't using AMD modules");
            }
            global.postal = prevPostal;
            return this;
        },
        getSubscribersFor: function () {
            var channel = arguments[0],
                tpc = arguments[1];
            if (arguments.length === 1) {
                channel = arguments[0].channel || this.configuration.DEFAULT_CHANNEL;
                tpc = arguments[0].topic;
            }
            if (this.subscriptions[channel] && Object.prototype.hasOwnProperty.call(this.subscriptions[channel], tpc)) {
                return this.subscriptions[channel][tpc];
            }
            return [];
        },
        reset: function () {
            if (this.subscriptions) {
                _.each(this.subscriptions, function (channel) {
                    _.each(channel, function (topic) {
                        while (topic.length) {
                            topic.pop().unsubscribe();
                        }
                    });
                });
                this.subscriptions = {};
            }
            this.configuration.resolver.reset();
        }
    };
    _postal.subscriptions[_postal.configuration.SYSTEM_CHANNEL] = {};
    if (global && Object.prototype.hasOwnProperty.call(global, "__postalReady__") && _.isArray(global.__postalReady__)) {
        while (global.__postalReady__.length) {
            global.__postalReady__.shift().onReady(_postal);
        }
    }
    return _postal;
}));