96 lines
2.1 KiB
JavaScript
96 lines
2.1 KiB
JavaScript
var redis = require('redis');
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function Presence() {
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this.client = redis.createClient({
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host: process.env.REDIS_ENDPOINT
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});
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}
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module.exports = new Presence();
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/**
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* Remember a present user with their connection ID
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*
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* @param {string} connectionId - The ID of the connection
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* @param {object} meta - Any metadata about the connection
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**/
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Presence.prototype.upsert = function(connectionId, meta) {
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this.client.hset(
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'presence',
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connectionId,
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JSON.stringify({
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meta: meta,
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when: Date.now()
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}),
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function(err) {
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if (err) {
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console.error('Failed to store presence in redis: ' + err);
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}
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}
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);
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};
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/**
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* Remove a presence. Used when someone disconnects
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*
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* @param {string} connectionId - The ID of the connection
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* @param {object} meta - Any metadata about the connection
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**/
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Presence.prototype.remove = function(connectionId) {
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this.client.hdel(
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'presence',
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connectionId,
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function(err) {
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if (err) {
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console.error('Failed to remove presence in redis: ' + err);
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}
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}
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);
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};
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/**
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* Returns a list of present users, minus any expired
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*
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* @param {function} returnPresent - callback to return the present users
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**/
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Presence.prototype.list = function(returnPresent) {
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var active = [];
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var dead = [];
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var now = Date.now();
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var self = this;
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this.client.hgetall('presence', function(err, presence) {
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if (err) {
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console.error('Failed to get presence from Redis: ' + err);
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return returnPresent([]);
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}
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for (var connection in presence) {
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var details = JSON.parse(presence[connection]);
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details.connection = connection;
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if (now - details.when > 8000) {
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dead.push(details);
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} else {
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active.push(details);
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}
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}
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if (dead.length) {
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self._clean(dead);
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}
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return returnPresent(active);
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});
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};
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/**
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* Cleans a list of connections by removing expired ones
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*
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* @param
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**/
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Presence.prototype._clean = function(toDelete) {
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console.log(`Cleaning ${toDelete.length} expired presences`);
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for (var presence of toDelete) {
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this.remove(presence.connection);
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}
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};
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