70 lines
2.0 KiB
JavaScript
70 lines
2.0 KiB
JavaScript
import { WebSocketServer } from 'ws';
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import { MongoClient } from 'mongodb';
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const mongo = new MongoClient(process.env.MONGO_CONN_STR);
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const db = mongo.db();
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const collections = {};
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const wss = new WebSocketServer({ port: 7130 });
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const connections = [];
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const subscriptions = [];
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async function executeSet(message, ws) {
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let subject = collections[message.subject];
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if (!subject) {
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subject = collections[message.subject] = db.collection(message.subject);
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}
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let newValue = {$set: {}};
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newValue.$set[message.field + '.modifiedAt'] = Date.now();
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newValue.$set[message.field + '.modifiedBy'] = 'anonymous';
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newValue.$set[message.field + '.transientValue'] = message.value;
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await subject.updateMany(message.filter, newValue, { upsert: true })
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}
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wss.on('connection', function connection(ws) {
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connections.push(ws);
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console.log('accepted new connection');
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ws.on('error', console.error);
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ws.on('close', e => {
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console.log('closed a connection');
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connections.splice(connections.indexOf(ws), 1);
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});
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ws.on('message', function message(data, isBinary) {
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console.log('received a new message');
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try {
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let message = JSON.parse(data);
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console.log('message action is ' + message.action);
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switch (message.action) {
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case 'set':
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executeSet(message, ws).catch(console.error);
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break;
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case 'subscribe':
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let subject = collections[message.subject];
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if (!subject) {
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subject = collections[message.subject] = db.collection(message.subject);
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}
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subject.find(message.filter, {}).toArray().then(r => {
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ws.send(JSON.stringify({
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subject: message.subject,
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field: message.field,
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filter: message.filter,
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value: r.map(v => v[message.field])
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}));
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});
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break;
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}
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} catch (e) {
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console.error('error while processing message', e);
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ws.send(JSON.stringify(e));
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}
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});
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});
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