94 lines
3.0 KiB
JavaScript
94 lines
3.0 KiB
JavaScript
const { MongoClient } = require("mongodb");
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const express = require('express');
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const minio = require('minio');
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/*============== VARIABLE DECLARATION ==============*/
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// Mongo set-up variables
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const mongoEndpoint = process.env.ME_CONFIG_MONGODB_SERVER;
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const mongoPort = parseInt(process.env.ME_CONFIG_MONGODB_PORT);
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const mongoDatabase = process.env.ME_CONFIG_MONGODB_DB;
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const mongoCollection = process.env.ME_CONFIG_MONGODB_COLLECTION;
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// Minio set-up variables
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const minioEndpoint = process.env.MINIO_ENDPOINT;
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const minioBucket = process.env.MINIO_BUCKET;
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const minioPort = parseInt(process.env.MINIO_SERVING_PORT);
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const minioKey = process.env.MINIO_ACCESS_KEY;
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const minioSecret = process.env.MINIO_SECRET_KEY;
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// Stream set-up variables
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let changeStream;
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const options = { fullDocument: "updateLookup" };
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const pipeline = [];
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const PORT = process.env.PORT || 3002;
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// Create Mongo client
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const MONGO_URI = `mongodb://${mongoEndpoint}:${mongoPort}`;
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const mongoClient = new MongoClient(MONGO_URI);
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/*============== CODE ==============*/
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async function run() {
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console.log('server.js has been launched')
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const app = express();
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// Configuring mongoDB connection
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await mongoClient.connect();
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const database = mongoClient.db(mongoDatabase);
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const collection = database.collection(mongoCollection);
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// Notify connection
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console.log(`Connection established with Mongo Database at ${MONGO_URI}`);
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// Opening event listener on the database
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changeStream = collection.watch(pipeline, options);
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console.log("Started watching changes in database");
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app.get('/events', async function (request, response) {
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let eventArray = [];
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let minioClient = new minio.Client({
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endPoint: minioEndpoint,
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port: minioPort,
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useSSL: false,
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accessKey: minioKey,
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secretKey: minioSecret
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});
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// notifies GET requests
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console.log('/events was requested');
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// Setting the header to event-stream for Server Sent Events (Eventsource)
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const header = { 'Content-Type': 'text/event-stream', 'Connection': 'keep-alive' }
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response.writeHead(200, "OK", header);
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response.write('Connection established \n\n');
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// Triggers callback on every change in collection set up
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changeStream.on("change", data => {
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// Retrieves modified document on the db and stores it
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let document = JSON.stringify(data.fullDocument);
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eventArray = [document, ...eventArray];
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// Fetch screenshot if there is one
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if (data.fullDocument.screenshot_count) {
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minioClient.presignedUrl('GET', minioBucket, `${data.fullDocument.camera}/${data.fullDocument._id}/1.jpg`, 60 * 60, (err, presignedUrl) => {
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if (err) { return console.log(err) };
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const realURL = JSON.stringify({ picUrl: presignedUrl });
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eventArray = [realURL, ...eventArray];
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})
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}
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// sends updated array
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response.write(`data: [${[...eventArray]}]\n\n`);
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});
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});
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app.listen(PORT);
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console.log(`Server listening at 127.0.0.1:${PORT}`);
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}
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run().catch(console.dir);
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