Add frontend and backend files

backend/.dockerignore

@@ -0,0 +1,5 @@
+./node_modules
+./build
+.git
+*.md
+.gitignore

backend/Dockerfile

@@ -1 +1,16 @@
+# pull official node image
 FROM node
+
+# define /app as working directory
+WORKDIR /app
+
+# copy package.json and package-lock.json to /app
+COPY package.json /app
+COPY package-lock.json /app
+
+# install node dependencies
+RUN npm install
+COPY . /app
+
+# launch node server
+ENTRYPOINT node server.js

backend/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "app",
+  "version": "1.0.0",
+  "description": "",
+  "main": "server.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "start": "node server.js",
+    "build": "cd frontend && npm install && npm run build"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^4.17.2",
+    "minio": "^7.0.26",
+    "mongodb": "^4.3.1"
+  }
+}

backend/server.js

@@ -0,0 +1,93 @@
+const { MongoClient } = require("mongodb");
+const express = require('express');
+const minio = require('minio');
+
+  /*============== VARIABLE DECLARATION ==============*/
+// Mongo set-up variables
+const mongoEndpoint = process.env.ME_CONFIG_MONGODB_SERVER;
+const mongoPort = parseInt(process.env.ME_CONFIG_MONGODB_PORT);
+const mongoDatabase = process.env.ME_CONFIG_MONGODB_DB;
+const mongoCollection = process.env.ME_CONFIG_MONGODB_COLLECTION;
+
+// Minio set-up variables
+const minioEndpoint = process.env.MINIO_ENDPOINT;
+const minioBucket = process.env.MINIO_BUCKET;
+const minioPort = parseInt(process.env.MINIO_SERVING_PORT);
+const minioKey = process.env.MINIO_ACCESS_KEY;
+const minioSecret = process.env.MINIO_SECRET_KEY;
+
+// Stream set-up variables
+let changeStream;
+const options = { fullDocument: "updateLookup" };
+const pipeline = [];
+const PORT = process.env.PORT || 3002;
+
+// Create Mongo client
+const MONGO_URI = `mongodb://${mongoEndpoint}:${mongoPort}`;
+const mongoClient = new MongoClient(MONGO_URI);
+
+
+/*============== CODE ==============*/
+async function run() {
+
+  console.log('server.js has been launched')
+
+  const app = express();
+
+  // Configuring mongoDB connection
+  await mongoClient.connect();
+  const database = mongoClient.db(mongoDatabase);
+  const collection = database.collection(mongoCollection);
+
+  // Notify connection
+  console.log(`Connection established with Mongo Database at ${MONGO_URI}`);
+
+  // Opening event listener on the database
+  changeStream = collection.watch(pipeline, options);
+  console.log("Started watching changes in database");
+
+  app.get('/events', async function (request, response) {
+    let eventArray = [];
+
+    let minioClient = new minio.Client({
+      endPoint: minioEndpoint,
+      port: minioPort,
+      useSSL: false,
+      accessKey: minioKey,
+      secretKey: minioSecret
+    });
+
+    // notifies GET requests
+    console.log('/events was requested');
+
+    // Setting the header to event-stream for Server Sent Events (Eventsource)
+    const header = { 'Content-Type': 'text/event-stream', 'Connection': 'keep-alive' }
+    response.writeHead(200, "OK", header);
+    response.write('Connection established \n\n');
+
+    // Triggers callback on every change in collection set up
+    changeStream.on("change", data => {
+
+      // Retrieves modified document on the db and stores it
+      let document = JSON.stringify(data.fullDocument);
+      eventArray = [document, ...eventArray];
+
+      // Fetch screenshot if there is one
+      if (data.fullDocument.screenshot_count) {
+        minioClient.presignedUrl('GET', minioBucket, `${data.fullDocument.camera}/${data.fullDocument._id}/1.jpg`, 60 * 60, (err, presignedUrl) => {
+          if (err) { return console.log(err) };
+          const realURL = JSON.stringify({ picUrl: presignedUrl });
+          eventArray = [realURL, ...eventArray];
+        })
+      }
+
+      // sends updated array
+      response.write(`data: [${[...eventArray]}]\n\n`);
+    });
+  });
+
+  app.listen(PORT);
+  console.log(`Server listening at 127.0.0.1:${PORT}`);
+}
+
+run().catch(console.dir);