Implement react-hooks-sse library

.gitignore

@@ -1,7 +1,8 @@
 .env
 .overnodebundle
 *.old
-node/node_modules
+backend/node_modules
+frontend/node_modules
 nginx-react/node_modules
 nginx-react/build
 .vscode

backend/server.js

@@ -10,7 +10,7 @@ const mongoUri = process.env.MONGO_URI || 'mongodb://127.0.0.1:27017/default?rep
 // Minio set-up variables
 const minioURI = new URL(process.env.MINIO_URI || 'http://kspace-mugshot:2mSI6HdbJ8@127.0.0.1:9000/kspace-mugshot');
 const minioBucket = minioURI.pathname.substring(1);
-const historyNumber = process.env.HISTORY_AMOUNT || 10;
+const historyNumber = parseInt(process.env.HISTORY_AMOUNT) || 1000;
 
 // Stream set-up variables
 let changeStream;
@@ -28,16 +28,15 @@ async function run() {
   console.log('server.js has been launched');
   const app = express();
 
-  // Configuring mongoDB connection
   await mongoClient.connect();
   const collection = mongoClient.db().collection(mongoCollection);
 
   let eventArray = [];
 
-  // Opening event listener on the database
   changeStream = collection.watch(pipeline, options);
   console.log("Started watching changes in database");
 
+  // Triggers on GET at /event route
   app.get('/events', async function (request, response) {
     let minioClient = new minio.Client({
       endPoint: minioURI.hostname,
@@ -47,19 +46,24 @@ async function run() {
       secretKey: minioURI.password
     });
 
-    // Setting the header to event-stream for Server Sent Events (Eventsource)
+    // Notify SSE to React
     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
+    const historyCursor = collection.find({}).sort({$natural : -1}).limit(historyNumber);
+
+    historyCursor.forEach((document) => {
+      const stringFormat = JSON.stringify(document);
+      eventArray = [stringFormat, ...eventArray];
+    })
+    response.write(`event: events, data: [${[...eventArray]}]\n\n`)
+
     changeStream.on("change", data => {
 
-      // Retrieves modified document on the db and stores it
       let document = JSON.stringify(data.fullDocument);
       eventArray = [document];
 
-      // Fetch screenshot if there is one
       if (data.fullDocument.screenshot_count) {
 
         for (let i = 1; i <= data.fullDocument.screenshot_count ; i++) {
@@ -72,8 +76,8 @@ async function run() {
 
       };
 
-      // sends updated array
       response.write(`data: [${[...eventArray]}]\n\n`);
+
     });
   });
 

docker-compose.yml

@@ -11,6 +11,7 @@ x-common: &common
   ME_CONFIG_MONGODB_AUTH_DATABASE: admin
   MONGO_URI: mongodb://127.0.0.1:27017/default?replicaSet=rs0
   MONGO_COLLECTION: eventlog
+  HISTORY_AMOUNT: 10
   MINIO_ACCESS_KEY: kspace-mugshot
   MINIO_SECRET_KEY: 2mSI6HdbJ8
   MINIO_DEFAULT_BUCKETS: kspace-mugshot:download

frontend/package-lock.json

@@ -13,6 +13,7 @@
         "@testing-library/user-event": "^13.5.0",
         "react": "^17.0.2",
         "react-dom": "^17.0.2",
+        "react-hooks-sse": "^2.0.0",
         "react-scripts": "5.0.0",
         "web-vitals": "^2.1.3"
       }
@@ -12952,6 +12953,17 @@
       "resolved": "https://registry.npmjs.org/react-error-overlay/-/react-error-overlay-6.0.10.tgz",
       "integrity": "sha512-mKR90fX7Pm5seCOfz8q9F+66VCc1PGsWSBxKbITjfKVQHMNF2zudxHnMdJiB1fRCb+XsbQV9sO9DCkgsMQgBIA=="
     },
+    "node_modules/react-hooks-sse": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/react-hooks-sse/-/react-hooks-sse-2.0.0.tgz",
+      "integrity": "sha512-Bv/KYK+QUVS6UWwCyx6nyaOYIvaTMTCjmlXuBK9nATH2DOz+g4PGiIxi5q71ljUTmSPn/q9Cod7xwDA3/gqVQA==",
+      "dependencies": {
+        "@babel/runtime": "^7.1.5"
+      },
+      "peerDependencies": {
+        "react": ">= 16.7.0"
+      }
+    },
     "node_modules/react-is": {
       "version": "17.0.2",
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-17.0.2.tgz",
@@ -25025,6 +25037,14 @@
       "resolved": "https://registry.npmjs.org/react-error-overlay/-/react-error-overlay-6.0.10.tgz",
       "integrity": "sha512-mKR90fX7Pm5seCOfz8q9F+66VCc1PGsWSBxKbITjfKVQHMNF2zudxHnMdJiB1fRCb+XsbQV9sO9DCkgsMQgBIA=="
     },
+    "react-hooks-sse": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/react-hooks-sse/-/react-hooks-sse-2.0.0.tgz",
+      "integrity": "sha512-Bv/KYK+QUVS6UWwCyx6nyaOYIvaTMTCjmlXuBK9nATH2DOz+g4PGiIxi5q71ljUTmSPn/q9Cod7xwDA3/gqVQA==",
+      "requires": {
+        "@babel/runtime": "^7.1.5"
+      }
+    },
     "react-is": {
       "version": "17.0.2",
       "resolved": "https://registry.npmjs.org/react-is/-/react-is-17.0.2.tgz",

frontend/package.json

@@ -8,6 +8,7 @@
     "@testing-library/user-event": "^13.5.0",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
+    "react-hooks-sse": "^2.0.0",
     "react-scripts": "5.0.0",
     "web-vitals": "^2.1.3"
   },

frontend/src/components/app/App.js

@@ -1,28 +1,29 @@
-import React, { useState } from 'react';
+import React, { useState, useEffect } from 'react';
+import { useSSE, SSEProvider, createCustomSource } from 'react-hooks-sse';
 import './App.css';
 import EventList from '../eventList/EventList.js';
 
-function App(props) {
-  const [events, setEvents] = useState(['EventLog']); // initialises Event state
-  const [sse, setSse] = useState(new EventSource('/events', { withCredentials: true })) // creates eventSource listener in state
+function SSE() {
+  const state = useSSE('events');
+  const [events, setEvents] = useState([]); // initialises Event state
 
-  sse.onerror = (e) => {
-    console.error();
-    sse.close();
+  useEffect(() => {
+    console.log('render');
+    if (state) {
+      setEvents([JSON.parse(state.data), ...events]);
+    }
+  }, [state])
+
+  return events;
 }
 
-  sse.onmessage = (e) => {
-    // parses received data from string to JSON
-    const message = JSON.parse(e.data);
+function App() {
 
-    // initialises a new array with updated server-side event array
-    const newEvents = [...message, ...events];
-
-    // sets the updated event array as state
-    setEvents(newEvents);
-  };
-
-  return <EventList data={events} />
+  return (
+  <SSEProvider endpoint="/events">
+    <SSE/>
+  </SSEProvider>
+  )
 
 }
 

frontend/src/components/eventList/EventList.js

@@ -3,15 +3,13 @@ import Event from '../event/Event.js';
 import './EventList.css';
 
 function EventList(props) {
-    console.log(`FROM LIST: ${props.data}`);
+    return ;
+        // <ul className="eventListUl">
+        //     {props.data.map((event) => {
+        //         return <li className="eventListLi"><Event data={event} /></li>
+        //     })}
+        // </ul>
     
-    return (
-        <ul className="eventListUl">
-            {props.data.map((event) => {
-                return <li className="eventListLi"><Event data={event} /></li>
-            })}
-        </ul>
-    )
 
 }