From 3e7aa01e34b9d945d713504da91a23096dc895bd Mon Sep 17 00:00:00 2001
From: Fabien Benetou <fabien@benetou.fr>
Date: Mon, 25 Dec 2023 16:27:24 +0100
Subject: [PATCH] basic SSE examples for /events

---
 index.js | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 5bd8ec5..47b362f 100644
--- a/index.js
+++ b/index.js
@@ -10,7 +10,8 @@ const express = require("express");           // could be good to replace with c
 // Get port or default to 8082
 const port = process.env.PORT || 8082;
 const protocol = 'https'
-const subclass = '192.168.4.'
+const subclass = '10.160.168.'
+//const subclass = '192.168.4.'
 
 const publicKeyPath = path.resolve(process.env.HOME,'.ssh','id_rsa_offlineoctopus.pub')
 const publicKey = fs.readFileSync(publicKeyPath).toString().split(' ')[1]
@@ -250,6 +251,7 @@ app.get('/scan', (req, res) => {
 })
 
 function scanpeers(){
+	sendEventsToAll({'action':'scanning started'})
 	foundPeers = []
 	for (let i=1;i<25;i++){ // async so blasting, gives very quick result for positives
 		let url=protocol+'://'+subclass+i+':'+port+'/available'
@@ -381,3 +383,28 @@ const webServer = https.createServer(credentials, app);
 webServer.listen(port, () => {
     console.log("listening on "+protocol+"://localhost:" + port);
 });
+
+// SSE from https://www.digitalocean.com/community/tutorials/nodejs-server-sent-events-build-realtime-app
+// adapted from jxr-permanence
+let clients = [];
+
+function eventsHandler(request, response, next) {
+  const headers = {
+    'Content-Type': 'text/event-stream',
+    'Connection': 'keep-alive',
+    'Cache-Control': 'no-cache'
+  };
+  response.writeHead(200, headers);
+  const clientId = Date.now();
+  const newClient = { id: clientId, response };
+  clients.push(newClient);
+  request.on('close', () => { clients = clients.filter(client => client.id !== clientId); });
+}
+
+function sendEventsToAll(data) {
+  // function used to broadcast
+  clients.forEach(client => client.response.write(`data: ${JSON.stringify(data)}\n\n`))
+}
+
+app.get('/events', eventsHandler);
+// for example /events.html shows when /scan begings (but not ends)