149 lines
3.6 KiB
JavaScript
149 lines
3.6 KiB
JavaScript
var express = require("express");
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var app = express();
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const WebSocket = require("ws");
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//# TODO SSE https://www.digitalocean.com/community/tutorials/nodejs-server-sent-events-build-realtime-app
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var last_status = {};
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var last_image;
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var received_picture = false;
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var received_error = false;
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let sse_clients = [];
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app.use(express.static("public"));
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app.use(express.json());
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var ws;
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var api_connected = false;
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function send_events_to_clients(data) {
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// console.log("sending events to clients");
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sse_clients.forEach((client) => {
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client.response.write("event: message\n");
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client.response.write("data:" + JSON.stringify(data) + "\n\n");
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});
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}
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function send_image_data_to_clients(frameData) {
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sse_clients.forEach((client) => {
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// Create a Buffer from the frame data
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const buffer = Buffer.from(frameData);
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// Set the SSE event name as 'message'
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client.response.write("event: message\n");
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// Convert the Buffer to a base64-encoded string
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const base64Data = buffer.toString("base64");
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// Set the SSE event data as the base64-encoded string
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client.response.write(
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"data: " + JSON.stringify({ image: base64Data }) + "\n\n"
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);
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});
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}
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function handle_sse_client(request, response, next) {
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console.log("handling sse client");
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const headers = {
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"Content-Type": "text/event-stream",
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Connection: "keep-alive",
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"Cache-Control": "no-cache",
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};
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response.writeHead(200, headers);
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response.write(JSON.stringify("yeet") + "\n\n");
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const clientID = Date.now();
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const newClient = {
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id: clientID,
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response,
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};
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sse_clients.push(newClient);
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request.on("close", () => {
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console.log(`${clientID} Connection closed`);
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sse_clients = sse_clients.filter((client) => client.id !== clientID);
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});
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}
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var connect_to_api = function () {
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console.log("Connecting to API");
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ws = new WebSocket("ws://10.100.0.40:9001/");
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ws.on("open", function open() {
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console.log("connected with websockets to API!");
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api_connected = true;
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});
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ws.on("message", function message(message) {
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try {
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var msg = JSON.parse(message);
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if (msg.type != "IMAGE") {
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send_events_to_clients(msg);
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} else {
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console.log("got image");
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}
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} catch (error) {
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// console.log("could not parse as json, must be bytes");
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send_image_data_to_clients(message);
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}
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});
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ws.on("error", function error(err) {
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console.log("there was an error");
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console.error("error: " + err);
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received_error = true;
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});
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};
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// set the view engine to ejs
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app.set("view engine", "ejs");
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// use res.render to load up an ejs view file
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// index page
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app.get("/", function (req, res) {
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res.render("index", { api_connected: api_connected });
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});
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app.get("/events", handle_sse_client);
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app.get("/image", function (req, res) {
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console.log("got picture request");
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var request = JSON.stringify({
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command: 5,
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});
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console.log("sending picture request");
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ws.send(request);
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res.status(200).send(last_image);
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});
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app.post("/move", function (req, res) {
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console.log("got move request");
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var request = JSON.stringify({
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command: 3,
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up_down: req.body.up_down,
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left_right: req.body.left_right,
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forward_backward: req.body.forward_backward,
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yaw: req.body.turn_left_right,
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});
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ws.send(request);
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});
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app.get("/connect", function (req, res) {
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console.log("got connect request");
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connect_to_api();
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setTimeout(function () {
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if (api_connected) {
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res.status(200).json({ connected: true });
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} else {
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received_error = false;
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res.status(400).json({ connected: false });
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}
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}, 1000);
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});
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app.listen(8080);
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console.log("Server is listening on port 8080");
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