How can a TCP/IP server write data on a HTTP server? - node.js

Question

Here is my tcp/ip server that listens to IoT sensors sending it data:
const net = require('net')
const server = net.createServer(socket => {
socket.on('data', data => {
console.log(data.toString())
})
}).listen(1234)
I receive the data fine. A line of data received looks like 'DATA,zoneA,20'.
Now I want to write that stream of data to this http server:
const express = require('express')
const morgan = require('morgan')
const app = express()
const bodyParser = require('body-parser')
const {PORT} = 3000
app.use(morgan('tiny'))
app.use(express.json())
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({extended: true}))
const catchTCP = async dataLine => {
dataLine = 'DATA,zoneA,20'
try {
if (dataLine.indexOf("DATA") >= 0) {
var stream = dataLine.split(",")
var streamData = {
zone: stream[1],
battery: stream[2]
}
console.log(streamData)
}
} catch(err) {
console.log("error:", err)
}
}
catchTCP()
app.listen(PORT, () => console.log(`App listening at http://localhost:${PORT}`))
I would like to replace the 'dataLine' object by an entry point for this TCP/IP data. What would be the best way to forward TCP/IP data to the HTTP server's port?
Both servers run on the same network, so I've been told socket.io would not be the best fit.

Answer 1

Replace the catchTCP function on your HTTP server with a middleware route:
app.post("/receive", express.text(), function(req, res) {
var dataLine = req.body;
/* Your code from catchTCP */
res.end(); /* finish the HTTP response */
});
Then your TCP/IP server can send an HTTP request with the following code:
var s = net.createConnection(PORT, "localhost", function() {
s.end(`POST /receive HTTP/1.1
Content-Type: text/plain
Content-Length: ${data.toString().length}
${data}`);
});
This is the TCP/IP-level representation of the HTTP request. But I would not do it that way, I would rather use a proper HTTP client. Which is not a problem if your TCP/IP server is programmed in Node.js anyway:
const http = require("http");
http.request("http://localhost:${PORT}/receive", {
method: "POST",
headers: {"Content-Type": "text/plain"}
}).end(data.toString());