How to route nodejs requests to another nodejs application?

Question

Hi I am trying to build a really simple "API-gateway" to demonstrate a small scale microservice project. I am using Nodejs and Express and I wanted to write a really simple public facing api-gateway server to route requests to my different microservices. For example lets say I have microservice A B and C. I wanted requests to localhost:3000/api/A to go to microservice A and return the result and then all other requests to localhost:3000/api/B go to microservice B and return the result ect. I wanted to write this instead of using NGINX, could someone help me understand how I can achieve this? (Most of my other "microservices" are also nodejs/express apis)

Could I get a quick simple example in code? I would love to see a GET request to google and then the client be able to get the GET request. (use of other libraries or modules would be cool too! :D)

Answer 1

You can run B on port 3001, C on 3002.

Then dispach all request by A on port 3000.

You can use Http client like axios in A to request B or C.

Example

A.js

const express = require('express')
const axios = require('axios')

const app = express()

app.get('/api/B', (req, res) => {
  axios.get('http://localhost:3001/dosomething', {
    params: {...req.query, name: 'Device A'}, //Fetch datas from params
  }).then(result => {
    res.send(result)
  })
})

app.get('/api/C', (_, res) => {
  axios.get('http://localhost:3002/dosomething').then(result => {
    res.send(result)
  })
})

app.listen(3000, () => console.log('On 3000'))

B.js

const express = require('express')
const app = express()

app.get('/dosomething', (req, res) => {
  const data = req.query
  //Do something with data fetched here you know...
  res.send('No worry, I will do something for ' + data.name)
})

app.listen(3001, () => console.log('On 3001'))