How to put router in function and export it? - node.js

Question

I try to put router.post in a function and export it to app.js. But it didn't take effect. Here is my code.
crypto.js
function getPublicKey() {
console.log('111');
router.post('/get-public-key', (req, res) => {
fs.readFile(__dirname + '/keys/rsa-pub.pem', 'utf8', (err, data) => {
if (err) {
throw err
} else {
res.send(data)
}
})
});
}
module.exports = {
getPublicKey
}
app.js
const cryptoRouter = require('./modules/crypto/router');
cryptoRouter.getPublicKey();
It printed '111'.But I cannot POST /get-public-key.
How should I do?Thanks!

Answer 1

I think getPublicKey should return the public key instead
function getPublicKey() {
fs.readFile(__dirname + '/keys/rsa-pub.pem', 'utf8', (err, data) => {
if (err) {
throw err
}
return data
})
}
Then, in app.js
app.post('/get-public-key', (req, res) => {
res.send(getPublicKey)
})
Edit
If you wanna use router, you should do like this:
// ./routes/somewhere.js
const router = require('express').Router()
router.post('/something', (req, res) => {
res.send('You made it!')
})
module.exports = router
Then
// ./app.js
app.use('/somewhere', require('./routes/somewhere'))
Finally, you can make a post request to /somewhere/something.

Answer 2

You can pass the instance of app to your function and return the route
function getPublicKey(app) {
console.log('111');
return app.post('/get-public-key', (req, res) => {
fs.readFile(__dirname + '/keys/rsa-pub.pem', 'utf8', (err, data) => {
if (err) {
throw err
} else {
res.send(data)
}
})
})
}
module.exports = {
getPublicKey
}
Then in your app.js you could simply invoke by passing in the instance of app:
const cryptoRouter = require('./modules/crypto/router');
cryptoRouter.getPublicKey(app);