Reputation: 8313
I am starting to learn NodeJS and started to make a small application that encrypts and decrypts a file upon user click request. The below code works fine on first encryption request but crashes on another.
App.js
var fs = require('fs')
var crypto = require('crypto')
const express = require('express')
const app = express()
const port = 3000
var key = '1bd';
var cipher = crypto.createCipher('aes-256-cbc', key);
var decipher = crypto.createDecipher('aes-256-cbc', key);
app.use(express.static('public'))
app.get('/', (req, res) => {
res.sendFile('/enc-dec.html', { root: __dirname })
})
app.post('/encrypt', (req, res) => {
fs.createReadStream('input.txt')
.pipe(cipher)
.pipe(fs.createWriteStream('input.txt.enc'))
.on('finish', function() {
res.end("Encrypted")
});
})
app.listen(port, () => console.log(`App listening on port ${port}!`))
Error:
NodeError: write after end
at writeAfterEnd (_stream_writable.js:237:12)
at Cipher.Writable.write (_stream_writable.js:287:5)
at ReadStream.ondata (_stream_readable.js:646:20)
at ReadStream.emit (events.js:180:13)
at addChunk (_stream_readable.js:269:12)
at readableAddChunk (_stream_readable.js:256:11)
at ReadStream.Readable.push (_stream_readable.js:213:10)
at fs.read (fs.js:2123:12)
at FSReqWrap.wrapper [as oncomplete] (fs.js:680:17)
Emitted 'error' event at:
at Cipher.onerror (_stream_readable.js:670:12)
at Cipher.emit (events.js:180:13)
at writeAfterEnd (_stream_writable.js:239:10)
at Cipher.Writable.write (_stream_writable.js:287:5)
[... lines matching original stack trace ...]
at fs.read (fs.js:2123:12)
I am not expert in that but it seems issue with fs. Any help would be greatly appreciated. Thanks!
Upvotes: 3
Views: 2227
Reputation: 7004
Your problem is that you're reusing the same cipher multiple times. After it's used in a stream once, it cannot be reused; a new one must be created.
You should create your cipher in the request handler, like this:
app.post('/encrypt', (req, res) => {
var cipher = crypto.createCipher('aes-256-cbc', key);
fs.createReadStream('input.txt')
.pipe(cipher)
.pipe(fs.createWriteStream('input.txt.enc'))
.on('finish', function() {
res.end("Encrypted")
});
})
It doesn't look like you have the decrypt functionality done yet, but when you build that, you'll also need to move var decipher = crypto.createDecipher('aes-256-cbc', key);
down into the request handler, because deciphers can't be reused either.
Upvotes: 1