node 16 and aws-sdk

[Ockejanssen]

When using node 16 the following code fails with Error [ERR_MULTIPLE_CALLBACK]: Callback called multiple times It does not happen on node 14.

It seems to be a problem with the highWaterMark. When it is low enough, it works.

const fs = require('fs'); const NodeClam = require('clamscan');

const {Writable} = require('stream');

class MyWritable extends Writable { constructor(options) { super(options); } _write(chunk, encoding, callback) { // console.log("xxxxxx", arguments); callback(); } }

async function test() { const source = fs.createReadStream('./README.md', {highWaterMark: 512}); const clamscan = await new NodeClam().init({clamdscan: {host: 'localhost', port: 3310}, debugMode: true}); const av = clamscan.passthrough(); av.on('finish', () => {console.log('--------------av finished');}); av.on('error', (error) => {console.log('--------------av error', error);}); av.on('scan-complete', (result) => {console.log('--------------av scan-complete', result);}); const mywritable = new MyWritable(); mywritable.on('error', (error) => {console.log('--------------mw error', error);}); mywritable.on('finish', () => {console.log('--------------mv finished');}); source.pipe(av).pipe(mywritable).on('finish', () => {console.log('all done', arguments);}); }

test();

[kylefarris]

I'm running low on bandwidth at the moment. I'm very open to pull requests. The source is pretty straightforward and well-documented. I'll have to address this sooner or later as we have production services that use clamscan that need to be updated to node 16.

But, yeah... any help would be great!

[ngraef]

See discussion on https://github.com/nodejs/node/issues/39535. This is caused by a behavior change in node 16 that tried to support Promise-returning stream implementation methods. That behavior was quickly deprecated because of the issues it caused. The error occurs when you try to return a Promise (async) and call the callback in the same function, like here in passthrough()'s Transform implementation:

https://github.com/kylefarris/clamscan/blob/c1d4f4c6114dbe74e7e40954944b70f3ac871b90/index.js#L1185

I'll open a PR with a fix.