Object has no method 'copy' (Buffer API change in Node v4)

[STRML]

buffer.js:499
    buf.copy(buffer, pos);
        ^
TypeError: Object  has no method 'copy'
  at Function.Buffer.concat (buffer.js:499:9)
  at IncomingMessage.onData (/dev/node_modules/engine.io/lib/transports/polling.js:147:23)
  at IncomingMessage.EventEmitter.emit (events.js:95:17)
  at IncomingMessage.<anonymous> (_stream_readable.js:746:14)
  at IncomingMessage.EventEmitter.emit (events.js:92:17)
  at emitDataEvents (_stream_readable.js:771:10)
  at IncomingMessage.Readable.on (_stream_readable.js:692:5)
  at XHR.Polling.onDataRequest (/dev/node_modules/engine.io/lib/transports/polling.js:171:7)
  at XHR.Polling.onRequest (/dev/node_modules/engine.io/lib/transports/polling.js:55:10)
  at XHR.onRequest (/dev/node_modules/engine.io/lib/transports/polling-xhr.js:47:33)
  at /dev/node_modules/engine.io/lib/server.js:178:46
  at Server.verify (/dev/node_modules/engine.io/lib/server.js:126:3)
  at Server.handleRequest (/dev/node_modules/engine.io/lib/server.js:170:8)
  at [object Object].request (/dev/node_modules/primus/transformers/engine.io/server.js:59:18)
  at [object Object].emit (/dev/node_modules/primus/node_modules/eventemitter3/index.js:53:12)
  at emit (/dev/node_modules/primus/node_modules/fusing/index.js:131:24)
  at iterate (/dev/node_modules/primus/transformer.js:120:24)
  at done (/dev/node_modules/primus/transformer.js:142:7)

This has cropped back up with Node v4 as documented in this Primus ticket: primus/primus#196 (comment)

I'm going to try to investigate where this is happening: please see this comment for more information about the Buffer change in core.

[geyang]

👍 !

was just about to open one. I'm running into this problem as well.

[lpinca]

@STRML it should be here.

[STRML]

Ah I think I know how this happens:

The 'data' listener must be called with null at some point while not in Binary mode.

Because the param data is not a string, this calls Buffer.concat(['', null]) which throws the error.

A fix for this should simply be a if (!data) return at the beginning of the 'data' listener, because even in Binary mode this would cause a problem (Buffer.concat([new Buffer(0), null]) throws cannot read property 'length' of null).

Edit: Actually this is not quite right, it will throw the length error before throwing the no method 'copy' error. So whatever data is getting through must not be a String, must have a length property, but is not a Buffer. OR - a Buffer is coming through even though isBinary is false.

[STRML]

So if it can't be a null being passed (because it's the wrong error), and HTTP requests are always supposed to call 'data' with Strings when req.setEncoding() is called, the only thing I can think of is that maybe the 'data' event is firing immediately after setting up the event listener (is that possible?) and before we call setEncoding, causing a Buffer to come down with the event.

[lpinca]

We are disabling binary support in primus so binary data should not come in.

[lpinca]

@STRML there is an open pr exactly for what you are describing (#305) but it's odd.

[STRML]

Just saw this today on an instance running v4.1.2:

TypeError: buf.copy is not a function
    at Function.Buffer.concat (buffer.js:238:9)
    at IncomingMessage.onData (/srv/api/node_modules/engine.io/lib/transports/polling.js:147:23)
    at emitOne (events.js:77:13)
    at IncomingMessage.emit (events.js:169:7)
    at IncomingMessage.Readable.read (_stream_readable.js:360:10)
    at flow (_stream_readable.js:733:26)
    at resume_ (_stream_readable.js:713:3)
    ...

[necccc]

Saw this with 4.2.2 too, when used with primus

buf.copy is not a function

/buffer.js:238 → Function.Buffer.concat
/server/node_modules/engine.io/lib/transports/polling.js:147 → IncomingMessage.onData
/events.js:77 → emitOne
/events.js:169 → IncomingMessage.emit
/_stream_readable.js:360 → IncomingMessage.Readable.read
/_stream_readable.js:743 → flow
/_stream_readable.js:723 → resume_
/node.js:441 → doNTCallback2
/node.js:355 → process._tickCallback

[lpinca]

@necccc this has been fixed in #305 (comment). We have to wait for the next version of Engine.IO.

[noamshemesh]

still happens, even after upgrading to primus 4.0.4 and engine.io 1.6.4. node version 4.2.4
any ideas?

[lpinca]

@noamshemesh that's weird, do you have a way to reproduce it?

[noamshemesh]

we stream data from the db and send it with primus function spark.write
it works well for almost all the times but when there is a lot of data to stream it's crashing with this error:

TypeError: buf.copy is not a function
    at Function.Buffer.concat (buffer.js:238:9)
    at IncomingMessage.onData (/opt/bigpanda/web-api/node_modules/engine.io/lib/transports/polling.js:160:23)
    at emitOne (events.js:77:13)
    at IncomingMessage.emit (events.js:169:7)
...(wrappers)...
    at IncomingMessage.Readable.read (_stream_readable.js:360:10)
    at flow (_stream_readable.js:743:26)
    at resume_ (_stream_readable.js:723:3)

Thanks! in the meanwhile I will try to reproduce it separately

[lpinca]

@noamshemesh please also open a new issue on Primus or continue here: primus/primus#196.