Crash when reciving response split into multiple packets

[BamaJoe411]

`/home/bamajoe411/Documents/discord-bot/node_modules/modern-rcon/rcon.js:100
throw new RconError('Responded id did not match sent id');
^

RconError: Responded id did not match sent id
at Rcon._handleResponse (/home/bamajoe411/Documents/discord-bot/node_modules/modern-rcon/rcon.js:100:13)
at emitOne (events.js:116:13)
at Socket.emit (events.js:211:7)
at addChunk (_stream_readable.js:263:12)
at readableAddChunk (_stream_readable.js:250:11)
at Socket.Readable.push (_stream_readable.js:208:10)
at TCP.onread (net.js:597:20)
`

[levrik]

Ah, yeah. Splitted packets aren't supported at the moment. Which server-side implementation are you using for your project?

[BamaJoe411]

Minecraft 1.13.1 Java Edition

[levrik]

What did you exactly do to trigger a splitted packet?
I tested this with Minecraft 1.11.2 Java Edition back then and that seemed to didn't use splitted packets.

[BamaJoe411]

If the response is larger than the maximum allowed in one packet then the response is split up into multiple packets

https://wiki.vg/RCON#Implementation_details

[levrik]

Ah, okay. Since I don't have that much time at the moment it would be awesome if you could prepare a PR for me to review.
Let me know if it's not possible for you to do. Then I can take care of it but it will take time.

[BamaJoe411]

PR?

[levrik]

Pull Request

[BamaJoe411]

i see in the code that the id of the sending and receiving packets is the 5th field. where do i find which field is what? (if you cant tell i have no clue what im doing xD)

[levrik]

Not sure what you're asking. Can you rephrase your question?

[lewck]

I spent the best part of today attempting to implement this but got nowhere unfortunately, I'll dump my findings so anyone else looking to fix this can avoid the issues I ran into.

The simplest solution I found was checking the length in _handleResponse, if greater than max packet length (4096+10), add to an ephemeral mapping of id => messages and don't callback. When the next message comes in < (4096+10), join everything in the ephemeral mapping and callback.

This method worked well and was reliable as far as I could tell, however if a message came in at exactly max bytes, the service would hang and timeout waiting for more data. McTools gets around this by utilising the queuing nature of the RCON service and sending a dummy packet, once that packet has been received you can assume the previous message has completed. I'm not sure if it's a lower level network difference between the languages, this projects design or my poor attempt that meant I couldn't get this type of implementation to work reliably!

[levrik]

@lewck Could you let me know how I can reproduce this issue, meaning how to trigger a split packet from a MC RCON server? If I find some time I'll try to fix this.

[lewck]

Sure, the method I use to get a larger packet is running data get entity [username], but the player must be connected