ServerHandshake calls Packet.readNullTerminatedString without encoding

[tims-bsquare]

If using server_handshake.js and adding a listener for field_list then it will call const table = packet.readNullTerminatedString();.

It appears that the function expects an encoding and if it doesn't get one I see a stack trace like this

Error: Encoding not recognized: 'undefined' (searched as: 'undefined')
    at Object.getCodec (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/node_modules/iconv-lite/lib/index.js:104:23)
    at Object.getDecoder (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/node_modules/iconv-lite/lib/index.js:125:23)
    at Object.exports.decode (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/parsers/string.js:10:25)
    at Packet.readNullTerminatedString (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/packets/packet.js:412:25)
    at ServerHandshake.dispatchCommands (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/commands/server_handshake.js:141:32)
    at ServerHandshake.execute (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/commands/command.js:45:22)
    at Connection.handlePacket (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/connection.js:489:32)
    at PacketParser.onPacket (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/connection.js:94:12)
    at PacketParser.executeStart (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/packet_parser.js:75:16)
    at Socket.<anonymous> (/home/tstableford/projects/sq-dev/service-db-proxy/node_modules/mysql2/lib/connection.js:101:25)

I wouldn't have noticed though if not having to make use of the workaround documented here #528 (comment)

Thanks for providing utils to run as a server though :)

Hacky fix for anybody else who stumbles across this, written in TypeScript.

try {
  const Packet = require('../node_modules/mysql2/lib/packets/packet.js');
  Packet.prototype.readNullTerminatedStringOriginal = Packet.prototype.readNullTerminatedString;
  Packet.prototype.readNullTerminatedString = function (encoding?: string): string {
    return Packet.prototype.readNullTerminatedStringOriginal.call(this, encoding || 'utf8');
  }
} catch (err) {
  console.error('Failed to overwrite readNullTerminatedString. Connections using deprecated syntax will fail', err);
}

By the way I'm happy to PR this if you like.

[sidorares]

sure, happy to discuss a PR

[tims-bsquare]

Thanks @sidorares PR open

[sidorares]

@tims-bsquare https://github.com/sidorares/node-mysql2/releases/tag/v3.2.4

[tims-bsquare]

That's brilliant, thanks @sidorares !