Handy little well tested module for reading length-prefixed binary packets.
Since buffers come off a socket in randomly sized chunks you can't expect them to cleanly break on packet boundaries. This module allows you to push buffers in and read full packets out the other side, so you can get to parsing right away and not have to manage concatenating partial buffers and searching through them for packets.
$ npm install packet-reader
var Reader = require('packet-reader')
var reader = new Reader()
//assuming you have a socket emitting `data` events
socket.on('data', function(buffer) {
reader.addChunk(buffer)
var packet = reader.read()
while(packet) {
//do something with fully parsed packet
}
})here's a more full featured example:
let's assume our "packet" for our protocol is 32-bit Big Endian length-prefixed strings
so a "hello world" packet would look something like [length, string]
[0, 0, 0 0x0B, h, e, l, l, o, w, o, r, l, d]
var Transform = require('stream').Transform
var Reader = require('packet-reader')
var reader = new Reader()
var parser = new Transform()
parser._transform = function(chunk, encoding, cb) {
reader.addChunk(chunk)
var packet = reader.read()
while(packet) {
this.push(packet.toString('utf8'))
packet = reader.read()
}
cb()
}
var server = net.createServer(function(socket) {
socket.pipe(parser).pipe(stdout)
})There are a few config options for setting optional pre-length padding byte. Read the tests for details.
MIT
Copyright 2015 Brian M. Carlson All rights reserved.
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