Netpack NPM | npm.io

netpack

Fast + lightweight binary packet encoder/decoder for entities in multiplayer games

npm

Install

npm i netpack

Usage - Server

const Packer = require('netpack')

// Create packer instance
// Define your fields
// fieldName : dataType
let packer = new Packer({
    'name': 'string',
    'x': 'uint16',
    'y': 'uint16',
    'leaderboard': 'json', // json encodes with messagepack
})

// Construct your game's state object in this format:
// TIP: You can leave .entities or .messages undefined to send none
let gamestate = {
    entities: [
        {
            id: 10,
            fields: {
                'name': 'Mike Tromba',
                'x': 50,
                'y': 50,
            }
        }
        // ...
    ],
    messages: {
        'leaderboard': [124, 564, 2135, 7455]
    }
}

// Encode and send it
let buffer = packer.pack(gamestate)
// Now send to client via websocket or whatever transport you're using

Usage - Client

// ON CLIENT:
// Construct your packer instance the same way you did on server.
// When you recieve a packet from the server, decode it with .unpack()
let unpacked = packer.unpack(buffer)
console.log(unpacked)

Available Data Types

For more info, see: https://github.com/phretaddin/schemapack

Type Name	Aliases	Bytes	Range of Values
bool	boolean	1	True or false
int8		1	-128 to 127
uint8		1	0 to 255
int16		2	-32,768 to 32,767
uint16		2	0 to 65,535
int32		4	-2,147,483,648 to 2,147,483,647
uint32		4	0 to 4,294,967,295
float32		4	3.4E +/- 38 (7 digits)
float64		8	1.7E +/- 308 (15 digits)
string		varuint length prefix followed by bytes of each character	Any string
json		encodes to a string via JSON.stringify	Any object or array
varuint		1 byte when 0 to 127 2 bytes when 128 to 16,383 3 bytes when 16,384 to 2,097,151 4 bytes when 2,097,152 to 268,435,455 etc.	0 to 2,147,483,647
varint		1 byte when -64 to 63 2 bytes when -8,192 to 8,191 3 bytes when -1,048,576 to 1,048,575 4 bytes when -134,217,728 to 134,217,727 etc.	-1,073,741,824 to 1,073,741,823
buffer		varuint length prefix followed by bytes of buffer	Any buffer

Performance

To run your own, modify `tests/benchmark.js`

These tests were run with a realistically-large payload for a multiplayer game running at a 20 tickrate
I optimized each as best I could to squeeze out extra performance. For example, for the msgpack-lite and JSON.stringify payloads, I crushed all of the json keys (ex. 'name' becomes 'n')
JSON.stringify produced by far the largest payloads... not recommended for heavy realtime networking
kbps is estimated per-player

netpack:  11.48 kbps
msgpack-lite:  13.62 kbps
JSON.stringify:  25.78 kbps

netpack encode x 46,798 ops/sec ±1.76% (87 runs sampled)
msgpack-lite encode x 27,174 ops/sec ±0.77% (96 runs sampled)
JSON.stringify x 94,533 ops/sec ±0.72% (95 runs sampled)