msgpack5 ![Build Status](https://travis-ci.org/mcollina/msgpack5.png)
A msgpack v5 implementation for node.js, with prototype-based extension points.
This library was built as the data format for
JSChan.
Install
npm install msgpack5 --save
Usage
var msgpack = require('msgpack5')()
, assert = require('assert')
, a = new MyType(2, 'a')
, encode = msgpack.encode
, decode = msgpack.decode
msgpack.register(0x42, MyType, mytipeEncode, mytipeDecode)
console.log(encode({ 'hello': 'world' }).toString('hex'))
console.log(decode(encode({ 'hello': 'world' })))
console.log(encode(a).toString('hex'))
console.log(decode(encode(a)) instanceof MyType)
console.log(decode(encode(a)))
function MyType(size, value) {
this.value = value
this.size = size
}
function mytipeEncode(obj) {
var buf = new Buffer(obj.size)
buf.fill(obj.value)
return buf
}
function mytipeDecode(data) {
var result = new MyType(data.length, data.toString('utf8', 0, 1))
, i
for (i = 0; i < data.length; i++) {
if (data.readUInt8(0) != data.readUInt8(i)) {
throw new Error('should all be the same')
}
}
return result
}
API
API
msgpack()
Creates a new instance on which you can register new types for being
encoded.
encode(object)
Encodes object
in msgpack, returns a bl.
decode(buf)
Decodes buf from in msgpack. buf
can be a Buffer
or a bl instance.
registerEncoder(check(obj), encode(obj))
Register a new custom object type for being automatically encoded.
The arguments are:
check
, a function that will be called to check if the passed
object should be encoded with the encode
functionencode
, a function that will be called to encode an object in binary
form; this function must return a Buffer
which include the same type
for registerDecoder.
registerDecoder(type, decode(buf))
Register a new custom objet type for being automatically decoded.
The arguments are:
type
, is a positive integer identificating the type once serializeddecode
, a function that will be called to decode the object from
the passed Buffer
register(type, constructor, encode(obj), decode(buf))
Register a new custom objet type for being automatically encoded and
decoded. The arguments are:
type
, is a positive integer identificating the type once serializedconstructor
, the function that will be used to match the objects
with instanceof
encode
, a function that will be called to encode an object in binary
form; this function must return a Buffer
that can be
deserialized by the decode
functiondecode
, a function that will be called to decode the object from
the passed Buffer
This is just a commodity that calls
registerEncoder
and
registerDecoder
internally.
encoder(opts)
Builds a stream in object mode that encodes msgpack. By default it writes
an 4 byte length header containing the message length as a UInt32BE. This
header can be disabled by passing { header: false }
as an option.
decoder(opts)
Builds a stream in object mode that decodes msgpack. By default it expects
msgpack to have a 4 byte length header containing the packaged length as
a UInt32BE. This header can be disabled by passing { header: false }
as an option.
Disclaimer
This library is built fully on JS and on bl to
simplify the code. Every improvement that keeps the same API is welcome.
Acknowledgements
This project was kindly sponsored by nearForm.
License
MIT