binary-parse-stream

binary-parse-stream

Painless streaming binary protocol parsers using generators.

Installation

npm install binary-parse-stream

Usage

var BinaryParseStream = require('binary-parse-stream')
  , One = BinaryParseStream.One

BinaryParseStream is a TransformStream that consumes buffers and outputs objects on the other end. It expects your sublcass to implement a _parse method that is a generator. When your generator yields a number, it'll be fed a buffer of that length from the input. If it yields the special One object, it'll be given the value of the first byte. When your generator returns, the return value will be pushed to the output side.

Example

The following module parses a protocol that consists of a 32-bit unsigned big-endian type parameter, an unsigned 8-bit length parameter, and a buffer of the specified length. It outputs {type, buf} objects.

var BinaryParseStream = require('binary-parse-stream')
  , One = BinaryParseStream.One
  , inherits = require('util').inherits

module.exports = SillyProtocolParseStream
function SillyProtocolParseStream(options) {
  BinaryParseStream.call(this, options)
}
SillyProtocolParseStream.prototype._parse = function*() {
  var type = (yield 4).readUInt32BE(0, true)
    , length = yield One
    , buf = yield length
  return { type: type, buf: buf }
}