Painless streaming binary protocol parsers using generators.
npm install binary-parse-streamPainless streaming binary protocol parsers using generators.
npm install binary-parse-stream
This module uses the exact same generator interface as binary-parser, which presents a synchronous interface to a generator parser.
``javascript`
var BinaryParseStream = require('binary-parse-stream')
, One = BinaryParseStream.One // -1
BinaryParseStream is a TransformStream that consumes buffers and outputs objects on the other end.
It expects your subclass 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 -1, it'll be given the value of the first byte instead of a single-byte buffer.
When your generator returns, the return value will be pushed to the output side.
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.
`js
var BinaryParseStream = require('binary-parse-stream')
, inherits = require('util').inherits
module.exports = SillyProtocolParseStream
inherits(SillyProtocolParseStream, BinaryParseStream)
function SillyProtocolParseStream(options) {
BinaryParseStream.call(this, options)
}
SillyProtocolParseStream.prototype._parse = function*() {
var type = (yield 4).readUInt32BE(0, true)
, length = yield -1
, buf = yield length
return { type: type, buf: buf }
}
`
There is also a shorter syntax for when you don't want to explicitly subclass: BinaryParseStream.extend(function*())`.