javascript - How do I write a Node.js module to handle an incoming piped stream -

i'm trying write node module accepts incoming piped binary (or base-64-encoded) stream, frankly don't know start. can't see examples in node docs handling incoming streams; see examples on consuming them?

say example want able this:

var asset = new projectasset('myfile', __dirname + '/image.jpg') var stream = fs.createreadstream(__dirname + '/image.jpg', { encoding: 'base64' }).pipe(asset) stream.on('finish', function() {     done() }) 

i've gotten projectasset looking this, i'm @ loss of go next:

'use strict'  var stream = require('stream'),     util = require('util')  var projectasset = function() {     var self =      object.defineproperty(self, 'binarydata', {         configurable: true,         writable: true     })      stream.stream.call(self)      self.on('pipe', function(src) {         // happen here? how set self.binarydata?     })      return self }  util.inherits(projectasset, stream.stream)  module.exports = projectasset module.exports.default_file_name = 'file' 

it possible inherit stream.stream , make work, based on what's available in documentation suggest inheriting stream.writable. piping stream.writable you'll need have _write(chunk, encoding, done) defined handle piping. here example:

var asset = new projectasset('myfile', __dirname + '/image.jpg') var stream = fs.createreadstream(__dirname + '/image.jpg', { encoding: 'base64' }).pipe(asset) stream.on('finish', function() {     console.log(asset.binarydata); }) 

project asset

'use strict'  var stream = require('stream'),     util = require('util')  var projectasset = function() {     var self =      self.data     self.binarydata = [];      stream.writable.call(self)      self._write = function(chunk, encoding, done) {         // can handle data want         self.binarydata.push(chunk.tostring())         // call after processing data         done()     }     self.on('finish', function() {         self.data = buffer.concat(self.binarydata)     })      return self }  util.inherits(projectasset, stream.writable)  module.exports = projectasset module.exports.default_file_name = 'file' 

if you're looking read stream, take @ inheriting stream.duplex , including _read(size) method.

there's simplified constructors api if you're doing simpler.