node-datapipe

An extendable Node.js Buffer class with promised-based piping.

This library was built to be used as a base class for node-task buffer interfaces.

API

Inherits Node.js Buffer.

constructor(source, encoding, data)

Create a Node.js Buffer with additional properties and methods.

source

An property identifying the buffer's source: filepath, url, object, etc.

encoding

String property containing buffer's encoding.

clone()

Return a clone of the instance.

content(input)

Fill buffer synchronously and return self for chaining. Input may be any Buffer, or a string which is valid for the instance's encoding.

read(opts)

Read contents of source into buffer and return a promise which resolves to self. If any additional parameters are required for loading (i.e. providing a s3 client), they can be passed in via opts. If the buffer already contains data this should immediately return a promise which resolves to self. This is a noop until extended (see node-filebuffer and node-s3buffer for examples).

write(opts)

Write contents of buffer to source and return a promise which resolves to self. If any additional parameters are required for saving (i.e. providing a s3 client, acl settings, etc), they can be passed via opts. This is a noop until extended (see node-filebuffer and node-s3buffer for examples).

pipe(method)

Load data into buffer (if not already loaded) and process it with method, yielding a promise which resolves to methods's return value.

::extend(config)

Create a new DataPipe constructor with the keys of config object assigned to its prototype. At a minimum, this should define read and write methods (see node-filebuffer and node-s3buffer for examples).

Usage

var DataPipe = require('datapipe');
var buffer = new DataPipe('path/to/source');
buffer.source; // path/to/source
buffer.content('foo'); // <Buffer 66 6f 6f>
buffer.toString(); // 'foo'
buffer.content('data').toString(); // 'data'
buffer.content(new Buffer('data')).toString(); // 'data'
buffer.content(new Buffer('64617461', 'hex')).toString(); // 'data'

var buffer = new DataPipe('path/to/source', 'hex');
buffer.content('data'); // TypeError: Invalid hex string (encoding defaults to hex)
buffer.content(new Buffer('data','utf8')).toString(); // '64617461'

var buffer = new DataPipe('path/to/source');
buffer.content('foo');
var addBar = function(buffer) {
  var input = buffer.toString();
  return buffer.content(input+" bar");
};
var addBaz = function(buffer) {
  var input = buffer.toString();
  return buffer.content(input+" baz");
}
buffer.pipe(addBar).then(addBaz).then(function(piped) {
  console.log(piped.toString()); // 'foo bar baz'
});