node-stream-reader v0.0.4

node-stream-reader

Buffered stream reader allowing asynchronous requests for a specified number of bytes.

Purpose

Node ReadableStream instances allow receiving data as a sequence of asynchronous data events or by calling the synchronous read([size]). data events send blocks of data as it is avaialble, but the number and size of the blocks is unpredicatable, leaving the receiver to wait for and reassemble the desired data. The read([size]) method will return a block of the requested size if enough data is available, but if not it returns null and the caller must try again.

In some use cases--such as for message protocols with messages of known size--the reader wants to wait for a block of a specific size.

node-stream-reader allows a client to request a block of a specific size via an asynchronous callback.

API

constructor(stream)

Create a new instance to read from stream. The stream is paused until calling read so any incoming data will be buffered.

read(read_size, callback(err, data) , timeout)

Read a buffer of read_size bytes from the stream. When enough data is available, callback is called with the requested buffer.

If the read fails with an error, the first parameter err will be non-null.

Sequential reads can be performed with a single reader instance.

close()

Close the reader and remove all event listeners installed by the reader. The socket is left open and paused.

Usage Example

const TIMEOUT_MS = 5000;
var StreamReader = require('node-stream-reader');

var stream = getReadableStreamSomehow();
var reader = new StreamReader(stream);

//Read 1K from the stream, waiting up to 5 seconds if necessary
reader.read(1024, function(err, data){
	if( err ) {
		//...handle the error...
	} else {
		//...do something with the data
	}
	reader.close();	
}, TIMEOUT_MS);