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until-stream

0.2.2 • Public • Published

until-stream Build Status

Ever wanted to pause a stream when a certain String or a binary signature is reached? UntilStream is the answer. Pipe UntilStream and automatically stop when your pattern is reached or call read() until the returned data matches your pattern, without excessively buffering your stream's content in memory.







Stability - API is somewhat unstable







read() and pipe() are implemented with some limitations.
For example, UntilStream supports piping to only a
single destination stream.

Installation


$ npm install until-stream


Quick Examples


Pipe


var UntilStream = require('until-stream');
var streamBuffers = require("stream-buffers");
 
var us = new UntilStream({ pattern: 'World'});
 
var sourceStream = new streamBuffers.ReadableStreamBuffer();
sourceStream.put("Hello World");
var writableStream = new streamBuffers.WritableStreamBuffer();
 
sourceStream.pipe(us).pipe(writableStream);
 
writableStream.once('close', function () {
  //writeableStream contains all data before the pattern occurs
  var str = writableStream.getContentsAsString('utf8'); // 'Hello '
  //Now the next call to read() returns the pattern
  var data = us.read(); // 'World'
});


Read


var UntilStream = require('until-stream');
var streamBuffers = require("stream-buffers");
 
var us = new UntilStream({ pattern: 'jumps'});
 
var sourceStream = new streamBuffers.ReadableStreamBuffer({ chunkSize: 8 });
sourceStream.put("The quick brown fox jumps over the lazy dog");
 
sourceStream.pipe(us);
 
us.on('readable', function() {
  if (us.read() === 'jumps') {
    console.log('Pattern reached!');
  }
});


API Index


UntilStream



UntilStream also includes stream.Readable and
stream.Writable methods. See the node v0.9 Stream documentation for more.


API Documentation


## UntilStream

### new UntilStream([options])

Arguments


    

  • options (optional)

      

    • pattern - String or Buffer If provided, UntilStream will
stop reads or pipes when reached
      • 

    

    • 



### us.read([size])

Synchronously consume data from UntilStream's internal
buffer. If the specified pattern is detected within the
current chunk, slice off the portion prior to the pattern.
The next call to read() will return exactly the pattern.
Otherwise return the current chunk.


Arguments


    

  • size (optional) - Mininum number of bytes to read. If not
specified return the entire content of
the internal buffer or up to the pattern
    • 



Return


Buffer | null


Example


var us = new UntilStream({ pattern: '\n' });
 
us.write("Hello\nWorld");
var hello = us.read();
console.log(hello.toString('utf8'));
us.read(); //matches '\n' pattern!
var world = us.read();
console.log(world.toString('utf8'));


### us.pipe(destination, [options])

Pipe incoming data from UntilStream to the destination
WriteStream. If the pattern is reached, leave the pattern
on the internal buffer, disconnect the pipe, and call end()
on the destination. Back-pressure is properly managed.


Arguments


    

  • destination - The Stream to pipe data to
    • 

  • options (optional)

      

    • end Boolean Default=false
      • 

    

    • 



Return


Stream - the destination stream


Example


var us = new UntilStream({ pattern: '\n' });
var loremIpsumStream = fs.createReadStream('loremIpsum.txt');
var outputStream = fs.createWriteStream(path.join(__dirname, 'loremIpsum.out'));
 
loremIpsumStream.pipe(us).pipe(outputStream).on('close', function() {
  console.log('single line of Lorem Ipsum written to disk');
});


### us.reconfigure([options])

Reconfigure the pattern option. It's unwise to call this method
while piping to a destination stream.


Arguments


    

  • options (optional)

      

    • pattern - String or Buffer If provided, UntilStream will
stop reads or pipes when reached
      • 

    

    • 



Example


var us = new UntilStream();
 
us.write("Hello\nWorld");
us.reconfigure({ pattern: '\n' });
var hello = us.read();
console.log(hello.toString('utf8'));
us.read(); //matches '\n' pattern!
var world = us.read();
console.log(world.toString('utf8'));


License


MIT


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Install
npm i until-stream
Repository
github.com/EvanOxfeld/until-stream
Homepage
github.com/EvanOxfeld/until-stream#readme
Weekly Downloads
4
Version
0.2.2
License
MIT
Last publish
Collaborators
  • evanoxfeld
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