pump-chain

A module that glues pump and bubble-stream-error to make life easier when piping streams internally and returning an outer stream.

what problem does it solve?

Consider the situation when you are piping multiple streams internally and returning an outer stream. That stream will be handled by users of your module so you need to make sure that the errors coming from the internal streams propagate to the outer one (which bubble-stream-error takes care of), otherwise they can't be caught and will blow up the process. Also if one of the inner streams closes you want to make sure that the others get closed as well (which pump does).

usage

Simply pass the streams you want to pipe together to pump-chain.

1var pump = require('pump-chain');
2var crypto = require('crypto');
3var fs = require('fs');
4var zlib = require('zlib');
5
6function getEncryptedCompressedWordsStream() {
7  var gzip = zlib.createGzip();
8  var password = new Buffer('car cat tree fireman');
9  var aes = crypto.createCipher('aes-256-cbc', password);
10
11  var rs = fs.createReadStream('/usr/share/dict/words');
12
13  // uncomment to simulate an error
14  /*
15  var i = 0;
16  rs.on('data', function() {
17    if (++i === 3) {
18      this.emit('error', new Error('3 is unlucky!'));
19    }
20  });
21  */
22
23  return pump(rs, aes, gzip);
24}
25
26getEncryptedCompressedWordsStream().on('error', function handleError(err) {
27  console.error('\n!!! something bad happened while streaming stuff !!!\n');
28  throw err;
29}).pipe(process.stdout);

tests

1npm test

related

mississippi stream utility collection which includes more useful stream modules similar to this one

license

MIT