What is it?

Module provides WriteStream which behaves like fs.WriteStream (and has underlying one, actually), but has some specifics to work in non-blocking way with Unix named pipes (aka FIFO).

What's the difference?

In addition to fs streams, WriteStream provides event nofifo and method init.

Stream fires nofifo if pipe became unavailable for writing. At this point you have two options:

• if listener for the nofifo event was not set, then error will be emitted as fs stream does;
• you can set a listener for nofifo and call WriteStream#init() inside to try to open pipe again.

While pipe is not available for non-blocking write (and underlying fs stream is not initialized), WriteStream#write() returns false. When pipe becomes available, WriteStream emits drain event and client can continue to write into the stream.

Example

var pipePath = '/var/run/mydaemon.pipe',
    fifo = require('fifo-stream').createWriteStream(pipePath);

fifo.on('nofifo', function() {
    // if pipe became unavailable, then wait 1 second and try to reopen it
    setTimeout(function() {
        fifo.init();
    }, 1000);
});

var i = 0,
    messagesToSend = 1000000;

function writeMessages() {
    if (i++ > messagesToSend) {
        return;
    }

    if ( ! fifo.write('the message')) {
        // wait until pipe became available
        fifo.once('drain', writeMessages);
    } else {
        setImmediate(writeMessages);
    }
}

writeMessages();