nondest

Super simple, dependency-free temporary file creator for 'non-destructive' operations in your node.js app.

About

nondest is for times when you need to be able to safely edit (or hack away at) the contents of a file from within a node application for some purpose, without ever wanting to actually alter the data on disk.

I've experienced file corruption during long running operations with open file streams, so with this I'm safely working on copied data.

Node.js compatibility

v0.8.0+

Installation

npm install nondest

Usage

There's not much to it. Call create with the path and options to use, and work with the files after the available event fires.

NOTE: a call to remove() is required to delete the temp directory.

Setup

    var nondest = require('nondest');

Create the temporary copy & wait for it's availability:

nondest.create('../filepath', {
    }).on('available', function(tmppath) {
    
		// hack away on files in tmppath	
	
	}).on('error', function(err){
		// do something with err
	});

Cleanup

If you want to keep $TMPDIR tidy:

process.on('exit', function(){
	nondest.remove(function(err){
		// handle error during rmdir
    });
});

Events

The following events are emitted:

• available: files have finished copying and are ready at the returned tmppath path
• error: domain error occurred within the module

Options

The following options are available:

• id: the temp directory name, defaults to util.format('_nondest_%s_%s', process.pid, new Date().getTime()), or you can pass in something super unique
• limit: the number of simultaneous "workers" allowed during copy operation - defaults to 12
• filter: a RegExp or function() to filter what gets copied
• temppath: provide a path to override the use of $TMPDIR if you wish

Info

A couple of notes:

All functionality in the module is wrapped in a domain so any errors encountered should only bubble up to nondest's domain.on('error') which then will fire it's error event for you to handle.

I have not yet tested this on every platform so please open an issue if you find any platform or other bugs. And be sure to submit a pull request if you tweak, correct, or otherwise improve the code ; )