fingerprinting

[![Version npm][version]](http://browsenpm.org/package/fingerprinting)[![Build Status][build]](https://travis-ci.org/3rd-Eden/fingerprinting)[![Dependencies][david]](https://david-dm.org/3rd-Eden/fingerprinting)[![Coverage Status][cover]](https://coveralls.io/r/3rd-Eden/fingerprinting?branch=master)

[version]: https://img.shields.io/npm/v/fingerprinting.svg?style=flat-square
[build]: https://img.shields.io/travis/3rd-Eden/fingerprinting/master.svg?style=flat-square
[david]: https://img.shields.io/david/3rd-Eden/fingerprinting.svg?style=flat-square
[cover]: https://img.shields.io/coveralls/3rd-Eden/fingerprinting/master.svg?style=flat-square

Fingerprinting is a cache-busting technique which allows you to expire files
when they actually change this is done by altering the filenames of the files.
This way you can set far future expire headers without having to worry that your
users might see stale or old files. Providing you with best of 2 worlds, cached
assets for increased performance with sacrificing your ability to instantly
modify files.

Installation

The module is released in the public npm registry and can be installed by
running:

``
npm install --save fingerprinting
`

Usage

The fingerprinting module is exposed as a single function that generates the
new filenames for your files. In all examples we assume that you've already
required the module as followed;

`js
'use strict';

var finger = require('fingerprinting');
`

The exported finger function accepts the following arguments:

- file The path to the file or filename of the file where we're generating
the file from. This is used to extract the file extension and read the file
contents if no contents option is provided (please do note that reading is
done using a sync fs method).
- options Optional configuration for the fingerprint generation:
- format: Template that specifies the format of the generated fingerprint.
Defaults to {hash}.{suffix}.{ext}.
- algorithm Hashing algorithm to be used to generate source hash. Defaults
to md5.
- map Also generate an unique id for source maps. Defaults to false.
- env Environment that we're generating it for. It is used to generate the
suffix in the filename format. For example production generates a min
suffix while a mising or development generates a dev suffix. Defaults to
NODE_ENV.
- content The actual content of the filename. This eliminates the need to
do a fs.readFileSync within the code. It can be either a string or Buffer.

The function returns an object with 2 keys:

- file This is the new filename for the given file.
- map If the map option was set to true this will contain the filename
for your source map file.

#### Example

`js
var fs = require('fs');

fs.readFile(__dirname + '/index.js', function (err, buffer) {
if (err) throw err;

var print = finger('index.js', {
content: buffer
});

console.log('print:', print.file); // 167f581dd914ba9d3d2e6c8820a5caa6.dev.js
});
``

License

MIT