cachifest

This is a command line tool for watching for directory changes. Each time a file is updated in this directory, cachifest assembles an updated manifest.json file which has a map of file renames

cachifest is useful for making efficient http caching with following features:

1. All static files have far future expiration without revalidation.
2. If a static file changed it should be invalidated by composing a new unique url for it.
3. Developers and admins don't need to run any maintenance scripts after rolling new changes to servers.

It can be achieved bu using cachifest in this scheme:

1. you run cachifest (consider running it using upstart, monit, supervisord, etc.) to monitor a directory. Usually it should be static files dir in your project and it should be accessible via http.
2. an http app (site, flash, etc) loads manifest.json:

{
     'client.swf': 'client_v1354729620000203.swf',
     'assets/bg.swf': 'assets/bg_v1354729620000203.swf',
     ...
}

It's usually better to load manifest.json?rand=... with some random payload to avoid manifest.json caching for sure. 3. in order to load a file it makes a lookup for a path, e.g. 'client.swf'. 4. if the file is mentioned in the manifest.json it can be accessed by an alternative name client_v1354729620000203.swf. 5. then your app loads the file by the alternative name. 6. whatever web server you use it should be configured to rewrite client_v1354729620000203.swf back to client.swf and send this file.

Installation

npm install [-g] cachifest

Usage

$ ./cachifest.js --help
Usage: node ./cachifest.js [--help] [--manifest file] [--dir dir]

Options:
  --help      print out help and exit  [boolean]
  --manifest                           [default: "manifest.json"]
  --dir                                [default: "."]

Nginx snippet

location /static {
    location ~ ^(/static/.*)_v[0-9]+(\.(swf|dat|jpeg|jpg|png|gif|ogg|mp3|js|json))$ {
        expires max;
        rewrite ^(/static/.*)_v[0-9]+(\..*)$ $1$2 break;
    }
}

Supervisord snippet

[program:cachifest]
directory=/var/www/project/htdocs/static
command=cachifest
autostart=true
autorestart=true
startretries=10
stdout_logfile=/var/www/project/log/cachifest.txt
stderr_logfile=/var/www/project/log/cachifest.txt