Prerender BA filesystem cache

This is a cache plugin for prerender.

Its a simple file cache or AWS S3 cache but with one quirk, it will always serve a cached page regardless of its TTL. But if the cached file is older than the TTL it will be updated after it's sent the old answer.

Note that the cache is never purged, to do that you simple need to remove the files, there are several other scrips and programs that can remove files older than a certain limit if you need to.

The cache saves a gzipped version of the page (if the request can't handle compression its unpacked before transfer) on disk, the filename is a sha1 hash of the entire URL and is saved

<domain>/<first-two-chars-of-hash>/<sha1-hash-of-entire-url>

In the case of S3 the name is <prefix>/<sha1-hash-of-entire-url>.

Usage file cache

Order of prerender plugins is important, probably best to keep it last in the list.

server.use(require('prerender-ba-fs-cache')({
  cache: 'file',
  ttl: 1000*60*60*5,
  baseDir: '/tmp'
}));

Options

---

Name	Purpose
cache	'file' for file cache
ttl	If the cached file is older than this, then start rendering the page after cached file is served
baseDir	Path to where the cached files should be stored

Usage S3 cache

Order of prerender plugins is important, probably best to keep it last in the list.

server.use(require('prerender-ba-fs-cache')({
  cache: 'S3',
  bucket: 'my-awesome-bucket',
  ttl: 1000*60*60*5,
  prefix: 'file-name-prefix'
  region: 'eu-west-1',
  accessKeyId: '...or set key in ENV variable, config file etc. See aws-sdk docs',
  secretAccessKey: '...same here'.
}));

Options

---

Name	Purpose
cache	'S3' for AWS S3 cache
ttl	If the cached file is older than this, then start rendering the page after cached file is served
bucket	Name of bucket to use
prefix	Prefix to use
region	Wich region to use
accessKeyId	Aws accessKeyId. Can also be set in an ENV variable, config file etc. See aws-sdk docs',
secretAccessKey	Aws secret. Can also be set in an ENV variable, config file etc. See aws-sdk docs',