0.0.1 • Published 6 years ago
express-middleware-cache v0.0.1
@MomsFriendlyDevCo/express-middleware-cache
Express middleware for caching the result of a server action in-memory, MongoDB or MemcacheD.
Features:
- Easy to use syntax - Specify cache times in shorthand durations such as
app.get('/some/api', cache('1h'), (req, res) => ...) - Cache invalidation - Provide a tag for your cache setup and quickly invalidate all matching routes if necessary
- Etag support - Allows the client to make a request by the server generated hash and recieve either a code 200 (with data) or a 304 (Not Modified) response without actually making a full request
- Pluggable interface - Not just in-memory storage! Add any FIXME plugin to hold cache contents over server restarts
Simple example
var cache = require('@momsfriendlydevco/route-cache');
// This route should cache for about about 30 seconds
app.get('/some/api/hourly', cache('30s'), (req, res) => ...)
// This route should cache for about a minute and a half
app.get('/some/api/hourly', cache('1m30s'), (req, res) => ...)
// This route should cache for an hour
app.get('/some/api/hourly', cache('1h'), (req, res) => ...)Cache invalidation
When setting up a cache specify tag / tags and invalidate against them when you want all calls to that route to be refreshed.
// Make a route which only gets refreshed every hour
app.get('/some/api', cache('1h', {tag: 'myApi'}), (req, res) => ...)
// Later after some action which requires a cache reset:
cache.invalidate('myApi');API
cache.defaults
Object containing any future caching objects options.
Supported options:
| Option | Type | Default | Description |
|---|---|---|---|
duration | string | 1h | Default duration to cache for |
cache | object | {} | Options passed to @momsfriendlydevco/cache to setup a cache instance |
hashObject | function | Complex | Method which returns the hashable object to use as the key in the cache. Defaults to hashing req.{method,path,query,body} |
tag | string / array | '' | Optional tag or tags to associate with the cache. These can be used to invalidate the cache later |
tags | string / array | '' | Alias of tag |
cache(duration, options)
The basic cache factory. This function returns Express middleware tuned to the duration and options specified.
Options extend cache.defaults.
cache.invalidate(...tags)
Reset the caching of any cache matching the given tag, array of tags or multiple tags.
cache.events
An EventEmitter instance which can be bound to in order to retrieve events.
Events fired:
| Event | Called as | Description |
|---|---|---|
routeCacheHit | (req) | Fired when a route is requested that is handled by route-cache |
routeCacheHashError | (err, req) | Fired when a route hashing system fails |
routeCacheEtag | (req, info) | The client requested the current hash via the etag header and will be served a 304 "Not Modified" response |
routeCacheExisting | (req, info) | Fired when a route is requested, a cached version exists and will be provided instead of recomputing the result |
routeCacheFresh | (req, info) | Fired when a route is requested, a valid cache does not exist and we need to compute the result |
routeCacheInvalidate | (tag, hash) | Fired when a single tag is invalidated |
The info object contains the following structure:
| Key | Type | Description |
|---|---|---|
isFresh | boolean | Whether the cache response was generated for this specific request |
hash | string | The internal, unqiue hashing value used to identify this cache session |