An ultra-simplified API response caching middleware for Express/Node using plain-english durations.
Because caching of simple data/responses should ALSO be simple.
This day and age, with less and less heavy lifting done on the server, the most common thing we find ourselves doing is letting the server power the API. Whether the data is stored in Mongo, SQL, CouchDB, or whatever - you get a request, you fetch the data, and you return the data. Sometimes these fetches are costly and you want to cache the response so the next hit doesn't hammer your server. This is why caching exists.
The problem is, with so many cache options, people are still left to fend for themselves when it comes to implementation. It often boils down to a manual process similar to the following:
You're still left wrapping the content of each request with this cache-checking mechanism.
Now it can be as simple as telling the request that you want to use a cache, and for how long results should be cached (in plain English, not milliseconds, because who really wants to calculate that each time?).
npm install apicache
None, unless using this with Redis.
To use, simply inject the middleware (example:
apicache.middleware('5 minutes', [optionalMiddlewareToggle])) into your routes. Everything else is automagic.
let app =let cache = apicachemiddlewareapp
let cache = apicachemiddlewareappapp
let app =// if redisClient option is defined, apicache will use redis client// instead of built-in memory storelet cacheWithRedis = apicacheoptions redisClient: redismiddlewareapp
let cache = apicachemiddlewareapp// routes are automatically added to index, but may be further added// to groups for quick deleting of collectionsapp// add route to display cache indexapp// add route to manually clear target/groupapp/*GET /api/foo/bar --> caches entry at /api/foo/bar and adds a group called 'foo' to indexGET /api/cache/index --> displays indexGET /api/cache/clear/foo --> clears all cached entries for 'foo' group/collection*/
// higher-order function returns false for requests of other status codes (e.g. 403, 404, 500, etc)const onlyStatus200 = reqstatusCode === 200const cacheSuccesses =appapp
apicache.clear([target])- clears cache target (key or group), or entire cache if no value passed, returns new index.
apicache.getIndex()- returns current cache index [of keys]
apicache.middleware([duration], [toggleMiddleware])- the actual middleware that will be used in your routes.
durationis in the following format "[length] [unit]", as in
"1 day". A second param is a middleware toggle function, accepting request and response params, and must return truthy to enable cache for the request.
apicache.options([options])- getter/setter for options. If used as a setter, this function is chainable, allowing you to do things such as... say... return the middleware.
apicache.newInstance([options])- used to create a new ApiCache instance (by default, simply requiring this library shares a common instance)
apicache.clone()- used to create a new ApiCache instance with the same options as the current one
debug: false|true // if true, enables console outputdefaultDuration: 3600000 // should be a number (in ms), defaults to 1 hourenabled: true|false // if false, turns off caching globally (useful on dev)redisClient: client // if provided, uses the [node-redis]() client instead of [memory-cache]()appendKey: // if you want the key (which is the URL) to be appended by something in the req object, put req properties here that point to what you want appended. I.E. req.session.id would be ['session', 'id']statusCodes:exclude: // list status codes to specifically exclude (e.g. [404, 403] cache all responses unless they had a 404 or 403 status)include: // list status codes to require (e.g.  caches ONLY responses with a success/200 code)
Oftentimes it benefits us to group cache entries, for example, by collection (in an API). This
would enable us to clear all cached "post" requests if we updated something in the "post" collection
for instance. Adding a simple
req.apicacheGroup = [somevalue]; to your route enables this. See example below:
var apicache =var cache = apicachemiddleware// GET collection/idapp;// POST collection/idapp;
Additionally, you could add manual cache control to the previous project with routes such as these:
// GET apicache index (for the curious)app;// GET apicache index (for the curious)app;
$ export DEBUG=apicache$ export DEBUG=apicache,othermoduleThatDebugModuleWillPickUp,etc
apicacheoptions debug: true
GET routes between admin and public sites, you'll likely want the
routes to be cached from your public client, but NOT cached when from the admin client. This
is achieved by sending a
"x-apicache-bypass": true header along with the requst from the admin.
The presence of this header flag will bypass the cache, ensuring you aren't looking at stale data.
Special thanks to all those that use this library and report issues, but especially to the following active users that have helped add to the core functionality!