Introduction
This module creates a cache is shared within the feathers instance as a global state. For multi-instance, multi-container caching, use feathers-redis-cache instead. With this cache, scaling your app to 4 containers will produce 4 independent caches.
By default, the cache's scope is global but can be setup on a per-service basis or even more granular.
Quick Start
To cache the /books service, simply add the following hooks
// src/services/books/books.hooks.js
const { cacheBefore, cacheAfter } = require('feathers-memory-cache');
module.exports = {
before: {
all: [
cacheBefore()
],
//...
},
after: {
all: [
cacheAfter()
],
//...
},Advanced usage
To cache the /books service with authentication, make sure the cacheBefore is after the authentication check. For example:
before: {
all: [
authenticate('basic'),
cacheBefore(),
],
//...
}To modify the TTL or the max cache size:
before: {
all: [
cacheBefore({
max:10, // Cache will max hold 10 elements
maxAge: 300000 // TTL set to 5min in milliseconds
}),
],
//...
}To apply different cache configurations to different routes, add a scope parameter:
// /books/books.hooks.js
before: {
all: [
cacheBefore({
scope:'books'
max:10, // Cache will max hold 10 elements
maxAge: 300000 // TTL set to 5min in milliseconds
}),
],
//...
},
after: {
all: [cacheAfter({scope:'books'})]
}
// /librarians/librarians.hooks.js
before: {
all: [
cacheBefore({
scope:'other-scope-for-librarians'
max:5, // Cache will max hold 5 elements
maxAge: 1000 // TTL set to 1 second
}),
],
//...
},
after: {
all: [cacheAfter({scope:'other-scope-for-librarians'})]
}You can also use two caches in the same service, you can do the following. Make sure to close out BOTH scopes in the after hook
// /books/books.hooks.js
before: {
all: [
iffElse(
isAuthed(),[
cacheBefore({
scope:'auth-cache'
max:10, // Cache will max hold 10 elements
maxAge: 300000 // TTL set to 5min in milliseconds
}),
],[
cacheBefore({
scope:'auth-no-cache'
max:100, // Cache will max hold 10 elements
maxAge: 1000 // TTL set to 5min in milliseconds
}),
])
],
//...
},
after: {
all: [
iffElse(isAuthed(),[cacheAfter({scope:'auth-cache'})],[cacheAfter({scope:'auth-no-cache'})])
],
//...
},To set a custom hash to the cache key for your scoped cache:
// /books/books.hooks.js
before: {
all: [
cacheBefore({
customHash:(ctx)=>`${Math.floor(Math.random*1000)}`
}),
],
//...
}To set a custom keying function:
// /books/books.hooks.js
before: {
all: [
cacheBefore({
key:(ctx)=>ctx.method+ctx.path+ctx.id
}),
],
//...
}NOTE: if you override key or customHash it will override all of the services using that cache, even if the scope is unspecified and thus, global.