Use https://github.com/hmrc/hmrc-mongo#cache instead

Micro-library containing functionality to cache generic JSON data in MongoDB

Include the following dependency in your SBT build

resolvers += Resolver.bintrayRepo("hmrc", "releases")

libraryDependencies += "uk.gov.hmrc" %% "mongo-caching" % "[INSERT_VERSION]"

For Java 7 use a version <= 0.7.1

Supports Play 2.6, 2.7, 2.8 (Scala 2.12)

• CacheController has been removed. The code (from v6.x.x) can be included in the client service if required.
• The deprecated CacheRepository has been removed. Use CacheMongoRepository instead.
• play.allowGlobalApplication = true is no longer required in your application.conf to use this library.

The library comprises two central classes, CacheMongoRepository, and CacheController.

Most use-cases should use the CacheMongoRepository unless you have a concrete need to expose your cache via HTTP. The Controller class wraps the Repository class in a Play Controller, and can be wired directly into a routes file.

Example usage of CacheMongoRepository in Scala:

@Singleton
class SessionCacheRepository @Inject()(
  @Named("mongodb.session.expireAfterSeconds") expireAfterSeconds: Int,
  mongo: ReactiveMongoComponent)(implicit ec: ExecutionContext)
    extends CacheMongoRepository("sessions", expireAfterSeconds)(mongo.mongoConnector.db, ec)

This creates a repository class, which can be called from elsewhere in your application. You should only create this class on application start-up, rather than dynamically calling new, as the class constructor will check for, and optionally create, database indexes.

The CacheMongoRepository class exposes a method createOrUpdate that is used to upsert data into the cache.

def createOrUpdate(id: Id, key: String, toCache: JsValue): Future[DatabaseUpdate[Cache]]

Data inserted using this method has a time-to-live (TTL) that applies per Id. The amount of time is configured when creating the class; expireAfterSeconds in our example. Any modifications of data for an Id will reset the TTL.

The JSON structure that is cached in Mongo:

{
	"id": {
		"key1": "value1",
		"key2": "value1"
	}
}

This structure allows caching multiple keys against an ID. As cached values expire per ID, this provides a way to expire related data at the same time.

Simpler use-cases for this library can hardcode key to a constant, and provide a cache of ID to value.

This code is open source software licensed under the Apache 2.0 License.