Scalacache

The Play cache API

The default implementation of the Cache API uses EHCache and it's enabled by default. You can also provide your own implementation via a plug-in.

Accessing the Cache API

The cache API is provided by the play.api.cache.Cache object. It requires a registered cache plug-in.

Note: The API is intentionally minimal to allow several implementation to be plugged. If you need a more specific API, use the one provided by your Cache plugin.

Using this simple API you can either store data in cache:

Cache.set("item.key", connectedUser)

And then retrieve it later:

val maybeUser: Option[User] = Cache.getAs[User]("item.key")

There is also a convenient helper to retrieve from cache or set the value in cache if it was missing:

val user: User = Cache.getOrElse[User]("item.key") {
  User.findById(connectedUser)
}

How to remove the key is as follows. (Note: the Play 2.0 removal method is from the Google Groups Conversation given that Ehcache allows nulls internally).

// 2.0 final 
import play.api.cache.{EhCachePlugin, Cache}
import play.api.Play
Play.current.plugin[EhCachePlugin].map {
      ehcache =>
        ehcache.cache.remove(key)
}.getOrElse(false) 
// later
Cache.remove("item.key")

Caching HTTP responses

You can easily create smart cached actions using standard Action composition.

Note: Play HTTP Result instances are safe to cache and reuse later.

Play provides a default built-in helper for standard cases:

def index = Cached("homePage") {
  Action {
    Ok("Hello world")
  }
}

Or even:

def userProfile = Authenticated { user =>
  Cached(req => "profile." + user) {      
    Action { 
      Ok(views.html.profile(User.find(user)))
    }   
  }
}

Next: Calling WebServices