Filters

In most applications, we need to perform the same operation for all requests. We might be required to add a few fields to all the responses at a later stage, after we have already defined all the actions needed for our application.

So, in this case, will we have to update all the Actions?

No. This is where the filter API comes to our rescue. We don't need to modify how we define our Actions to solve the problem. All we need to do is define a filter and use it.

Let's see how we can define our filter:

import org.joda.time.DateTime 
import org.joda.time.format.DateTimeFormat
import play.api.mvc._
import play.api.http.HeaderNames._ 
import play.api.libs.concurrent.Execution.Implicits.defaultContext 

object HeadersFilter {
  val noCache = Filter { 
    (nextFilter, rh) => 
      nextFilter(rh) map { 
        case result: Result => addNoCacheHeaders(result) 
      } 
  } 

  private def addNoCacheHeaders(result: Result): Result = { 
    result.withHeaders(PRAGMA -> "no-cache", 
...