Hi friends, today, I came accross an interesting challenge of adding CORS in Lagom MicroServices, but didn't find anything other than few google group threads. So, after completing the challenge I thought about sharing the working solution. So let's go ahead.

Adding CORS filter in Lagom is a few steps work.

For this we are going to use CORS filter provided by Play Framework as Lagom is also based on PlayFramework.(https://www.playframework.com/documentation/2.5.x/CorsFilter)

Credits: This google groups thread. https://groups.google.com/d/msg/lagom-framework/dtYN_1Ds4SQ/U3lzjwspBwAJ

Now come to the point, How to?

So, Step 1, go to build.sbt residing in the root folder containing the api and implementations of services. Now find the code-block having the following similar code, and add filters project dependencies.

CorsFilter is a Play project, but we need not to explicitly add PlayFramework plugin in our plugins.sbt and plugin configuation in build.sbt as Lagom is based on Play, it consists all Play Projects.

lazy val `YOUR_SERVICE_NAME-impl` = (project in file("YOUR_SERVICE_NAME-impl"))
  .enablePlugins(LagomScala)
  .settings(
    libraryDependencies ++= Seq(
      .....,
      filters,//We have to add this
      ........
    )
  )

Now, we can use this filters project in our service.

In step 2, we will change the Your_Service_NameApplication class which resides along with the class with service implementation.

So, go to the block having just mentioned class, and extend it with CORSComponent class. After this, in same code block, we have to add one more line of code for overiding the httpFilters and adding the CORS filter.

import play.filters.cors.CORSComponents//Import #1
import play.api.mvc.EssentialFilter//Import 2
abstract class WebtrackingApplication(context: LagomApplicationContext)
  extends LagomApplication(context)
    with .....
    with CORSComponents {//Step #2.a
....
  override lazy val httpFilters: Seq[EssentialFilter] = Seq(corsFilter)//Step #2.b
....
}

Remember to import CORSComponent class and EssentialFilter type class.

Now, Reload the project in SBT.

$>sbt

then ……>runAll

Cheers Guys. If you liked the post please share it in your group.