Configure JSON-P in Liberty

We can configure our Liberty environment to use JSON-P by enabling the default jsonp-1.0 feature or by implementing the jsonpContainer-1.0 feature.

In version 21.0.0.1 and later, for information about using JSON-P with Liberty, see the Open Liberty website.

JSON Processing (JSON-P) 1.1 for WebSphere Application Server Liberty is built on the JSON-P reference implementation.

Glassfish JSON is the reference implementation of the JSON-P 1.1 specification, and is the JSON-P implementation that Liberty provides by default when the jsonp-1.1 feature is enabled. It is possible to configure an alternative implementation of JSON-P through the jsonpContainer-1.1 feature.

• Select the correct JSON-P feature in Liberty. The following features that are offered for JSON-P 1.1 integration with Liberty:
  • jsonp-1.1
  • jsonpContainer-1.0

  The default JSON-P feature is jsonp-1.1, which provides generic JSON-P support and can use any specification-compliant implementation. This feature provides the JSON-P API to applications and features that depend on it. Unless specified otherwise by other features, this feature uses the Glassfish JSON reference implementation included in Liberty.

  The jsonpContainer-1.1 feature provides the JSON-P API and provides JSON-P support using a user supplied JSON-P implementation configured as a BELL (Basic Extension using Liberty Libraries). The <bell> server configuration element is used to configure this implementation as a BELL.

  For example, Apache Johnzon is another JSON-P compliant implementation. In this example, a server is configured to use Johnzon instead of Glassfish:

  <server>
    <featureManager>
      <feature>jsonpContainer-1.0</feature>
    </featureManager>
  
    <bell libraryRef="johnzon"/>
  
    <library id="johnzon">
      <fileset dir="${server.config.dir}/johnzon"includes="*.jar"/>
    </library>
  </server>

• Write features that depend on JSON-P.

  When you write a feature that depends on JSON-P, special design considerations must be made: Instead of obtaining a javax.json.spi.JsonProvider instance using standard mechanisms, such as JsonProvider.provider(), features declare OSGi service dependencies on JsonpProvider, and use these injected services when building objects. The following code is an example:

  @Component( ... )  
  public class ServiceThatRequiresJsonp { 
    @Reference
    private JsonProvider jsonpProvider;
  
    public void doSomethingWithJsonp() {     JsonObject o = jsonpProvider.createObjectBuilder().build();
      // ...
    }
  }