Configuring JSON-P in Liberty

You can configure your Liberty environment to use JSON-P by enabling the default jsonp-1.0 feature or by implementing the jsonpContainer-1.0 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 that is included in Liberty.

  The jsonpContainer-1.1 feature provides the JSON-P API and provides JSON-P support by using a user supplied JSON-P implementation that is 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 by 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();
      // ...
    }
  }