Adding the HTTP client connectivity plug-in to a project

In Apama applications, you can configure and use the HTTP client connectivity plug-in provided with Apama.

To add the HTTP client connectivity plug-in to a project

1. Add the HTTP client connectivity plug-in as described in Adding connectivity and adapter bundles to projects.

2. In the Connectivity and Adapters dialog, expand the HTTP Client node and select the desired option.

There are several options to choose from:

an option that uses application-specific event definitions, transports and mapping configurations, and

an option that uses generic Apama event definitions and a chain configuration to invoke HTTP services with JSON payloads. This option can be added only once and can be used to invoke multiple HTTP services.

In the Project Explorer view, the following files are created in the Connectivity and Adapters > HTTP Client > HTTP_Client_bundle_instance node:

HTTP_Client_bundle_instance.properties

HTTP_Client_bundle_instance.yaml

If you have selected the "generic" option, you should not update these files because all configuration options and mappings are provided at runtime through the EPL application.

The HTTP_Client_bundle_instance.properties file contains properties for configuring the HTTP client transport.

3. Optional. If you have not selected the "generic" option, edit the HTTP_Client_bundle_instance.yaml file to specify more advanced configurations, such as customizing the way HTTP messages are mapped to Apama events, using codecs for converting the message payload, or configuring the HTTP client transport. For more information, see The HTTP Client Transport Connectivity Plug-in.

For the "generic" option, additional bundles are added to the Dependent Bundles node (you need not make any changes to these bundles). The HTTP client adds a reference to com.apama.util.AnyExtractor which is useful for easily extracting data from an any type; see the API Reference for EPL (ApamaDoc) for more details.