Apama Community Edition release announcement

The latest release of Apama Community Edition provides a new connectivity plug-in which is a transport allowing the Apama correlator to access REST or other web services. The transport is a client for other webservices, rather than allowing the correlator to act as a web service itself. In order to use the HTTP client transport you need to configure a chain within the connectivity system using the correlator configuration YAML. This chain provides the mapping between Apama events inside the correlator and HTTP requests/responses to the external web service. Each event sent from Apama is converted to one request to the webservice and a corresponding response (or error) sent back to Apama.

For example, for these events:

You would create a chain like:

Once you have created an appropriate chain you then just need to send events to the correct channel from EPL and wait for responses. The requestId is used to tie a particular request to a particular response:

This chain is assuming that the data from the web service is a simple string. As with all connectivity plug-in transports, you can use other codecs and mapper rules to transform the data from different formats. For example, the product also contains a JSON codec which lets you communicate with a web-service where the data is encoded in the JSON format.

You can find the full documentation at Using HTTP and REST

– Matthew Johnson