SAP Event Stream Processor WebSocket Provider

The SAP Event Stream Processor WebSocket Provider can be used by a WebSocket client to publish data to ESP streams or windows within ESP projects, or to subscribe to output from ESP.

The main difference between Web service providers and adapters is that providers have more extended functionality in comparison with adapters. Specifically, providers can receive requests from multiple Web services and publish data to multiple projects while adapters can only send and receive data from one source and publish it to one project. Additionally, some providers, such as the REST provider, provide the ability to deploy, start, and stop projects.

The ESP WebSocket Provider has two modes, a REST-like mode and a streaming mode. However, SAP recommends using the streaming mode as the REST-like mode is deprecated and is only available for backwards compatibility. The REST-like mode is for publishing and subscribing to lower volumes of data. This requires a single connection.

Use the streaming mode for higher throughput and volumes of data, as well as for enhanced performance. This requires separate connections for publishing and subscribing. The URIs for the two modes also differ. For example, for the REST-like URI only requires a host and port specified whereas the streaming mode URI requires additional subscribing or publishing information.

Install and configure your own WebSocket client before configuring and using the ESP WebSocket Provider. You can expose your ESP project as a web service, and send requests to it using your WebSocket client.

Use a WebSocket client to send JSON messages to the WebSocket provider and subscribe/publish data to an SAP Event Stream Processor project that has been exposed as a Web service.

For installation details for the provider, see the section on Performing a Custom Installation in the SAP Event Stream Processor: Installation Guide. If you enabled the ESP Web Services Provider using the installer, the configuration is complete and the provider is ready for use. If you did not enable the provider using the installer, see Configuring the ESP REST Provider for instructions on manually configuring the provider.

For instructions on exposing a project as a Web service, see Exposing a Project as a Web Service Using the SAP Event Stream Processor Web Services Provider in the SAP Event Stream Processor: Studio Users Guide.

For information on navigating ESP resources to find streams or windows, see REST Requests for SAP Event Stream Processor Resource Navigation.