The ABAP Channels infrastructure offers best support for native event-driven interactive and collaborative scenarios in ABAP and is generally available with ABAP 7.40 Support Package 5 (SP05). The ABAP 7.40 Support Package 8 (SP08) contains various enhancements including API refactoring to support WebSocket subprotocols.and message exchange with SAP Push Channel Protocol (PCP).
Take your time to watch these YouTube video tutorials to learn how to implement and use ABAP Channels.
See also the blog ABAP Channels Examples.
How to implement ABAP Push Channel (APC)
ABAP Push Channel enables bi-directional communication via WebSockets in ABAP. This video gives you step-by-step introduction on how to implement and use ABAP Push Channel.
How to implement ABAP Messaging Channel (AMC)
ABAP Messaging Channel enables event-driven communication based on publish/subscribe mechanism for message exchange between different ABAP sessions which can reside on different ABAP Servers. Any ABAP session can subscribe to channels and any ABAP session can publish messages to channels. This video gives you step-by-step introduction on how to implement and use ABAP Messaging Channel.
How to implement collaboration using ABAP Push Channel (APC) and ABAP Messaging Channel (AMC)
The collaboration scenario provides the possibility on the basis of publish/subscribe mechanism of ABAP Messaging Channels and WebSocket implementation of ABAP Push Channel to exchange messages between different WebSocket Clients. This video gives you step-by-step introduction on how to implement collaboration scenario using ABAP Messaging Channel and ABAP Push Channel.