is SSE on an AS ABAP (NetWeaver) system possible?
Ever since I've been working with WebSockets in the SAP world, making use of the ABAP Channels infrastructure (since ~2014), I've wondered:
Can we use the more lightweight alternative Server-Sent Events (SSE)? Of course that only makes sense when no bi-directional streaming is required.
So I checked online and quickly realized that I might be one of the very few people that actually asked themselves this question. I only found one other interesting post about it on stackoverflow and even went so far as to reach out to the creator of said post on LinkedIn (don't do that btw.; I was very desperate).
I also tested it myself, of course, creating my own ICF implementations on some on-premise as well as locally hosted SAP instances.
Sadly though, I've had to come to the same conclusion as the peer before me (the one from SO). It seems just not possible to keep the sessions, or rather that this feature isn't implemented on the ICM level in general. The HTTP connection is immediately closed after the initial request and cannot be kept open for streaming. This is true even for more up-to-date S/4 systems (i.e. S/4HANA 2020 w. SAP_GWFND 755 or S/4HANA 2023)
Now you may ask yourself "Why this blog post?".
Well, I wanted a more up-to-date and more conclusive version of this topic to be written down somewhere. Also, even cooler, if you're lucky enough you may be in the situation to now actually use it yourself (read further)!
SSE now possible!
Server Sent Events are now available! However, as of writing, only for:
- SAP BTP ABAP Environment and
- SAP S/4HANA Cloud Public Edition
Check out the documentation and get started implementing the corresponding interfaces:
if_http_service_extension_sseandif_http_service_extension
in your ICF node (or, to stay with the modern theme, in your HTTP Service1)
References/Links
Footnotes
They're essentially the same↩