WebSocket ​

Stateless roundtrips are fine for click-driven UIs, but some scenarios need the server to push — a news feed, a job-status indicator, a chat. abap2UI5 has no special API for this; you use SAP's standard WebSocket stack and feed the messages into the rendered view via custom JavaScript.

The building blocks:

Once both channels are configured, any COMMIT WORK that fires an AMC publish reaches every connected browser within milliseconds — no polling, no timer.

Server Side ​

An APC class extending cl_apc_wsp_ext_stateless_base binds an AMC consumer when a client connects, so AMC messages are forwarded to that socket. Broadcasting is then a one-liner from anywhere in the system:

DATA(lo_producer) = cl_amc_channel_manager=>create_message_producer(
    i_application_id = `Z2UI5_SAMPLE`
    i_channel_id     = `/news_feed` ).
lo_producer->send( i_message = `New order arrived` ).

A full reference implementation lives in the samples-stack repository — Z2UI5_CL_SMPS_APP_489_WS for the APC handler and Z2UI5_CL_SMPS_APP_489 for the consuming app.

Client Side ​

The browser opens the socket via raw JavaScript embedded in the view. The connection stays open across normal abap2UI5 roundtrips — incoming messages can update a model, trigger a toast, or fire an abap2UI5 event to pull fresh data from the backend:

const ws = new WebSocket("wss://" + window.location.host + "/sap/bc/apc/sap/z2ui5_sample");
ws.onmessage = (e) => {
  sap.m.MessageToast.show(e.data);
};

When to Reach For It ​

WebSockets cost a permanent connection per user — comparable to a stateful session in resource terms. Use them when push really matters:

• live dashboards, monitoring screens
• multi-user collaboration (chat, shared editing)
• long-running background jobs reporting status

For "refresh every few seconds" the Timer is cheaper and simpler.

Working Samples ​

Complete apps from the sample catalog that use what this page describes. Each is a single class in abap2UI5/samples unless its row names another of the three sample repositories — pull that repository with abapGit and start the class with ?app_start=<class>.