ABAP Channels: Push-Nachrichten und Echtzeit-Kommunikation

kategorie
ABAP-Statements
Veröffentlicht
autor
Johannes

ABAP Channels ermöglichen Echtzeit-Kommunikation zwischen ABAP-Anwendungen und Web-Clients. Mit ABAP Messaging Channels (AMC) und ABAP Push Channels (APC) können Push-Nachrichten und WebSocket-Verbindungen implementiert werden.

Channel-Typen

TypBeschreibung
AMCABAP Messaging Channel - Server-zu-Server
APCABAP Push Channel - Server-zu-Client (WebSocket)

ABAP Messaging Channels (AMC)

AMC-Kanal definieren (SAMC)

Transaktion SAMC:
1. Kanal-ID: /ZORDER/UPDATES
2. Nachrichtentyp: TEXT oder BINARY
3. Extension-ID (optional): Für Sub-Channels
4. Aktivieren und transportieren

Nachricht senden

" Einfache Textnachricht senden
TRY.
    DATA(lo_producer) = cl_amc_channel_manager=>create_message_producer(
      i_application_id = 'ZORDER_APP'
      i_channel_id     = '/zorder/updates' ).


    " Text-Nachricht
    lo_producer->send( i_message = 'Bestellung 1000000001 wurde aktualisiert' ).


  CATCH cx_amc_error INTO DATA(lx_error).
    MESSAGE lx_error->get_text( ) TYPE 'E'.
ENDTRY.

Nachricht mit Extension-ID

" Nachricht an spezifischen Sub-Channel
TRY.
    DATA(lo_producer) = cl_amc_channel_manager=>create_message_producer(
      i_application_id = 'ZORDER_APP'
      i_channel_id     = '/zorder/updates'
      i_extension_id   = |ORDER_{ lv_order_id }| ).  " Pro Bestellung


    lo_producer->send( i_message = lv_json_message ).


  CATCH cx_amc_error INTO DATA(lx_error).
    MESSAGE lx_error->get_text( ) TYPE 'E'.
ENDTRY.

Binäre Nachricht senden

" XString-Daten senden
DATA: lv_binary TYPE xstring.


" Daten serialisieren
CALL TRANSFORMATION id
  SOURCE data = ls_order_data
  RESULT XML lv_binary.


TRY.
    DATA(lo_producer) = cl_amc_channel_manager=>create_message_producer_bin(
      i_application_id = 'ZORDER_APP'
      i_channel_id     = '/zorder/binary' ).


    lo_producer->send( i_message = lv_binary ).


  CATCH cx_amc_error INTO DATA(lx_error).
    MESSAGE lx_error->get_text( ) TYPE 'E'.
ENDTRY.

AMC-Consumer (Empfänger)

CLASS zcl_order_amc_consumer DEFINITION
  PUBLIC FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    INTERFACES if_amc_message_receiver.


    METHODS start_listening.
ENDCLASS.


CLASS zcl_order_amc_consumer IMPLEMENTATION.


  METHOD start_listening.
    TRY.
        cl_amc_channel_manager=>create_message_consumer(
          i_application_id = 'ZORDER_APP'
          i_channel_id     = '/zorder/updates'
        )->start_message_delivery( i_receiver = me ).


      CATCH cx_amc_error INTO DATA(lx_error).
        MESSAGE lx_error->get_text( ) TYPE 'E'.
    ENDTRY.
  ENDMETHOD.


  METHOD if_amc_message_receiver~receive.
    " Nachricht empfangen
    DATA(lv_message) = i_message.


    " Verarbeitung
    CASE lv_message.
      WHEN 'REFRESH'.
        " UI aktualisieren...
      WHEN OTHERS.
        " JSON parsen...
    ENDCASE.
  ENDMETHOD.


ENDCLASS.

AMC im Background Job

" Nachricht aus Hintergrundprozess senden
REPORT zr_send_amc_notification.


DATA: lv_order_id TYPE zorder_id.


SELECT-OPTIONS: s_order FOR lv_order_id.


START-OF-SELECTION.
  " Bestellungen verarbeiten
  SELECT * FROM zorders INTO TABLE @DATA(lt_orders)
    WHERE order_id IN @s_order.


  LOOP AT lt_orders INTO DATA(ls_order).
    " Verarbeitung...


    " Benachrichtigung senden
    TRY.
        cl_amc_channel_manager=>create_message_producer(
          i_application_id = 'ZORDER_APP'
          i_channel_id     = '/zorder/updates'
          i_extension_id   = |ORDER_{ ls_order-order_id }|
        )->send( |Bestellung { ls_order-order_id } verarbeitet| ).


      CATCH cx_amc_error.
        " Logging...
    ENDTRY.
  ENDLOOP.

ABAP Push Channels (APC)

APC-Anwendung definieren (SAPC)

Transaktion SAPC:
1. APC-Anwendung: ZORDER_PUSH
2. Verbindungsart: WebSocket
3. Handler-Klasse: ZCL_ORDER_APC_HANDLER
4. Pfad: /sap/bc/apc/zorder
5. Aktivieren und transportieren

APC Handler-Klasse

CLASS zcl_order_apc_handler DEFINITION
  PUBLIC FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    INTERFACES if_apc_wsp_extension.


  PRIVATE SECTION.
    DATA: mv_context_id TYPE apc_context_id.
ENDCLASS.


CLASS zcl_order_apc_handler IMPLEMENTATION.


  METHOD if_apc_wsp_extension~on_start.
    " WebSocket-Verbindung geöffnet
    mv_context_id = i_context->get_context_id( ).


    " AMC-Consumer für diesen Client starten
    TRY.
        cl_amc_channel_manager=>create_message_consumer(
          i_application_id = 'ZORDER_APP'
          i_channel_id     = '/zorder/updates'
        )->start_message_delivery(
          i_receiver = NEW zcl_apc_amc_bridge( i_context ) ).


      CATCH cx_amc_error.
        " Fehlerbehandlung
    ENDTRY.
  ENDMETHOD.


  METHOD if_apc_wsp_extension~on_message.
    " Nachricht vom Client empfangen
    DATA(lv_text) = i_message->get_text( ).


    " JSON parsen
    DATA: ls_request TYPE ty_request.
    /ui2/cl_json=>deserialize(
      EXPORTING json = lv_text
      CHANGING  data = ls_request ).


    " Request verarbeiten
    CASE ls_request-action.
      WHEN 'SUBSCRIBE'.
        " Client abonniert bestimmte Updates
        handle_subscribe( ls_request-order_id ).


      WHEN 'UNSUBSCRIBE'.
        handle_unsubscribe( ls_request-order_id ).
    ENDCASE.


    " Antwort senden
    DATA(lv_response) = /ui2/cl_json=>serialize(
      data = VALUE ty_response( status = 'OK' ) ).


    i_message_manager->send( i_message = cl_apc_wsp_message=>create_text( lv_response ) ).
  ENDMETHOD.


  METHOD if_apc_wsp_extension~on_close.
    " WebSocket-Verbindung geschlossen
    " Aufräumen...
  ENDMETHOD.


  METHOD if_apc_wsp_extension~on_error.
    " Fehler behandeln
    DATA(lv_error) = i_error->get_text( ).
  ENDMETHOD.


ENDCLASS.

AMC-zu-APC Bridge

" Leitet AMC-Nachrichten an WebSocket-Client weiter
CLASS zcl_apc_amc_bridge DEFINITION
  PUBLIC FINAL
  CREATE PUBLIC.


  PUBLIC SECTION.
    INTERFACES if_amc_message_receiver.


    METHODS constructor
      IMPORTING io_apc_context TYPE REF TO if_apc_wsp_context.


  PRIVATE SECTION.
    DATA: mo_context TYPE REF TO if_apc_wsp_context.
ENDCLASS.


CLASS zcl_apc_amc_bridge IMPLEMENTATION.


  METHOD constructor.
    mo_context = io_apc_context.
  ENDMETHOD.


  METHOD if_amc_message_receiver~receive.
    " AMC-Nachricht an WebSocket-Client weiterleiten
    TRY.
        DATA(lo_message) = cl_apc_wsp_message=>create_text( i_message ).
        mo_context->get_message_manager( )->send( lo_message ).


      CATCH cx_apc_error.
        " Client möglicherweise disconnected
    ENDTRY.
  ENDMETHOD.


ENDCLASS.

JavaScript WebSocket-Client

// Browser-seitiger WebSocket-Client
const socket = new WebSocket('wss://server:port/sap/bc/apc/zorder');


// Verbindung geöffnet
socket.onopen = function(event) {
  console.log('WebSocket verbunden');


  // Bestellung abonnieren
  socket.send(JSON.stringify({
    action: 'SUBSCRIBE',
    order_id: '1000000001'
  }));
};


// Nachricht empfangen
socket.onmessage = function(event) {
  const data = JSON.parse(event.data);
  console.log('Update erhalten:', data);


  // UI aktualisieren
  updateOrderDisplay(data);
};


// Verbindung geschlossen
socket.onclose = function(event) {
  console.log('WebSocket getrennt');
  // Reconnect-Logik...
};


// Fehler
socket.onerror = function(error) {
  console.error('WebSocket Fehler:', error);
};

Broadcast an alle Clients

" Nachricht an alle verbundenen Clients
CLASS zcl_order_notifier DEFINITION.
  PUBLIC SECTION.
    CLASS-METHODS notify_all
      IMPORTING iv_message TYPE string.
ENDCLASS.


CLASS zcl_order_notifier IMPLEMENTATION.
  METHOD notify_all.
    TRY.
        " AMC-Nachricht senden (erreicht alle APC-Clients)
        cl_amc_channel_manager=>create_message_producer(
          i_application_id = 'ZORDER_APP'
          i_channel_id     = '/zorder/broadcast'
        )->send( iv_message ).


      CATCH cx_amc_error.
        " Fehlerbehandlung
    ENDTRY.
  ENDMETHOD.
ENDCLASS.

Nachricht an spezifischen Client

" Nachricht an bestimmten WebSocket-Client
METHOD send_to_client.
  DATA: lv_context_id TYPE apc_context_id.


  " Context-ID aus Registry/Tabelle holen
  lv_context_id = get_client_context( iv_user_id ).


  TRY.
      " Direkter AMC-Kanal mit Extension
      cl_amc_channel_manager=>create_message_producer(
        i_application_id = 'ZORDER_APP'
        i_channel_id     = '/zorder/direct'
        i_extension_id   = lv_context_id
      )->send( iv_message ).


    CATCH cx_amc_error.
      " Client nicht mehr verbunden
  ENDTRY.
ENDMETHOD.

Heartbeat implementieren

" Periodische Ping-Nachrichten
METHOD if_apc_wsp_extension~on_message.
  DATA(lv_text) = i_message->get_text( ).


  IF lv_text = 'PING'.
    " Pong zurücksenden
    i_message_manager->send(
      cl_apc_wsp_message=>create_text( 'PONG' ) ).
    RETURN.
  ENDIF.


  " Normale Nachrichtenverarbeitung...
ENDMETHOD.


" Client-seitig (JavaScript)
// Heartbeat alle 30 Sekunden
setInterval(() => {
  if (socket.readyState === WebSocket.OPEN) {
    socket.send('PING');
  }
}, 30000);

Session-Management

" Verbundene Clients tracken
CLASS zcl_apc_session_manager DEFINITION.
  PUBLIC SECTION.
    CLASS-DATA: gt_sessions TYPE TABLE OF ty_session.


    CLASS-METHODS register
      IMPORTING iv_context_id TYPE apc_context_id
                iv_user_id    TYPE sy-uname.


    CLASS-METHODS unregister
      IMPORTING iv_context_id TYPE apc_context_id.


    CLASS-METHODS get_sessions_for_user
      IMPORTING iv_user_id          TYPE sy-uname
      RETURNING VALUE(rt_sessions) TYPE ty_session_tab.
ENDCLASS.


CLASS zcl_apc_session_manager IMPLEMENTATION.
  METHOD register.
    APPEND VALUE #(
      context_id = iv_context_id
      user_id    = iv_user_id
      timestamp  = sy-datum && sy-uzeit
    ) TO gt_sessions.
  ENDMETHOD.


  METHOD unregister.
    DELETE gt_sessions WHERE context_id = iv_context_id.
  ENDMETHOD.


  METHOD get_sessions_for_user.
    rt_sessions = VALUE #( FOR session IN gt_sessions
      WHERE ( user_id = iv_user_id ) ( session ) ).
  ENDMETHOD.
ENDCLASS.

Sichere WebSocket-Verbindung

" APC mit Authentifizierung
METHOD if_apc_wsp_extension~on_start.
  " Benutzer prüfen
  DATA(lv_user) = i_context->get_user( ).


  " Berechtigungsprüfung
  AUTHORITY-CHECK OBJECT 'Z_APC_AUTH'
    ID 'ACTVT' FIELD '03'.


  IF sy-subrc <> 0.
    " Verbindung ablehnen
    i_context->get_message_manager( )->send(
      cl_apc_wsp_message=>create_text( '{"error": "Unauthorized"}' ) ).


    i_context->close( ).
    RETURN.
  ENDIF.


  " Normale Verarbeitung...
ENDMETHOD.

Typische Anwendungsfälle

AnwendungBeschreibung
Live-UpdatesBestellstatus in Echtzeit
BenachrichtigungenPush-Notifications
ChatEchtzeit-Kommunikation
DashboardsLive-Metriken
CollaborationGemeinsames Bearbeiten

Architektur

┌─────────────────┐     ┌─────────────────┐
│  Web-Client     │     │  Web-Client     │
│  (JavaScript)   │     │  (JavaScript)   │
└────────┬────────┘     └────────┬────────┘
         │ WebSocket             │ WebSocket
         │                       │
         ▼                       ▼
┌─────────────────────────────────────────┐
│            ABAP Push Channel            │
│              (APC Handler)              │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│        ABAP Messaging Channel           │
│              (AMC Broker)               │
└────────────────────┬────────────────────┘
                     │
                     ▼
┌─────────────────────────────────────────┐
│          ABAP Backend Logic             │
│    (Background Jobs, BAPIs, etc.)       │
└─────────────────────────────────────────┘

Best Practices

  1. Error Handling: Robuste Fehlerbehandlung für Disconnects
  2. Heartbeat: Verbindung aktiv halten
  3. Reconnect: Client-seitige Wiederverbindung
  4. Security: Authentifizierung und Autorisierung
  5. Skalierung: Extension-IDs für gezielte Nachrichten
  6. Logging: Verbindungen und Nachrichten protokollieren

Wichtige Transaktionen

TransaktionBeschreibung
SAMCAMC-Kanäle pflegen
SAPCAPC-Anwendungen pflegen
SMICMICM-Monitor (WebSocket)

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