S4HANA For ABAP(6):ABAP Channels

1.26 ABAP Channels: ABAP Messaging Channels

Programs之间可以通过共享内存分享信息，但是相同系统，不同Application Server之间不能通信；

ABAP Messaging Channels (AMC)提供跨Application通信，结合ABAP Push Channels (APC)，可以和外部网络通信，例如：SAP UI5;

Tcode: AMC_LOG_ADMIN,打开Logging;

Tcode: AMC_LOG_PROCESSING,Logging监视器；

Tcode: SMAMC,AMC recipient;

创建AMC方式：

1.使用Tcode:SAMC,可以打开AMC Workbench;

2.使用Tcode:SE80,选择Package->右键Create->Connectivity->ABAP Messaging Channel Applications;

创建一个AMC,通过Application,Channel name区分;

Channel Name:需要/开头，大小写敏感；

Message Type:定义发送Message类型;

TEXT,ABAP类型STRING

Producer interface: IF_AMC_MESSAGE_PRODUCER_TEXT

Receiver interface: IF_AMC_MESSAGE_RECEIVER_TEXT

BINARY,ABAP类型XSTRING

Producer interface: IF_AMC_MESSAGE_PRODUCER_BINARY

Receiver interface: IF_AMC_MESSAGE_RECEIVER_BINARY

PCP, Push Channel Protocol

Corresponding ABAP interface:IF_AC_MESSAGE_TYPE_PCP

Producer interface: IF_AMC_MESSAGE_PRODUCER_PCP

Receiver interface: IF_AMC_MESSAGE_RECEIVER_PCP

定义PCP类型：CL_AC_MESSAGE_TYPE_PCP=>CREATE( )；

Scope:定义可以接收Message范围，System,Client,User；

Tcode:SM02,可以看到System中message;

Authorized programs:定义可以接收或发送信息的Program;

Program可以是Reports,Function,Classes;

定义Program: ZTOM_AMC_RECEIVE_TEXT,接收message;

示例代码：

REPORT ZTOM_AMC_RECEIVE_TEXT.

DATA:gt_message_text TYPE TABLE OF string.
SELECTION-SCREEN BEGIN OF BLOCK blk1.
PARAMETERS:p_sec TYPE i. "等待时间
PARAMETERS:p_msgn TYPE i. "message条数
SELECTION-SCREEN END OF BLOCK blk1.

CLASS zcl_amc_receive_text DEFINITION.
PUBLIC SECTION.
INTERFACES if_amc_message_receiver_text.
ENDCLASS.

CLASS zcl_amc_receive_text IMPLEMENTATION.
  "实现receive方法
  METHOD:if_amc_message_receiver_text~receive.
    APPEND i_message TO gt_message_text.
  ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.
PERFORM f_get_amc_text.

"获取amc text
FORM f_get_amc_text.
DATA:lo_consumer TYPE REF TO if_amc_message_consumer.
DATA:lo_text_receiver TYPE REF TO zcl_amc_receive_text.

TRY .
    "创建msg消费者
    lo_consumer = cl_amc_channel_manager=>create_message_consumer(
      i_application_id = 'ZT_AMC1'
      i_channel_id = '/test'
    ).
    lo_text_receiver = NEW #( ).
    "start message delivery
    lo_consumer->start_message_delivery(
      i_receiver = lo_text_receiver
    ).
    "等待message
    WAIT FOR MESSAGING CHANNELS UNTIL
    lines( gt_message_text ) >= p_msgn UP TO p_sec SECONDS.

"写出接收message
    LOOP AT gt_message_text INTO DATA(gs_message_text).
      WRITE:/ gs_message_text.
    ENDLOOP.
  CATCH cx_root INTO DATA(lo_exception).
    WRITE:/ lo_exception->get_text( ).
  ENDTRY.
ENDFORM.

定义Program:ZTOM_AMC_SEND_TEXT,发送message;

示例代码：

REPORT ZTOM_AMC_SEND_TEXT.

SELECTION-SCREEN BEGIN OF BLOCK blk1.
PARAMETERS:p_msg TYPE string LOWER CASE. "message
SELECTION-SCREEN END OF BLOCK blk1.

AT SELECTION-SCREEN.
PERFORM f_send_amc_text.

"发送amc text
FORM f_send_amc_text.
  DATA:lo_producer TYPE REF TO if_amc_message_producer_text.
  TRY.
    "创建msg消费者
    lo_producer ?= cl_amc_channel_manager=>create_message_producer(
      i_application_id = 'ZT_AMC1'
      i_channel_id = '/test'
    ).
    lo_producer->send( i_message = p_msg ).
  CATCH cx_root INTO DATA(lo_exception).
    WRITE:/ lo_exception->get_text( ).
  ENDTRY.
ENDFORM.

示例Package:SABAPDEMOS，Application：DEMO_AMC;

示例代码: CL_AMC_CHANNEL_MANAGER,AMC Channel管理类，message生产者；

FORM f_amc_send_message.
  DATA:lo_producer TYPE REF TO if_amc_message_producer_text.
  TRY.
    lo_producer ?= cl_amc_channel_manager=>create_message_producer(
      i_application_id = 'DEMO_AMC'
      i_channel_id = '/demo_text'
    ).
    lo_producer->send( 'test message' ).
  CATCH cx_root INTO DATA(lo_exception).
    WRITE:/ lo_exception->get_text( ).
  ENDTRY.
ENDFORM.

获取Message Consumer，可以自定义类，通过实现接口IF_AMC_MESSAGE_RECEIVER_<message_type>,定义receiver;

示例代码:

"message consumer
FORM f_amc_get_message.
  DATA:lo_consumer TYPE REF TO if_amc_message_consumer.
  TRY.
    lo_consumer = cl_amc_channel_manager=>create_message_consumer(
        i_application_id = 'DEMO_AMC'
        i_channel_id = '/demo_text'
    ).
  CATCH cx_root INTO DATA(lo_exception).
    WRITE:/ lo_exception->get_text( ).
  ENDTRY.
ENDFORM.

示例代码：Receiver类定义

"AMC reveiver类定义
CLASS zcl_receiver DEFINITION.
  PUBLIC SECTION.
    INTERFACES: if_amc_message_receiver_text.
    EVENTS message_received EXPORTING VALUE(ev_message) TYPE string.
ENDCLASS.

CLASS zcl_receiver IMPLEMENTATION.
  METHOD:if_amc_message_receiver_text~receive.
    RAISE EVENT message_received EXPORTING ev_message = i_message.
  ENDMETHOD.
ENDCLASS.

"使用receiver
FORM f_amc_receiver.
  DATA:lo_receiver TYPE REF TO zcl_receiver.
  DATA:lo_consumer TYPE REF TO if_amc_message_consumer.
  TRY.
    lo_consumer = cl_amc_channel_manager=>create_message_consumer(
        i_application_id = 'DEMO_AMC'
        i_channel_id = '/demo_text'
    ).
    "CREATE OBJECT lo_receiver.
    lo_receiver = NEW #( ).
    lo_consumer->start_message_delivery( lo_receiver ).
  CATCH cx_root INTO DATA(lo_exception).
    WRITE:/ lo_exception->get_text( ).
  ENDTRY.
ENDFORM.

示例代码：等待AMC信息；

"wait 语句
FORM f_amc_wait.
"WAIT FOR MESSAGING CHANNELS UNTIL <condition> UP TO <n> SECONDS.
ENDFORM.

1.27 ABAP Channels: ABAP Push Channels

A Web Service can push data to ABAP Program;

ABAP Program Push Message to a web page;

使用Tcode:SAPC,可以打开APC Workbench;

右键->Create->输入Application名称；

Class Name:ZCL_APC_WSP_EXT_ZT_APC1;

点击Generate Class and Service;

Connection Type:可以设置链接类型，WebSocket或者TCP Socket;

Protocol:可以设置协议；

选择重写ON_START方法，ON_MESSAGE方法；

示例代码:

method IF_APC_WSP_EXTENSION~ON_START.
*CALL METHOD SUPER->IF_APC_WSP_EXTENSION~ON_START
*  EXPORTING
*    I_CONTEXT         =
*    I_MESSAGE_MANAGER =
*    .
    TRY.
        " send the message on websocket connection
        DATA(lo_message) = i_message_manager->create_message( ).
        lo_message->set_text( |{ sy-mandt }/{ sy-uname }: ON_START has been successfully executed !| ).
        i_message_manager->send( lo_message ).
    CATCH cx_apc_error INTO DATA(lx_apc_error).
        MESSAGE lx_apc_error->get_text( ) TYPE 'E'.
    ENDTRY.
  endmethod.

示例代码:

method IF_APC_WSP_EXTENSION~ON_MESSAGE.
*CALL METHOD SUPER->IF_APC_WSP_EXTENSION~ON_MESSAGE
*  EXPORTING
*    I_MESSAGE         =
*    I_MESSAGE_MANAGER =
*    I_CONTEXT         =
*    .
    TRY.
        " retrieve the text message
        DATA(lv_text) = i_message->get_text( ).
        " create the message manager and message object
        DATA(lo_message) = i_message_manager->create_message( ).
        " send 1st message
        lo_message->set_text( |{ sy-mandt }/{ sy-uname }: ON_MESSAGE has been successfully executed !| ).
        i_message_manager->send( lo_message ).

" send 2nd message, i.e. echo the incoming message
        lo_message->set_text( lv_text ).
        i_message_manager->send( lo_message ).
      CATCH cx_apc_error INTO DATA(lx_apc_error).
        MESSAGE lx_apc_error->get_text( ) TYPE 'E'.
    ENDTRY.
  endmethod.

保存Class激活后，点击执行；

弹出Web页面；

WDA Component：WDR_TEST_APC_WSP

如何AMC和APC一起使用，实现Web发送信息给ABAP Program,ABAP Program发送信息给Web？

1.修改APC中的on_start,on_message方法；

示例代码：on_start

TRY.
      "start时绑定为消费者,接收ABAP program message
      DATA(lo_binding) = i_context->get_binding_manager( ).
      lo_binding->bind_amc_message_consumer(
        i_application_id = 'ZT_AMC1'
        i_channel_id = '/test'
      ).
    CATCH cx_apc_error INTO DATA(lo_exception).
      MESSAGE lo_exception->get_text( ) TYPE 'E'.
    ENDTRY.

示例代码：on_message

"案例2
    "作为producer,生成message给ABAP program
    TRY .
      DATA:lo_producer TYPE REF TO if_amc_message_producer_text.
      DATA(lv_text) = i_message->get_text( ).
      lo_producer ?= cl_amc_channel_manager=>create_message_producer(
        i_application_id = 'ZT_AMC1'
        i_channel_id = '/test'
      ).
      lo_producer->send( i_message = lv_text ).
    CATCH cx_amc_error INTO DATA(lo_amc_exception).
      MESSAGE lo_amc_exception->get_text( ) TYPE 'E'.
    CATCH cx_apc_error INTO DATA(lo_apc_exception).
      MESSAGE lo_apc_exception->get_text( ) TYPE 'E'.
    ENDTRY.

2.将APC对应Class，维护为AMC的Authorized Program;

3.执行测试APC

通过Web发送信息，然后Program: ZTOM_AMC_RECEIVE_TEXT接收信息；

通过Program: ZTOM_AMC_SEND_TEXT发送信息,Web接收信息；

参考Blog:

https://blogs.sap.com/2015/09/07/abap-push-channel-messaging-channel-and-sapui5-demo-application/