拉取订阅

此代码示例可用于使用订阅拉取已发布到 Pub/Sub 主题的消息。

如需查看 SAP BTP 版本的 ABAP SDK for Google Cloud 代码示例的全面集合,请参阅 GitHub 上的代码示例代码库

如需查看本地或任何云版本的 ABAP SDK for Google Cloud 代码示例的全面集合,请参阅 GitHub 上的代码示例代码库

代码示例

SAP BTP 版本

" --------------------------------------------------------------------
"  Copyright 2024 Google LLC                                         -
"                                                                    -
"  Licensed under the Apache License, Version 2.0 (the "License");   -
"  you may not use this file except in compliance with the License.  -
"  You may obtain a copy of the License at                           -
"      https://www.apache.org/licenses/LICENSE-2.0                   -
"  Unless required by applicable law or agreed to in writing,        -
"  software distributed under the License is distributed on an       -
"  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,      -
"  either express or implied.                                        -
"  See the License for the specific language governing permissions   -
"  and limitations under the License.                                -
" --------------------------------------------------------------------
CLASS zcl_cs_pull_subscriptions DEFINITION
  PUBLIC FINAL
  CREATE PUBLIC.

  PUBLIC SECTION.
    INTERFACES if_oo_adt_classrun.
ENDCLASS.


CLASS zcl_cs_pull_subscriptions IMPLEMENTATION.
  METHOD if_oo_adt_classrun~main.
    " Data Declarations
    DATA lv_p_projects_id      TYPE string.
    DATA lv_p_subscriptions_id TYPE string.
    DATA ls_input              TYPE /goog/cl_pubsub_v1=>ty_026.
    DATA ls_input_ack          TYPE /goog/cl_pubsub_v1=>ty_001.

    TRY.

        " Open HTTP Connection
        DATA(lo_pubsub) = NEW /goog/cl_pubsub_v1( iv_key_name = 'PUBSUB_DEMO' ).

        " Populate relevant parameters
        " Derive project id from the client object
        lv_p_projects_id = lo_pubsub->gv_project_id.
        " Name of the subscription from where we want to pull data
        lv_p_subscriptions_id = 'SAMPLE_SUBSCRIPTION'.
        " Max number of messages that will be received in 1 API call
        ls_input-max_messages = 1.

        " Call API method
        lo_pubsub->pull_subscriptions( EXPORTING iv_p_projects_id      = lv_p_projects_id
                                                 iv_p_subscriptions_id = lv_p_subscriptions_id
                                                 is_input              = ls_input
                                       IMPORTING es_output             = DATA(ls_output)
                                                 ev_ret_code           = DATA(lv_ret_code)
                                                 ev_err_text           = DATA(lv_err_text)
                                                 es_err_resp           = DATA(ls_err_resp) ).

        IF /goog/cl_http_client=>is_success( lv_ret_code ).
          IF ls_output-received_messages IS NOT INITIAL.
            " Messages published to Pub/Sub should be base-64 encoded
            " Therefore in order to get the exact message, we need to decode the data field.
            " However, attributes published to Pub/Sub should be accessible without any additional logic.
            DATA(lv_msg) = | MESSAGE Received: { cl_http_utility=>decode_base64(
                                                     encoded = ls_output-received_messages[ 1 ]-message-data ) }|.
            APPEND ls_output-received_messages[ 1 ]-ack_id TO ls_input_ack-ack_ids.

            " Call API method: pubsub.projects.subscriptions.acknowledge
            " Acknowledge the messages so it is not pulled again.
            lo_pubsub->acknowledge_subscriptions( EXPORTING iv_p_projects_id      = lv_p_projects_id
                                                            iv_p_subscriptions_id = lv_p_subscriptions_id
                                                            is_input              = ls_input_ack
                                                  IMPORTING es_output             = DATA(ls_output_ack)
                                                            ev_ret_code           = lv_ret_code
                                                            ev_err_text           = lv_err_text
                                                            es_err_resp           = ls_err_resp ).

            IF lo_pubsub->is_success( lv_ret_code ).
              out->write( | Error occurred: { lv_msg }| ).
            ELSE.
              out->write( | Error occurred: { lv_err_text }| ).
            ENDIF.
          ELSE.
            out->write( | No Messages were received!| ).
          ENDIF.
        ELSE.
          out->write( | Error occurred: { lv_err_text }| ).
        ENDIF.

        " Close HTTP Connection
        lo_pubsub->close( ).

      CATCH /goog/cx_sdk INTO DATA(lo_exception).
        lv_err_text = lo_exception->get_text( ).
        out->write( |Exception occurred: { lv_err_text } | ).
    ENDTRY.
  ENDMETHOD.
ENDCLASS.

本地或任何云版本

**********************************************************************
*  Copyright 2023 Google LLC                                         *
*                                                                    *
*  Licensed under the Apache License, Version 2.0 (the "License");   *
*  you may not use this file except in compliance with the License.  *
*  You may obtain a copy of the License at                           *
*      https://www.apache.org/licenses/LICENSE-2.0                   *
*  Unless required by applicable law or agreed to in writing,        *
*  software distributed under the License is distributed on an       *
*  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,      *
*  either express or implied.                                        *
*  See the License for the specific language governing permissions   *
*  and limitations under the License.                                *
**********************************************************************

REPORT zr_pull_subscriptions.

DATA:
  lv_p_projects_id      TYPE string,
  lv_p_subscriptions_id TYPE string,
  ls_input              TYPE /goog/cl_pubsub_v1=>ty_026,
  ls_input_ack          TYPE /goog/cl_pubsub_v1=>ty_001.

TRY.

* Open HTTP Connection
    DATA(lo_client) = NEW /goog/cl_pubsub_v1( iv_key_name = 'CLIENT_KEY' ).

* Populate relevant parameters
    " Derive project id from the client object
    lv_p_projects_id = lo_client->gv_project_id.
    " Name of the subscription from where we want to pull data
    lv_p_subscriptions_id = 'SAMPLE_SUBSCRIPTION'.
    " Max number of messages that will be received in 1 API call
    ls_input-max_messages = 1.

* Call API method
    CALL METHOD lo_client->pull_subscriptions
      EXPORTING
        iv_p_projects_id      = lv_p_projects_id
        iv_p_subscriptions_id = lv_p_subscriptions_id
        is_input              = ls_input
      IMPORTING
        es_output             = DATA(ls_output)
        ev_ret_code           = DATA(lv_ret_code)
        ev_err_text           = DATA(lv_err_text)
        es_err_resp           = DATA(ls_err_resp).

    IF /goog/cl_http_client=>is_success( lv_ret_code ).
      IF ls_output-received_messages IS NOT INITIAL.
        "Messages published to Pub/Sub should be base-64 encoded, hence in order to get the exact message, we need to decode the data field.
        "However, attributes published to Pub/Sub should be accessible without any additional logic.
        DATA(lv_msg) = | Message Received: { cl_http_utility=>decode_base64( encoded = ls_output-received_messages[ 1 ]-message-data ) }|.
        APPEND ls_output-received_messages[ 1 ]-ack_id TO ls_input_ack-ack_ids.

* Call API method: pubsub.projects.subscriptions.acknowledge
        "Acknowledge the messages so it is not pulled again.
        CALL METHOD lo_client->acknowledge_subscriptions
          EXPORTING
            iv_p_projects_id      = lv_p_projects_id
            iv_p_subscriptions_id = lv_p_subscriptions_id
            is_input              = ls_input_ack
          IMPORTING
            es_output             = DATA(ls_output_ack)
            ev_ret_code           = lv_ret_code
            ev_err_text           = lv_err_text
            es_err_resp           = ls_err_resp.

        IF lo_client->is_success( lv_ret_code ).
          MESSAGE lv_msg TYPE 'S'.
        ELSE.
          MESSAGE lv_err_text TYPE 'E'.
        ENDIF.
      ELSE.
        MESSAGE 'No Messages were received!' TYPE 'S'.
      ENDIF.
    ELSE.
      MESSAGE lv_err_text TYPE 'E'.
    ENDIF.

* Close HTTP Connection
    lo_client->close( ).

  CATCH /goog/cx_sdk INTO DATA(lo_exception).
    MESSAGE lo_exception->get_text( ) TYPE 'E'.
ENDTRY.