Consume API directly into ABAP

Background

As API is getting famous with so many APIs available how can we consume it into ABAP directly without any middle wares.

One of the easiest way to call an external API directly into ABAP system using API Key.

Step 1 – What do you need –

Postman – To verify if the data is coming as expected

API Key – To fetch data form source system into ABAP

SSL Certificates – You can download the certificate and it needs to install in SAP. In SAP, certificates can be installed using t-code Strust.

Postman – We will need the parameters to get data in ABAP

Step 2 – Certificate needs to be installed in “SSL Server Standard”

Step 2 – ABAP Program

The below program has been developed on 750 but the classes exist from 730 itself and can be used

*&---------------------------------------------------------------------*
*& Report ZTEST_API
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ztest_api.


SELECTION-SCREEN: BEGIN OF BLOCK b1 WITH FRAME TITLE TEXT-s01.
PARAMETERS: p_inv TYPE belnr_d DEFAULT '12345'.
SELECTION-SCREEN: END OF BLOCK b1.

START-OF-SELECTION.

*HTTP Client Abstraction
  DATA  lo_client TYPE REF TO if_http_client.

*Data variables for storing response in xstring and string
  DATA  : lv_xstring   TYPE xstring,
          lv_string    TYPE string,
          lv_node_name TYPE string.

  CLEAR : lv_xstring, lv_string, lv_node_name.

*Pass the URL to get Data
  lv_string = |https://XXXXXX.com/api/XXXXX/{ p_inv }|.

*Creation of New IF_HTTP_Client Object
  cl_http_client=>create_by_url(
  EXPORTING
    url                = lv_string
  IMPORTING
    client             = lo_client
  EXCEPTIONS
    argument_not_found = 1
    plugin_not_active  = 2
    internal_error     = 3
    ).

  IF sy-subrc IS NOT INITIAL.
* Handle errors
  ENDIF.

  lo_client->propertytype_logon_popup = lo_client->co_disabled.
  lo_client->request->set_method( 'GET' ).


  CALL METHOD lo_client->request->set_header_field
    EXPORTING
      name  = 'XXXXXXXX'
      value = ' XXXXXXXX '.


  CALL METHOD lo_client->request->set_header_field
    EXPORTING
      name  = 'Accept'
      value = 'application/xml'.

*Structure of HTTP Connection and Dispatch of Data
  lo_client->send( ).
  IF sy-subrc IS NOT INITIAL.
* Handle errors
  ENDIF.

*Receipt of HTTP Response
  lo_client->receive( ).
  IF sy-subrc IS NOT INITIAL.
* Handle errors
  ENDIF.

END-OF-SELECTION.

*Return the HTTP body of this entity as binary data
  lv_xstring = lo_client->response->get_data( ).

**Displays XML File
  CALL METHOD cl_abap_browser=>show_xml
    EXPORTING
      xml_xstring = lv_xstring
      size        = cl_abap_browser=>large.

Step 4 – Output

Once the program is executed, you will be able to see the data directly in form of XML. The XML data can also be converted into internal table and be used/displayed as per requirement

Conclusion 

It is simple to call API from ABAP. We have standard classes available to read data and to transform data into internal table.