How to call a remote OData service from the trial version of SAP Cloud Platform ABAP environment

Updates

•  21.10. use of more inline declarations and filter to overcome the BT restriction

We recently made the trial version of SAP Cloud Platform ABAP Environment availalble as described in my blog It’s Trial Time for ABAP in SAP Cloud Platform.

One of the known limitations is that you can’t use the destination service and it is thus not possible to use http or RFC destinations to communicate to remote systems.

There is however the option to create a destination through providing a URL

data base_url type string.
base_url = '<base url of an OData service>'.
http_client = cl_web_http_client_manager=>create_by_http_destination( i_destination =  cl_http_destination_provider=>create_by_url( i_url = base_url ) ).

    http_client->get_http_request( )->set_authorization_basic(
        i_username = '<username>'
        i_password = '<password>'
    ).

!!! Warning !!!

An obvious drawback of this option when being used in a shared trial version is that everybody else can read your code and would thus be able to read your username and password as well.

Demo service being used

The demo service that I will use is a simple OData service that is published on the SAP Gateway demo system ES5.

https://sapes5.sapdevcenter.com/sap/opu/odata/sap/ZE2E100_SOL_2_SRV/$metadata

How to get a user in ES5 is described in my following blog.

Creating the Service consumption model

We first have to download the $metadata file of the OData service we want to consume. Firefox is a good option.

We start by creating a service consumption model ZSC_SALESORDERDEMO which has to be used by the client proxy that we use in our ABAP code to call the remote OData service by uploading the Service Metadata File that we have just downloaded.

In the next step you are able to select then entity sets of the OData service you want to consume.This option comes very handy since it allows to minimize the number of repository objects (CDS views that contain abstract entities) that are going to be created to the bare minimum needed.

Please note that it is in this step where you can provide another name for the ABAP artifacts that will be generated.

You just have to confirm that the below shown artifacts will be generated.

As a result three repository objects are generated

such as a Service Consumption Model

A Service Definition

@EndUserText.label: 'ZSC_SALESORDERDEMO'
@OData.schema.name: 'ZE2E100_SOL_2_SRV'
define service ZSC_SALESORDERDEMO {
 expose ZSALESORDERDEMO; 
 } 

as well as a Data Definition that contains an abstract entity

/********** GENERATED on 10/19/2019 at 18:25:05 by CB0000000083**************/
 @OData.entitySet.name: 'Zsepm_C_Salesorder_SOL' 
 @OData.entityType.name: 'Zsepm_C_Salesorder_SOLType' 
 define root abstract entity ZSALESORDERDEMO { 
 key SalesOrder : abap.char( 10 ) ; 
 @Semantics.amount.currencyCode: 'TransactionCurrency' 
 NetAmountInTransactionCurrency : abap.dec( 16, 3 ) ; 
 @Semantics.amount.currencyCode: 'TransactionCurrency' 
 TaxAmountInTransactionCurrency : abap.dec( 16, 3 ) ; 
 SalesOrderLifeCycleStatus : abap.char( 1 ) ; 
 SalesOrderBillingStatus : abap.char( 1 ) ; 
 SalesOrderDeliveryStatus : abap.char( 1 ) ; 
 SalesOrderOverallStatus : abap.char( 1 ) ; 
 Opportunity : abap.char( 35 ) ; 
 SalesOrder_Text : abap.char( 255 ) ; 
 CreationDateTime : tzntstmpl ; 
 LastChangedDateTime : tzntstmpl ; 
 IsCreatedByBusinessPartner : abap_boolean ; 
 IsLastChangedByBusinessPartner : abap_boolean ; 
 Customer : abap.char( 10 ) ; 
 @Semantics.currencyCode: true 
 TransactionCurrency : abap.cuky( 5 ) ; 
 @Semantics.amount.currencyCode: 'TransactionCurrency' 
 GrossAmountInTransacCurrency : abap.dec( 16, 3 ) ; 
 
 } 

Please note that also sample code is generated to consume your OData service for all CRUD-Q operations.

Consuming the service using a simple class

I have taken the above code as a starting point and replaced the Hungarian notation prefixes ? and tried to provide a sample code that follows the clean ABAP principles.

Any suggestions to improve the code are welcome.

The class has basically two methods

• get_http_client
• get_odata_response

The method get_http_client( ) creates an instance of the http_client object using the base URL of our OData service. The http_client object is than used by the method get_odata_response( ) to consume the OData service.

The client proxy needs three parameters:

•  the name of the consumption model that ZSC_SALESORDERDEMO
•  the http_client object
•  the relative URL /sap/opu/odata/sap/ZE2E100_SOL_2_SRV/ that points to the service document of the OData service

Based on the client proxy object another object is created to perform the READ request on the entity set Zsepm_C_Salesorder_SOL. Please note that you have to use the ABAP internal name ZSEPM_C_SALESORDER_SOL here which is in upper case .

In the following a filter tree is created to filter for the key field SalesOrder and the property NetAmountInTransactionCurrency which is of type currency.

Please note that the filter node for the property NetAmountInTransactionCurrency needs the currency provided via the optional parameter iv_currency_code.

If you omit to provide this information you will get the error message:

No currency code supplied for property path ‘NETAMOUNTINTRANSACTIONCURRENCY’.

How to create filter statements for intervals

In my example I want to retrieve only sales orders with a net amount between $3000 and $7000. To achieve this goal we currently have to create two child nodes that both contain filter options to retrieve sales orders. One node for sales orders with a net amount larger than $3000 and one node for sales orders with a net amount smaller than $7000. This is because currently range tables with the option BT are NOT supported.

Not supported:
range_for_netamounts2 = VALUE #( ( sign = ‘I’ option = ‘BT‘ low = ‘3000’ high = ‘8000’) ).

The code looks like follows:

CLASS zcl_call_odata_from_trial DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.
    INTERFACES if_oo_adt_classrun.
  PROTECTED SECTION.
    DATA salesorders TYPE STANDARD TABLE OF zsalesorderdemo.
  PRIVATE SECTION.

    METHODS get_http_client
      IMPORTING base_url           TYPE string
      RETURNING VALUE(http_client) TYPE REF TO if_web_http_client
      RAISING
                cx_web_http_client_error
                cx_http_dest_provider_error.

    METHODS get_odata_response
      IMPORTING http_client TYPE REF TO if_web_http_client
      EXPORTING entityset   LIKE salesorders
      RAISING
                cx_web_http_client_error
                /iwbep/cx_gateway.

ENDCLASS.



CLASS zcl_call_odata_from_trial IMPLEMENTATION.

  METHOD if_oo_adt_classrun~main.

    DATA base_url TYPE string.
    base_url = 'https://sapes5.sapdevcenter.com/'.

    TRY.
        DATA(http_client) = get_http_client( base_url = base_url ).
      CATCH cx_web_http_client_error cx_http_dest_provider_error INTO DATA(error_creating_http_client).
        out->write( error_creating_http_client->get_longtext(  )  ).
        EXIT.
    ENDTRY.

    TRY.
        get_odata_response(
         EXPORTING http_client = http_client
         IMPORTING entityset = DATA(salesorders) ).
      CATCH cx_web_http_client_error /iwbep/cx_gateway INTO DATA(error_calling_OData_service).
        "handle exception
        out->write( error_calling_OData_service->get_longtext(  )  ).
        EXIT.
    ENDTRY.

    LOOP AT salesorders INTO DATA(salesorder).
      out->write( salesorder ).
    ENDLOOP.

  ENDMETHOD.

  METHOD get_http_client.
    http_client = cl_web_http_client_manager=>create_by_http_destination( i_destination =  cl_http_destination_provider=>create_by_url( i_url = base_url ) ).

    http_client->get_http_request( )->set_authorization_basic(
        i_username = '<your ES5 user>'
        i_password = '<password of your ES5 user>'
    ).
  ENDMETHOD.

  METHOD get_odata_response.

    DATA entity LIKE LINE OF entityset.
    DATA range_for_salesorders LIKE RANGE OF entity-salesorder.
    DATA range_for_salesorders2 LIKE RANGE OF entity-salesorder.
    DATA range_for_netamounts LIKE RANGE OF entity-netamountintransactioncurrency.
    DATA range_for_netamounts2 LIKE RANGE OF entity-netamountintransactioncurrency.
    DATA(client_proxy) = cl_web_odata_client_factory=>create_v2_remote_proxy(
      EXPORTING
        iv_service_definition_name = 'ZSC_SALESORDERDEMO'
        io_http_client             = http_client
        iv_relative_service_root   = '/sap/opu/odata/sap/ZE2E100_SOL_2_SRV/' ).

    DATA(odata_request) = client_proxy->create_resource_for_entity_set( 'ZSEPM_C_SALESORDER_SOL' )->create_request_for_read( ).

    odata_request->set_top( 5 )->set_skip( 0 ).

* filter
    range_for_salesorders = VALUE #(
      ( sign = 'I' option = 'GE' low = '500000100' ) ).
    range_for_netamounts = VALUE #(
      ( sign = 'I' option = 'LE' low = '8000' ) ).
    range_for_netamounts2 = VALUE #(
      ( sign = 'I' option = 'GE' low = '3000' ) ).
    DATA(filter_factory) = odata_request->create_filter_factory( ).
    DATA(filter_child_node_1)  = filter_factory->create_by_range( iv_property_path     = 'SALESORDER'
                                                                  it_range             = range_for_salesorders ).
    DATA(filter_child_node_2)  = filter_factory->create_by_range( iv_property_path     = 'NETAMOUNTINTRANSACTIONCURRENCY'
                                                                  it_range             = range_for_netamounts
                                                                  iv_currency_code     = 'USD' ).
    DATA(filter_child_node_3)  = filter_factory->create_by_range( iv_property_path     = 'NETAMOUNTINTRANSACTIONCURRENCY'
                                                                  it_range             = range_for_netamounts2
                                                                  iv_currency_code     = 'USD' ).
    DATA(filter_root_node) = filter_child_node_1->and( filter_child_node_2->and( filter_child_node_3 ) ).
    odata_request->set_filter( filter_root_node ).

* retrieve business data
    DATA(odata_response) = odata_request->execute( ).
    odata_response->get_business_data( IMPORTING et_business_data = entityset ).

  ENDMETHOD.

ENDCLASS.

And if you run it via F9 you get the following result.

All salesorders have a net amount between 3000$ and 8000$ and the Salesorder ID is larger than 500000100 and the result set is limited to the first 5 hits.