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Exercise 2

• Create the service consumption model
• Create a console application to test the OData service
• Create a custom entity and implement the query implementation class
  • Create a custom entity
  • Implement the query implemenation class
• Add the custom entity as a value help
• Test the service
• Summary
• Solution

When creating a new entry with your inventory application you see that there is no value help for the field ProductId. Since this information resides in a SAP S/4 HANA backend we will it retrieve via OData.

In this exercise you will thus learn how to consume an OData Service from an on premise system in order to fetch business partner data. You will then learn how to expose this data as a value help for the Inventory entity.

In this exercise, we will ...

• Create a Service Consumption Model for the on premise OData Service
• Create a console application to test the OData Service call
• Create a Custom Entity and implement its custom query
• Expose your Custom Entity within your existing OData Service
• Add the Custom Entity as a value help for the field ProductId in your inventory application

Please note:

Since it must be possible to run this demo on the trial systems where no destination service is available we cannot use RFC calls to retrieve data from a backend system. We have rather to use services that are publically available in the Internet. In our demo we will thus use an OData Service that is available in the SAP Gateway Demo System ES5 and that does not require any authentication.

Create the Service Consumption Model

In this step we will generate a so called Service Consumption Model. This type of object takes an external interface description as its input. Currently OData, SOAP and RFC are supported.
Based on the information found in the $metadata file or the wsdl file appropriate repository objects are generated (OData Client proxy or SOAP proxy objects). For RFC function modules the metadata file is created in the backend using the transaction ACO_PROXY.
Using these objects you will be able to write ABAP code that lets you consume remote OData services, SOAP services or RFC function modules.

We start by creating a service consumption model for an OData service that provides demo product data. This service resides on the public SAP Gateway System ES5 and does not require any authentication

1. The $metadata file of the OData service that we want to consume must be uploaded in file format. You have hence to download it first.

• Click on the following URL https://sapes5.sapdevcenter.com/sap/opu/odata/sap/ZPDCDS_SRV/$metadata

  When you are asked to select a certificate or to authenticate, simply press the Cancel button, since this URL does not require any authentication.

  

• Download the $metadata file to your computer, you will need it later in this exercise.

  
  

2. Switch to ADT and right click on your package ZRAP_INVENTORY_####. Select New > Other ABAP Repository Object.

2. In the New ABAP Repository Object dialogue do the following

   • Start to type Service
   • In the list of objects select Service Consumption Model
   • Click Next

4. The New Service Consumption Model dialogue opens. Here enter the following data:

   • Name: ZSC_RAP_PRODUCTS_####
   • Description: Products from ES5
   • Remote Consumption Model: OData (to be selected from the drop down box)

   Caution

   Be sure that you have selected OData as the Remote Consumption Mode from the drop down box. We will create a service consumption model for a SOAP web service in the following exercise.

   

5. The $metadata file of the OData service that we want to consume must be uploaded in file format. If you have not yet downloaded the $metadata file you have to do this now.

   • Click Browse to select the $metadata file that you have downloaded earlier in this exercise
   • Prefix: RAP_####_

Please note

The prefix that you have entered will be added to the names of the repository objects that are generated, namely the abstract entity(ies). If you don't select a prefix and if the wizard finds out that there would be name clashes the wizard will propse unique names by adding arbitrary characters to the repository object names. In any case you will be able to change the values that will be proposed by this wizard.

6. Check the ABAP Artifact Name and click Next.

   You will notice that the name of the ABAP artifact has been set to ZRAP_####_SEPMRA_I_PRODUCT_E since we have provided the prefix RAP_####_.

   Press Next.

Additional Information

If you have not provided a prefix the ABAP Artifact Name might contain several arbritray characters that have been added to the name ZSEPMRA_I_PRODUCT. This can happen if other users in the same system have already imported the same $metadata file. In order to avoid name clashes the wizard then adds arbitrary characters so that a unique name for the ABAP artifact is ensured.

7. The wizard will now list the repository objects that will be generated, namely a service definition and an abstract entity in addition to the service consumption model.

   • Service Definition: ZSC_RAP_PRODUCTS_####
   • Abstract Entity: ZRAP_####_SEPMRA_I_PRODUCT_E

Click Next.

8. Selection of transport request
   • Select or create a transport request
   • Press Finish

9. Let us briefly investigate the service consumption model.

   For each operation (Read List, Read, Create, Update and Delete) some sample code has been created that you can use when you want to call the OData Service with one of these operations. Since we want to retrieve a list of Product-IDs, we will select the operation Read List and click on the button Copy to Clipboard. We will use this code in the following step where we create a console application to test the call to the remote OData service.

Remove dimension fields from abstract entity

In order to avoid an error when the custom entity is used as a value help we have to remove the dimension fields from the abstract entity. Otherwise a convesion error occurs that will lead to a dump. The root cause is being analyzed but was not solved before our session took place.

1. Remove dimensions from the abstract entity

   Please open the entity ZRAP_####_SEPMRA_I_PRODUCT_E (Press Ctrl+Shift+A) and paste the name (of course with your number ####) and comment out following part:

// @OData.property.valueControl: 'Height_vc' 
// @Semantics.quantity.unitOfMeasure: 'DimensionUnit' 
// Height : abap.dec( 13, 3 ) ; 
// Height_vc : rap_cp_odata_value_control ; 
// @OData.property.valueControl: 'Width_vc' 
// @Semantics.quantity.unitOfMeasure: 'DimensionUnit' 
// Width : abap.dec( 13, 3 ) ; 
// Width_vc : rap_cp_odata_value_control ; 
// @OData.property.valueControl: 'Depth_vc' 
// @Semantics.quantity.unitOfMeasure: 'DimensionUnit' 
// Depth : abap.dec( 13, 3 ) ; 
// Depth_vc : rap_cp_odata_value_control ; 

2. Afterwards please activate your changes.

Create a console application to test the OData service

We can now test the service consumption model by creating a small console application ZCL_CE_RAP_PRODUCTS_#### that implements the interface if_oo_adt_classrun. This is a useful additional step since this way it is easier to check whether the OData consumption works and debugging a console application is much easier than trying out your coding in the full fledged RAP business object.

Please note

We will use this class at a later stage also as an implementation for our custom query and we hence choose a name ZCL_CE_RAP_PRODUCTS_#### that already contains the name of the to be created custom entity. CE denotes that this class will act as a query implementation for a Custom Entity.

1. Right click on the folder Source Code Library and select New > ABAP Class.

   

2. The New ABAP class dialogue opens. Here you have to enter the following:

   • Name: ZCL_CE_RAP_PRODUCTS_####
   • Description: Query implementation custom entity
   • Click Add

   The Add ABAP Interface dialogue opens.

   • Start to type if_oo
   • Select IF_OO_ADT_CLASSRUN from the list of matching items
   • Press OK or double-click on IF_OO_ADT_CLASSRUN

   

3. Check the input and press Next

4. Selection of transport request

   • Select or create a transport request
   • Click Finish

ZRAP_CE

5. Check the source code template

You will notice that the wizard has automatically added an implementation for the method IF_OO_ADT_CLASSRUN~MAIN.

CLASS zcl_ce_rap_products_#### - Implementation

1. Let's start with the implementation of our test class.

   In the public section we add two TYPES definitions. t_product_range is used to provide filter conditions for ProductIDs in form of SELECT-OPTIONS to the method get_products( ).
   The second type t_business_data is used to retrieve the business data returned by our remote OData service.
   The get_products( ) method takes filter conditions in form of SELECT-OPTIONS via the importing parameter it_filter_cond. In addition it is possible to provide values for top and skip to leverage client side paging.

   So the DEFINITION section of your class should now look like follows:

CLASS zcl_ce_rap_products_#### DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC .

  PUBLIC SECTION.

    INTERFACES if_oo_adt_classrun .

    TYPES t_product_range TYPE RANGE OF zrap_####_sepmra_i_product_e-product.
    TYPES t_business_data TYPE TABLE OF zrap_####_sepmra_i_product_e.

    METHODS get_products
      IMPORTING
        it_filter_cond   TYPE if_rap_query_filter=>tt_name_range_pairs   OPTIONAL
        top              TYPE i OPTIONAL
        skip             TYPE i OPTIONAL
      EXPORTING
        et_business_data TYPE  t_business_data
      RAISING
        /iwbep/cx_cp_remote
        /iwbep/cx_gateway
        cx_web_http_client_error
        cx_http_dest_provider_error
      .

  PROTECTED SECTION.
  PRIVATE SECTION.
ENDCLASS.

You will get a warning that the method get_products( ) has not been implemented yet. Press Ctrl+1 to start the quick fix to add an implementation for get_products( ).

6. Now we will add code in the IMPLEMENTATION section of the method get_products( ).

   The public method get_products( ) is used to retrieve the data from the remote OData service. Since it is not possible to leverage the destination service in the trial systems, we will use the method cl_http_destination_provider=>create_by_url which allows us to create a http destination object based on the target URL. As the target URL we choose the root URL https://sapes5.sapdevcenter.com of the ES5 system since the relative URL that points to the OData service will be added when creating the OData client proxy.

   Caution:
   Do not forget to replace the placeholder '####' with your unique number.

   Please note

   In a normal SAP Cloud Platform, ABAP Environment system one would leverage the destination service of the underlying Cloud Foundry Environment and one would use the statement cl_http_destination_provider=>create_by_cloud_destination to generate a http destination in the ABAP Environment system based on these settings.

METHOD get_products.

    DATA: filter_factory   TYPE REF TO /iwbep/if_cp_filter_factory,
          filter_node      TYPE REF TO /iwbep/if_cp_filter_node,
          root_filter_node TYPE REF TO /iwbep/if_cp_filter_node.

    DATA: http_client        TYPE REF TO if_web_http_client,
          odata_client_proxy TYPE REF TO /iwbep/if_cp_client_proxy,
          read_list_request  TYPE REF TO /iwbep/if_cp_request_read_list,
          read_list_response TYPE REF TO /iwbep/if_cp_response_read_lst.

    DATA(http_destination) = cl_http_destination_provider=>create_by_url( i_url = 'https://sapes5.sapdevcenter.com' ).
    http_client = cl_web_http_client_manager=>create_by_http_destination( i_destination = http_destination ).

    odata_client_proxy = cl_web_odata_client_factory=>create_v2_remote_proxy(
      EXPORTING
        iv_service_definition_name = 'ZSC_RAP_PRODUCTS_####'
        io_http_client             = http_client
        iv_relative_service_root   = '/sap/opu/odata/sap/ZPDCDS_SRV/' ).

    " Navigate to the resource and create a request for the read operation
    read_list_request = odata_client_proxy->create_resource_for_entity_set( 'SEPMRA_I_PRODUCT_E' )->create_request_for_read( ).

    " Create the filter tree
    filter_factory = read_list_request->create_filter_factory( ).
    LOOP AT  it_filter_cond  INTO DATA(filter_condition).
      filter_node  = filter_factory->create_by_range( iv_property_path     = filter_condition-name
                                                              it_range     = filter_condition-range ).
      IF root_filter_node IS INITIAL.
        root_filter_node = filter_node.
      ELSE.
        root_filter_node = root_filter_node->and( filter_node ).
      ENDIF.
    ENDLOOP.

    IF root_filter_node IS NOT INITIAL.
      read_list_request->set_filter( root_filter_node ).
    ENDIF.

    IF top > 0 .
      read_list_request->set_top( top ).
    ENDIF.

    read_list_request->set_skip( skip ).

    " Execute the request and retrieve the business data
    read_list_response = read_list_request->execute( ).
    read_list_response->get_business_data( IMPORTING et_business_data = et_business_data ).

  ENDMETHOD.

8. Finally we add the following code into the IMPLEMENTATION section of your main method

The main method creates a simple filter for products with a name greater or equal HT-1200. At the same time we use client side paging to skip the first result and limit the response to 3 products.

  METHOD if_oo_adt_classrun~main.

    DATA business_data TYPE TABLE OF zrap_####_sepmra_i_product_e.
    DATA filter_conditions  TYPE if_rap_query_filter=>tt_name_range_pairs .
    DATA ranges_table TYPE if_rap_query_filter=>tt_range_option .
    ranges_table = VALUE #( (  sign = 'I' option = 'GE' low = 'HT-1200' ) ).
    filter_conditions = VALUE #( ( name = 'PRODUCT'  range = ranges_table ) ).

    TRY.
        get_products(
          EXPORTING
            it_filter_cond    = filter_conditions
            top               =  3
            skip              =  1
          IMPORTING
            et_business_data  = business_data
          ) .
        out->write( business_data ).
      CATCH cx_root INTO DATA(exception).
        out->write( cl_message_helper=>get_latest_t100_exception( exception )->if_message~get_longtext( ) ).
    ENDTRY.

  ENDMETHOD.

9. The code should now look as follows

   Source code zcl_ce_rap_products_####

10. You can now run the console application by pressing F9.

    

Create a custom entity and implement the query implementation class

Since we want to use the results of the remote OData service in our managed inventory app we will create a custom entity. The syntax of a custom entity differs from the one used in normal CDS views but is very similar to the syntax of an abstract entity and we can thus reuse most of the DDL source code of the abstract entity that has been generated when the service consumption model was created.

In order to leverage the remote OData service in our application we have to perform two steps.

1. We have to create a custom entity.
2. We have to create a class that implements the query for the custom entity. (Here we will reuse the class that we have created earlier and that we have used to test the remote OData service).

Create a custom entity

In constrast to "normal" CDS views that read data from the database from tables or other CDS views the so called custom entities act as a wrapper for a code based implementation that provides the data instead of a database table or a CDS view.

The custom entity has to be created manually and it uses a similar syntax as the abstract entity that has been created when we have created our service consumption model.

In order to be able to retrieve the data from the remote OData service we have to built a class that implements the interface if_rap_query_provider. We will reuse the class that we have created earlier and add this interface to it.

The interface if_rap_query_provider interface only offers one method which is called select. Within this select method we will call the public get_products( ) method. The select method also expects that the incoming requests provide certain OData specific query parameters. These we will set in our coding as well.

1. Right-click on the folder Data Definition and select New Data Definition.

   

2. Let’s start with creating a new data definition ZCE_RAP_PRODUCTS_#### using the template for a custom entity.

3. The New Data Defintion dialogue opens

   • Name: ZCE_RAP_PRODUCTS_####
   • Description: Custom entity for products from ES5

   Press Next

   

4. Selection of a transport request

   • Select or create a transport request.
   • !!! ONLY !!! Press Next. Do NOT press Finish.

   Caution

   If you were to press Finish instead of Next, the wizard would use the template that was used the last time when this wizard was used by the developer.

   In order to be sure that the correct template is selected, we MUST press Next and not Finish which would skip the step of template selection.

   

5. Select Template

   • Use the scroll bar to navigate down the list
   • Select the template Define custom entity with parameters
   • Press Finish

Please note

There is only a template for a custom entity with parameters. But this doesn’t matter. We use this template and remove the statement with parameters parameter_name : parameter_type.

5. Edit the source code of the custom entity

   • Remove the statement

     with parameters parameter_name : parameter_type

• Copy the field list from the abstract entity ZRAP_####_SEPMRA_I_PRODUCT_E

• and paste it between the curly brackets as the new field list of our custom entity.

  

6. Now add the annoation @ObjectModel.query.implementedBy: 'ABAP:ZCL_CE_RAP_PRODUCTS_####'

7. Activate your changes

   

8. The DDL source code should now look like follows

   Source code ZCE_RAP_PRODUCTS_####

Please note: You have to adapt the number of decimals for the property Price

10. Change the number of decimals for the property Price.

    Change the number of decimals for the property Price from 3 to 2, so that it now reads as follows:

     Price                   : abap.curr( 16, 2 ); 

    

Implement the query implemenation class

After having created the custom entity ZRAP_CE_PRODUCTS_#### we now have to enhance the query implementation class ZCL_CE_RAP_PRODUCTS_####that we have created earlier in this exercise.

1. Add interface IF_RAP_QUERY_PROVIDER to the query implementation class ZCL_CE_RAP_PRODUCTS_####

   • You can use the quick fix Ctrl+1 to add the implementation for the method if_rap_query_provider~select

  INTERFACES if_rap_query_provider.
  

2. Implement the method if_rap_query_provider~select

Within the select() method we can retrieve the details of the incoming OData call using the object io_request. Using the method get_paging() we can find out whether client side paging was requested with the incoming OData call. Using the method get_filter() we can retrieve the filter that was used by the incoming OData request as ranges. This comes in handy so we can provide this data when calling the method get_products().

Please note: It is mandatory that the response not only contains the retrieved data via the method set_data() but also the number of entities being returned via the method set_total_number_of_records().

  METHOD if_rap_query_provider~select.
    DATA business_data TYPE TABLE OF zrap_####_sepmra_i_product_e.
    DATA(top)     = io_request->get_paging( )->get_page_size( ).
    DATA(skip)    = io_request->get_paging( )->get_offset( ).
    DATA(requested_fields)  = io_request->get_requested_elements( ).
    DATA(sort_order)    = io_request->get_sort_elements( ).

    TRY.
        DATA(filter_condition) = io_request->get_filter( )->get_as_ranges( ).

        get_products(
                 EXPORTING
                   it_filter_cond    = filter_condition
                   top               = CONV i( top )
                   skip              = CONV i( skip )
                 IMPORTING
                   et_business_data  = business_data
                 ) .

        io_response->set_total_number_of_records( lines( business_data ) ).
        io_response->set_data( business_data ).

      CATCH cx_root INTO DATA(exception).
        DATA(exception_message) = cl_message_helper=>get_latest_t100_exception( exception )->if_message~get_longtext( ).
    ENDTRY.
  ENDMETHOD.

 
 

3. Activate your changes

4. Your ABAP source code should now look like follows

Source code ZCL_CE_RAP_PRODUCTS_####

Add the custom entity to your service definition

1. Open the Service Definition ZRAP_INVENTORY_####

   • add the statement

     expose ZCE_RAP_PRODUCTS_#### as Products;

     so that the custom entity is added to the OData service.
   • Activate your changes

Add the custom entity as a value help

1. Open the projection view for your inventory data ZC_RAP_INVENTORY_####

• Add the annotation @Consumption.valueHelpDefinition to the field ProductID

  @Consumption.valueHelpDefinition: [{ entity : {name: 'ZCE_RAP_PRODUCTS_####', element: 'Product'  } }]
  ProductID,
  

This will add the custom entity ZCE_RAP_PRODUCTS_#### as a value help for the field ProductId.

Test the service

1. Open the service binding ZUI_RAP_INVENTORY_####_02

   • You will notice that now two entities are visible. Products and Inventory

     

     Caution:
     At this point you might receive an error message such as
     Amount field PRICE with currency decimals not equal to two is not supported.
     If this is the case go back to your custom entity ZCE_RAP_PRODUCTS_####
     And change the number of decimals for the property price from 3 to 2, so that it now reads as follows:

      Price                   : abap.curr( 16, 2 ); 

     

2. Start the Fiori Elements preview

   • Create a new inventory
   • Click on the value help icon

   

3. The search results are on the buttom of the window. So you have to scroll down using the scroll bar on the right hand side.

4. Select a product e.g. HT-1000

5. Check the result on the object page

Summary

You are now able to: · Explore an existing application with the Fiori Elements preview · Consume external OData Service using the Service Consumption Model · Create and expose Custom Entites · Implement Custom Queries for Custom Entities · Define value helps for OData entities

Continue to - Exercise 3 - Excercise 3