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Create an HTTP Service

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Create an HTTP Service
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Create an HTTP Service

Julie Plummer
Julie Plummer
July 12, 2021
Created by
Julie Plummer
September 12, 2018
Beginner
15 min.
ABAP Development, SAP Business Technology Platform, SAP BTP, ABAP environment, Beginner, Tutorial, ABAP Connectivity
Create an HTTP service in the ABAP environment that can be called from the browser.

You will learn

  • How to create an HTTP service that can be accessed from a browser
  • How to return system data using a (whitelisted) ABAP utility class
  • How to expose the service for external consumption, by defining the necessary inbound communication artifacts
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Prerequisites

  • IMPORTANT: This tutorial cannot be completed on a trial account

Important: If you are working in SAP S/4HANA:
ICF services are direct entry points into the ABAP system via the HTTP protocol. Implementing ICF services is a security-critical task with implications on the system and landscape configuration.

Therefore, to follow the best practices adopted by SAP internally, consider implementing your service as an OData service.

Step 1: Create an HTTP service

  1. Select a package and choose New > Other Repository Object from the context menu:

    Image depicting step-1a-new-repo-object

  2. Enter the filter text HTTP and choose Next:

    Image depicting step-1b-choose-HTTP-service

  3. Enter a Name:Z_GET_DATE_HTTP_XXX and Description:Get system date for your service and choose Next:

    Image depicting step-1c-name-service

  4. Choose or create a transport request:

    Image depicting step-1d-transport-request

The new HTTP service is displayed on a new tab. The handler class and URL are generated automatically, in the form:
https://<server:port>/sap/bc/http/sap/<service_name>?sap-client=100

Image depicting step-1e-new-service-created
Done
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Step 2: Implement the handler class

Now, you will implement the handler class, starting with a simple text output.

  1. Open the handler class by clicking on the hyperlink:

    Image depicting step-2a-open-handler-class

  2. The structure of the class and the interfaces statement for IF_HTTP_SERVICE_EXTENSION are generated automatically.

  3. Go to the class implementation section and insert the following statement in the method:

    response->set_text('Hello!').

    Image depicting step-2b-insert-method
Done
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Step 3: Save and activate

Save (Ctrl+S) and Activate (Ctrl+F3) your class.

Done
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Step 4: Test the service

  1. Go back to your HTTP Service. Test your service in the browser by clicking the URL link:

    Image depicting step-4-test-http-service

  2. If necessary, log in again. The preview open automatically in a new tab and display something like this:

    Image depicting step-4b-hello
Done
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Step 5: Add method `get_html`
View Full Instructions

Now you will add a method to get system data and format this in HTML

In the ABAP environment, you can only use whitelisted APIs. Therefore, for example, you cannot use SY-UNAME. Instead, you call the appropriate method of the class CL_ABAP_CONTEXT_INFO.

  1. In your class definition, add the following statement: 
    METHODS: get_html RETURNING VALUE(ui_html) TYPE string.
  2. You will get the error “Implementation missing…”. Resolve this by choosing Quick Assist ( Ctrl+1 ) and choosing Add implementation…. Ignore the two warnings for now. 

    DATA(user_formatted_name) = cl_abap_context_info=>get_user_formatted_name( ).
DATA(system_date) = cl_abap_context_info=>get_system_date( ).

ui_html =  |<html> \n| &&
|<body> \n| &&
|<title>General Information</title> \n| &&
|<p style="color:DodgerBlue;"> Hello there, { user_formatted_name } </p> \n | &&
|<p> Today, the date is:  { get_system_date }| &&
|<p> | &&
|</body> \n| &&
|</html> | .

  3. Now change the method implementation of the method handle_request

    response->set_text( get_html(  ) ).

  4. Now select the warning for the method get_html and choose Quick Assist ( Ctrl + 1 ). (You cannot resolve the warning for the method handle_request).

  5. Choose Add raising declaration, then choose Finish.

  6. Format, save, and activate the class ( Shift + F1, Ctrl + S, Ctrl + F3 ).

  7. Test the service again using the URL. Your page should look roughly like this:

    step8a-formatted-html
Done
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Step 6: Check code
View Full Instructions

Your code should look like this:

CLASS Z_GET_DATE_HTTP_XXX DEFINITION
  PUBLIC
  CREATE PUBLIC .

  PUBLIC SECTION.

    INTERFACES if_http_service_extension .

    METHODS: get_html RETURNING VALUE(ui_html) TYPE string
    RAISING
        cx_abap_context_info_error.

  PROTECTED SECTION.
  PRIVATE SECTION.
ENDCLASS.



CLASS Z_GET_DATE_HTTP_XXX IMPLEMENTATION.


  METHOD if_http_service_extension~handle_request.
    response->set_text( get_html(  ) ).
  ENDMETHOD.

  METHOD get_html.

    DATA(user_formatted_name) = cl_abap_context_info=>get_user_formatted_name( ).
    DATA(system_date) = cl_abap_context_info=>get_system_date( ).

    ui_html =  |<html> \n| &&
    |<body> \n| &&
    |<title>General Information</title> \n| &&
    |<p style="color:DodgerBlue;"> Hello there, { user_formatted_name } </p> \n | &&
    |<p> Today, the date is:  { get_system_date }| &&
    |<p> | &&
    |</body> \n| &&
    |</html> | .

  ENDMETHOD.

ENDCLASS.
Done
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Step 7: Create an inbound Communication Scenario

You will now create the artifacts you need to allow other systems to call your service compliantly. This involves some overhead for one consumer; however, the advantage is that you can add several consumer systems, or users (for example, with different authentication) pointing to the same HTTP service, wrapped in the same Communication Scenario.

step9-create-comm-artefacts-overview

First, create the Communication Scenario.

  1. Select your package, then choose New > Other Repository Object… from the context menu.

    step9a-new-other

  2. Add the filter scen, then choose Communication Scenario, then choose Next.

    step9c-create-comm-scenario

  3. Add a Name: Z_WRAP_HTTP_INBOUND_XXX and Description, choose a transport request, then choose Finish.

Your Communication Scenario appears.

step9-new-comm-scen
Done
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Step 8: Add the HTTP service

  1. On the Inbound tab, choose Add….

    step10-add-http-service

  2. IMPORTANT: Choose Browse. You cannot simply enter the name. Then add a filter, such as Z_HTTP, select your service, then choose Finish.

    step10a-browse-for-service

  3. Your service appears. Choose Publish Locally.

    step10-b-publish-locally
Done
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Step 9: Create Communication Arrangement

  1. Open the dashboard for your system. You can find the URL for the dashboard by selecting your system (that is, ABAP Project in Project Explorer), then choosing Properties > ABAP Development from the context menu.

    step11a-open-flp

  2. From Communication Management, choose Communication Arrangement. Then choose New.

    step11b-new

  3. Choose your scenario, Z_WRAP_HTTP_INBOUND_XXX from the drop-down list. Accept the default (identical) Arrangement name.

    step11c-name-comm-arr
Done
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Step 10: Create Communication System

  1. From the Dashboard Home screen, choose Communication Systems.

  2. Enter the name of your Communication Arrangement, then for Communication System, choose New.

  3. Enter a System ID and Accept the default (identical) System name, then choose Create.

  4. In Technical Data > General > Host Name, enter Dummy. Leave the other defaults and choose Save.

    step12a-new-system
Done
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Step 11: Create Communication User

  1. Scroll down to Users for Inbound Communication, then create a new user by choosing the + icon.

    step13a-create-comm-user

  2. Choose New User and the Authentication Method: User name and password.

    step13b-choose-new-user

  3. Enter a name and description, then choose Propose password, then choose Create > OK > Save.

Done
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Step 12: Save Communication Arrangement
step14-save-comm-arr
Done
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Step 13: Test yourself
What is the correct syntax to Implement the method `IF_HTTP_SERVICE_EXTENSION~HANDLE_REQUEST`
so that it returns the current user name (`UNAME`), not the system date. Choose only one option.
×

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