--- parser: v2 auto_validation: true time: 40 tags: [ tutorial>intermediate, topic>abap-development] primary_tag: topic>abap-connectivity author_name: Felix Draeger author_profile: https://github.com/felixdraeger slug: abap-websocket-rfc canonical_url: https://developers.sap.com/tutorials/abap-websocket-rfc --- # WebSocket RFC to Cloud Learn how to establish a WebSocket RFC connection from an on-premise to a cloud system. ## You will learn - How to connect an on-premise system to cloud using WebSocket RFC. ## Prerequisites - Access to an SAP S/4HANA system of at least version 1909 - Access to the ABAP environment in a cloud system - Access to the communication management apps in SAP Fiori launchpad. - Latest version of ABAP Development Tools (ADT) installed with a project for each system. > In this tutorial, wherever **`XXX`** appears, use a number (e.g. **`000`**). --- ## Intro The following tutorial describes how to establish a connection between an on-premise ABAP system and a cloud-based ABAP system. > If the on-premise ABAP System is an S/4HANA older than version 1909, the underlying ABAP platform can't perform WebSocket RFC calls. The SAP Business Connector is required in this case. See [WebSocket RFC to Cloud Using SAP Business Connector](https://developers.sap.com/tutorials/abap-websocket-rfc-bc.html) for more information. ### Setting up the provider system First, you have to create a communication scenario based on a remote-enabled function module (RFM) in the provider cloud system. You can also use your own communication scenario and RFM, or use one of the SAP-delivered communication scenarios, for example `SAP_COM_0636`. For this tutorial, we will create a simple RFM that can receive a string, adds another string to it and returns the result to the sender. ![WebSocket RFC](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-websocket-rfc/WSRFC_1.png) ### Create a remote-enabled function module 1. Launch ABAP development tools (ADT) in the provider cloud system. 2. Select the relevant package, open the context menu and choose **New > Other ABAP Repository Object > ABAP Function Group** - Name: **`Z_Function_Group_XXX`** - Description: **`Function Group for RFM`** 3. Save and activate the function group. 4. Select the newly created function group, open the context menu and choose **New > ABAP Function Module**. - Name: **`Z_RFM_XXX`** - Description: **`RFM for WebSocket RFC`** 5. Paste the following code. ```ABAP FUNCTION Z_RFM_XXX IMPORTING VALUE(input) TYPE string EXPORTING VALUE(output) TYPE string. output = input && ' How are you?'. ENDFUNCTION. ``` 6. Save and activate the function module. ### Enable the function module for remote function call 1. In the project explorer, select the RFM. 2. Choose **File > Properties > Specific**. - Processing Type: **`RFC`** - RFC Scope: **`From any system`** - RFC Interface Contract: **`Any`** ![Remote Enabling the RFM](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-websocket-rfc/WSRFC_2.png) 3. Save and activate the RFM. ### Create and publish a communication scenario 1. In the relevant package, open the context menu and choose **New > Other ABAP Repository Object > Communication Scenario**. - Name: **`Z_WS_RFC_XXX`** - Description: **`Communication Scenario for WebSocket RFC`** 2. Go to tab **Inbound**. 3. In the section **Inbound Services**, choose **Add**. 4. In the field **Inbound Service ID**, enter the name of your RFM: **`Z_RFM_XXX_RFC`**. The **`_RFC`** is automatically added. 5. Make sure that in the field **Service Type**, the value **`RFC`** is specified. 6. Choose **Finish**. 7. Save the communication scenario. 8. Choose **Publish Locally**. ### Create a communication arrangement 1. In the provider system, log on to SAP Fiori launchpad. 2. Go to **Communication Management** and choose **Communication Arrangements**. 3. Choose **New**. - Scenario: **`Z_WS_RFC_XXX`** - Arrangement Name: **`Z_WS_RFC_ARRANGEMENT_XXX`** 4. Choose **Create**. 5. In the section **Common Data** in field **Communication System**, choose **New**. - System ID: **`Z_WS_RFC_SYSTEM_XXX`** - System Name: **`Z_WS_RFC_SYSTEM_XXX`** 6. Choose **Create**. 7. In the section **Technical Data**, activate **Inbound Only**. 8. Under **Users for Inbound Communication**, choose **Add**. 9. In the **New Inbound Communication User**, choose **New User**. - User Name: **`IB_RFC_XXX`** - Description: **`User for inbound WebSocket RFC`** - Password: **`Inbound_WebSocket_RFC_XXX`** 10. Choose **Create**. 11. In the **New Inbound Communication User** window, choose **OK**. 12. Choose **Save**. You are redirected back to the communication arrangements screen. 13. Under **Inbound Communication**, make sure the new inbound communication user **`IB_RFC_XXX`** is entered. 14. Choose **Save**. 15. Copy the API-URL. ![API-URL](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-websocket-rfc/WSRFC_5.png) ### Create a destination in the consumer system Now that you have set up the provider cloud system, you have to create a destination in the consumer on-premise system. This destination allows you to connect to the provider system. 1. Log on to the consumer system in SAP Logon and run transaction **`SM59`**. 2. Choose **Create**. - Destination: **`Z_WSRFCDEST_XXX`** - Connection Type: **`W RFC connection to other ABAP system using WebSockets`** 3. On the tab **Technical Settings**, enter the following properties: - Host: The API URL you have copied in step *5.15.* without the **`https://`** prefix. - Port: **`443`** ![Logon Settings](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-websocket-rfc/WSRFC_4.png) **Including the `https://` prefix leads to an error when you test the connection.** 4. On the tab **Logon & Security**, enter the following properties. Use the data of the inbound communication user from your communication system: - Explicit Client: **`by Hostname`** - by User/Password: activate **Alias User** - Alias User: **`IB_RFC_XXX`** - Password: **`Inbound_WebSocket_RFC_XXX`** ![Logon Settings](https://raw.githubusercontent.com/sap-tutorials/abap-core-development/main/tutorials/abap-websocket-rfc/WSRFC_3.png) 5. Choose **Save**. 6. Choose **Connection Test**. The connection test returns a ping result. ### Perform the WebSocket RFC call 1. Open ADT in the consumer on-premise system. 2. Select the relevant package, open the context menu and choose **New ABAP Class**. - Name: **`Z_WS_RFC_CALL_XXX`** - Description: **`WebSocket RFC Call`** 3. Paste the following code. ```ABAP CLASS z_ws_rfc_call_xxx DEFINITION PUBLIC FINAL CREATE PUBLIC . PUBLIC SECTION. INTERFACES if_oo_adt_classrun . PROTECTED SECTION. PRIVATE SECTION. ENDCLASS. CLASS z_ws_rfc_call_xxx IMPLEMENTATION. METHOD if_oo_adt_classrun~main. DATA lv_output TYPE string. DATA lv_input TYPE string VALUE 'Hello world!'. CALL FUNCTION 'Z_RFM_XXX' DESTINATION 'Z_WSRFCDEST_XXX' EXPORTING input = lv_input IMPORTING output = lv_output. out->write( lv_output ). ENDMETHOD. ENDCLASS. ``` 4. Save and activate the class. 5. Choose **Run > Run AS > ABAP Application (Console)**. > You can use also a service consumption model for the RFC call. See [Generating Proxies for Remote Function Call (RFC)](https://help.sap.com/docs/ABAP_PLATFORM_NEW/c238d694b825421f940829321ffa326a/32812d950d3848359ce391dae477f201.html?version=LATEST) and [Enable RFC Communication in Your ABAP Code](https://help.sap.com/docs/ABAP_PLATFORM_NEW/b5670aaaa2364a29935f40b16499972d/bbbd14283e984d6aa7b05062f197ef5b.html?version=LATEST). You can download the required service metadata file from the communication arrangement in SAP Fiori launchpad. ### Result You have sent a test string (`Hello world!`) to the RFM in the provider system. The string is returned as `Hello world! How are you?` to the consumer system. ### Test yourself