Tip 3: How to call a low-code module from an RPG program

This tip documents how to:

1. Create a low-code module to consume a REST API.

2. Call the low-code module from an RPG program, by using the PJSCALL program.

Create a low-code module to consume a REST API

• Navigate to the workspace "pjstips".

• Click New/Module File.

• Click Edit/Source, to bring up the Source view.

• Clear the current default code, and enter the code below.

• 
  
  

  pjstips_03_1.module.json

  { "routines": [ { "name": "routine1", "inputs": [ { "type": "decimal", "ibmiLength": 4, "name": "custno", "ibmiDecimals": 0 } ], "outputs": [ { "type": "string", "ibmiLength": 30, "name": "name" } ], "steps": [ { "text": "Consume REST service", "answers": { "plugin": "Custom:web-service", "uri": "http://localhost:8081/run/pjstips/pjstips_02_3", "method": "POST", "headers": "", "body": "{\n \"custno\": input[\"custno\"]\n}", "json": true, "auth": "", "capture_response": true, "capture_on_error": false, "capture_as": "Value", "specific_property": "", "destination": "Work variable", "work_variable": "myres" } }, { "text": "Set Module output", "answers": { "plugin": "Program Data:set-module-output", "module-output-values": { "name": "myres[\"name\"]" } } } ] } ] }

  
  
  

• Click Edit/Design, to bring up the Design view.

• If needed, in the "Consume REST service" step, change the Endpoint URL to point to the correct host/port.

• Click Home/Save As, and save as pjstips_03_1.module.json.

• You've created a low-code module, as shown below, with a routine named "routine1" that:
  
  

  • Takes an input parameter of "custno".

  • Uses plugin "Consume REST service" to issue a POST request to URL http://localhost:8081/run/pjstips/pjstips_02_3 (created in a previous example).

  • The input "custno" is specified in the "body" of the POST request.

  • The returned JSON object from the REST web service is saved in a work variable named "myres".

  • The value of myres["name"] is used to set the output value output["name"].

• Open

  

Open

Call the low-code module from an RPG program

• You can call this low-module from another low-code module, from another "regular" (i.e. NOT low-code) PJS module, or from an RPG program. To call it from an RPG program, use the code generated in the panel "IBM i Call Interface" panel.

• Below is an example, where the input custno is set to 1234 to pass to the low-code module, which calls the REST service to get the customer name, which is then returned to the RPG program, which is then displayed on the screen.

PJSTIPS031.rpgle