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Example of a low-code module with a bug

• 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.

• 
  

  Code Block
  language js title pjstips_04_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": "{\"Content-Type\": \"application/x-www-form-urlencoded\"}", "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_04_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 plug "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"].
  • But, it has a bug; we'll learn how to debug this problem.
  • 

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• Below is an example, there 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.

**free

  Dcl-PR PJSCALL ExtPgm;
    ParmType        Char(30)          Const;
    ModuleID        VarUCS2(500)      Const;
    RoutineName     VarUCS2(70)       Const;
    InputParms      Char(16773104)    Const Options(*Varsize:*Omit:*NoPass);
    InputParmSize   Int(10)           Const Options(*Omit:*NoPass);
    OutputParms     Char(16773104)    Options(*Varsize:*Omit:*NoPass);
    OutputParmSize  Int(10)           Const Options(*Omit:*NoPass);
  End-PR;

  Dcl-DS InputDS Qualified Inz;
    custno  Zoned(4: 0);
  End-DS;

  Dcl-DS OutputDS Qualified Inz;
    name  VarChar(30);
  End-DS;

  InputDS.custno = 1234;			// pass input to the low-code module in "InputDS"

  Monitor;

    PJSCALL('*MODULE'
      : 'pjstips:pjstips_04_1.module.json'
      : 'routine1'
      : InputDS
      : %Size(InputDS)
      : OutputDS
      : %Size(OutputDS)
    );

  On-Error;


  EndMon;

  dsply  OutputDS.name;				// output from the low-code module in "OutputDS"		
  *inlr = *on;
  return;

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If you want to debug that low-code module, you can do go through the follow following steps to "convert" it into "real" PJS code and call it as an Express Route (web service). This is also a good way to learn how things are done behide behind the scenescenes. When a low-code module is called, the JSON file is "transformed" into "real" PJS code, and the then that "transformed" module is run.

• 1. On the PJS IDE, on code panel (upper center panel), in the top-left cordercorner, click the </> button to "transform" the low-code steps into real PJS code.

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• 2. On the popup message below, click OK.

• 3. VERY IMPORTANT! You can convert from low-code to real code only, not the other way! You can NOT go back! That is, you can NOT convert from real code back to low-code. So, after you see the real code show up on the next step, do NOT save the module file, if you want to keep it as low-code.
• 4. The "real" PJS code is shown below:

• 5. Copy/paste that code to somewhere (e.g. Notepad++) and save it.
• 6. Close the file. Do NOT save it! If you save it, your module now will contain real code, not low-code anymore.
• 7. Now, create a new web service with the code saved in step (5) above, with some minor adjustments, so that you can call it from a browser and debug it. Refer to As a general reference, click here to see how to create a web service. Follow the steps below to create a web service for this example.
• 8. Click New/Javascript file.
• 9. Enter the code below. This is pretty much the same as the code you saved in step (5) above, but changed so that it can be called as a web service from the browser, so you can debug it easily.

function app(req, res) {
  
  // init these 2 objects that would normally be done when a low-code module is called
  var input = {};
  var output = {};

  // set input data
  input.custno = 1234;

  // start of code converted from low-code module in step (5) above --------------------------
  // Consume REST service
  var _data = pjs.sendRequesthttpRequest({
    method: "POST",
    uri: `http://localhost:8081/run/pjstips/pjstips_02_3`,
    headers: {"Content-Type": "application/x-www-form-urlencoded"},
    body: {
    "custno": input["custno"]
    },
    json: true
  });
  var myres = _data;

  // Set Module output
  output["name"] = myres["name"];
  // end of code converted from low-code module in step (5) above ----------------------------
  
  // send back "output" from low-code module as JSON
  res.json(output);

}

exports.run = app;

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