POWERUp 2020 Guided Lab (Use Node.js to build Business Apps)

This lab walks you through building a series of Node.js applications that work with employee data. To get started, make sure your browser is pointed to: https://spaces.profoundjs.com/ide/profound-logic/guided-lab/.

The lab requires only a browser to complete. You can use the virtual lab PC provided by POWERUp or your own computer to complete the exercises.

To view this document in a separate browser tab, click here.

Agenda

You will use Profound.js Spaces to build the following modules:

• Employee Lookup Module (Exercise 1, Exercise 2, and Exercise 3)
• Employee Listing Module (Exercise 4, Exercise 5, and Exercise 6)
• Employee Listing Web Service (Exercise 7)
• Employee Details Web Service (Exercise 8)
• Module to consume an Employee Listing Web Service (Exercise 9)
• Module to use npm to email an employee list (Exercise 10)

The exercises are intended to be followed in order.

What is the Profound.js Spaces website?

• Cloud environment for Node.js development
• Full IDE with Visual Designer, Editor, Debugger, and Node.js preinstalled
• Capabilities
  • Design Screens
  • Develop and Run applications
  • Full Debugging
  • Install npm Packages
  • Manage, start, and stop your own Node.js Sever
  • Work with Active Sessions to see end-user activity
  • Hosted Database and built-in Database Explorer
  • Command-line Terminal for full control of your space
  • Share and collaborate with other developers

What you need to get started and complete the exercises

The Profound.js Spaces site (https://spaces.profoundjs.com) provides all the tools you need. You just need a modern browser, such as:

• Google Chrome
• Mozilla Firefox

Using Spaces

• Everyone can have their own isoldated space (or as many spaces as you need) on the site
• The spaces are hosted in the cloud
• Free to use for the purpose of building and testing applications; however, hosting full-blown production applications in the Profound.js Spaces cloud environment can have costs
• Each space has:
  • Its own files
  • Its own database
  • Its own server
  • Its own git repositary
• Create spaces by either:
  • Visiting https://spaces.profoundjs.com and clicking "New Space" (you can select a template or start from scratch)
  • Forking another space (this is how we'll get started with this Lab)
• To save your space permanently:
  • You must create a Profound.js Spaces account (or sign in using GitHub, Google, or Facebook)
  • You must then publish the space and give it a name
• You can share your spaces with others:
  • Each space has its own unique URL for opening and running the space
  • Set public permission on your space as you wish and invite contributors if you want to work together with others

Let's get started!

• Visit https://spaces.profoundjs.com/ide/profound-logic/guided-lab/
• Click Fork... on the Home Menu
• If you are not signed in, Create an Account or Sign In
• Give your space a name. For example: My Lab

• Click Fork
• Click Close
• Notice the URL in your browser will change to show your profile name and your new workspace name

Exercise 1 (Employee Lookup)

• Select New -> Rich Display File
• Add Panel

   

Build Employee Lookup Screen

• Add labels
• Add Ok and Cancel buttons

Find employee database table

• Find employees under the Database Tab
• Review the data

 

Use employee database table

• In Input Mode, drag employeeNumber to screen

  

• In Output Mode, drag lastName, firstName, email, jobTitle to screen

  

Bind Buttons

• Bind response of Ok button to ok

• Similarly, bind response of Cancel button to cancel

The case of the field names matters. "ok" is not the same as "Ok".

Name your screen + Save

• Click the Edit Name icon under Screens and type lookup

• Click Save and name the file lookup.json

Create Node.js script for Employee Lookup

• Select New -> JavaScript File

• Write code as shown below

• Save as lookup.js

Code Explained

exports.default = lookup

• In Node.js, every public function must be exported
• The name run indicates the main function to run when this script is executed

pjs.defineDisplay("display", "lookup.json");

• The pjs.defineDisplay() API declares a Rich Display File and all of its fields within the function
• The first parameter ("display") becomes an object that contains all Rich Display screens as properties
• The second parameter ("lookup.json") refers to the Rich Display json file

display.lookup.execute();

• display is the Rich Display File object
• lookup is the screen name
• The execute() method sends the screen to the browser, waits for the user to respond, and reads input from the user

while (!cancel) {
  // ...
}

• Keeps executing while the Cancel button is not pressed
• cancel is a field bound to the response property of the Cancel button

pjs.query("SELECT * FROM employees WHERE employeeNumber = ?", [employeeNumber]);

• The pjs.query() API executes an SQL query and returns a JavaScript array of records
• The first parameter is an SQL statement where ?’s are parameter markers
• The second parameter is an array of values to use for the parameter markers

var record = results[0];

• The SQL query expects only 1 record, so we retrieve the first record
• In JavaScript, arrays start with index 0

pjs.setFields(record);

• The pjs.setFields() API assigns fields from a JavaScript record or object to any field defined in your Node.js script, including fields defined with pjs.defineDisplay()
• It's a quick way to move queried data directly to the screen

Try your application

• Select Launch App in Browser Tab

• The running application will look like this:

Exercise 2 (Using database-driven auto-complete)

• Switch back to the Visual Designer and select the employeeNumber textbox
• Type +data under Find Property
• Type employees in the choices database table property
• Select the first 3 fields for the choice options field property and press OK

 

• Click Save

Try using the auto-complete feature

• Refresh (or exit and relaunch) the application
• Then start typing a value in the Employee# box

Exercise 3 (Adding a dynamic image)

In this exrecise, we'll add an employee photo to the Employee Lookup screen.

Add employee photo as Image Widget

Drag image widget to the Visual Designer canvas:

Bind the image source property to the field name source

Assign employee photo source field

Add the following line of code:

Test employee photo feature

Exercise 4 (Employee Listing)

• Select New -> Rich Display File
• Add Panel

   

Add Grid and Ok Button

• Drag grid widget to the canvas and drag a button to the canvas
• Add columns by click the plus (+) sign on the grid widget
• Rename columns by double-clicking each column
• Drag database fields into the first row of the grid
• Doubel-click to change the button text to "Ok", then bind the ok field to the response property of the Ok button

Name screen and grid; then save Rich Display File

• Screen must be named list, and grid must be named grid

• Rich Display File should be named list.json

  

  

Create Node.js script for Employee Listing

• Select New -> JavaScript File

  

• Write code as shown below

  

• Save as list.js

Code Explained

display.grid.replaceRecords(data);

• display is your Rich Display File object
• grid is the name given to your grid on the screen
• The replaceRecords() method replaces all records in the grid with an array of records passed in as a paramater
• Profound.js supports a variety of methods to populate grids

Try running Employee Listing option from Menu

Exercise 5 (Enhance the grid)

In the Visual Designer, select the grid and set the following properties to true:

• sortable columns
• movable columns
• xlsx export
• find option
• filter option
• hide columns option

Save, then rerun the Employee Listing to test out the features

Exercise 6 (Connect listing to lookup)

This exercise allows users to click on an employee in the grid to see employee details.

Configure row selection

Set the following grid properties:

• row selection: single (Select this value from the dropdown)

• selection field: Bind to a boolean named selected

  

Add call from list.js to lookup.js

Code Explained

display.grid.readChanged();
if (!display.endOfData() && selected) {
  pjs.call("lookup.js", rec.employeeNumber);
}

• The readChanged() method reads the grid for changed records one at a time and populates display fields from the records found
• display.endOfData() returns a boolean value of true if no changed records were found
• selected is the boolean field we used to identify whether a specific record is selected or not
• pjs.call() calls another script or program
• Number() converts a delcared strongly-typed field to a primitive JavaScript value, which forces the employee number to be passed by value rather than by reference

Alternate approach

There are multiple ways to retrieve record data from a grid.

Using ES6 syntax, we can quickly retrieve all selected records into an array and then use the first record in the array.

var selectedRecords = display.grid.filter(entry => entry.selected);
var record = selectedRecords[0];
if (record) {
  pjs.call("lookup.js", record.employeeNumber);
}

selectedRecords[0] works well because single selection only allows one record to be selected at a time.

Modify lookup.js to receive parameter

Code Explained

if (parm) employeeNumber = parm;

• Checks if parm was passed, and if so, assign to employeeNumber as default value
• If we don't check for the existence of the parameter, a data decimal error may occur

Test connected modules

Exercise 7 (Listing Web Service)

• Select New -> JavaScript File

  

• Write code as shown below

  

• Save as get_employees.js

  Code Explained

---

function get_employees(request, response) {
  // ...
}

Profound.js Spaces use the popular Express.js web framework as its foundation. All Express.js Web Services receive a request and a response parameter.

• request is an object that represents everything about the Web Services request
• response is an object that supplies the methods you need to constuct and send a response

Create Web Service out of get_employees.js

Right-click the saved file under Files and select Properties:

Then select the following:

• Express Route
• HTTP Method: get
• Route Path: employees

Test Listing Web Service

 

Exercise 8 (Details Web Service)

• Select New -> JavaScript File

  

• Write code as shown below

  

• Save as get_employee.js

Code Explained

var records = pjs.query("SELECT * FROM employees WHERE employeeNumber = ?", [request.params.empNum]);

if (records.length > 0) response.send({ success: true, record: records[0] });
else response.send({ success: false });

• request.params allows you to access parameters passed as part of the URL
• Other types of request parameters can be accessed as well
  • request.query gives you query string parameters
  • request.body gives you POST data parameters
• records.length specifies how many record were retrieved; if 0, we send a { success: false } response

Create Web Service out of get_employee.js

Right-click the saved file under Files and select Properties:

Then select the following:

• Express Route
• HTTP Method: get
• Route Path: employee/:empNum

Test Details Web Service

 

Try modifying employee number in the URL.

Exercise 9 (Consuming a Web Service)

• Open list.js

• Save As list2.js

  

Call a Web Service

Replace:

With:

Code Explained

• The pjs.sendRequest() API makes a Web Services request
• The URI can be specified as relative or absolute
• The data is now requested from a Web Service instead of connecting to the database directly

Test Consuming a Web Service

Exercise 10 (Using npm to email Employee List)

In this exercise, you will write code to email a list of employees to yourself.

Install gmail-send npm package

You can install pacakges from the Server menu:

 

Alternatively, use the Terminal feature and type: npm install gmail-send

What is npm?

• www.npmjs.com hosts a repository of reusable Node.js packages
• There are many packages for almost every imaginable purpose
• Packages will often use other packages
• For example, nodemailer is popular package for sending emails
• gmail-send is a package that implements nodemailer, but simplifies usage specifically for sending emails from a gmail account

Create Node.js script named email.js

• Select New -> JavaScript File

  

• Write code as shown below

  

• Save as email.js

Code Explained

• require() is a Node.js API that loads files or loads installed npm packages
• require('gmail-send') loads the gmail-send package
• require('./credentials.json') loads gmail account credentials from a json file

Test the email functionality

• Don't click the option more than once! The menu will remain on screen after the email is sent.
• Check your inbox to see if you received the employee list.

You are all done! Thank you!

Thanks for trying out this lab!

As a next step, try to think of creative ways to enhance the screens or the funcionality behind the screens you built.

Leave questions or comments for us here:

• https://spaces.profoundjs.com/view/profound-logic/guided-lab/
• https://discuss.profoundjs.com/