About This Space

This lab walks you through building a series of Node.js applications that work with employee data.


Last updated on July 2, 2019

Forked from: /plus/guided-lab/

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NodeRun Guided Lab

This lab walks you through building a series of Node.js applications that work with employee data.

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

Agenda

You will use NodeRun.com to build the following modules:

The exercises are intended to be followed in order.

What is NodeRun.com?

  • 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

NodeRun.com provides all the tools you need. You just need a modern browser, such as:

  • Google Chrome
  • Mozilla Firefox

NodeRun Spaces

  • Everyone can have their own isoldated space (or as many spaces as you need)
  • Each space has:
    • Its own files
    • Its own database
    • Its own server
  • Create spaces by either:
    • Visiting NodeRun.com (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 have a NodeRun.com account (free to create 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!

screenshot

  • 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

screenshot   screenshot   screenshot

Build Employee Lookup Screen

  • Add labels
  • Add Ok and Cancel buttons

screenshot

Find employee database table

  • Find employees under the Database Tab
  • Review the data

screenshot   screenshot

Use employee database table

  • In Input Mode, drag employeeNumber to screen

    screenshot

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

    screenshot

Bind Buttons

  • Bind response of Ok button to ok

screenshot screenshot

  • 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

screenshot

  • Click Save and name the file lookup.json

screenshot

Create Node.js script for Employee Lookup

  • Select New -> JavaScript File

screenshot

  • Write code as shown below

screenshot

  • Save as lookup.js

Code Explained

exports.default = lookup
  • In Node.js, every public function must be exported
  • In NodeRun, 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

screenshot

  • The running application will look like this:

screenshot

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

screenshot   screenshot

  • Click Save

Try using the auto-complete feature

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

screenshot

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:

screenshot

Bind the image source property to the field name source

screenshot

screenshot

Assign employee photo source field

Add the following line of code:

screenshot

Test employee photo feature

screenshot

Exercise 4 (Employee Listing)

  • Select New -> Rich Display File
  • Add Panel

screenshot   screenshot   screenshot

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

screenshot

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

    screenshot

    screenshot

Create Node.js script for Employee Listing

  • Select New -> JavaScript File

    screenshot

  • Write code as shown below

    screenshot

  • 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
  • NodeRun supports a variety of methods to populate grids

Try running Employee Listing option from Menu

screenshot

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

screenshot

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

    screenshot

Add call from list.js to lookup.js

screenshot

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

screenshot

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

screenshot

Exercise 7 (Listing Web Service)

  • Select New -> JavaScript File

    screenshot

  • Write code as shown below

    screenshot

  • Save as get_employees.js

Code Explained

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

NodeRun uses 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:

screenshot

Then select the following:

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

screenshot

Test Listing Web Service

screenshot   screenshot

Exercise 8 (Details Web Service)

  • Select New -> JavaScript File

    screenshot

  • Write code as shown below

    screenshot

  • 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:

screenshot

Then select the following:

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

screenshot

Test Details Web Service

screenshot   screenshot

Try modifying employee number in the URL.

Exercise 9 (Consuming a Web Service)

  • Open list.js

  • Save As list2.js

    screenshot

Call a Web Service

Replace:

screenshot

With:

screenshot

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

screenshot

screenshot

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:

screenshot   screenshot

screenshot

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

    screenshot

  • Write code as shown below

    screenshot

  • 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

screenshot

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

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