Install required packages

sudo apt-get update
sudo apt-get install php-mbstring
sudo apt-get install php-curl
sudo apt-get install php-xml

Install Laravel via composer

composer create-project laravel/laravel example-app
composer install

php artisan --version
php artisan serve

Generating app key

php artisan key:generate 
php artisan key:generate --show

What are namespaces?

Namespaces are a way of encapsulating items.
e.g. In any operating system directories serve to group related files, and act as a namespace for the files within them.

As a concrete example, the file foo.txt can exist in all 4 directories with different contents in each.

Similarly to avoid ambiguity in PHP we have namespaces. Namespaces solve the confusion of having same class name in program.

Let’s understand this with example.

AdminAccount.php

<?php

class AdminAccount {
        public function __construct() {
                echo "Admin Account Controller..." . PHP_EOL;
        }
}

UserAccount.php

<?php

class UserAccount {
        public function __construct() {
                echo "User Account Controller..." . PHP_EOL;
        }
}

index.php

<?php

require("UserAccount.php");
require("AdminAccount.php");

new UserAccount();
new AdminAccount();

Now, what if we have the same class name in both files.
This scenario always comes when you use third-party libraries or any framework.

AdminAccount.php

<?php
class Account {
        public function __construct() {
                echo "Admin Account Controller..." . PHP_EOL;
        }
}

UserAccount.php

<?php
class Account {
        public function __construct() {
                echo "User Account Controller..." . PHP_EOL;
        }
}

index.php

<?php

require("UserAccount.php");
require("AdminAccount.php");

new Account();
new Account();

This will create confusion about which instance to be created.
Now let’s resolve this problem using namespaces.

AdminAccount.php

<?php
namespace Admin;

class Account {
        public function __construct() {
                echo "Admin Account Controller..." . PHP_EOL;
        }
}

UserAccount.php

<?php
namespace User;

class Account {
        public function __construct() {
                echo "User Account Controller..." . PHP_EOL;
        }
}

index.php

<?php

require("UserAccount.php");
require("AdminAccount.php");

new User\Account();
new Admin\Account();

To install phpunit framework make sure you have installed composer
If not follow instructions from this link http://codeinsightacademy.com/blog/php/composer/

Installation

Install php-xml
As we are going to use phpunit.xml we need to install php-xml

sudo apt install php-xml
#To install specific version
sudo apt install php7.4-xml

Install mbstring

sudo apt-get install php-mbstring

Create composer.json file in project root directory

{
"autoload" : {}
}

Run one of the composer command

composer dump-autoload -o
OR
composer update

Install sluggable

composer require cviebrock/eloquent-sluggable

Install intl
This is required when you are using Code Igniter framework

apt-get install php-intl
#OR specific version
apt-get install php7.4-intl

Install php unit framework

composer require phpunit/phpunit ^9

Create function

global_functions.php

<?php

function add($x = 0, $y = 0) {
        return $x + $y;
}

index.php

<?php

require_once("vendor/autoload.php");

echo add(5, 6);

composer.json

{
    "autoload": {
            "files": ["global_functions.php"]
    },
    "require": {
        "cviebrock/eloquent-sluggable": "^8.0",
        "phpunit/phpunit": "^9"
    }
}

Run index.php file

php index.php

Write Testcase

phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>

<phpunit bootstrap = "vendor/autoload.php"
 colors = "true">
    <testsuites>
        <testsuite name="Sample test suite">
            <directory>tests</directory>
        </testsuite>
    </testsuites>

</phpunit>

tests/GlobalFunctionsTest.php
NOTE: MAKE SURE TO GIVE test PREFIX TO YOUR TEST FUNCTION

<?php

class GlobalFunctionsTest extends \PHPUnit\Framework\TestCase {
        public function testAdd() {
                $result = add(5, 6);
                $this->assertEquals(11, $result);
        }
}

Get all assertions functions from here
https://phpunit.readthedocs.io/en/9.5/assertions.html

Run TestCase from root directory

./vendor/bin/phpunit

./vendor/bin/phpunit --testdox

project directory structure

tree -I "vendor"

What is INI file

An INI file is a configuration file for computer software that consists of a text-based content with a structure and syntax comprising key–value pairs for properties, and sections that organize the properties.

parse_ini_file function

Parse ini file is a function to parse any configuration file which has key-value pair
This is required when you want to keep all application-level configuration parameters in one place
Maintaining configuration level parameter/variables is easy when you use ini file
You need to make changes in one file and it will reflect changes throughout the application

Syntax

parse_ini_file(file, process_sections, scanner_mode)

myapp.ini

#comment goes here

APP_NAME	= UMS
ADMIN_EMAIL	= admin@umsapp.com


#local database credentials
[localdb]
DB_HOSTNAME	= localhost
DB_USERNAME	= root
DB_PASSWORD	= ""
DB_PORT		= 3306
DB_NAME		= ecom


#production database credentials
[proddb]
PRD_DB_HOSTNAME	= localhost
PRD_DB_USERNAME	= root
PRD_DB_PASSWORD	= ""
PRD_DB_PORT	= 3306
PRD_DB_NAME	= ecom

global_functions.php

function getConnection() {
	
	$db = parse_ini_file('config/myapp.ini', true)['localdb'];
	
	$conn = null;
	
	$servername	= $db['DB_HOSTNAME'];
	$dbname		= $db['DB_NAME'];
	$username 	= $db['DB_USERNAME'];
	$password	= $db['DB_PASSWORD'];
	
	try {
	  $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
	  $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);	
	} catch(PDOException $e) {
	  echo "Error: " . $e->getMessage();
	}
	
	return $conn;
}

Ref: https://www.w3schools.com/php/func_filesystem_parse_ini_file.asp

A Dependency Manager for PHP

Composer is an application-level package manager for the PHP programming language that provides a standard format for managing dependencies of PHP software and required libraries. It was developed by Nils Adermann and Jordi Boggiano in 2012, who continue to manage the project.

To install composer in windows download and install executable file
https://getcomposer.org/download/

To install in ubuntu

apt install composer

To install latest version of composer on ubuntu

cd ~
curl -sS https://getcomposer.org/installer -o composer-setup.php

sudo php composer-setup.php --install-dir=/usr/bin --filename=composer

OR

sudo php composer-setup.php --install-dir=/usr/local/bin --filename=composer

composer.json
Keep this file in the project’s root directory
NOTE: This file is mandatory to in root directory to use composer as composer look for this file when you run dump-autoload

{
	"autoload" : {
		"files" : ["lib/global_functions.php"],
	}
}

lib/global_functions.php

function getMessage() {
	
	echo "Hello World" . PHP_EOL;

}

Create autoload file by running any one following command

composer dump-autoload
composer dump-autoload -o

index.php

<?php
require("vendor/autoload.php");
echo "=====================\n";
getMessage();

How to autoload classes using composer

app/admin/Account.php

<?php
namespace App\Admin;

class Account {
	//this is magic method as it will invoked automatically 
        //when you create instance of account
	public function __construct() {
		
		echo "I am from Admin Account" . PHP_EOL;
	}
}

app/user/Account.php

<?php
namespace App\User;

class Account {
	//this is magic method as it will invoked automatically 
	//when you create instance of account
	public function __construct() {
		echo "I am from User Account" . PHP_EOL;
	}	
}

modify composer.json

{
	"autoload" : {
		"files" : ["lib/global_functions.php"],
		"classmap" : ["app"]
	}
}

Once you modify composer.json file run dump-autoload command again to add classmapping in autoload file

composer update

OR

composer dump-autoload -o

modify index.php

<?php

require("vendor/autoload.php");

echo "=====================\n";

getMessage();

echo "=====================\n";

new App\User\Account();

echo "=====================\n";

new App\Admin\Account();

echo "=====================\n";

Ref Code: https://gitlab.com/codeinsightacademy/composer-demo.git