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PHP II - Sep 2022

Last Slide: http://localhost:8882/#/3/28

TODO

Class repos: https://github.com/MPSimon/php2 From Aaron Hoffman to Everyone 09:09 PM https://github.com/HoffmanProgress/tvasset From michelle nesbitt to Everyone 09:13 PM https://github.com/nerdommicro/zend-php2 Forks: https://github.com/dbierer/php2_[max|michelle|aaron]

Homework

For Thu 29 Sep 2022

  • Lab: Validate an Email Address: Use preg_match() to validate an email address
  • Lab: Composer with OrderApp For Tue 27 Sep 2022
  • Lab: Prepared Statements
  • Lab: Stored Procedure
  • Lab: Transaction
  • If you want to use the database in the VM, use these connection params:
'db' => [
	'dsn' => 'mysql:unix_socket=/var/run/mysqld/mysqld.sock;dbname=phpcourse',
	'username' => 'vagrant',
	'password' => 'vagrant',
	'options'  => [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION],
],
  • Look at Zend\workspaces\DefaultWorkspace\orderapp\src\OrderApp\Core\Db\Db.php
  • Also: Zend\workspaces\DefaultWorkspace\orderapp\src\OrderApp\Model\OrdersModel.php

For Thu 22 Sep 2022

  • Lab: Type Hinting
  • Lab: Build Custom Exception Class
  • Lab: Traits
  • Lab: Review the OrderApp in the VM

For Tues 20 Sep

  • Lab: Create an Extensible Super Class
  • Lab: Magic Methods
  • Lab: Abstract Classes
  • Lab: Interfaces For Thu 15 Sep 2022
  • Update the VM
  • Create a repository on github
  • Lab: Namespaces
  • Lab: Create a Class
  • Collabedit: https://collabedit.com/cknea

VM Notes

Info

  • Username: vagrant
  • Password: vagrant

Install git

  • Open a terminal window and run this command:
sudo apt install -y git

Update everything!

  • Open a terminal window and run this command:
sudo apt update
sudo apt -y upgrade
  • NOTE: this task might take some time

Install phpMyAdmin

  • Download the latest version from https://www.phpmyadmin.net
  • Make note of the version number (e.g. 5.2.0)
cd
VER=5.2.0
unzip Downloads/phpMyAdmin-$VER-all-languages.zip
sudo cp -r phpMyAdmin-$VER-all-languages/* /usr/share/phpmyadmin
sudo cp /usr/share/phpmyadmin/config.sample.inc.php /usr/share/phpmyadmin/config.inc.php
  • Create the "blowfish secret"
sudo -i
export SECRET=`php -r "echo md5(date('Y-m-d-H-i-s') . rand(1000,9999));"`
echo "\$cfg['blowfish_secret']='$SECRET';" >> /usr/share/phpmyadmin/config.inc.php
exit

Set permissions

sudo chown -R www-data /usr/share/phpmyadmin

Snapshot

  • Be sure to take a snapshot of the VM before you start any of the labs!

System Problem

  • If you see this message: System program problem detected
  • Do this:
sudo rm -r /var/crash*

Resources

Code examples: https://github.com/dbierer/classic_php_examples PHP Road Map: https://wiki.php.net/rfc Where it all started:

Class Notes

Namespaces

Autoloader Examples:

<?php
spl_autoload_register(function ($class) {
	require_once __DIR__
		   . DIRECTORY_SEPARATOR
		   . str_replace('\\', DIRECTORY_SEPARATOR, $class)
		   . '.php';
});

use Test\Something\{Test,Whatever};
$test = new Test();
var_dump($test->getIterator([1,2,3,4,5]));
$what = new Whatever();
var_dump($what->whatever());

Class example:

<?php
namespace My\Different\Space;

// you can identify PHP classes like this:
use ArrayObject;
class Test
{
    public function test()
    {
        return __NAMESPACE__;
    }
    public function getArrayObject(array $arr)
    {
    	// or: use leading backslash:
    	return new \ArrayObject($arr);
    }
}

Calling program:

<?php
include __DIR__ . '/Test.php';
use My\Different\Space\Test;

// alternatively, you can do this:
// $test = new \My\Different\Space\Test();

$test = new Test();
echo $test->test();

$arr = [1,2,3,4,5];
$obj = $test->getArrayObject($arr);
var_dump($obj);

Call methods from inside a class: use $this

<?php
class Test
{
	protected string $first = 'fred';
	protected string $last  = 'flintstone';
	public function getFirst()
	{
		return ucfirst($this->first);
	}
	public function getLast()
	{
		return ucfirst($this->last);
	}
	public function getName()
	{
		return $this->getFirst() . ' ' . $this->getLast();
	}
}
$test = new Test();
echo $test->getName();

Example using __construct()

<?php
class UserEntity {
    protected string $firstName;
    protected string $lastName;
    public function __construct($firstName, $lastName) {
        $this->firstName = $firstName ;
        $this->lastName = $lastName ;
    }
    public function getName()
    {
		return $this->firstName . ' ' . $this->lastName;
	}
}

$user[] = new UserEntity('Jack' , 'Ryan');
$user[] = new UserEntity('Monte' , 'Python');
foreach ($user as $obj)
	echo $obj->getName() . "\n";

Constructor argument promotion example:

<?php
class Test
{
	// contructor argument promotion
	// only in PHP 8.0 and above
	public function __construct(public string $first = '', public string $last = '')
	{
		// do nothing
	}
	public function getFirst()
	{
		return ucfirst($this->first);
	}
	public function getLast()
	{
		return ucfirst($this->last);
	}
	public function getName()
	{
		return $this->getFirst() . ' ' . $this->getLast() . "\n";
	}
}
$test1 = new Test('Fred', 'Flintstone');
echo $test1->getName();

$test2 = new Test('Wilma', 'Flintstone');
echo $test2->getName();

var_dump($test1, $test2);

Inheritance example:

//             Transportation
//             	  $capacity + $passengers
//    Land           Sea                   Air
//     etc.
//  Car  Truck    Sailboat Freighter   PropPlane   Jet
//   etc.

Practical anonymous class example:

Restrictions when overriding a method:

  • When overriding a method, you can "expand" the data type in the signature
  • But you can't "narrow" it down
  • You are free to add additional arguments as long as you respect the data types of the original args
  • OR ... just remove the data type entirely which frees you from any restrictions
<?php
class Base
{
	public int $a;
	public int $b;
	public function add(int $a, int $b)
	{
		return $a + $b;
	}
}

//
class Whatever extends Base
{
	// this works:
	public function add(int|float $a, int|float $b, int|float $c = 0)
	{
		return $a + $b + $c;
	}
	/*
	// this does *not* work:
	public function add(float $a, float $b, float $c = 0)
	{
		return $a + $b + $c;
	}
	*/
}

$what = new Whatever();
echo $what->add(1, 2, 3);

Magic Methods

Example of __destruct()

<?php
class UserEntity
{
	public $status = ['A','B','C'];
    public function __construct(
        protected string $firstName,
        protected string $lastName,
        protected float $balance,
        protected int $id
    ) {}
	public function getFullName()
	{
		return $this->firstName . ' ' . $this->lastName;
	}
}
$user = new UserEntity('Fred', 'Flintstone', 999.99, 101);
$text = serialize($user);
//$text = json_encode($user);
echo $text . "\n";
$obj = unserialize($text);
//$obj = json_decode($text);
echo $obj->getFullName() . "\n";
var_dump($obj);

Example of __sleep() and __wakeup()

<?php
class UserEntity {
	public $hash = '';
    public function __construct(
        protected string $firstName,
        protected string $lastName)
    {
		$this->hash = bin2hex(random_bytes(8));
    }
    public function __sleep()
    {
		return ['firstName','lastName'];
	}
	public function __wakeup()
	{
		$this->hash = bin2hex(random_bytes(8));
	}
	public function getFullName()
	{
		return $this->firstName . ' ' . $this->lastName;
	}
    public function getNativeString(): string {
        return serialize($this);
    }
}
$userEntity = new UserEntity('Mark', 'Watney');
var_dump($userEntity);
echo PHP_EOL;

$native = $userEntity->getNativeString();
$obj  = unserialize($native);
echo $native;
echo PHP_EOL;
var_dump($obj);

Example of __serialize() and __unserialize()

<?php
class UserEntity {
	public $hash = '';
    public function __construct(
        protected string $firstName,
        protected string $lastName)
    {
		$this->hash = bin2hex(random_bytes(8));
    }
    public function __serialize()
    {
		return [
			'firstName' => $this->firstName,
			'lastName' => $this->lastName,
			'sleep_date' => date('Y-m-d H:i:s')];
	}
	public function __unserialize($array)
	{
		// $array contains values restored from the serialization
		$this->hash = bin2hex(random_bytes(8));
		$this->firstName = $array['firstName'];
		$this->lastName = $array['lastName'];
	}
	public function getFullName()
	{
		return $this->firstName . ' ' . $this->lastName;
	}
    public function getNativeString(): string {
        return serialize($this);
    }
}
$userEntity = new UserEntity('Mark', 'Watney');
var_dump($userEntity);
echo PHP_EOL;

$native = $userEntity->getNativeString();
$obj  = unserialize($native);
echo $native;
echo PHP_EOL;
var_dump($obj);

Example of when getters and setters are useful:

class Test
{
    protected $date;
    const DEFAULT_FMT = 'Y-m-d H:i:s';
    // use getters and setters if there's a need for further processing
    public function setDate(string $str) : void
    {
		$this->date = new DateTime($str);
	}
	public function getDate(string $fmt = self::DEFAULT_FMT) : string
	{
		return $this->date->format($fmt);
	}
}

Example of controlled unlimited properties

<?php
class Test
{
	public const FIELDS = ['fname','lname','balance'];
	public $vars = [];
    // Returns an inaccessible property
    public function __set($key, $value) {
        if (in_array($key, self::FIELDS)) {
			$this->vars[$key] = $value;
		}
    }
    public function __get($key) {
        return $this->vars[$key] ?? '';
    }
}

$test = new Test();
$test->fname = 'Fred';
$test->lname = 'Flintstone';
$test->balance = 999.99;
$test->doesNotExist = 'TEST';
echo $test->fname . ' ' . $test->lname
	 . ' has a balance of ' . $test->balance
	 . ' and ' . $test->doesNotExist;

Other examples of magic methods:

Example of Abstract class with abstract method:

Examples of what is callable

<?php
function cmp($a, $b)
{
    if ($a == $b) {
        return 0;
    }
    return ($a < $b) ? -1 : 1;
}

$anon = function ($a,$b) {
    if ($a == $b) {
        return 0;
    }
    return ($a < $b) ? -1 : 1;
};

$class = new class() {
	public function __invoke($a,$b)
	{
		if ($a == $b) {
			return 0;
		}
		return ($a < $b) ? -1 : 1;
	}
};

$a = array(3, 2, 5, 6, 1);

usort($a, $class);

foreach ($a as $key => $value) {
    echo "$key: $value\n";
}

Example of going from a specific data type to a more general data type

<?php
interface Foo {
    public function test(array $input);
}

class Bar implements Foo {
    // type omitted for $input
    public function test(iterable $input) {
		$text = '';
		foreach($input as $item) $text .= ' ' . $item;
        return 'You requested ' . trim($text);
    }
}

$bar = new Bar();
echo $bar->test(['A','B','C']);
echo $bar->test(new ArrayIterator(['A','B','C']));
  • Using static to get an instance of the lowest level in inheritance tree
<?php
class Foo
{
	public function whatever()
	{
		return 'Whatever';
	}
	public function getInstance() : static
	{
		// this returns an error:
		// return new self();
		return new static();
	}
}
class Bar extends Foo {}

$foo = new Foo();
$bar = new Bar();
var_dump($foo->getInstance());	// Foo
var_dump($bar->getInstance());	// Bar

Exception / Error example:

<?php
try {
	$pdo = new PDO('sqlite://xyz');
} catch (PDOException $a) {
	// catches PDOException
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
} catch (Exception $a) {
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
} catch (Error $a) {
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
}

try {
	$pdo = new PDO();
} catch (PDOException $a) {
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
} catch (Exception $a) {
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
} catch (Error $a) {
	// catches Error
	echo __LINE__ . ':' . get_class($a) . ':' . $a . "\n";
}
// actual output:
/*
6:PDOException:PDOException: SQLSTATE[HY000] [14] unable to open database file in C:\Users\ACER\Repos\classic_php_examples\oop\test.php:3
Stack trace:
#0 C:\Users\ACER\Repos\classic_php_examples\oop\test.php(3): PDO->__construct()
#1 {main}
21:ArgumentCountError:ArgumentCountError: PDO::__construct() expects at least 1 argument, 0 given in C:\Users\ACER\Repos\classic_php_examples\oop\test.php:14
Stack trace:
#0 C:\Users\ACER\Repos\classic_php_examples\oop\test.php(14): PDO->__construct()
#1 {main}
*/

Using static functionality to get a singleton instance

PDO

Adding options as 4th argument:

try {
    // Get the connection instance
    $opts = [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION];
    $pdo = new PDO('mysql:host=localhost;dbname=phpcourse', 'vagrant', 'vagrant', $opts);
    // Statements ...
} catch (PDOException $e ){
    // Handle exception...
}

To find the exact DSN for a given database in PDO, look at the Driver class documentation

try {
    // Execute a one-off SQL statement and get a statement object
    $stmt = $pdo->query('SELECT * FROM orders');

    // Returns an associative array indexed by column name
    while ($row = $stmt->fetch(PDO::FETCH_ASSOC) {
		// do something with the resulting row
	}

} catch (PDOException $e){
    //Handle error
}

Alternative way to execute without using bindParam()

$data = [
	'eventTitle' => 'Wagner, Bryant',
	'eventURL' => 'http://bryant.prestosports.com/sports/bsb/2021-22/schedule#6irpaohben8y4ati',
	'eventDescription' => 'Baseball on May 21, 2022 at 3:00 PM: Wagner, Bryant, Conaty Park',
	'eventCategory' => 'Baseball',
	'eventDateString' => 'Sat, 21 May 2022 19:00:00 GMT',
	'eventGUID' => 'http://bryant.prestosports.com/sports/bsb/2021-22/schedule#6irpaohben8y4at',
	'eventOpponent' => 'Wagner',
];
$stmt->execute($data);

Example of PDO::FETCH_CLASS mode:

Output Buffering

To start output buffering automatically, in the php.ini file:

// sets buffer size to 4K + activates it
output_buffering=4096

Email

Headers can include any valid headers as per RFC 2822

Regex

Alternatives to finding chars at beginning or end of a string:

<?php
$str = '/home/doug/whatever/';

// Any PHP above 4
echo ($str[0] ==='/') ? 'Y' : 'N';
echo ($str[-1] ==='/') ? 'Y' : 'N';

// PHP 8
echo (str_starts_with($str,'/')) ? 'Y' : 'N';
echo (str_ends_with($str,'/')) ? 'Y' : 'N';

Examples using sub-patterns

<?php
$str = '<p>One</p><p>Two</p><p>Three</p>';
$pat = '/<p>(.*?)<\/p>/';
preg_match_all($pat, $str, $match);
var_dump($match);


$str = 'Click here to go to <a target="_blank" href="http://zend.com/">Zend</a>!';
$pat = '/<a.*?href=("|\')(.*?)("|\').*?>/';
preg_match_all($pat, $str, $match);
var_dump($match);

Composer

Example of advanced usage including scripts

Web Services

Example of SOAP Client

<?php
$data = array ('foo' => 'bar', 'bar' => 'baz');
$data = http_build_query($data);
$context_options = array (
        'http' => array (
            'method' => 'POST',
            'header'=> "Content-type: application/x-www-form-urlencoded\r\n"
                . "Content-Length: " . strlen($data) . "\r\n",
            'content' => $data
            )
        );

$context = stream_context_create($context_options)
$fp = fopen('https://url', 'r', false, $context);

Study by Oracle that compares SOAP and REST

Output Control

Example using output buffering to create inner content

<?php
ob_start ();

$values = ['TH'=>'Thailand','GB'=>'Great Britain','FR'=>'France'];
foreach ($values as $key => $val)
	echo '<tr><th>' . $key . '</th><td>' . $val . '</td></tr>';

$contents = ob_get_clean();

echo '<h1>My Cool Webpage</h1>';
echo '<table>';
echo $contents;
echo '</table>';

Simplified ETag Example:

Regex

Misc examples

<?php
$data = [
	'/^[A-Z].*/'     => ['The quick brown fox', '12345'],
	'/.*(jpg|png)$/' => ['image.png', 'info.php'],
	'/\bERROR\b/'    => ['ERROR 309: undefined error','This contains ERROR_REPORTING'],
	'/^[A-Za-z ]*$/'  => ['The quick brown fox', '9977 quick brown foxes'],
	'/^[^A-Za-z]*$/' => ['997799989887777','The quick brown fox'],
	'!^http(s)?://\w*!i' => ['https://zend.com','http://sandbox','ftp://whatever.com'],
];

foreach ($data as $pattern => $value) {
	foreach ($value as $item) {
		echo "Testing $item\n";
		echo (preg_match($pattern, $item)) ? 'MATCH' : 'NO MATCH';
		echo PHP_EOL;
	}
}

PHP 5 to PHP 7 code converter using preg_replace_callback_array()

Change Request

Class Vehicle {
    use GroundVehicleTrait, AirVehicleTrait {
        GroundVehicleTrait::getType insteadof AirVehicleTrait;
        AirVehicleTrait::getType as getAirType;
    }
}

Q & A