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PHP II - May 2023

Last Slide: http://localhost:8882/#/3/24

VM Notes

Expanded VM Instructions

Info

  • Username: vagrant
  • Password: vagrant

Do Not Accept the Update or Upgrade Prompts

  • Once you login it's important to wait a few seconds for the system to come fully up.
  • At this point you'll see two prompts: one to update, one to upgrade. Be sure to decline both of these options! Confirm that no unattended upgrades are in progress:
ps -ax |grep unattended

If you see any listed (except for the last one which is the grep command):

  • Make a note of the "process ID" (PID)
  • Kill the process as follows:
sudo kill [PID]

Now you can do the full update/upgrade

  • This doesn't upgrade the OS, just the packages
  • Open a command terminal and run these commands.
sudo dpkg --configure -a
sudo apt -y update && sudo apt -f -y install && sudo apt -y full-upgrade

It will take several hours to complete so it's best to let it run overnight.

Accept New Configuration

  • At some point you will be asked if you wish to retain the original php.ini configuration or accept the new. Go ahead and accept the new configuration.

Update Apache PHP Module

  • So far PHP from the command line (PHP-CLI) has been updated. You'll still need to update the PHP Apache module using these commands. Please note that "8.0" is the old version, and "8.2" is the new version. You may have to change these two values as more recent versions become available.
sudo apt-add-repository ppa:ondrej/apache2
sudo apt install libapache2-mod-php8.2
sudo a2dismod php8.0
sudo systemctl restart apache2
sudo a2enmod php8.2
sudo systemctl restart apache2

Add vhost definition for sandbox

Follow these instructions to add an Apache vhost (virtual host) definition to sandbox in VM to use as a website

  • From a terminal window (command prompt):
    • Run gedit as the root user:
sudo gedit
  • Open the file /etc/hosts
  • Add an entry to the local hosts file to simulate a server named "sandbox"
127.0.0.1 sandbox
  • Save the file
  • Open a new file (press the "+" icon next to "Open")
  • Paste this into the editor:
<VirtualHost *:80>
   ServerName sandbox
   DocumentRoot /home/vagrant/Zend/workspaces/DefaultWorkspace/sandbox
   <Directory /home/vagrant/Zend/workspaces/DefaultWorkspace/sandbox/>
       Options Indexes FollowSymlinks MultiViews
       AllowOverride All
       Require all granted
   </Directory>
</VirtualHost>
  • Save as /etc/apache2/sites-available/sandbox.conf
  • Exit gedit
  • Test the new simulated server
ping -c3 sandbox
  • Enable the new vhost
sudo a2ensite sandbox
  • Restart Apache
sudo systemctl restart apache2
  • Access sandbox from the VM browser: http://sandbox

Install git

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

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

Other Stuff

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

Namespace standard: PSR-4

Differences between PHP 7 and 8:

// works in PHP 7 but not 8 (notice the spaces)
namespace This \ Is \ Normal;
// works in PHP 8 but not 7 (notice the key word "list")
namespace This\Is\A\List;

Keyword as is used to resolve ambiguities

<?php
namespace A\B\C {
    class Test
    {
        public $name = 'ABC';
    }
}

namespace X\Y\Z {
    class Test
    {
        public $name = 'XYZ';
    }
}

namespace {
    // if aliases weren't used, you'd get a Fatal Error
    use A\B\C\Test as ATest;
    use X\Y\Z\Test as ZTest;
    $test = new ATest();
    echo $test->name;
}

Autoloader Examples:

Autoloading example:

<?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);

Example using get_object_vars() to return JSON representation of object properties

<?php

class UserEntity {
    public function __construct(
        public string $firstName,
        public string $lastName
    ) {}
    public function getJson()
    {
        return json_encode(get_object_vars($this), TRUE);
    }
}

$user1 = new UserEntity('Jack' , 'Ryan');
$user2 = new UserEntity('Monte' , 'Python');

echo $user1->getJson();
echo PHP_EOL;
echo $user2->getJson();

Inheritance example:

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

Practical anonymous class example:

<?php

class UserEntity {
    public function __construct(
        public string $firstName,
        public string $lastName
    ) {}
    public function getData()
    {
        return new class($this->firstName, $this->lastName)
        {
            public function __construct(public string $firstName, public string $lastName)
            {}
            public function getJson()
            {
                return json_encode(get_object_vars($this), TRUE);
            }
            public function getArrayCopy()
            {
                return get_object_vars($this);
            }
        };
    }
}

$user1 = new UserEntity('Jack' , 'Ryan');
$user2 = new UserEntity('Monte' , 'Python');

echo $user1->getData()->getJson();
echo PHP_EOL;
var_dump($user2->getData()->getArrayCopy());

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 __toString()

<?php

class UserEntity {
    public function __construct(
        protected string $firstName,
        protected string $lastName) {
    }

    public function __toString(): string {
        return get_class($this);
        // return json_encode(get_object_vars($this), TRUE);
    }
}

$userEntity = new UserEntity('Mark', 'Watney');
//echo $userEntity;

$reflect = new ReflectionObject($userEntity);
echo $reflect;

// NOTE: this is what you'll see in the 1st of Reflection:
// Object of class [ <user> class UserEntity implements Stringable ] {
// This interface is automatically assigned by PHP 8 and above
// as long as you define __toString()

Example of __destruct()

Serialization example:

<?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:

Interface example:

<?php
interface ServiceInterface {
    public function getService(string $key);
    public function setService(string $key, callable $service);
}

abstract class AbstractController implements ServiceInterface {
    public const FORMAT = 'l, d M Y H:i:s';
    protected array $services = [];
}

class MvcController extends AbstractController
{
    public function getService(string $key)
    {
        return $this->services[$key] ?? NULL;
    }
    public function setService(string $key, callable $service)
    {
        $this->services[$key] = $service;
    }
}

$callback = new class () {
    protected $date = NULL;
    public function __construct()
    {
        $this->date = new DateTime('now');
    }
    public function __invoke()
    {
        return $this->date->format(AbstractController::FORMAT);
    }
};

$controller = new MvcController();
$controller->setService('date', $callback);
echo $controller->getService('date')();

Example of "type widening"

  • The subclass can have a data type that's "wider" than the super class
<?php
interface TestInterface
{
    public function doIterate(array $arr) : string;
}

class Test implements TestInterface
{
    // you could also use "iterable" as a data type
    // which is a combo of array|Traversable
    public function doIterate(iterable $arr) : string
    {
        $output = '';
        foreach ($arr as $item) $output .= $item . PHP_EOL;
        return $output;
    }
}

$test = new Test();
$arr = range('A','F');
echo $test->doIterate($arr);
echo $test->doIterate(new ArrayIterator($arr));

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";
}
  • Another example of what is considered callable:
<?php

class Test {
    public function callIt(callable $callback, array $params) {
        return $callback($params);
    }
}

$operands[0] = 2;
$operands[1] = 3;
$callback = function ($p) {
    return 'The result of '
           . $p[0] . ' times ' . $p[1]
           . ' is ' . ($p[0] * $p[1]);
};

$anon = new class() {
    public function __invoke(array $params)
    {
        return 'The sum is: ' . array_sum($params);
    }
};

$stat = new class() {
    public function sum(array $params)
    {
        return 'The sum is: ' . array_sum($params);
    }
};

class Whatever
{
    public static function sum(array $params)
    {
        return 'The sum is: ' . array_sum($params);
    }
}


$test = new Test;
echo $test->callIt($callback, $operands);
echo PHP_EOL;
echo $test->callIt('array_sum', $operands);
echo PHP_EOL;
echo $test->callIt($anon, $operands);
echo PHP_EOL;
echo $test->callIt([$stat, 'sum'], $operands);
echo PHP_EOL;
echo $test->callIt('Whatever::sum', $operands);

Type int can "widen" to float without any loss of precision

<?php
declare(strict_types=1);
class Test
{
    public function add(float $a, float $b)
    {
        return 'The sum is: ' . ($a + $b);
    }
}

$test = new Test();
// still works OK: int --> float doesn't lose precision
echo __LINE__ . ':' . $test->add(2, 2);
echo PHP_EOL;
echo __LINE__ . ':' . $test->add(2.555, 2.666);
echo PHP_EOL;

If declare(strict_types=1) is not in effect, it does a soft typecast

<?php
//declare(strict_types=1);
class Test
{
    public function add(float $a, float $b) : float
    {
        return $a + $b;
    }
}

$test = new Test();
// works OK
echo __LINE__ . ':' . $test->add(2, 2);
echo PHP_EOL;

// works OK
echo __LINE__ . ':' . $test->add(2.555, 2.666);
echo PHP_EOL;

// works OK
echo __LINE__ . ':' . $test->add('2.555', '2.666');
echo PHP_EOL;

// Fatal Error
echo __LINE__ . ':' . $test->add('x2.555', 'x2.666');
echo PHP_EOL;

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

Simple Trait example

<?php
trait TestTrait
{
    public function test()
    {
        return 'TRAIT';
    }
}

class Top
{
    use TestTrait;
}

class Child extends Top
{
}

$top = new Top();
$child = new Child();

echo $top->test();
echo PHP_EOL;
echo $child->test();

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);

Example email validation

<?php
$email = [
    '[email protected]',
    '[email protected]',
    '[email protected]',
    '[email protected]',
    '[email protected]',
    'invalid&/*@company',
    '[email protected]',
];
$pattern = '/^[a-z][a-z0-9.-]*@([a-z0-9]+\.)+[a-z]{2,4}$/i';
foreach ($email as $item) {
    echo $item . ' [';
    echo (preg_match($pattern, $item)) ? 'VALID' : 'INVALID';
    echo ']' . PHP_EOL;
}

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

Example of searching for a specific file name pattern in a directory

<?php
$list = scandir(__DIR__);
var_dump($list);
$pattern = '/^exam.*\.php$/';
foreach ($list as $item) {
    echo $item . ': ';
    preg_match($pattern, $item, $match);
    echo (!empty($match[0])) ? 'MATCH' : '';
    echo PHP_EOL;
}

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;
    }
}

Shows the use of "?" to indicate an optional "s"

<?php
$list = [
    'http://zend.com',
    'https://www.perforce.com',
    'ftp://unlikelysource.com',
    'file:///some/path/to/file',
];
// searches for http:// or https://
$pattern = '!^https?://\w*!i';
foreach ($list as $item) {
    echo $item . ': ';
    preg_match($pattern, $item, $match);
    echo (!empty($match[0])) ? 'MATCH' : '';
    echo PHP_EOL;
}

Example of preg_replace()

<?php
$test = '<script>alert("test");</script>';
$pattern = ['/</','/>/','/;/'];

echo preg_replace($pattern, '', $test);
echo PHP_EOL;
// output: "scriptalert("test")/script"

$test = '$script{"alert"} = "script"';
$pattern = ['/{/','/}/'];
$replace = ['[', ']'];
echo preg_replace($pattern, $replace, $test);
// $script["alert"] = "script"

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

error_reporting=E_ALL
display_errors=on
  • Q: What are the typical settings for max-age in this header:
header('Cache-Control: must-revalidate, max-age=0');

<?php
class Test
{
    const FORMAT = 'l, d M Y';
    // this doesn't work:
    // public $time = new DateTime();
    // this DOES work:
    public function __construct(public DateTime $time = new DateTime()) {}
    public function getTime()
    {
        return $this->time->format(self::FORMAT);
    }
}
$test = new Test();
echo $test->getTime();