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PHP Foundations -- Aug 2023

TODO

Homework

For Last Day

For Tues 15 Aug 2023

For Thurs 10 Aug 2023

For Tues 8 Aug 2023

XAMPP Setup

XAMPP web server document root: C:\xampp\htdocs

  1. Open XAMPP control panel
  2. Start Apache and MySQL
  3. From the browser launch phpMyAdmin: http://localhost/phpmyadmin
  4. Create a database phpcourse
  5. Select that database
  6. Import from the file: /path/to/project/orderapp/sql/phpcourse.sql
  • Ignore warnings
  1. Create a user vagrant with a password vagrant with all privileges to phpcourse on localhost
  2. Create Apache virtual host definitions for orderapp and sandbox
  • Place this config into C:/xampp/apache/conf/extra/httpd-vhosts.conf:
<Directory C:/Users/azure/php-foundations>
	AllowOverride All
	Require all granted
</Directory>

<VirtualHost *:80>
    DocumentRoot "C:/xampp/htdocs/"
    ServerName localhost
    ErrorLog "logs/localhost-error.log"
    CustomLog "logs/localhost-access.log" common
</VirtualHost>

<VirtualHost *:80>
    DocumentRoot "C:/Users/azure/php-foundations/orderapp/public"
    ServerName orderapp
    ErrorLog "logs/orderapp-error.log"
    CustomLog "logs/orderapp-access.log" common
</VirtualHost>

<VirtualHost *:80>
    DocumentRoot "C:/Users/azure/php-foundations/sandbox/public"
    ServerName sandbox
    ErrorLog "logs/sandbox-error.log"
    CustomLog "logs/sandbox-access.log" common
</VirtualHost>
  • Change C:/Users/azure/php-foundations to the path where you unzipped the course applications
  1. Restart Apache from control panel
  2. Open the hosts file in C:\windows\system32\drivers\etc
  • Open using Notepad with Administrator privileges
  1. Add these host entries:
127.0.0.1     localhost
127.0.0.1     orderapp
127.0.0.1     sandbox
  1. Test:
  • http://sandbox/
  • http://orderapp/

Here's a good overview:

Class Notes

Useful string functions:

  • substr()
  • str_replace()
  • strpos()

How PHP actually works:

Pre-assigning default values that match the data type:

<?php
$a = '';	// string
$b = 0;		// int
$c = 0.0;	// float
$d = TRUE;	// bool

var_dump($a, $b, $c, $d);

Example using the modulus operator to determine remaining minutes:

<?php
$min = 795;
$hours = (int) ($min / 60);
$remain = $min % 60;
echo '$min is $hours hours and $remain minutes\n';

Determining the datatype at runtime

<?php
// use is_* functions to check the data type
$astronaut = ['Mark', 'Watney', 'Botanist'];
if (is_array($astronaut)) {
	print_r($astronaut);
} elseif (is_string($astronaut)) {
	echo $astronaut;
} else {
	echo 'Unknown';
}
// use gettype() to reveal the data type
echo gettype($astronaut);

Using the spread operator to flatten two sub-arrays

<?php
$business = ['Mon','Tue','Wed','Thu','Fri'];
$weekend  = ['Sat','Sun'];
$days     = [$business, $weekend];
var_dump($days);
// actual output:
/*
 * array(2) {
  [0]=>
  array(5) {
    [0]=>
    string(3) 'Mon'
    [1]=>
    string(3) 'Tue'
    [2]=>
    string(3) 'Wed'
    [3]=>
    string(3) 'Thu'
    [4]=>
    string(3) 'Fri'
  }
  [1]=>
  array(2) {
    [0]=>
    string(3) 'Sat'
    [1]=>
    string(3) 'Sun'
  }
}
*/

// the spread op flattens the 2 sub-arrays into a single linear array
$days     = [...$business, ...$weekend];
var_dump($days);
// actual output:
/*
 * array(7) {
  [0]=>
  string(3) 'Mon'
  [1]=>
  string(3) 'Tue'
  [2]=>
  string(3) 'Wed'
  [3]=>
  string(3) 'Thu'
  [4]=>
  string(3) 'Fri'
  [5]=>
  string(3) 'Sat'
  [6]=>
  string(3) 'Sun'
*/

Packing arguments

<?php
// example using ... to pack an array

function test(...$a)
{
	return array_sum($a);
}

echo test(1,2,3,4,5);
echo PHP_EOL;
echo test(6,7,8,8,10,11,12,13,14,15);
// output: 15
//         104

Adding elements to a multi-dimensional array

<?php
$mission = [
    'STS395' => [
        ['firstName' => 'Mark', 'lastName' => 'Watney', 'specialty' => 'Botanist'],
        ['firstName' => 'Melissa', 'lastName' => 'Lewis', 'specialty' => 'Commander'],
        ['firstName' => 'Beth', 'lastName' => 'Johanssen', 'specialty' => 'Computer Specialist 2'],s
        // here's how to add as part of the initial assignment
        ['firstName' => 'Fernanda', 'lastName' => 'Fernandes', 'specialty' => 'Computer Specialist 1'],
    ]
];

// here's how to add *after* the initial assignment
$mission['STS395'][] = ['firstName' => 'William', 'lastName' => 'Hodge', 'specialty' => 'Drupal Specialist'];

// here's how to make specific direct assignments
$mission['STS395'][5]['firstName'] = 'William';
$mission['STS395'][5]['lastName']  = 'Hodge';
$mission['STS395'][5]['specialty'] = 'Drupal Specialist';

// overwrite existing values
$mission['STS395'][2]['specialty'] = 'WordPress Specialist';

print_r($mission);

Example using the ternary operator to establish a default value when accessing URL params

<?php
$name = (!empty($_GET['name'])) ? strip_tags($_GET['name']) : 'Default';
echo '<h1>' . $name . '</h1>';

You can use the '??' in place of a series of if/elseif

<?php
$status = (int) ($_REQUEST['status'] ?? $_SESSION['status'] ?? $_COOKIE['status'] ?? 1);
// same thing but using if/elseif:
if (!empty($_REQUEST['status'])) {
	$status = $_REQUEST['status'];
} elseif (!empty($_SESSION['status'])) {
	$status = $_SESSION['status'];
} elseif (!empty($_COOKIE['status'])) {
	$status = $_COOKIE['status'];
} else {
	$status = 1;
}

You can also add a 'default' option to match expressions:

<?php
// NOTE: match does a *strict* comparison (checks data type first)
$result = match ('1') {
    0 => 'Foo',
    1 => 'Bar',
    2 => 'Baz',
    default => 'None of the above'
};
echo $result; // None of the above

Iterating through nested foreach() loops

  • NESTING_LEVEL -1 == the number of foreach() loops needed to get to the lowest level of information
<?php
// Build the crew
$missions = [
	'STS395' => [
		['firstName' => 'Mark', 'lastName' => 'Watney', 'specialty' => 'Botanist'],
		['firstName' => 'Melissa', 'lastName' => 'Lewis', 'specialty' => 'Commander'],
		['firstName' => 'Beth', 'lastName' => 'Johanssen', 'specialty' => 'Computer Specialist'],
	]
];

foreach($missions as $mission => $astronauts) {
	echo $mission . PHP_EOL;
    foreach ($astronauts as $row) {
		echo '{$row['specialty']} {$row['lastName']} on board' . PHP_EOL;
    }
}

Using for() to count backwards

<?php
$max = 100;
$min = 50;
for ( $i = $max; $i >= $min; $i--) {
    echo 'Count to $i' . '<br>' . PHP_EOL;
}

Break out sub-arrays in a foreach() loop using list() (or alternatively [])

<?php
$arr = [
	['Fred','Flintstone','Caveman'],
	['Wilma','Flintstone','Cavewoman'],
	['George','Slate','Boss'],
];

foreach ($arr as [$first,$last,$role]) {
	echo '$first $last is a $role\n';
}

// NOTE: you could also write the foreach() loop as follows:
// foreach ($arr as list($first,$last,$role)) {

// actual output:
/*
Fred Flintstone is a Caveman
Wilma Flintstone is a Cavewoman
George Slate is a Boss
*/

You should provide a data type hint for functions with components that are sensitive to the wrong data type

  • Protects the function from abuse
  • Makes the real source of the error quite clear
function searchForError(array $messages) : int
{
	$found = 0;
	$search = 'ERROR';
	foreach ($messages as $item) {
		if (str_contains($item, $search)) {
			$found++;
			break;
		}
	}
	return $found;
}
$messages = [
	'Operation succeeded',
	'ERROR 402',
	'Parse ERROR',
	'Everything OK',
];

echo (searchForError('WHATEVER'))
	? 'ERROR found'
	: 'All OK';

If you allow for NULL and pass it as a value, it overrides the default assignment:

<?php
// allows "string" as a type hint
function welcome(string|null $arg = 'JavaScript') :string {
    return "Welcome to the wonderful world of $arg coding\n";
}

$type = 'Python';

echo welcome();
echo welcome('PHP');
echo welcome($type);
echo welcome(NULL);

// actual output:
/*
Welcome to the wonderful world of JavaScript coding
Welcome to the wonderful world of PHP coding
Welcome to the wonderful world of Python coding
Welcome to the wonderful world of  coding
*/

Producing an HTML list from an array using the "splat" operator to allow unlimited args

<?php
function arrayToHtml(...$args)
{
    $output = '<ul>' . PHP_EOL;
    // $args = func_get_args();
    if(count($args)){
        foreach($args as $arg){
            $output .= '<li>' . $arg . '</li>' . PHP_EOL;
        }
    }
    $output .= '</ul>' . PHP_EOL;
    return $output;
}

echo arrayToHtml('Mark', 'Watney', 'Botanist', 'Doctor of Philosophy');

// output:
/*
<ul>
<li>Mark</li>
<li>Watney</li>
<li>Botanist</li>
<li>Doctor of Philosophy</li>
</ul>
*/

Use declare(strict_types=1) to enforce all type hints for that file

<?php
// if the following line is omitted, the type-hint acts like a filter (type-cast)
declare(strict_types=1);
// Example of function using 'type hinting'
function add(int $a, int $b) : int
{
	return $a + $b;
}

echo 'The sum of 2 and 2 is ' . add(2, 2) . '\n';
echo 'The sum of 33.33 and 22.22 is ' . add(33.33, 22.22) . '\n';

Nullable type: ?string === string|null

<?php
// union types were introduced in PHP 8

function get_full_name(string $first, string $last, string|null $middle = NULL)
{
	return ($middle) ? '$first $middle $last\n' : '$first $last\n';
}

echo get_full_name('Fred', 'Flintstone', 'John');
echo get_full_name('Barney', 'Rubble');

// prior to PHP 8, a hybrid type:
// ?string === string|null

function get_full_name2(string $first, string $last, ?string $middle = NULL)
{
	return ($middle) ? '$first $middle $last\n' : '$first $last\n';
}

echo get_full_name2('Fred', 'Flintstone', 'John');
echo get_full_name2('Barney', 'Rubble');

Union types can go overboard:

<?php
// a bit ridiculous:
function dump(int|float|string|bool|array|object $whatever)
{
	var_dump($whatever);
}

dump(new ArrayObject());
dump([1,2,3,4,5]);

// this makes more sense:
function dump2(mixed $whatever)
{
	var_dump($whatever);
}

dump(new ArrayObject());

// another example of ridiculous:
// dump(true|false|bool $yesNo) {}

Array navigation functions example with while() loop

<?php
$invoiceItems = [
  ['invoiceNumber' => 123, 'invoiceAmount' => 100],
  ['invoiceNumber' => 124, 'invoiceAmount' => 50],
  ['invoiceNumber' => 125, 'invoiceAmount' => 150],
  ['invoiceNumber' => 126, 'invoiceAmount' => 55],
];

$tax = 0.10;

while ($items = current($invoiceItems)) {
    $amountWithTax =  $items['invoiceAmount'] + ($items['invoiceAmount'] * $tax);
    echo 'invoice #' . $items['invoiceNumber'] . ' with invoice amount ' . $items['invoiceAmount'] . ' has the final amount of ' .  $amountWithTax . ' after adding the tax';
    echo '\n';
    next($invoiceItems);
    // might need to add a check to make sure you're not at the end of the array
    // maybe keep a count using "++" and use the count() function to see how many elements are in the array
}

Using named parameters

<?php
// PHP 7 and below:
setcookie('Test', 1, 0, '', '', false, TRUE);
// PHP 8 allows you to use "named parameters"
setcookie('Test', 1, httponly:TRUE);

Using reference to alias an array element:

<?php
$config = [
    'router' => [
        'routes' => [
            'market' => [
                'type' => 'literal',
                'options' => [
                    'route' => '/market',
                    'defaults' => [
                        'controller' => 'IndexController',
                        'action'     => 'index',
                    ],
                ],
            ],
        ],
    ],
];
// now $action is an alias for this array element
$action = &$config['router']['routes']['market']['options']['defaults']['action'];
echo $action . PHP_EOL;
$action = 'test';
print_r($config);

Example using substr()

<?php
$url = 'http://training.zend.com/';
$scheme = substr($url, 0, 5);
if ($scheme === 'https') {
	echo 'Secure URL';
	$path = substr($url, 7);
} else {
	echo 'Insecure URL';
	$path = substr($url, 6);
}
echo PHP_EOL;
echo 'This is the path: ' . $path . PHP_EOL;

// output:
/*
Insecure URL
This is the path: /training.zend.com/
*/

Sorting examples

<?php
$arr = ['A' => 111, 'C' => 333, 'E' => 555, 'B' => 222, 'D' => 444];
var_dump($arr);
ksort($arr);
var_dump($arr);

// NOTE: using sort() is fast, but you lose the keys
$arr = ['A' => 111, 'C' => 333, 'E' => 555, 'B' => 222, 'D' => 444];
sort($arr);
var_dump($arr);

// NOTE: asort() is very very slightly slower, but keys are retained
$arr = ['A' => 111, 'C' => 333, 'E' => 555, 'B' => 222, 'D' => 444];
asort($arr);
var_dump($arr);

Reading a CSV file and echoing the results:

<?php
// Open and test for success
if (!$fh = fopen(__DIR__ . '/bitcoin.csv', 'r')) exit('Unable to open file');

$data = [];
while (!feof($fh)) {
    $data[] = fgetcsv($fh);
}

// Iterate the retrieved contents and output
foreach ($data as $row) {
	if (empty($row) || !is_array($row)) continue;
    echo implode("\t", $row);
    echo '<br>' . PHP_EOL;
}

// Close the resource when finished
fclose($fh);

Example using file_put_contents() and file_get_contents()

<?php
$file = 'target.txt';
$contents = 'This is a text file' . PHP_EOL;
// NOTE: file_put_contents doesn't add a linefeed
$bytes = file_put_contents( $file, $contents, FILE_APPEND);
echo "$bytes bytes written to the file: $file" . PHP_EOL;
echo file_get_contents($file);
echo PHP_EOL;

Redirect to another web page:

<?php
// this is how you redirect to another web page:
header('Location: https://training.zend.com/');
exit;

Example of HTML form + security measures

<?php
$item = '';
$priority = 0;
if(!empty($_POST)) {
    $item = $_POST['item'] ?? '';
    $priority = $_POST['priority'] ?? '';
    if(!empty($item) && !empty($priority)) {
        $item = filter_var(strip_tags($item), FILTER_SANITIZE_STRING);
        $priority = (int) $priority;
        echo 'Data is validated and sanitized, handle it ...';
    } else {
        echo 'Invalid input';
        exit;
    }
} else {
    // no form data has been posted
    echo 'No form data has been posted';
}
?>
<form action="test.php" method="post">
    <fieldset>
        <legend>Add Checklist Item</legend>
        <label for="item">Enter the checklist item</label>
        <input type="text" name="item" id="item" value="<?= htmlspecialchars($item); ?>">
        <label for="priority">Enter the priority</label>
        <input type="text" name="priority" id="priority" value="<?= htmlspecialchars($priority); ?>" >
        <input type="submit" value="Submit">
    </fieldset>
</form>

Example of a callback tree that produces output in different formats

  • Uses anonymous functions
<?php
$arr = ['A' => 111,'B' => 222,'C' => 333];

$callbacks = [
	// arrow function works well here
	'json' => fn(array $data) => json_encode($data, JSON_PRETTY_PRINT),
	// needs multiple lines of code, so we use an anonymous function
	'html' => function (array $data) {
		$out = '<table>';
		foreach ($data as $key => $value)
			$out .= '<tr><th>' . $key . '</th><td>' . $value . '</td></tr>';
		$out .= '</table>';
		return $out; }
];

echo $callbacks['json']($arr);
echo "\n";
echo $callbacks['html']($arr);
echo "\n";

Anonymous functions examples:

  • This example "stores" an SQL query for later use:
<?php
function get_select(string $table, string $where, PDO $pdo)
{
	$sql = 'SELECT * FROM ' . $table . ' WHERE ' . $where;
	return function () use ($sql) {
		$stmt = $pdo->query($sql);
		$result = [];
		while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
			$result[] = $row;
		}
		return $result;
	};
}
$select = get_select('orders', 'id = 1', $pdo);

// do something
// ...
// do something

foreach ($select() as $row) {
	// display the row
	// maybe using printf()
}

Typical production settings:

<?php
// start session and define key global constants
define('BASE_DIR', __DIR__);
define('HTML_DIR', BASE_DIR . '/templates/site');
define('SRC_DIR', BASE_DIR . '/src');
// set up error handling
error_reporting(E_ALL);
ini_set('display_errors', 0);   // change this to "1" during website development
ini_set('error_log', BASE_DIR . '/logs/error.log');
// uses Composer autoloader
require BASE_DIR . '/vendor/autoload.php';
// start session
session_start();
return require SRC_DIR . '/config/config.php';

Update/Upgrade the VM

sudo dpkg --configure -a
sudo apt -y update && sudo apt -f -y install && sudo apt -y full-upgrade
  • Apache reconfig:
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

Resources

Automatic documentation generation

Errata