PHP Summary

```
  <?php

  ?>
```
Variables
```
  $myVar = 100;
```

Constants

  define('GREETING', 'Hello Everyone');

Arrays

Indexed

  $people = array('Kevin', 'Jeremy', 'Sara');
  echo $people[0];

  $cars = ['Honda', 'Toyota', 'Ford'];
  echo $cars[0];
  $cars[] = 'BMW'; // add to the end of the array
  count($cars);  // number of items in the array

Associative

  $people = array('Brad' => 35);  // Brad is a key, the value is 35

  $people = array('Brad' => 35, 'Jose' => 32, 'William' => 37);
  echo $people['Brad'];
  $people['Jill']=42;  // add to array

Multi-dimensions

  $cars = array(
    array('Honda', 20, 10),
    array('Toyota', 30, 20),
    array('Ford', 23, 12),
  );

  echo $cars[1][2];

Print Items of the Array

  print_r($cars);  // echo - show all array

  var_dump($cars);  // echo the datatype and the number of characters

  echo "<pre>";
  var_export($_SERVER['QUERY_STRING']);

Array Actions
- array_shift()
  Remove the first element from an array, and return the value of the removed element.
- array_push()
  Push one or more elements onto the end of array
```
  $names = array("Raya", "Nir", "Anat", "Shirly");
  array_push($names, "Gill");
```

Strings

explode()
Split a string by a string. Return an array of strings.
```
  $str = "hello,world";
  $arr = explode(",", $str);
```

implode()

Join array elements with a string

  $array = array('lastname', 'email', 'phone');
  $space_separated = implode(" ", $array);
  
  echo $space_separated; // lastname email phone

strtolower()
Make a string lowercase
```
  $str = strtolower($str);
```
strtoupper()
Make a string uppercase
```
  $str = strtoupper($str);
```

substr()

  $output = substr('Hello', 1);     // 1 is a start index  --> ello

  $output = substr('Hello', 1, 3);  // 3 is an end index  --> ell

  $output = substr('Hello', -2);    // start from the back  --> lo

strlen()

Returns the length of the string

  $output = strlen('Hello World');  // 11

strpos()
Finds the position of the FIRST occurence of a sub string
```
  $output = strpos('Hello World', 'o'); // 4
```
strrpos()
Finds the position of the LAST occurence of a sub string
```
  $output = strrpos('Hello World', 'o'); // 7
```

is_string()

Returns 1 if string

  $val = 'Hello';
  $output = is_string($val);

str_replace()

Replace all occurence of a search string with a replacement

  $text = 'Hello World';
  $output = str_replace('World', 'Everyone', $text);

ucwords()
Capitalize every word
```
  $output = ucwords('hello world');
```
trim()
Strips whitespace
```
  $trimmed = trim($text);
```

Shorthands

  <?php if($loggedIn):  ?>
    <h1>Welcome </h1>
  <?php endif; ?>

  <?php if($loggedIn):  ?>
    <h1>Welcome User</h1>
  <?php else: ?>
    <h1>Welcome Guest</h1>
  <?php endif; ?>

  <?php if($popup == 1):?>
    <div class="popup">
    </div>
  <?php elseif($popup == 2):?>
    <div class="popup">
    </div>
  <?php else:?>
    <div class="popup">
    </div>
  <?php endif;?>

foreach

  <div>
    <?php foreach($arr as $val): ?>
      <?php echo $val; ?>
    <?php endforeach; ?>
  </div>

for

  <div>
    <?php for($i = 0; $i < 10; $i++): ?>
      <li><?php echo $i; ?></li>
    <?php endfor; ?>
  </div>

Loops

For

for($i = 0; $i < 10; $i++) {
echo 'Number '.$i; 
echo '<br>';    
}

While

$i = 0;
while($i < 10) {
echo $i;
echo '<br>';    
$i++;
}

Do..While

$i = 0;
do {
echo $i;
echo '<br>';  
$i++;
}
while($i < 10);

Foreach

$people = array('Brad', 'Jose', 'William');

foreach($people as $person) {
echo $person;
echo '<br>';  
}

$people = array('Brad' => 'brad@gmail.com', 'Jose' => 'jose@gmail.com', 'William' => 'william@gmail.com');

foreach($people as $key => $val) {
echo $key.': '.$val;
echo '<br>';  
}

$server = [
'Host Server Name' => $_SERVER['SERVER_NAME'],
'Document Root' => $_SERVER['DOCUMENT_ROOT'],
'Current Page' => $_SERVER['PHP_SELF'],
'Script Name' => $_SERVER['SCRIPT_NAME'],
];

<?php if($server): ?>
<ul class="list-group">
<?php foreach($server as $key => $value): ?>
  <li class="list-group-item">
    <strong><?php echo $key; ?>: </strong>
    <?php echo $value; ?>
  </li>
<?php endforeach; ?>
</ul>
<?php endif; ?>

Functions

function sayHello($name = 'World') {
echo "Hello $name<br>";    
}

sayHello('Raya');

function addNumbers($num1, $num2) {
return $num1 + $num2;
}

echo addNumbers(5, 6);

By Reference
```
function addTen(&$num) {
$num += 10;
}
```

  $y = 1234;
  function x() {
    global $y;
    return $y;
  }

Conditionals

```
==
===
<
> 
<=
>=
!=
!==
```

Logical Operators

AND  &&
OR   ||
XOR  only one is true, not both

Switch

switch($favColor) {
  case 'red':
    echo "
 Your favorite color is red 
";
    break;
  default:
    echo "
 Your favorite color is something else 
";
    break;
}

<?php if($server): ?>
  <h2>Html is here </h2>
<?php endif; ?>

GET and POST

<?php 	
  if (isset($_POST['name'])) {
    print_r($_POST);
    $name = htmlentities($_POST['name']);
  }
?>

<form method="GET" action="<?php echo $_SERVER['PHP_SELF']; ?>">
  <div>
    <label>Name</label><br>
    <input type="text" name="name">
  </div>
  <input type="submit" value="Submit">
</form>

Casting

  ...
  if($_SERVER['REQUEST_METHOD'] == 'GET') {
    $x = (int)htmlentities($_GET['x']);
  ...

Contact Form

  <?php
    // Message Vars
    $msg = '';
    $msgClass = '';

    // Check for Submit
    if(filter_has_var(INPUT_POST, 'submit')) {
      //  Get Form Data
      $name =  htmlspecialchars($_POST['name']);
      $email = htmlspecialchars($_POST['email']);
      $message = htmlspecialchars($_POST['message']);

      //  Check Required Fields
      if(!empty($name) && !empty($email) && !empty($message)) {
        // Check Email
        if(filter_var($email, FILTER_VALIDATE_EMAIL) !== false) {  
          ...              
        } else {
          // Failed
          $msg = 'Please fill a valid email.';
          $msgClass = 'alert-danger';
        }    
      } else {
          // Failed
          $msg = 'Please fill in all fields.';
          $msgClass = 'alert-danger';
      }
    }
  ?>

  <div class="container">
    <?php if($msg !== ''): ?>
      <div class="alert <?php echo $msgClass; ?>">
        <?php echo $msg; ?>
      </div>
    <?php endif; ?>

    <form method="POST" action="<?php echo $_SERVER['PHP_SELF']; ?>">
      <div class="form-group">
        <label>Name</label>
        <input type="text" name="name" class="form-control" value="<?php echo isset($_POST['name']) ? $name : ''; ?>">
      </div>
      <div class="form-group">
        <label>Email</label>
        <input type="text" name="email" class="form-control" value="<?php echo isset($_POST['email']) ? $email : ''; ?>">
      </div>
      <div class="form-group">
        <label>Message</label>
        <textarea type="text" name="message" class="form-control"><?php echo isset($_POST['message']) ? $message : ''; ?></textarea>
      </div>
      <button type="submit" name="submit" class="btn btn-primary btn-block">Submit</button>
    </form>
  </div>

Filters and Validations

  <?php

  // Check for posted data
  // if (filter_has_var(INPUT_GET, 'data')) {     // when method is get

    if (filter_has_var(INPUT_POST, 'data')) {     
      echo 'Data found';
    } else {
        echo 'Data not found';
    }
  ?>

  if (filter_has_var(INPUT_POST, 'data')) {
    $email = $_POST['data'];
  
    // Remove illegal chars
    $email = filter_var($email, FILTER_SANITIZE_EMAIL); //    Raya///<>()@////<>()test.com --> Raya@test.com
    echo $email.'
';
    
    if(filter_var($email, FILTER_VALIDATE_EMAIL)) {
      echo 'Email is valid';      
    } else {
      echo 'Email is NOT valid';
    }
  }

  <form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
    <input type="text" name="data">
    <input type="text" name="data2">
    <button type="submit">Submit</button>
  </form>

  $filters = array(
		"data" => FILTER_VALIDATE_EMAIL,
		"data2" => array(
			"filter" => FILTER_VALIDATE_INT,
			"options" => array(
				"min_range" => 1,
				"max_range" => 100
			)
		)
	);

  print_r(filter_input_array(INPUT_POST, $filters));

  $arr = array(
    "name" => "raya levinson",
    "age" => "35",
    "email" => "raya@gmail.com"
  );

  $filters = array(
    "name" => array(
        "filter" => FILTER_CALLBACK,   // apply function to this value
        "options" => "ucwords"
    ),
    "age" => array(
      "filter" => FILTER_VALIDATE_INT,
      "options" => array(
				"min_range" => 1,
				"max_range" => 120
      )
    ),
    "email" => FILTER_VALIDATE_EMAIL
  );

  print_r(filter_var_array($arr, $filters));

  FILTER_VALIDATE_BOOLEAN
  FILTER_VALIDATE_EMAIL
  FILTER_VALIDATE_FLOAT
  FILTER_VALIDATE_INT
  FILTER_VALIDATE_IP
  FILTER_VALIDATE_REGEXP
  FILTER_VALIDATE_URL

  FILTER_SANITIZE_EMAIL
  FILTER_SANITIZE_ENCODED
  FILTER_SANITIZE_NUMBER_FLOAT
  FILTER_SANITIZE_NUMBER_INT
  FILTER_SANITIZE_SPECIAL_CHARS
  FILTER_SANITIZE_STRING
  FILTER_SANITIZE_URL

Include and Require

<?php include './inc/header.php'; ?>
  <h1>Home</h1>
<?php include ('./inc/footer.php'); ?>

<?php require './inc/header.php'; ?>
  <h1>Contact</h1>
<?php require './inc/footer.php'; ?>

<?php require_once './inc/header.php'; ?>
  <h1>About</h1>
<?php require_once './inc/footer.php'; ?>

Redirect

        if(!empty($searchText)) {        
          header('Location: https://www.google.co.il/search?q=' . $searchText);
          exit;
        }

Date and Time

Date

echo date('d');      // Day i.e 30
echo date('m');      // Month
echo date('Y');      // Year
echo date('l');      // day of the week
echo date('Y/m/d');  // 2020/08/30

echo date('d/m/Y');  // 30/08/2020
echo date('d-m-Y');  // 30-08-2020

Time

echo date('h');      // Hour
echo date('i');      // Minutes
echo date('s');      // Seconds
echo date('a');      // AM or PM

echo date('h:i:sa');    // 11:53:16am
echo date('h:i:s');     // 11:53:16

Timezone

date_default_timezone_set("Asia/Jerusalem");
echo date('h:i:s');

Timestamp

Unix timestamp is a long integer containing the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

$timestamp = mktime(10, 14, 54, 9, 10, 1981); //hours, munutes, seconds, month, day, year

echo $timestamp;  // 368957694
echo date('m/d/Y', $timestamp);
echo date('m/d/Y h:i:s', $timestamp);

$timestamp2 = strtotime('7:00pm March 22 2016');

echo $timestamp2;     // 1458669600
echo date('m/d/Y h:i:s', $timestamp2); //  03/22/2016 07:00:00

$timestamp3 = strtotime('tomorrow');
echo date('d/m/Y', $timestamp3);

$timestamp4 = strtotime('next Sund');
echo date('d/m/Y', $timestamp4);

// $timestamp5 = strtotime('+2 Month');
// $timestamp5 = strtotime('+2 Days');
$timestamp5 = strtotime('+2 Years');
echo date('d/m/Y h:i:s', $timestamp5);