PHP Session

Cookie

Operations on cookies:

• Setting
• Reading
• Deleting

Set Cookie

setcookie(name, value, expire, path, domain, secure, httponly);

e.g.

// $_COOKIE['userid'] is set as Henry 60*60 seconds which is 1 hour.
setcookie('user', 'Henry', time() + 60*60);
echo "Hello, " . $_COOKIE['user'];

First respond will give warning since the cookie is set after the client sends the cookie back on a subsequent request it appear in $_COOKIE.

Second respond

delete cookie

setcookie('user', '');

A cookie set by http://www.example.com/catalog/list.php is sent back with other requests in the catalog directory, such as

• http://www.example.com/catalog/search.php
• http://www.example.com/catalog/detailed/search.php

Not for such as

• http://www.example.com/sell.php
• http://www.example.com/users/profile.php

Session

To use a session in a page, call session_start() at the beginning of your script.

Session data is stored in the $_SESSION auto-global array.

The $_SESSION array is a way of sharing information between pages.

session_start();
if (isset($_SESSION['count'])){
    $_SESSION['count'] = $_SESSION['count'] + 1;
}
else{
    $_SESSION['count'] = 1;
}
echo "You have looked this page " . $_SESSION['count'] . "times";

simple example using session

processForm($input){
    $_SESSION['order'][] = array('menu' => $input['menu'], 'quantity' => $input['quantity'])
}

$menus = array('beef' => 'beef soup', 'chicken' => 'chicken soup', 'pork' => 'pork soup')

if (isset($_SESSION['order']) && (count($_SESSION['order']) > 0)){
    echo '<ul>';
    foreach ($_SESSION['order'] as $order){
        $menu = $menus[$order['menu']];
        echo "<li> $order[quantity] of $menu </li>";
    }
    echo '</ul>';
}
else{
    echo "You haven't ordered anything";
}

Login and User Identification

function validateForm(){
    $input = array();
    $errors = array();

    $users = array('a' => 'a123', 'b' => 'b123' ,'c' => 'c123');

    $input['username'] = $_POST['username'] ?? '';
    if (!array_key_exists($input['username'], $users)){
        $errors[] = 'Please enter a valid username and password';
    }
    else{
        $savedPassword = $users[$input['username']];
        $submittedPassword = $_POST['password']?? '';
        if ($savedPassword != $submittedPassword){
            $errors[] = 'Please enter a vlid username and password';
        }
    }
    return array($erros, $input);
}

if ($_SERVER['REQUEST_METHOD'] == 'POST'){
    list($errors, $input) = validateForm();
    if ($errors){
        showForm($errors);
    }
    else{
        echo "Hello, $_SESSION['username']";
    }
}
else{
    showForm();
}

Use unset() to remove a key and value from $_SESSION.

unset($_SESSION['username']);