Instructor: Jeffrey Way
To get up and running quickly on Ubuntu 12.04, try XAMPP for Linux.
<?php echo "Hello, world!" ?><?php
$day_of_the_week = array(
'Sunday',
'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday',
'Saturday'
);
var_dump($days_of_the_week);
?><?php
/* Tells Apache we need to execute some PHP. */
?>We can either use single or double quotes to specify a string.
<?php
echo 'Hello, world!';
echo "My name is Dwayne.";
?>Variables in PHP are represented by a dollar sign followed by the name of the variable. The variable name is case-sensitive.
We create constants in PHP using define. See here.
<?php
define('PI', 3.14159265359);
?># php.ini
error_reporting = E_ALL # http://php.net/error-reporting
display_errors = On # http://php.net/display-errors
Tip: If you can't find your php.ini file, open the terminal, and type: php -i | grep "Loaded Configuration File".
<?php
$month = 'Feb';
// $month = 'April';
$months = array(
'Jan' => 'It is January',
'Feb' => 'It is February',
'Mar' => 'It is March',
...
);
echo isset($months[$month]) ? $months[$month] : 'Not the right month!';
?>| <?php | |
| // helper functions | |
| function is_blank($str) { | |
| return !isset($str) || $str === ''; | |
| } | |
| function redirect($url) { | |
| header("Location: $url"); | |
| exit; // or die(); | |
| } | |
| $contact_form = new stdClass; | |
| $contact_form->name = ''; | |
| $contact_form->email = ''; | |
| $contact_form->message = ''; | |
| $errors = array(); | |
| if ($_SERVER['REQUEST_METHOD'] == 'POST') { | |
| // name - required | |
| // email - required, must be a valid email address | |
| // message - required, length at least 10 chars | |
| $contact_form->name = filter_var($_POST['name'], FILTER_SANITIZE_STRING); | |
| $contact_form->email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL); | |
| $contact_form->message = filter_var($_POST['message'], FILTER_SANITIZE_FULL_SPECIAL_CHARS); | |
| if (is_blank($contact_form->name)) { | |
| $errors['name'][] = 'Name is required.'; | |
| } | |
| if (is_blank($contact_form->email)) { | |
| $errors['email'][] = 'Email is required.'; | |
| } | |
| if (!filter_var($contact_form->email, FILTER_VALIDATE_EMAIL)) { | |
| $errors['email'][] = 'Email is invalid.'; | |
| } | |
| if (is_blank($contact_form->message)) { | |
| $errors['message'][] = 'Message is required.'; | |
| } | |
| if (strlen($contact_form->message) < 10) { | |
| $errors['message'][] = 'Message must be at least 10 characters long.'; | |
| } | |
| if (empty($errors)) { | |
| $to = '[email protected]'; | |
| $subject = 'I used your contact form'; | |
| $message = "Hi,\n\nMy name is $contact_form->name.\n\n$contact_form->message"; | |
| $headers = "From: $contact_form->email"; | |
| $mail_sent = mail($to, $subject, $message, $headers); | |
| redirect(sprintf('/mail.php?sent=%s', $mail_sent ? 'true' : 'false')); | |
| } | |
| } | |
| ?> | |
| <!DOCTYPE html> | |
| <html lang="en"> | |
| <head> | |
| <meta charset="utf-8"> | |
| <!-- Always force latest IE rendering engine (even in intranet) & Chrome Frame --> | |
| <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> | |
| <title>Contact Us</title> | |
| <style> | |
| label { | |
| display: block; | |
| } | |
| .error-field label { | |
| color: red; | |
| } | |
| .error-field input[type="text"], .error-field textarea { | |
| background-color: red; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <h1>Contact Us</h1> | |
| <?php if (!empty($errors)) : ?> | |
| <ul class="errors"> | |
| <?php | |
| foreach ($errors as $field => $messages) : | |
| foreach ($messages as $message) : | |
| ?> | |
| <li><?php echo $message; ?></li> | |
| <?php endforeach; endforeach; ?> | |
| </ul> | |
| <?php endif; ?> | |
| <form action="" method="post"> | |
| <p <?php if (!empty($errors['name'])) : echo 'class="error-field"'; endif; ?>> | |
| <label for="name">Name:</label> | |
| <input type="text" id="name" name="name" value="<?php echo $contact_form->name; ?>"> | |
| </p> | |
| <p <?php if (!empty($errors['email'])) : echo 'class="error-field"'; endif; ?>> | |
| <label for="email">Email:</label> | |
| <input type="text" id="email" name="email" value="<?php echo $contact_form->email; ?>"> | |
| </p> | |
| <p <?php if (!empty($errors['message'])) : echo 'class="error-field"'; endif; ?>> | |
| <label for="message">Message:</label> | |
| <textarea id="message" name="message"><?php echo $contact_form->message; ?></textarea> | |
| </p> | |
| <p> | |
| <input type="submit" value="Send my message"> | |
| </p> | |
| </form> | |
| </body> | |
| </html> |
<?php
// Example sscanf and list usage
$results = sscanf("June 7th, 2012", "%s %[^,], %d");
print_r($results);
list($month, $day, $year) = sscanf("June 7th, 2012", "%s %[^,], %d");
sscanf("June 7th, 2012", "%s %[^,], %d", $m, $d, $y);
// $results[0] === $month === $m
// $results[1] === $day === $d
// $results[2] === $year === $y
?><?php
function hello($name = 'world') {
return "Hello, $name!";
}
echo hello('Dwayne');
?><?php
// PHP's scoping rules causes this code to fail
// function array_pluck($to_pluck, $arr) {
// return array_map(function ($elem) {
// // $to_pluck - doesn't exist in this function's local scope
// return $elem[$to_pluck]; // error
// }, $arr);
// }
// However, this works
function array_pluck($to_pluck, $arr) {
return array_map(function ($elem) use($to_pluck) {
return $elem[$to_pluck];
}, $arr);
}
?>Heredocs can be an enormous help when preparing HTML and SQL statements.
<?php
$post = array(
'title' => 'How to Register a Business in Trinidad and Tobago',
'author' => 'Dwayne R. Crooks',
'body' => 'Step 1. Do a name search.',
'published-date' => '10-10-2012'
);
// common to see EOT or EOD, but you can call it whatever you want
$email = <<<EOT
<h1>{$post['title']}</h1>
<p>By: {$post['author']}</p>
<div>
{$post['body']}
</div>
EOT; // N.B. Cannot end the file with a heredoc
echo $email;
// alternatively
extract($post);
$email = <<<EOT
<h1>$title</h1>
<p>By: $author</p>
<div>$body</div>
EOT; // N.B. Must be on it's own line with no spaces at the beginning
echo $email;
?>A database system.
$ mysql
or
$ mysql -u username -p
Enter password:
It's a good practice to setup different users with access to specific databases. N.B. Don't use the root account for user databases.
Let's assign a unique password to the root user:
$ mysql -u root -p
mysql> SET PASSWORD FOR root@localhost = PASSWORD('root');
See SET PASSWORD for further details.
# Showing the databases
mysql> SHOW DATABASES;
# Creating a database
mysql> CREATE DATABASE blog;
# Using a specific database
mysql> USE blog;
# Showing the tables in the database
mysql> SHOW TABLES;
# Creating a table
mysql> CREATE TABLE users(
-> id INT AUTO_INCREMENT,
-> first_name varchar(50) NOT NULL,
-> last_name varchar(50) NOT NULL,
-> email_address varchar(100) NOT NULL,
-> PRIMARY KEY (id)
-> );
# Viewing the structure of a table, i.e. it's schema
mysql> DESCRIBE users;
# Selecting all rows from a table
mysql> SELECT * FROM users;
mysql> INSERT INTO users VALUES(null, 'John', 'Doe', '[email protected]');
or
mysql> INSERT INTO users (first_name, last_name, email_address) VALUES('John', 'Doe', '[email protected]');
mysql> SELECT email_address FROM users;
mysql> SELECT first_name, last_name FROM users;
Ordering your selections:
mysql> SELECT * FROM users ORDER BY last_name ASC;
mysql> SELECT * FROM users ORDER BY last_name DESC;
Limiting the number of rows returned:
mysql> SELECT * FROM users LIMIT 2;
mysql> DELETE FROM users WHERE [condition];
mysql> DELETE FROM users WHERE id = 123;
mysql> DELETE FROM users WHERE last_name = 'Crooks';
To update a row in a table we use the UPDATE query.
mysql> UPDATE users SET last_name = 'Alexander' WHERE first_name = 'Jane';
To change a column name and type in a table use the ALTER query.
mysql> ALTER TABLE users CHANGE last_name surname varchar(80);
Superglobals are built-in variables that are always available in all scopes.
You can use the superglobal array $_GET to fetch information from the query string. Use isset to determine if a variable is set and is not NULL.
<?php
$name = 'world';
if (isset($_GET['name'])) {
$name = $_GET['name'];
}
echo "Hello, $name!";
?>N.B. Always assume that data taken from the user is dangerous. What if the user entered the url http://www.example.com/index.php?name=<h3>Dwayne</h3>.
Here are two ways to test if a page is called via an HTTP POST:
<?php
// Way #1
if (empty($_POST)) {
echo 'not posted';
} else {
echo 'posted';
}
// Way #2
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
echo 'posted';
} else {
echo 'not posted';
}
?>Generally we use sessions to store user specific data. Sessions are stored on the server. The PHP engine sets a cookie (a way to store little bits of information on the client) and stores a session ID (a really long, randomly generated, string that's difficult to guess). When the user requests a specific URL on the website that session ID cookie that we set will be sent back to the server at which point the PHP engine would validate it and then subsequently retrieve the data that's associated with that specific session.
The first step when working with sessions is to call session_start. It's important that this occurs before any HTML is echoed out. This is because, session_start actually sets some HTTP headers. Once this is done we can start setting values via keys on the session superglobal $_SESSION.
<?php
session_start();
$_SESSION['username'] = 'dwayne';
?>When it's time to cleanup our sessions, we use session_destroy. Think of a session as a user specific life-cycle. You open the browser, you visit a webpage, you close the browser. That was a session. In this case, the session would automatically be destroyed. However, say you want to manually destroy the session, for e.g. as part of some logout functionality. Then, that's where session_destroy comes into play.
<?php
session_start();
// do your stuff with sessions
// cleanup after yourself
session_destroy();
$_SESSION = array(); // or [] if using PHP 5.4+
// may also need to delete the cookie being used to propagate the session ID
?>TODO: Write a login form
Think of cookies as text files that can store a maximum of 4KB worth of information.
N.B. You should never use cookies to store private information. Instead you'd use a cookie to store more casual information.
We can create cookies using the setcookie function. You access cookies values using the cookie superglobal $_COOKIE.
To delete a cookie you need to also use the setcookie function, but this time setting the expiration time to any time in the past.
phpsh is an interactive shell for PHP.
python setup.py buildpython setup.py install --prefix=~/localexport PYTHONPATH=~/local/lib/python2.7/site-packages~/local/bin/phpshArticles that I think any modern PHP developer should be reading.