====== PHP Programming ====== PHP is a web-native language that essentially embeds itself within HTML. While the wiki is still being built, refer to: [[https://www.devdungeon.com/topics/php]] and [[https://github.com/DevDungeon/Cookbook/tree/master/php]] ===== Installing ===== In Debian and most Linux distributions, it's as simple as using the package manager:


apt install php php-pdo-sqlite
php --version

# For Apache2 httpd
apt install apache2 libapache2-mod-php

See the [[:web|web servers]] page for more info on configuring ===== Built-in webserver ===== PHP has a built-in web server that is useful for local developing and testing.


# Serves current directory, no directory listing
php -S localhost:9999

# Specify path to serve
php -S localhost:9999 -t /path/to/serve

===== Phar files ===== Phar files are essentially tarballs of PHP content. In addition to the convenience of having a single .phar containing many files, the phar can be marked executable and treated like an executable Java JAR. See the [[https://www.php.net/manual/en/intro.phar.php|official phar documentation]]. It can be treated as a special protocol for referencing files like this: ''phar:%%//%%myphar.phar/file.php'' You can read or include files in this manner. ===== Composer ===== Composer is an optional tool for managing depedencies. See: [[https://www.devdungeon.com/content/php-composer-basics]] ===== Code examples ===== Here are some snippets for reference. ==== Hello world ==== Here is a simple "Hello world" application.




==== PHP info ====



==== Show all errors ====




==== Functions ====




==== Include a PHP file ====




==== Forms ====






  
  

  






==== Redirect ====

Use the PHP function [[https://www.php.net/manual/en/function.header.php|header()]] to send a new ''Location'' header.




==== SQLite database ====

This example is for SQLite3 using the [[https://www.php.net/manual/en/ref.pdo-sqlite.php|PHP PDO_SQLITE]], but essentially the same for other databases too.

''apt install php-pdo-sqlite''


exec(
"CREATE TABLE IF NOT EXISTS urls (
    url TEXT,
    notes TEXT
    )"
);

// Prepared statement for changes
$query = $db->prepare('INSERT INTO urls (url) VALUES (?)');
$query->execute(['https://www.devdungeon.com/']);

// Query
$result = $db->query('SELECT * FROM urls');
foreach ($result as $result) {
    print($result['url'].'
');
}

$db = null;  // Close it


==== libgit2 ====

See: https://www.devdungeon.com/content/how-perform-git-operations-php

==== Crop images ====


// Crop using GD (`apt install php-gd`)
$src_img = imagecreatefrompng('300x200.png');
if(!$src_img) {
    die('Error when reading the source image.');
}
$thumbnail = imagecreatetruecolor(200, 200);
if(!$thumbnail) {
    die('Error when creating the destination image.');
}
// Take 200x200 from 200x200 starting at 50,0
$result = imagecopyresampled($thumbnail, $src_img, 0, 0, 50, 0, 200, 200, 200, 200);
if(!$result) {
    die('Error when generating the thumbnail.');
}
$result = imagejpeg($thumbnail, '200x200gd.png');
if(!$result) {
    die('Error when saving the thumbnail.');
}
$result = imagedestroy($thumbnail);
if(!$result) {
    die('Error when destroying the image.');
}



// Crop image using Imagick (`apt install php-imagick`)
$inFile = "300x200.png";
$outFile = "200x200_imagick.png";
$image = new Imagick($inFile);
$image->cropImage(200,200, 50,0);
$image->writeImage($outFile);



==== JSON ====


 JSON string
$json_string = json_encode(['my_key' => 'my value', 'other_key' => 'other value']);
echo $json_string;

# JSON string -> PHP object
$json_string = '{"my_key":"my value","other_key":"other value"}';
$my_array =  json_decode($json_string);
print_r($my_array)

// Dump/read from file
file_put_contents('test.json', json_encode([2, 4, 6]));
$my_array = json_decode(file_get_contents('test.json'));
print_r($my_array);


==== Sockets ====

=== TCP server ===




=== Generate SSL certificate ===


 "US",
    "stateOrProvinceName" => "Texas",
    "localityName" => "Houston",
    "organizationName" => "Example.com",
    "organizationalUnitName" => "Development",
    "commonName" => "My Company",
    "emailAddress" => "example@example.com"
);

// Generate certificate
$privateKey = openssl_pkey_new();
$certificate = openssl_csr_new($certificateData, $privateKey);
$certificate = openssl_csr_sign($certificate, null, $privateKey, 365);

// Generate PEM file
$pem_passphrase = 'abracadabra'; // empty for no passphrase
$pem = array();
openssl_x509_export($certificate, $pem[0]);
openssl_pkey_export($privateKey, $pem[1], $pem_passphrase);
$pem = implode($pem);

// Save PEM file
$pemfile = './server.pem';
file_put_contents($pemfile, $pem);


=== SSL server ===




=== SSL client ===





array('local_cert'=> $cert))
);
if ($socket = stream_socket_client(
        'ssl://'.$host.':'.$port,
        $errno,
        $errstr,
        30,
        STREAM_CLIENT_CONNECT,
        $context)
) {
    fwrite($socket, "\n");
    echo fread($socket,8192);
    fclose($socket);
} else {
   echo "ERROR: $errno - $errstr\n";
}


==== Tail a file ====


&1", 'r');
while(!feof($handle)) {
    $buffer = fgets($handle);
    echo "$buffer
\n";
    ob_flush();
    flush();
}
pclose($handle);


==== Simple HTTP request ====




==== cURL requests ====

Install [[https://packages.debian.org/buster/php-curl|php-curl]] on Debian. [[https://curl.se|cURL]] lets you make all kinds of requests, not just HTTP. See my tutorial: [[https://www.devdungeon.com/content/curl-tutorial|cURL Tutorial]].