PHP 코드 품질을 향상시키는 방법

require_once('../../lib/some_class.php');

define('ROOT' , '/var/www/project/');require_once(ROOT . '../../lib/some_class.php');//rest of the code

//suppose your script is /var/www/project/index.php//Then __FILE__ will always have that full path.define('ROOT' , pathinfo(__FILE__, PATHINFO_DIRNAME));require_once(ROOT . '../../lib/some_class.php');//rest of the code

require_once('lib/Database.php');require_once('lib/Mail.php');require_once('helpers/utitlity_functions.php');

function load_class($class_name){    //path to the class file
    $path = ROOT . '/lib/' . $class_name . '.php');    require_once( $path );
}

load_class('Database');
load_class('Mail');

function load_class($class_name){    //path to the class file
    $path = ROOT . '/lib/' . $class_name . '.php');    if(file_exists($path))
    {        require_once( $path );
    }
}

define('ENVIRONMENT' , 'development');if(! $db->query( $query )
{    if(ENVIRONMENT == 'development')
    {        echo "$query failed";
    }    else
    {        echo "Database error. Please contact administrator";
    }
}

define('ENVIRONMENT' , 'production');if(! $db->query( $query )
{    if(ENVIRONMENT == 'development')
    {        echo "$query failed";
    }    else
    {        echo "Database error. Please contact administrator";
    }
}

/**
	Method to execute a command in the terminal
	Uses :	1. system
	2. passthru	3. exec
	4. shell_exec

*/
function terminal($command)
{
	//system
	if(function_exists('system'))
	{
		ob_start();
		system($command , $return_var);
		$output = ob_get_contents();
		ob_end_clean();
	}
	//passthru
	else if(function_exists('passthru'))
	{
		ob_start();
		passthru($command , $return_var);
		$output = ob_get_contents();
		ob_end_clean();
	}

	//exec
	else if(function_exists('exec'))
	{
		exec($command , $output , $return_var);
		$output = implode("\n" , $output);
	}

	//shell_exec
	else if(function_exists('shell_exec'))
	{
		$output = shell_exec($command) ;
	}

	else
	{
		$output = 'Command execution not possible on this system';
		$return_var = 1;
	}

	return array('output' => $output , 'status' => $return_var);
}

terminal('ls');

function add_to_cart($item_id , $qty){
    $_SESSION['cart']['item_id'] = $qty;
}

add_to_cart( 'IPHONE3' , 2 );

function add_to_cart($item_id , $qty){    if(!is_array($item_id))
    {
        $_SESSION['cart']['item_id'] = $qty;
    }    else
    {        foreach($item_id as $i_id => $qty)
        {
            $_SESSION['cart']['i_id'] = $qty;
        }
    }
}

add_to_cart( 'IPHONE3' , 2 );
add_to_cart( array('IPHONE3' => 2 , 'IPAD' => 5) );

<?phpecho "Hello";//Now dont close this tag

<?phpclass super_class{    function super_function()
    {        //super code
    }
}?>//super extra character after the closing tag

require_once('super_class.php');//echo an image or pdf , or set the cookies or session data

<?phpclass super_class{    function super_function()
    {        //super code
    }
}//No closing tag

function print_header(){    echo "<p id=&#39;header&#39;>Site Log and Login links</p>";
}function print_footer(){    echo "<p id=&#39;footer&#39;>Site was made by me</p>";
}

print_header();for($i = 0 ; $i < 100; $i++)
{    echo "I is : $i <br />&#39;;
}
print_footer();

function print_header(){
    $o = "<p id=&#39;header&#39;>Site Log and Login links</p>";    return $o;
}function print_footer(){
    $o = "<p id=&#39;footer&#39;>Site was made by me</p>";    return $o;
}echo print_header();for($i = 0 ; $i < 100; $i++)
{    echo "I is : $i <br />&#39;;
}
echo print_footer();

$xml = &#39;<?xml version="1.0" encoding="utf-8" standalone="yes"?>&#39;;
$xml = "<response>
  <code>0</code>
</response>";//Send xml dataecho $xml;

$xml = &#39;<?xml version="1.0" encoding="utf-8" standalone="yes"?>&#39;;
$xml = "<response>
  <code>0</code>
</response>";//Send xml dataheader("content-type: text/xml");echo $xml;

header("content-type: application/x-javascript");
echo "var a = 10";

header("content-type: text/css");echo "#p id { background:#000; }";

//Attempt to connect to database$c = mysqli_connect($this->host , $this->username, $this->password);//Check connection validityif (!$c) 
{	die ("Could not connect to the database host: <br />". mysqli_connect_error());
}//Set the character set of the connectionif(!mysqli_set_charset ( $c , &#39;UTF8&#39; ))
{	die(&#39;mysqli_set_charset() failed&#39;);
}

$value = htmlentities($this->value , ENT_QUOTES , CHARSET);