PHP Coding Standards and Naming Conventions

Basic Requirements

PHP 5 code is required.

All code must be E_STRICT-compatible. This means that it must not produce any warnings or errors when PHP's error reporting level is set to E_ALL | E_STRICT.

Layout and indentation

Indenting code is a must. Tabs size is 4 characters and your editor must insert TAB as TAB not as 4 SPACES

Array keys

Array keys myst be quoted with single quote (')

echo $row['something'];

Strings

Strings can be with single or double quote

$s = "This is 1st example";
$s = 'This is 1st example';

PHP variables in string

Must be in brackets, instead of this:

$s = "This is $variable example";

Use this

$s = "This is {$variable} example";

$s = 'This is '.$variable.' example';

Comments

Comment code ad much as possbile and as long as it makes sense.


/**
 * This is what function does
 * 
 * @access public
 * @param $var1 (string) - username
 * @param $var2 (int) - user id
 * @return bool
 */

public function getUser ($var1, $var2 = 0)
{
	// do something
	return true;
}

Also use one line comments when needed

$activated = User::isValid(); // check if user activated account

No need to comment obvious things

while ($i < $something)
{
	...
	$i++; // increment $i by one <- THIS IS STUPID COMMENT
}

Basic rules

Equal sign (=) must have at least one space before and one after

$a = 'something';

If you have more assignments one after another, try to align =

$a       = 'something';
$another = 45;

Compare sign (==, =>, >, <, <=, !=) also need minimum one space before and after

if ($condition == 'I know')

If else

Always use brackets { } even for simple if () statement

if ($condition == CONSTANT)
{
	$this->doSomethingCool ($condition);
}

If you have more similar if/else statements, you can align brackets but you still have to use brackets:

if ($condition == CONSTANT)	{ $this->doSomethingCool ($condition); }
elseif ($condition = 24)	{ Object::staticFunction (); }
else				{ $this->doOtherThing (); }

Between "if", "for", "switch", "foreach" and () must be one space

Example

if ($condition == CONSTANT)
{
	$this->doSomethingCool ($condition);
}
elseif ($condition = 24 || !empty($stuff))
{
	Object::staticFunction ();
}
elseif ($condition == 'I know')
{
	Another_Object::newStaticFunction ();
}
else
{
	$this->doOtherThing ();
}


public static function functionName ($variable_one, $variable_two = '')
{
	if ($something)
	{
		$this->get();
	}
}

Multiple conditions

If you have if statements with long multiple conditions try to separate in different lines

if ($something == 'Something' && $another_thing > 45)
{
	// do something
}

For more complex conditions split in 2 lines

if (($something == 'Something' && $another_thing > 45)
	|| (User::isValid() && $product->id))
{
	// do something
}

Or even better

if (  ($something == 'Something' && $another_thing > 45)
   || (User::isValid() && $product->id)
   )
{
	// do something
}

Conditions order

If you have multiple conditions put the most common condition first.

if (!empty($var) && $var == 'something')

So the second condition never checks if the first one is false ( $var is empty )

Switch

switch ($condition)
{
	case 'something':

		// do something here
		break;

	case 48:
		// do the stuff
		// no break; - if you need case with no "break" you have to write comment

	case SOME_CONSTANT:
	default:
		
		// do some magic
		break;
}

Functions

Function variables

All function variables myst be

Required variables first
Varibables with default values last

function someFunction ($var1)
{
	// function body
}

function otherFunction ($var1, $variable_two)
{
	// function body
}

function thirdFunction ($var1, $variable_two = 'default')
{
	// function body
}

Functions with default variables as first parameters are just plain stupid

function thirdFunction ($var1 = 'default', $variable_two)
{
	// function body
}

Try to avoid more than 4-5 function parameters, but if you absolutely need it, then separate in several lines:

function thirdFunction ($var1,
	$another_variable,
	$third_variable, 
	$yet_another_variable = 44, 
	$variable_two = 'default')
{
	// function body
}

Loops

Array loops

For single dimension arrays user $val for array values and $key for array keys

foreach ($item as $key => $val)
{
	// do something here
}

Multidimensional array loops

For multi dimension arrays user $row for array values and $key for array keys

foreach ($data as $key => $row)
{
	// do something here
}

Nested loops

foreach ($data as $key => $row)
{
	// do something here

	foreach ($row as $k => $v)
	{
		// do this for this row
	}
}

For loops and counters

for ($i = 0; $i < 5; $i++)
{
	// do something
}

Nested For loops

for ($i = 0; $i < 5; $i++)
{
	// do something
	for ($j = $i; $j < 100; $j++)
	{
		// do something
	}
}

Operators

Allways use space between operators

$a=$something*$b+$i

Replace it with:

$a = $something * $b + $i;

Except for string concatenation

$s = 'This is my '.$order.' example';

$s = 'And this is my '.($order + 1).' example';

$s = 'And this is my '.round (max ($order / 100) * 100).'% example';

Exceptions

try {
	if (!App::dosomething())
	{
		throw new Exception('Hey, we screwed up');
	}

	// do whatever you wanted to do

} catch (Exception $e) { customExceptionHandler ($e); }

Include() and require()

Include and require are statements not functions therefore use it like this:

include "/path/to/file/some.php";
require "/path/to/file/some.php";

Prefered methods are require_once and include_once

include_once "/path/to/file/some.php";
require_once "/path/to/file/some.php";

Appendix

Document Date and Version

Document created in december 2008. Version 1.0 beta