Table of contents
Consistency is important, even more so when writing open-source code, since the code belongs to millions of eyeballs, and bug-fixing relies on these teeming millions to actually locate bugs and understand how to solve it.
This is why, when writing anything for PrestaShop, be it a theme, a module or a core patch, you should strive to follow the following guidelines. They are the ones that the PrestaShop developers adhere to, and following them is the surest way to have your code be elegantly integrated in PrestaShop.
In short, having code consistency helps keeping the code readable and maintainable.
If use an IDE, you can use the CodeSniffer code validator to help you write better code.
Just like class, method and function names, variable names should be written in English so as to be readable to as many people as possible.
Use lowercase letters, and separate words using underscores. Do not ever use CamelCase for variable names, only for method/function and object/class names.
$my_var
.$my_var
.private $my_var
.$my_var = 17; $a = $b; |
"+
", "-
", "*
", "/
", "=
" and any combination of them (e.g. "/=
") need a space between their left and right members.
$a + 17; $result = $b / 2; $i += 34; |
".
" does not have a space between its left and right members.
echo $a.$b; $c = $d.$this->foo(); |
For performance reasons, please do not overuse concatenation. |
".=
" needs a space between its left and right members.
$a .= 'Debug'; |
When testing a boolean variable, do not use a comparison operator, but directly use the value itself, or the value prefixed with an exclamation mark:
// do not use this if ($var == true) // ...nor this if ($var == false) // use this if ($var) // ...or this if (!$var) |
if
, elseif
, while
, for
: need a space between the if
keyword and the parentheses ()
.
if (<condition>) while (<condition>) |
When a combination of if
and else
is used and both can return a value, the else
statement has to be omitted.
if (<condition>) return false; return true; |
We recommend you to use only one |
When a method/function returns a boolean and the current method/function's returned value depends on it, the if
statement has to be avoided.
public aFirstMethod() { return $this->aSecondMethod(); } |
Tests must be grouped by entity.
if ($price AND !empty($price)) ... if (!Validate::$myObject OR $myObject->id === NULL) ... |
The order of the method properties should be: visibility static function functionName()
.
private static function foo() |
Method and function names always use CamelCase: begin with a lowercase character and each following words must begin with an uppercase character.
public function myExampleMethodWithALotOfWordsInItsName() |
Braces introducing method code have to be proceeded by a carriage return.
public function myMethod($arg1, $arg2) { ... } |
Method and function names must be explicit, so function names such as b()
or ef()
are completely forbidden.
The only exceptions are the translation function (called |
Commas have to be followed (and not preceded) by a space.
protected function myProtectedMethod($arg1, $arg2, $arg3 = null) |
Object name must be singular.
class Customer |
Class name must follow the CamelCase practice, except that the first letter is uppercase.
class MyBeautifulClass |
ENT_NOQUOTE
, true
.Constant names have to be prefixed with "PS_
" inside the core and module.
define('PS_DEBUG', 1); define('PS_MODULE_NAME_DEBUG', 1); |
All keywords have to be lowercase: as, case, if, echo, null
.
Configuration variables follow the same rules as defined above.
Strings have to be surrounded by simple quotes, never double ones.
echo 'Debug'; $myObj->name = 'Hello '.$name; |
//
" comment tag is allowed.After the "//
" comment marker, a space is required:
// My great comment |
The "//
" comment marker is tolerated at the end of a code line.
$a = 17 + 23; // A comment inside my example function |
Outside of functions and methods, only the "/*
" and "*/
" comment markers are allowed.
/* This method is required for compatibility issues */ public function foo() { // Some code explanation right here ... } |
A phpDoc comment block is required before the declaration of the method.
/** * Return field value if possible (both classical and multilingual fields) * * Case 1: Return value if present in $_POST / $_GET * Case 2: Return object value * * @param object $obj Object * @param string $key Field name * @param integer $id_lang Language id (optional) * @return string */ protected function getFieldValue($obj, $key, $id_lang = NULL) |
For more information about the PHP Doc syntax: http://manual.phpdoc.org/HTMLSmartyConverter/HandS/phpDocumentor/tutorial_tags.pkg.html. |
The return
statement does not need brackets, except when it deals with a composed expression.
return $result; return ($a + $b); return (a() - b()); return true; |
The return
statement can be used to break out of a function.
return; |
Performing a function call preceded by a "@
" is forbidden, but beware of function/method call with login/password or path arguments.
myfunction(); // In the following example, we put a @ for security reasons @mysql_connect(...); |
There must be an empty line after the PHP opening tag.
<?php require_once('my_file.inc.php'); |
\t
") is the only indentation character allowed.Each indentation level must be represented by a single tabulation character.
function foo($a) { if ($a == null) return false; ... } |
The array
keyword must not be followed by a space.
array(17, 23, 42); |
When too much data is inside an array, the indentation has to be as follows:
$a = array( 36 => $b, $c => 'foo', $d => array(17, 23, 42), $e => array( 0 => 'zero', 1 => $one ) ); |
Braces are prohibited when they only define one instruction or a combination of statements.
if (!$result) return false; for ($i = 0; $i < 17; $i++) if ($myArray[$i] == $value) { $result[] = $myArray[$i]; return $result; } else $failed++; |
All users' data (data entered by users) has to be cast.
$data = Tools::getValue('name'); $myObject->street_number = (int)Tools::getValue('street_number'); |
|
All method/function's parameters must be typed (when Array
or Object
) when received.
public myMethod(Array $var1, $var2, Object $var3) |
For all other parameters, they have to be cast each time they are used, except when they are sent to other methods/functions.
protected myProtectedMethod($id, $text, $price) { $this->id = (int)$id; $this->price = (float)$price; $this->callMethod($id, $price); } |
echo ((true ? 'true' : false) ? 't' : 'f');
.&&
and ||
into your conditions: echo ('X' == 0 && 'X' == true)
.Please refrain from using reference parameters, such as:
function is_ref_to(&$a, &$b) { ... } |
Table names must begin with the PrestaShop "_DB_PREFIX_
" prefix.
... FROM `'. _DB_PREFIX_.'customer` ... |
ps_cart
".ps_order
"._lang
" suffix: "ps_product_lang
".Keywords must be written in uppercase.
SELECT `firstname` FROM `'._DB_PREFIX_.'customer` |
Back quotes ("`
") must be used around SQL field names and table names.
SELECT p.`foo`, c.`bar` FROM `'._DB_PREFIX_.'product` p, `'._DB_PREFIX_.'customer` c |
Table aliases have to be named by taking the first letter of each word, and must be lowercase.
SELECT p.`id_product`, pl.`name` FROM `'._DB_PREFIX_.'product` p NATURAL JOIN `'._DB_PREFIX_.'product_lang` pl |
When conflicts between table aliases occur, the second character has to be also used in the name.
SELECT ca.`id_product`, cu.`firstname` FROM `'._DB_PREFIX_.'cart` ca, `'._DB_PREFIX_.'customer` cu |
A new line has to be created for each clause.
$query = 'SELECT pl.`name` FROM `'._DB_PREFIX_.'product_lang` pl WHERE pl.`id_product` = 17'; |
JOIN
in a WHERE
clause.This is a brief tutorial on how to install a code validator on your PC and use it to validate your files. The code validator uses PHP CodeSniffer, which is a PEAR package (http://pear.php.net/package/PHP_CodeSniffer/). The PrestaShop code standard was created specifically for CodeSniffer, using many rules taken from existing standards, with added customized rules in order to better fit our project.
You can download the PrestaShop code standard using SVN: https://github.com/PrestaShop/PrestaShop-norm-validator (you must perform this step before going any further with this tutorial).
In order for it to be recognized as a basic standard, it must be placed in the CodeSniffer's / Standards folder |
If you use PhpStorm (http://www.jetbrains.com/phpstorm/), follow these steps:
phpcs
executable./Standards
folder).Several plugins are available online. For instance, you can use this one: https://github.com/bpearson/vim-phpcs/blob/master/plugin/phpcs.vim
Put in your ~/.vim/plugin
folder.
You can add two shortcuts (for instance, F9 to display everything and Ctrl+F9 to hide warnings) in your .vimrc
file in normal and insert mode:
nmap <C-F9>:CodeSniffErrorOnly<CR> imap <C-F9> <Esc>:CodeSniffErrorOnly<CR> nmap <F9>:CodeSniff<CR> imap <F9> <Esc>:CodeSniff<CR>a |
You do not have to use Eclipse to use PHP CodeSniffer, you can also install it so that it can be called from the command line.
$> apt-get install php-pear
$> pear install PHP_CodeSniffer
$> svn co
http://svn.prestashop.com/branches/norm/
/usr/share/php/PHP/CodeSniffer/Standards/Prestashop
$> phpcs --config-set default_standard Prestashop
The various options for this command are well explained in its documentation. For now, here is the easy way to launch it:
$> phpcs --standard=/path/to/norm/Prestashop /folder/or/fileToCheck |
In order to only display errors, not warnings:
$> phpcs --standard=/path/to/norm/Prestashop --warning-severity=99 /folder/or/fileToCheck |
If you have already manually installed PHP CodeSniffer, the program should be in PEAR's /scripts
folder.
Windows users: although the
|