Good practices for developing modules

DOs and DON’Ts

Do

  • Add a link to your documentation included in your ZIP File and to your support page on Addons in the module interface.
  • Follow our Coding Standards
  • Create your own database tables, do not alter PrestaShop’s.
  • Develop your module in English, then use PrestaShop translation system to translate your module.
  • Go through directories using PrestaShop constants like: _PS_CONFIG_DIR_ . '/config.inc.php'
  • CREATE TABLE SQL statements must be followed by IF NOT EXISTS to avoid SQL errors
  • DROP TABLE SQL statements must be followed by IF EXISTS to avoid SQL errors

Don’t

  • Don’t insert external links into your module code or module documentation.
  • Don’t provide your personal contact details in your module or module documentation.
  • Don’t send your customers to your own support/ticket management platform.
  • Don’t use external ajax files to perform ajax tasks.
  • Don’t go through directories using code and variables like: dirname(__FILE__).'/../../config/config.inc.php'
  • Don’t edit the SQL structure of PrestaShop tables.
  • Don’t obfuscate your code, making it not human readable.
  • Don’t use global variables to avoid any conflict. Also global variables are usually considered a bad practice.

A few recommendations for your modules

  • Prefix what belongs to you:

    • modules
    • configuration parameters (ps_configuration)
    • Smarty variables
    • tables
    • CSS classes

  • Consider deleting your configurations, tables, admin tabs, and all other entities unique to your product during the uninstallation of your modules.

  • You shouldn’t use HTML code in your PHP code. Here are alternatives to separate the view into your code:

    • display content with Smarty
    • use helpers for your configuration pages
    • include PrestUI, a graphic library created by the community for your configuration pages.

  • We recommend you to make your module interface matches the PrestaShop’s UI kit.

  • For modules compatible before the 1.7 PrestaShop version, the minimal compatibility has to be PHP 5.3. You will be then able to use, for example, namespaces.

  • If your module allows the upload of a file, check the type of the file to make sure you avoid security issues. Here are more information for the function mime_content_type().

  • When your module has forms, you should:

    • show a confirmation message if everything went fine or an error message if it did not.
    • make sure information entered by customers are correct. If you ask a sum, it has to be only numbers. More information about the Validate class of PrestaShop here.

  • Consider carefully casting your variables and use pSQL/bqSQL in the SQL requests to avoid any injections (read Best Practices of the Db Class). Make sure your files are properly protected (especially if your module uses a cron for example) to avoid anyone being able to execute them. As a result, you are required to use a token!

  • The use of overrides is permitted, however if we decide that too many (2 / 3 max) have been used and/or the modifications are too dangerous, we will refuse your module. If you’re unsure, don’t hesitate to get in touch.

  • If you need to load a .js or .tpl (containing JavaScript) to the backoffice, put restrictions in place on your hooks (hookbackofficeheader/top/footer)! Specific examples: if your JS only applies to your module’s configuration page, use:

    <?php
if (Tools::getValue('configure') === $this->name) {
  // code
}

  • A merchant is likely to have a shop running on a different shop than yours. In case a module is using PHP extensions not installed by default by PHP, add a preliminary check before using them (I.e with extension_loaded). This prevents fatal errors to be thrown on shops on which these extensions aren’t enabled.

A few recommendations for your themes

  • PrestaShop does not yet feature a “theme validator”. However, each of the modules present in your theme must be tested via our Validator.
  • Don’t remove the default hooks in PrestaShop, whether via PHP or in the theme! You will risk preventing a third party module from working properly.
  • Prefix what belongs to you:
    • modules
    • image standards
  • You should not have HTML in your PHP code; use Smarty or helper classes for views.
  • We do not accept themes using the PrestaShop base theme to which only color, font and image changes etc. have been made. You should create a unique theme! :-)
  • You should keep the store logo by default in your theme’s zip, in the header and footer of your theme.

A few recommendations for your email templates

  • Use our official SDK to develop your emails:
  • Make sure to submit on Addons a valid zip, built with the SDK.
  • Test your emails with the official module.