PHP Code Style Guide

This is ThinkUp’s Code Style guide for PHP. See the main page for guides specific to other languages.

Assume we’re using the Drupal PHP coding style unless otherwise noted here.

Always use <?php to delimit PHP code, not the shorthand, <?, as this is the most used and supported across PHP setups and the one PHP will continue supporting in the future.

Use PHP5 conventions

When in doubt, use PHP5 (not PHP4) coding conventions.

  • Class constructors should be public function __construct (), not the PHP4-style class name. Use destructors when appropriate.

  • Explicitly declare visibility (public, private, protected) for member variables and methods.

  • Do NOT use PHP closing tags for files that contain only PHP code:

    The ?> at the end of code files is purposely omitted. Removing it eliminates the possibility of unwanted whitespace at the end of files which can cause header already sent errors, XHTML/XML validation issues, and other problems.


Use an indent of 4 spaces, with no tabs.


Always use curly braces, even in situations where they are technically optional. Having them increases readability and decreases the likelihood of logic errors being introduced as the codebase continues to evolve.

Opening curly braces should never be on their own new line.

Closing curly braces should always be on their own new line.

Avoid multiple blank lines

Separating sections of code with a blank line is okay, but never more than 1 blank line at a time.

Maximum line length: 120 characters

The maximum length of any line of code is 120 characters, unless it contains a string that cannot have a break in it. (This differs from Drupal’s 80-character maximum length.)

Tip: If you’re using Eclipse, add a ruler to the 120 mark to see where you should break to the next line. See Developer Guide: Setting Up Eclipse PDT for how.

Include docblocks in all code

ThinkUp uses PHPDocumentor to ease code maintenance and auto-generate class documentation. Include PHPDoc-style “docblocks” in all of your PHP code. When writing your documentation, please use PHPDocumentor’s syntax.

Keyword case

Drupal style guide states use of uppercase value keywords (TRUE, FALSE, NULL), ThinkUp user lowercase.

Same-line curly braces

Unlike Drupal’s style guide, ThinkUp keeps opening and closing curly braces on the same line as the control keyword (if, else).

Boolean operator at the beginning of the line

Like the Drupal convention, when constructing multi line IFs, the boolean operator should be at the beginning of the line, not the end.

MVC architecture

ThinkUp implements the Model-View-Controller design pattern. All new PHP code should follow suit. Read more about ThinkUp’s MVC implementation.