PHP Developer
Best Practices
Burlington, VT PHP UG

23 April 2008

Matthew Weier O'PhinneySoftware ArchitectZend Technologies, Ltd.

About Me

Software Architect, Zend Framework

Development Lead: MVC, Zend_Form, Server components

Scope Releases

Promote and Implement best practices for team and contributors

Open Source Contributor

PEAR

Solar

Cgiapp

About You

Can you read your own code? Can others?

Is your software tested?

Is your software documented?

Are you using source control?

Does your team work efficiently?

Do you push buggy software into production?

Do you have a deployment plan? Does it include contingencies for rollbacks?

What we'll cover tonight

Coding Standards

Purpose of Coding Standards

Efficiency

Maintainability

Collaboration

Efficiency

You know you don't have a standard when:

You always need to reformat code originating with others

Code you wrote 6 months ago has a different visual structure than code you write today

Whenever you modify old code, it breaks -- usu. due to newly introduced syntax errors

e.g., missing braces in conditionals, missing commas in lists, etc.

Maintainability

When following a coding standard, your code has a predictable layout both in the file system and in the layout. Easier to read code is easier to:

understand

maintain

refactor

Collaboration

When a team follows a coding standard, any individual developer can pick up another developer's code and understand it, which will help them maintain and possibly refactor it. This leads to more efficient development... and thus happier customers.

Coding Standards Provide...

Consistency of file system layout

Consistency of code layout

Use Public Standards

Don't invent your own standard for you or your company. You are not special, and your PHP source code is not unique. Others have already argued the issues and you can benefit from their collective knowledge.

Why use a public standard?

Objectivity

Choices are no longer based on subjective preferences, but on empirical experience.

Requirement when hiring or outsourcing

Easily judge the candidate experience and code quality.

Compatibility

Use a standard that follows that of the libraries you use.

What Choices Exist?

PEAR Coding Standards*

Zend Framework Coding Standards

eZcomponents Coding Standards

PHPLIB

* PEAR CS actually derives from Horde

What We'll Cover

PEAR

PEAR standards are the most widely used and accepted coding standards, in large part due to the number of people using PEAR as well as the general quality and explicitness of the standard.

Zend Framework

Only to note the additions it makes to PEAR standards.

PEAR Overview

Popular component library

Issues have already been debated

Well known and accepted (used more than any other standard)

Basis for many other projects

Horde (actually, based on Horde)

Solar

Zend Framework

AdoDB

PEAR Naming Conventions

Class Names

MixedCase

Initial Cap

Underscores separate logical package and code boundaries

Examples

Spreadsheet_Excel_Writer

Services_Google_AdWords

PEAR Naming Conventions

Files

1:1 correspondence between class name and file name; one class per file

'.php' suffix

Class name underscores become directory separators

Spreadsheet_Excel_Writer

Spreadsheet/Excel/Writer.php

No loose PHP code

PEAR Naming Conventions

Variables

camelCased

initial character lowercase

Constants

ALL_CAPS

underscores for word separators

Private and protected properties

initial _underscore prefixes variable name

PEAR Naming Conventions

Functions and Methods

camelCased

Initial character lowercase

Private and protected methods

Initial _underscore

PEAR Code Formatting

Indentation

Spaces only; no tabs

Four (4) spaces per level of indentation

Purpose is consistency of viewing

looks the same regardless of editor

Line length

Suggested 75-85 character limit

No shell comments (#)

PEAR Block Formatting

One True Brace

Functions and Classes have the opening brace on the line following the declaration, at the same indent level

Control structures keep the opening brace on the same line as the declaration

All control structures use braces, no exceptions

PEAR Coding Standards

More information

Current standards:

http://pear.php.net/manual/en/standards.php

Proposed standards for PEAR2:

http://pear.php.net/manual/en/pear2cs.php

Zend Coding Standards

Follow PEAR for the most part

Additions

Omit closing ?> on any file containing only PHP code

Abstract and Interface classes

Should contain the keyword in the class name

Zend_Form_Decorator_Interface

Zend_Form_Decorator_Abstract

More information:

http://framework.zend.com/manual/en/coding-standard.html

Summary

Use a public coding standard

Use it always

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