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Coding Style

PHP Code Demarcation

PHP code must always be delimited by the full-form, standard PHP tags:

Short tags are never allowed. For files containing only PHP code, the closing tag must always be omitted (See General).

Strings

String Literals

When a string is literal (contains no variable substitutions), the apostrophe or "single quote" should always be used to demarcate the string:

$a = 'Example String';

String Literals Containing Apostrophes

When a literal string itself contains apostrophes, it is permitted to demarcate the string with quotation marks or "double quotes". This is especially useful for SQL statements:

$sql = "SELECT `id`, `name` from `people` WHERE `name`='Fred' OR `name`='Susan'";
This syntax is preferred over escaping apostrophes as it is much easier to read.

Variable Substitution

Variable substitution is permitted using either of these forms:

$greeting = "Hello $name, welcome back!";

$greeting = "Hello {$name}, welcome back!";

For consistency, this form is not permitted:

$greeting = "Hello ${name}, welcome back!";

String Concatenation

Strings must be concatenated using the "." operator. A space must always be added before and after the "." operator to improve readability:

$company = 'Zend' . ' ' . 'Technologies';

When concatenating strings with the "." operator, it is encouraged to break the statement into multiple lines to improve readability. In these cases, each successive line should be padded with whitespace such that the "."; operator is aligned under the "=" operator:

$sql = "SELECT `id`, `name` FROM `people` "
     . "WHERE `name` = 'Susan' "
     . "ORDER BY `name` ASC ";

Arrays

Numerically Indexed Arrays

Negative numbers are not permitted as indices.

An indexed array may start with any non-negative number, however all base indices besides 0 are discouraged.

When declaring indexed arrays with the array function, a trailing space must be added after each comma delimiter to improve readability:

$sampleArray = array(1, 2, 3, 'Zend', 'Studio');

It is permitted to declare multiline indexed arrays using the "array" construct. In this case, each successive line must be padded with spaces such that beginning of each line is aligned:

$sampleArray = array(1, 2, 3, 'Zend', 'Studio',
                     $a, $b, $c,
                     56.44, $d, 500);

Associative Arrays

When declaring associative arrays with the array construct, breaking the statement into multiple lines is encouraged. In this case, each successive line must be padded with whitespace such that both the keys and the values are aligned:

$sampleArray = array('firstKey'  => 'firstValue',
                     'secondKey' => 'secondValue');

Classes

Class Declaration

Classes must be named according to Zend Framework's naming conventions.

The brace should always be written on the line underneath the class name (the "one true brace" form).

Every class must have a documentation block that conforms to the PHPDocumentor standard.

All code in a class must be indented with four spaces.

Only one class is permitted in each PHP file.

Placing additional code in class files is permitted but discouraged. In such files, two blank lines must separate the class from any additional PHP code in the class file.

The following is an example of an acceptable class declaration:

/**
 * Documentation Block Here
 */
class SampleClass
{
    // all contents of class
    // must be indented four spaces
}

Class Member Variables

Member variables must be named according to Zend Framework's variable naming conventions.

Any variables declared in a class must be listed at the top of the class, above the declaration of any methods.

The var constuct is not permitted. Member variables always declare their visibility by using one of the private, protected, or public modifiers. Giving access to member variables directly by declaring them as public is permitted but discouraged in favor of accessor methods (set/get).

Functions and Methods

Function and Method Declaration

Functions must be named according to the Zend Framework function naming conventions.

Methods inside classes must always declare their visibility by using one of the private, protected, or public modifiers.

As with classes, the brace should always be written on the line underneath the function name (the "one true brace" form). Space between the function name and the opening parenthesis for the arguments is not permitted.

Functions in the global scope are strongly discouraged.

The following is an example of an acceptable function declaration in a class:

/**
 * Documentation Block Here
 */
class Foo
{
    /**
     * Documentation Block Here
     */
    public function bar()
    {
        // all contents of function
        // must be indented four spaces
    }
}

NOTE: Pass-by-reference is the only parameter passing mechanism permitted in a method declaration.

/**
 * Documentation Block Here
 */
class Foo
{
    /**
     * Documentation Block Here
     */
    public function bar(&$baz)
    {}
}

Call-time pass-by-reference is strictly prohibited.

The return value must not be enclosed in parentheses. This can hinder readability, in addtional to breaking code if a method is later changed to return by reference.

/**
 * Documentation Block Here
 */
class Foo
{
    /**
     * WRONG
     */
    public function bar()
    {
        return($this->bar);
    }

    /**
     * RIGHT
     */
    public function bar()
    {
        return $this->bar;
    }
}

Function and Method Usage

Function arguments should be separated by a single trailing space after the comma delimiter. The following is an example of an acceptable invocation of a function that takes three arguments:

threeArguments(1, 2, 3);

Call-time pass-by-reference is strictly prohibited. See the function declarations section for the proper way to pass function arguments by-reference.

In passing arrays as arguments to a function, the function call may include the "array" hint and may be split into multiple lines to improve readability. In such cases, the normal guidelines for writing arrays still apply:

threeArguments(array(1, 2, 3), 2, 3);

threeArguments(array(1, 2, 3, 'Zend', 'Studio',
                     $a, $b, $c,
                     56.44, $d, 500), 2, 3);

Control Statements

If/Else/Elseif

Control statements based on the if and elseif constructs must have a single space before the opening parenthesis of the conditional and a single space after the closing parenthesis.

Within the conditional statements between the parentheses, operators must be separated by spaces for readability. Inner parentheses are encouraged to improve logical grouping for larger conditional expressions.

The opening brace is written on the same line as the conditional statement. The closing brace is always written on its own line. Any content within the braces must be indented using four spaces.

if ($a != 2) {
    $a = 2;
}

For "if" statements that include "elseif" or "else", the formatting conventions are similar to the "if" construct. The following examples demonstrate proper formatting for "if" statements with "else" and/or "elseif" constructs:

if ($a != 2) {
    $a = 2;
} else {
   $a = 7;
}


if ($a != 2) {
    $a = 2;
} elseif ($a == 3) {
   $a = 4;
} else {
   $a = 7;
}
PHP allows statements to be written without braces in some circumstances. This coding standard makes no differentiation- all "if", "elseif" or "else" statements must use braces.

Use of the "elseif" construct is permitted but strongly discouraged in favor of the "else if" combination.

Switch

Control statements written with the "switch" statement must have a single space before the opening parenthesis of the conditional statement and after the closing parenthesis.

All content within the "switch" statement must be indented using four spaces. Content under each "case" statement must be indented using an additional four spaces.

switch ($numPeople) {
    case 1:
        break;

    case 2:
        break;

    default:
        break;
}

The construct default should never be omitted from a switch statement.

NOTE: It is sometimes useful to write a case statement which falls through to the next case by not including a break or return within that case. To distinguish these cases from bugs, any case statement where break or return are omitted should contain a comment indicating that the break was intentionally omitted.

Inline Documentation

Documentation Format

All documentation blocks ("docblocks") must be compatible with the phpDocumentor format. Describing the phpDocumentor format is beyond the scope of this document. For more information, visit: » http://phpdoc.org/

All class files must contain a "file-level" docblock at the top of each file and a "class-level" docblock immediately above each class. Examples of such docblocks can be found below.

Files

Every file that contains PHP code must have a docblock at the top of the file that contains these phpDocumentor tags at a minimum:

/**
 * Short description for file
 *
 * Long description for file (if any)...
 *
 * LICENSE: Some license information
 *
 * @copyright  2008 Zend Technologies
 * @license    http://framework.zend.com/license   BSD License
 * @version    $Id:$
 * @link       http://framework.zend.com/package/PackageName
 * @since      File available since Release 1.5.0
*/

Classes

Every class must have a docblock that contains these phpDocumentor tags at a minimum:

/**
 * Short description for class
 *
 * Long description for class (if any)...
 *
 * @copyright  2008 Zend Technologies
 * @license    http://framework.zend.com/license   BSD License
 * @version    Release: @package_version@
 * @link       http://framework.zend.com/package/PackageName
 * @since      Class available since Release 1.5.0
 * @deprecated Class deprecated in Release 2.0.0
 */

Functions

Every function, including object methods, must have a docblock that contains at a minimum:

  • A description of the function

  • All of the arguments

  • All of the possible return values

It is not necessary to use the "@access" tag because the access level is already known from the "public", "private", or "protected" modifier used to declare the function.

If a function/method may throw an exception, use @throws for all known exception classes:

@throws exceptionclass [description]

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Introduction to Zend Framework
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Zend_Acl
Introduction
Refining Access Controls
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Introduction
Database Table Authentication
Digest Authentication
HTTP Authentication Adapter
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Zend_Cache
Introduction
The theory of caching
Zend_Cache frontends
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Zend_Captcha
Introduction
Captcha Operation
Captcha Adapters
Zend_Config
Introduction
Theory of Operation
Zend_Config_Ini
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Zend_Console_Getopt
Introduction to Getopt
Declaring Getopt Rules
Fetching Options and Arguments
Configuring Zend_Console_Getopt
Zend_Controller
Zend_Controller Quick Start
Zend_Controller Basics
The Front Controller
The Request Object
The Standard Router: Zend_Controller_Router_Rewrite
The Dispatcher
Action Controllers
Action Helpers
The Response Object
Plugins
Using a Conventional Modular Directory Structure
MVC Exceptions
Migrating from Previous Versions
Zend_Currency
Introduction to Zend_Currency
How to work with currencies
Migrating from Previous Versions
Zend_Date
Introduction
Theory of Operation
Basic Methods
Zend_Date API Overview
Creation of dates
Constants for General Date Functions
Working examples
Zend_Db
Zend_Db_Adapter
Zend_Db_Statement
Zend_Db_Profiler
Zend_Db_Select
Zend_Db_Table
Zend_Db_Table_Row
Zend_Db_Table_Rowset
Zend_Db_Table Relationships
Zend_Debug
Dumping Variables
Zend_Dojo
Introduction
Zend_Dojo_Data: dojo.data Envelopes
Dojo View Helpers
Dojo Form Elements and Decorators
Zend_Dom
Introduction
Zend_Dom_Query
Zend_Exception
Using Exceptions
Zend_Feed
Introduction
Importing Feeds
Retrieving Feeds from Web Pages
Consuming an RSS Feed
Consuming an Atom Feed
Consuming a Single Atom Entry
Modifying Feed and Entry structures
Custom Feed and Entry Classes
Zend_File
Zend_File_Transfer
Validators for Zend_File_Transfer
Zend_Filter
Introduction
Standard Filter Classes
Filter Chains
Writing Filters
Zend_Filter_Input
Zend_Filter_Inflector
Zend_Form
Zend_Form
Zend_Form Quick Start
Creating Form Elements Using Zend_Form_Element
Creating Forms Using Zend_Form
Creating Custom Form Markup Using Zend_Form_Decorator
Standard Form Elements Shipped With Zend Framework
Standard Form Decorators Shipped With Zend Framework
Internationalization of Zend_Form
Advanced Zend_Form Usage
Zend_Gdata
Introduction to Gdata
Authenticating with AuthSub
Authenticating with ClientLogin
Using Google Calendar
Using Google Documents List Data API
Using Google Spreadsheets
Using Google Apps Provisioning
Using Google Base
Using the YouTube Data API
Using Picasa Web Albums
Catching Gdata Exceptions
Zend_Http
Zend_Http_Client - Introduction
Zend_Http_Client - Advanced Usage
Zend_Http_Client - Connection Adapters
Zend_Http_Cookie and Zend_Http_CookieJar
Zend_Http_Response
Zend_InfoCard
Introduction
Zend_Json
Introduction
Basic Usage
JSON Objects
XML to JSON conversion
Zend_Json_Server - JSON-RPC server
Zend_Layout
Introduction
Zend_Layout Quick Start
Zend_Layout Configuration Options
Zend_Layout Advanced Usage
Zend_Ldap
Introduction
Zend_Loader
Loading Files and Classes Dynamically
Loading Plugins
Zend_Locale
Introduction
Using Zend_Locale
Normalization and Localization
Working with Dates and Times
Supported Languages for Locales
Supported Regions for Locales
Zend_Log
Overview
Writers
Formatters
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Zend_Mail
Introduction
Sending via SMTP
Sending Multiple Mails per SMTP Connection
Using Different Transports
HTML E-Mail
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Additional Headers
Character Sets
Encoding
SMTP Authentication
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Reading Mail Messages
Zend_Measure
Introduction
Creation of Measurements
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Types of measurements
Zend_Memory
Overview
Memory Manager
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Zend_Mime
Zend_Mime
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Zend_OpenId
Introduction
Zend_OpenId_Consumer Basics
Zend_OpenId_Provider
Zend_Paginator
Introduction
Usage
Configuration
Advanced usage
Zend_Pdf
Introduction.
Creating and loading PDF documents.
Save changes to the PDF document.
Document pages.
Drawing.
Document Info and Metadata.
Zend_Pdf module usage example.
Zend_Registry
Using the Registry
Zend_Rest
Introduction
Zend_Rest_Client
Zend_Rest_Server
Zend_Search_Lucene
Overview
Building Indexes
Searching an Index
Query Language
Query Construction API
Character Set
Extensibility
Interoperating with Java Lucene
Advanced
Best Practices
Zend_Server
Introduction
Zend_Server_Reflection
Zend_Service
Introduction
Zend_Service_Akismet
Zend_Service_Amazon
Zend_Service_Audioscrobbler
Zend_Service_Delicious
Zend_Service_Flickr
Zend_Service_Nirvanix
Zend_Service_ReCaptcha
Zend_Service_Simpy
Introduction
Zend_Service_StrikeIron
Zend_Service_StrikeIron: Bundled Services
Zend_Service_StrikeIron: Advanced Uses
Zend_Service_Technorati
Zend_Service_Yahoo
Zend_Session
Introduction
Basic Usage
Advanced Usage
Global Session Management
Zend_Session_SaveHandler_DbTable
Zend_Soap
Zend_Soap_Server
Zend_Soap_Client
WSDL Accessor
AutoDiscovery. Introduction
Class autodiscovering.
Functions autodiscovering.
Autodiscovering. Datatypes.
Zend_Test
Introduction
Zend_Test_PHPUnit
Zend_Text
Zend_Text_Figlet
Zend_TimeSync
Introduction
Working with Zend_TimeSync
Zend_Translate
Introduction
Adapters for Zend_Translate
Using Translation Adapters
Zend_Uri
Zend_Uri
Zend_Validate
Introduction
Standard Validation Classes
Validator Chains
Writing Validators
Zend_Version
Reading the Zend Framework Version
Zend_View
Introduction
Controller Scripts
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Zend_View_Abstract
Zend_Wildfire
Zend_Wildfire
Zend_XmlRpc
Introduction
Zend_XmlRpc_Client
Zend_XmlRpc_Server
Zend Framework Requirements
PHP Version
PHP Extensions
Zend Framework Components
Zend Framework Dependencies
Zend Framework Coding Standard for PHP
Overview
PHP File Formatting
Naming Conventions
Coding Style
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