Coding Standards

PHP File Formatting

General

For files that contain only PHP code, the closing tag (“?>”) is never permitted. It is not required by PHP. Not including it prevents trailing whitespace from being accidentally injected into the output.

Note

Inclusion of arbitrary binary data as permitted by __HALT_COMPILER() is prohibited from any Doctrine framework PHP file or files derived from them. Use of this feature is only permitted for special installation scripts.

Indentation

Use an indent of 4 spaces, with no tabs.

Maximum Line Length

The target line length is 80 characters, i.e. developers should aim keep code as close to the 80-column boundary as is practical. However, longer lines are acceptable. The maximum length of any line of PHP code is 120 characters.

Line Termination

Line termination is the standard way for Unix text files to represent the end of a line. Lines must end only with a linefeed (LF). Linefeeds are represented as ordinal 10, or hexadecimal 0x0A.

You should not use carriage returns (CR) like Macintosh computers (0x0D) and do not use the carriage return/linefeed combination (CRLF) as Windows computers (0x0D, 0x0A).

Naming Conventions

Classes

The Doctrine ORM Framework uses the same class naming convention as PEAR and Zend framework, where the names of the classes directly map to the directories in which they are stored. The root level directory of the Doctrine Framework is the “Doctrine/” directory, under which all classes are stored hierarchially.

Class names may only contain alphanumeric characters. Numbers are permitted in class names but are discouraged. Underscores are only permitted in place of the path separator, eg. the filename “Doctrine/Table/Exception.php” must map to the class name “Doctrine_Table_Exception”.

If a class name is comprised of more than one word, the first letter of each new word must be capitalized. Successive capitalized letters are not allowed, e.g. a class “XML_Reader” is not allowed while “Xml_Reader” is acceptable.

Interfaces

Interface classes must follow the same conventions as other classes (see above).

They must also end with the word “Interface” (unless the interface is approved not to contain it such as Doctrine_Overloadable). Some examples:

Examples

  • Doctrine_Adapter_Interface
  • Doctrine_EventListener_Interface

Filenames

For all other files, only alphanumeric characters, underscores, and the dash character (“-”) are permitted. Spaces are prohibited.

Any file that contains any PHP code must end with the extension ”.php”. These examples show the acceptable filenames for containing the class names from the examples in the section above:

  • Doctrine/Adapter/Interface.php
  • Doctrine/EventListener/Interface

File names must follow the mapping to class names described above.

Functions and Methods

Function names may only contain alphanumeric characters and underscores are not permitted. Numbers are permitted in function names but are highly discouraged. They must always start with a lowercase letter and when a function name consists of more than one word, the first letter of each new word must be capitalized. This is commonly called the “studlyCaps” or “camelCaps” method. Verbosity is encouraged and function names should be as verbose as is practical to enhance the understandability of code.

For object-oriented programming, accessors for objects should always be prefixed with either “get” or “set”. This applies to all classes except for Doctrine_Record which has some accessor methods prefixed with ‘obtain’ and ‘assign’. The reason for this is that since all user defined ActiveRecords inherit Doctrine_Record, it should populate the get / set namespace as little as possible.

Note

Functions in the global scope (“floating functions”) are NOT permmitted. All static functions should be wrapped in a static class.

Variables

Variable names may only contain alphanumeric characters. Underscores are not permitted. Numbers are permitted in variable names but are discouraged. They must always start with a lowercase letter and follow the “camelCaps” capitalization convention. Verbosity is encouraged. Variables should always be as verbose as practical. Terse variable names such as “$i” and “$n” are discouraged for anything other than the smallest loop contexts. If a loop contains more than 20 lines of code, the variables for the indices need to have more descriptive names. Within the framework certain generic object variables should always use the following names:

Object type Variable name
Doctrine_Connection $conn
Doctrine_Collection $coll
Doctrine_Manager $manager
Doctrine_Query $q

There are cases when more descriptive names are more appropriate (for example when multiple objects of the same class are used in same context), in that case it is allowed to use different names than the ones mentioned.

Constants

Constants may contain both alphanumeric characters and the underscore. They must always have all letters capitalized. For readablity reasons, words in constant names must be separated by underscore characters. For example, ATTR_EXC_LOGGING is permitted but ATTR_EXCLOGGING is not.Constants must be defined as class members by using the “const” construct. Defining constants in the global scope with “define” is NOT permitted.

class Doctrine_SomeClass
{
    const MY_CONSTANT = 'something';
}

echo $Doctrine_SomeClass::MY_CONSTANT;

Record Columns

All record columns must be in lowercase and usage of underscores(_) are encouraged for columns that consist of more than one word.

class User
{
    public function setTableDefinition()
    {
        $this->hasColumn( 'home_address', 'string' );
    }
}

Foreign key fields must be in format [table_name]_[column]. The next example is a field that is a foreign key that points to user(id):

class Phonenumber extends Doctrine_Record
{
    public function setTableDefinition()
    {
        $this->hasColumn( 'user_id', 'integer' );
    }
}

Coding Style

PHP Code Demarcation

PHP code must always be delimited by the full-form, standard PHP tags and short tags are never allowed. For files containing only PHP code, the closing tag must always be omitted

Strings

When a string is literal (contains no variable substitutions), the apostrophe or “single quote” must always used to demarcate the string:

Literal String

$string = 'something';

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

String Containing Apostrophes

$sql = "SELECT id, name FROM people WHERE name = 'Fred' OR name = 'Susan'";

Variable Substitution

Variable substitution is permitted using the following form:

// variable substitution
$greeting = "Hello $name, welcome back!";

String Concatenation

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

$framework = 'Doctrine' . ' ORM ' . 'Framework';

Concatenation Line Breaking

When concatenating strings with the ”.” operator, it is permitted 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 user "
    . "WHERE name = ? "
    . "ORDER BY name ASC";

Arrays

Negative numbers are not permitted as indices and a indexed array may be started with any non-negative number, however this is discouraged and it is recommended that all arrays have a base index of 0. When declaring indexed arrays with the array construct, a trailing space must be added after each comma delimiter to improve readability. It is also permitted to declare multiline indexed arrays using the “array” construct. In this case, each successive line must be padded with spaces. When declaring associative arrays with the array construct, it is encouraged to break the statement into multiple lines. In this case, each successive line must be padded with whitespace such that both the keys and the values are aligned:

$sampleArray = array( 'Doctrine', 'ORM', 1, 2, 3 );

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

$sampleArray = array(
    'first'  => 'firstValue',
    'second' => 'secondValue'
);

Classes

Classes must be named by following the naming conventions. The brace is always written next line after the class name (or interface declaration). Every class must have a documentation block that conforms to the PHPDocumentor standard. Any code within a class must be indented four spaces and only one class is permitted per PHP file. Placing additional code in a class file is NOT permitted.

This is an example of an acceptable class declaration:

/**
 * Documentation here
 */
class Doctrine_SampleClass
{
    // entire content of class
    // must be indented four spaces
}

Functions and Methods

Methods must be named by following the naming conventions and must always declare their visibility by using one of the private, protected, or public constructs. Like classes, the brace is always written next line after the method name. There is no space between the function name and the opening parenthesis for the arguments. Functions in the global scope are strongly discouraged. This is an example of an acceptable function declaration in a class:

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

    public function bar2()
    {

    }
}

Note

Functions must be separated by only ONE single new line like is done above between the bar() and bar2() methods.

Passing by-reference is permitted in the function declaration only:

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

    }
}

Call-time pass by-reference is prohibited. The return value must not be enclosed in parentheses. This can hinder readability and can also break 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 arguments are separated by a single trailing space after the comma delimiter. This is an example of an acceptable function call for a function that takes three arguments:

threeArguments( 1, 2, 3 );

Call-time pass by-reference is prohibited. See above for the proper way to pass function arguments by-reference. For functions whose arguments permitted arrays, the function call may include the array construct and can be split into multiple lines to improve readability. In these cases, the standards for writing arrays still apply:

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

threeArguments( array( 1, 2, 3, 'Framework',
                       'Doctrine', 56.44, 500 ), 2, 3 );

Control Statements

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 of larger conditionals. 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 four spaces.

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

For if statements that include elseif or else, the formatting must be as in these examples:

if ( $foo != 1 )
{
    $foo = 1;
}
else
{
    $foo = 3;
}

if ( $foo != 2 )
{
    $foo = 2;
}
elseif ( $foo == 1 )
{
    $foo = 3;
}
else
{
    $foo = 11;
}

When ! operand is being used it must use the following formatting:

if ( ! $foo )
{

}

Control statements written with the switch construct must have a single space before the opening parenthesis of the conditional statement, and also a single space after the closing parenthesis. All content within the switch statement must be indented four spaces. Content under each case statement must be indented an additional four spaces but the breaks must be at the same indentation level as the case statements.

switch ( $case )
{
    case 1:
    case 2:
    break;
    case 3:
    break;
    default:
    break;
}

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

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/

Every method, 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 construct used to declare the function.

If a function/method may throw an exception, use @throws:

/*
 * Test function
 *
 * @throws Doctrine_Exception
 */
public function test()
{
    throw new Doctrine_Exception('This function did not work');
}

Conclusion

This is the last chapter of Doctrine ORM for PHP - Guide to Doctrine for PHP. I really hope that this book was a useful piece of documentation and that you are now comfortable with using Doctrine and will be able to come back to easily reference things as needed.

As always, follow the Doctrine :)

Thanks, Jon