Chapter 7. Best Practices in PHP Programming

So far, we discussed performance-related topics. Now, in this chapter, we will study best practices in PHP applications' development and deployment. This is a vast topic, but we will cover it briefly. PHP provides all levels of programmers with the ability to write quality code easily and quickly. However, when the application advances to a more complex nature, we forget to follow the best practices. To produce a high performance PHP application, it is necessary to keep in mind the performance at every line of the code.

We will cover the following topics:

Coding styles
Design patterns
Service-oriented architecture (SOA)
Test-driven development (TDD) and PHPUnit testing
PHP frameworks
Version control systems and Git
Deployment

Coding styles

There are too many coding styles out there, such as PSR-0, PSR-1, PSR-2, PSR-3, and so on. Programmers can use different standards as they want, but it is necessary to follow a standard that is already used in the libraries or a framework in use to make the code more readable. For example, Laravel uses the PSR-1 and PSR-4 coding standards, so if we are developing in Laravel, we should follow these coding standards. Some PHP frameworks, such as Yii 2 and Zend Framework 2, follow the PSR-2 coding standards. However, none of these frameworks stick to a single standard; most of them follow a mixed standard according to their requirements.

The important point is to follow the standard that is used in the libraries used in the application. An organization can also use its own coding standards for internal purposes. It is not a requirement for coding; it is a requirement for readability and producing quality code that others can understand.

PHP Framework Interop Group (PHP-FIG) is a group whose members defined coding standards for PHP. Full details about PSR standards can be found on their website at http://www.php-fig.org/.

Instead of discussing a specific coding standard, let's discuss best practices in coding styles for PHP:

The first letter of each word in the class name must be capital. The opening brace should be on the line after the class declaration, and the closing brace should be on the line after the class end line. Here's an example:
```
class Foo
{
  …
  …
  …
}
```
Class methods and function names should follow the camel case naming convention. The starting braces should be on the next line of the class declaration, and the end brace should be on the line at the end of the function definition. There should be no spaces between the method name and the parenthesis. Also, there should be no space between the first argument, the opening parenthesis, the last argument, and the closing parenthesis. Also, there should be no space between an argument and the comma at the end of this argument, but there should be a space between a comma and the next argument. Here's an example:
```
public function phpBook($arg1, $arg2, $arg3)
{
  …
  …
  …
}
```
If there is a namespace declaration, there must be a single empty line after its declaration. If there are use declarations, all of them must go after that namespace's declarations. There must be one use declaration per line, and there must be a space after the use block. Also, the extends and implements keywords must be on the same line as the class declaration. Here's an example:
```
namespace Packt\Videos;

use Packt\Books;
use Packt\Presentations;

class PacktClass extends VideosClass implements BaseClass
{
  …
  …
  …
}
```
Visibility must be declared for all properties, and the properties must be in camel case. Also, properties must not be prepended with an underscore for private or protected visibilities. Take a look at the following example:
```
class PacktClass
{
  public $books;
  private $electronicBooks;
  …
  …
  …
}
```
If there is an abstract keyword, it must come before the class keyword for classes, and the final keyword must come before the method's visibility in the case of methods. On the other hand, the static keyword must come after the method visibility. Take a look at this example:
```
abstract class PacktClass
{
  final public static function favoriteBooks()
  {
    …
    …
    …
  }
}
```
All PHP keywords must be used in lowercase, including the true and false keywords. Constants must be declared and used in capital case.
For all control structures, there must be a space after the control structure keyword. If there is an expression for this control structure, there must be no space between the parenthesis holding this expression and the block of code that follows. There must be a space after the parenthesis and the starting brace. The starting brace must be on the same line as the control structure. The closing brace must be on the line after the end of the body. Refer to the following code for a better understanding:
```
if ($book == "PHP 7") {
  …
  …
  …
} else {
  …
  …
  …
}
```

In the case of loops, the spaces must be as in the following examples:

for ($h = 0; $h < 10; $h++) {
  …
  …
  …
}

foreach ($books as $key => $value) {
  …
  …
  …
}

while ($book) {
  …
  …
  …
}

For the purpose of this book, I did not follow the rule of the opening brace being on the same line as the control structure declaration and always used it on the next line of the declaration. I did not find it clearer; it is a personal choice, and anybody can follow the standards mentioned here.

Standards are good to follow as they make the code more readable and professional. However, never try to invent your own new standards; always follow those that are already invented and followed by the community.

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Test-driven development (TDD)

Table of Contents for PHP 7: Real World Application Development

Chapter 7. Best Practices in PHP Programming

Coding styles

Table of Contents for
PHP 7: Real World Application Development