Essential Books

File Directory Constants

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Current file

You can get the name of the current PHP file (with the absolute path) using the __FILE__ magic constant. This is most often used as a logging/debugging technique. 

echo "We are in the file:" , __FILE__ , "\n";

Current directory

To get the absolute path to the directory where the current file is located use the __DIR__ magic constant. 

echo "Our script is located in the:" , __DIR__ , "\n";

To get the absolute path to the directory where the current file is located, use dirname(__FILE__). 

echo "Our script is located in the:" , dirname(__FILE__) , "\n";

Getting current directory is often used by PHP frameworks to set a base directory: 

// index.php of the framework

define(BASEDIR, __DIR__); // using magic constant to define normal constant

—``` // somefile.php looks for views:

$view = ‘page’; $viewFile = BASEDIR . ‘/views/’ . $view; 

# Separators

> Windows system perfectly understands the `/` in paths so the
> `DIRECTORY_SEPARATOR` is used mainly when parsing paths.

Besides magic constants PHP also adds some fixed constants for working with paths:

* `DIRECTORY_SEPARATOR` constant for separating directories in a path. Takes value  `/` on \*nix, and `\\` on Windows.
The example with views can be rewritten with:

$view = ‘page’; $viewFile = BASEDIR . DIRECTORY_SEPARATOR .’views’ . DIRECTORY_SEPARATOR . $view; ```

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Magic constants:
* Magic Constants
* Difference between FUNCTION and METHOD
* Difference between CLASS get class and get called class
* File Directory Constants
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