Extension_dir explained: How to locate and use this essential PHP setting

PHP is a popular programming language used for web development. To extend its functionality, PHP provides various built-in modules that can be enabled or disabled as per the requirements. These modules are called extensions and are essential parts of PHP.

Extensions add new functionalities that can help developers to enhance their applications. For example, if you want to use image processing in your application, you can enable the 'gd' (graphics library) extension. Similarly, if you want to connect to a database, you can enable the 'mysql' or 'mysqli' extension.

One of the important settings that need to be configured while using PHP extensions is 'extension_dir'. In this article, we will discuss everything about the extension_dir setting, its importance, and how to locate and use it.

What is extension_dir?

Extension_dir is a PHP configuration setting that defines the directory path where all enabled extensions are stored. Whenever PHP needs to load an enabled extension, it looks for it in this directory. By default, this setting is not defined in the PHP configuration file and needs to be set manually.

Why is extension_dir important?

Extension_dir is an essential setting because it allows PHP to locate and load the required extensions during runtime. Without it, PHP won't be able to use any extensions, no matter if they are installed on the server or not.

How to locate extension_dir?

The location of extension_dir depends on the PHP version and the installation type. Here are some ways to locate extension_dir:

1. Using phpinfo()

The phpinfo() function displays detailed information about the PHP configuration, including the extension_dir setting. To use this method, create a new PHP file and add the following code:

```

phpinfo();

?>

```

Save the file as info.php and put it in your web server's document root folder. Then, open your web browser and access the file by typing the URL 'http://localhost/info.php'. This will display the PHP information page, where you can find the extension_dir setting.

2. Checking PHP configuration file

Another way to locate extension_dir is by checking the PHP configuration file. The location of the file may vary depending on the server configuration. To find out the location of the file, you can use the following command in the terminal:

```

php --ini

```

This will display the location of the PHP configuration file. Open the file in a text editor and search for the 'extension_dir' setting.

How to set extension_dir?

Once you have located the extension_dir setting, you can modify it as per your requirements. Here are the steps to set extension_dir:

1. Open the php.ini file

To modify the extension_dir setting, you need to open the PHP configuration file, which is usually named as 'php.ini'. You can use the following command in the terminal to open the file:

```

sudo nano /etc/php/version_number/apache2/php.ini

```

Replace 'version_number' with the PHP version installed on your server.

2. Modify the extension_dir setting

Search for the 'extension_dir' setting in the file and modify it as required. Make sure to uncomment the line by removing the semicolon (;) at the beginning of the line.

For example, if you want to set the extension_dir to '/usr/lib/php/20190902/', modify the line as follows:

```

extension_dir = "/usr/lib/php/20190902/"

```

3. Save and close the file

Once you have modified the line, save the file and exit the editor.

4. Restart the web server

To apply the changes, you need to restart the web server. You can use the following command to restart the Apache web server:

```

sudo service apache2 restart

```

Conclusion

In this article, we discussed one of the essential PHP settings, the extension_dir setting. We learned why it is important, how to locate it, and how to modify it as per our requirements. By properly configuring the extension_dir setting, we can ensure that PHP can locate and use the required extensions, improving the functionality of our applications.