Enabling PHP Short Tags: A Step-by-Step Guide

Introduction

When developing web applications with PHP, you may encounter scenarios where using short tags (<? ?>) is more convenient than the full opening tag (<?php ?>). While both are syntactically valid in PHP, short tags require explicit enabling since they’re not enabled by default. This tutorial will guide you through the process of enabling PHP short tags on different server environments, ensuring your application remains consistent across platforms.

Understanding Short Tags

Short tags are a feature in PHP that allows for more concise code when embedding PHP into HTML. They serve as an alternative to the longer <?php ?> opening tag. The primary reason developers might prefer short tags is readability and brevity, especially in files with significant HTML content interspersed with PHP code.

Note on Compatibility

From PHP 5.4 onwards, the shorthand echo tag (<?= ?>) is always available regardless of whether short_open_tag is enabled or not. This means you can use <?= ... ?> to print data without requiring short tags to be enabled.

Enabling Short Tags in Different Server Setups

Method 1: Using PHP.INI Configuration File

The most direct way to enable short tags is by editing the php.ini file, which is the main configuration file for PHP. Here’s how you can do it:

Locate php.ini: The location of your php.ini file may vary depending on your server setup. You can find out where it’s located using:
```
php --ini
```
This command will display paths related to the configuration files PHP is using.
Edit php.ini:
- Open the specified php.ini file with a text editor.
- Search for the line that contains short_open_tag.
- Change it from Off to On.
Restart the Web Server: After saving changes, you need to restart your web server so that the new settings take effect.

For Apache:
```
service httpd restart
```
For Nginx (after PHP-FPM has been restarted):
```
sudo service nginx restart
```

Method 2: Using .htaccess for Shared Hosting

If you are on a shared hosting environment where direct access to php.ini is not available, you can try using an .htaccess file.

Create/Edit the .htaccess File: In your application’s root directory, create or edit the .htaccess file.
Add Configuration:
```
php_value short_open_tag 1
```
Note: This method may not work if your hosting provider has disabled php.ini settings in .htaccess.

Method 3: Using Command Line (Vagrant/Ubuntu)

For environments like Vagrant on Ubuntu, you can directly modify the configuration using command line:

sed -i "s/short_open_tag = .*/short_open_tag = On/" /etc/php5/apache2/php.ini

This command uses sed to find and replace the setting in place.

Method 4: PHP-FPM

If you are using PHP-FPM, make sure to restart it after modifying php.ini.

sudo service php-fpm restart

Restarting both PHP-FPM and your web server is necessary for changes to take effect.

Best Practices

Consistency: Ensure consistent use of tags throughout your application. If short tags are enabled, consider using them everywhere for uniformity.
Server Environment Awareness: Be aware that enabling short tags might not be possible in all environments due to security settings by hosting providers.
Future Compatibility: While short tags can enhance readability, always ensure your code remains maintainable and readable for others who may work on it without access to environment-specific configurations.

Conclusion

Enabling PHP short tags involves editing configuration files or using server-specific methods. By following the steps outlined in this guide, you can make your application’s deployment consistent across different environments, enhancing both portability and maintainability of your codebase.