php - Why is turning magic_quotes_gpc on considered a bad practice?

Question

Why is turning on magic_quotes_gpc in PHP considered a bad practice?

Answer 1

I don't think I can explain it any better than the makers of PHP itself (with followup comments on that page): Why not to use Magic Quotes

• Portability: Assuming it to be on, or off, affects portability. Use get_magic_quotes_gpc() to check for this, and code accordingly.
• Performance: Because not every piece of escaped data is inserted into a database, there is a performance loss for escaping all this data. Simply calling on the escaping functions (like addslashes()) at runtime is more efficient. Although php.ini-development enables these directives by default, php.ini-production disables it. This recommendation is mainly due to performance reasons.
• Inconvenience: Because not all data needs escaping, it's often annoying to see escaped data where it shouldn't be. For example, emailing from a form, and seeing a bunch of ' within the email. To fix, this may require excessive use of stripslashes().

Note - This feature has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.