How to handle PHP MAGIC_QUOTES_GPC correctly

Most PHP programs have this logic:

PHP automatically adds an escape slash for GPC if it finds that PHP.ini is configured to not automatically add an escape slash to the GPC variable

But in fact, this is wrong, because it changes the value of the GPC variable original.

The reason for this legacy is that PHP programs often work with MySQL, while MySQL escapes special characters by adding escape slashes, but other data such as mssql,oci are not necessarily the case.

If you are using a different type of database, such as mssql,oci,sybase, then adding an escape slash to the GPC is a mistake.

Further, if the GPC data does not need to be stored in the database and saved to the file system, or forwarded to other programs? is a very serious error logic.

So, the right thing to do is:
1.PHP Program Entry Remove escape slash (if PHP.ini is configured to automatically add escape slash)
2. When writing to MySQL, use mysql_real_escape_string instead of addcslashes to escape the variable
Because the former is more secure than the latter (character set-related)

This issue has been taken into account in the DB class, see db_mysql.class.php for details, searching for mysql_real_escape_string

There are currently the following cases:
The php.ini of the Point mall is configured to automatically add escape slashes, and when user-submitted data is written to the cookie, the slash must be removed in time
Discuz 6.0 of the forum, the special user name "頫" after addcslashes processing, unexpectedly become "頫 \", followed by a slash, which is Discuz 6 a bug.

So, to summarize:
1. For system administrators, you should configure the php.ini
Magic_quotes_gpc=off
Magic_quotes_runtime=off
Magic_quotes_sybase=off

For PHP developers, more accurate logic:

1. Check if the PHP environment is configured to automatically add escape slashes, if so, call stripslashes to remove $_request, $_get,$_post,$_cookie escape slash

2. When querying/writing/modifying data to MySQL, use mysql_real_escape_string to escape.

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