Detailed explanation of PHP escape usage_PHP tutorial-PHP Tutorial-php.cn

Detailed explanation of PHP escape usage_PHP tutorial

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Release： 2016-07-21 15:00:40

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Magic reference function for data in php magic_quotes_gpc or magic_quotes_runtime

When set to on, backslashes are automatically added when the data we quote encounters single quotes ', double quotes " and backslashes, helping us automatically translate symbols and ensure the correct operation of data operations
Two The difference between:

magic_quotes_gpc
Scope is: WEB client server;
Action time: The request starts, for example when the script is running.

magic_quotes_runtime
Scope: data read from a file or the result of executing exec() or obtained from a SQL query;
Time of action: every time when the script is accessed Data generated during operation.

It can be seen that the setting value of
magic_quotes_gpc will affect the data obtained through Get/Post/Cookies
The setting value of magic_quotes_runtime will affect the data read from the file Or data obtained from database query

Several functions that you want to associate:
set_magic_quotes_runtime():
Set the magic_quotes_runtime value. 0=off. 1=on. The default state is off. You can view magic_quotes_runtime through echo phpinfo();
get_magic_quotes_gpc():
View magic_quotes_gpc value.0=off.1=on
get_magic_quotes_runtime():
View magic_quotes_runtime value. 0=off. 1=on.
Note that there is no set_magic_quotes_gpc() function, that is, the value of magic_quotes_gpc cannot be set in the program.

Due to the setting problem of the two values, it will cause some confusion during programming or add an extra escape. In this case, it is necessary to set and judge at the beginning of the program, or configure the two by default
The values are all off. The escaping part is performed programmatically.

To ensure that data is inserted normally, addslashes is usually used to process it. When reading data, stripslashes is often used to remove added backslashes

Similar character conversion functions in php
addslashes Adds a backslash before the specified predefined characters backslash
htmlspecialchars Convert some predefined characters to HTML entities
htmlspecialchars_decode Convert some predefined HTML entities to characters
html_entity_decode() Convert HTML entities to characters
htmlentities() Convert characters to HTML Entity