Differences between stripslashes and addslashes in php

In php, we often use stripslashes and addslashes. next I will introduce the differences between stripslashes and addslashes in detail. The addslashes and addslashes () functions add a backslash before the specified predefined characters.

In php, we usually use stripslashes and addslashes. next I will introduce in detail the differences between stripslashes and addslashes.

Addslashes

The addslashes () function adds a backslash before the specified predefined character.

The predefined characters are:

• Single quotes (')

• Double quotation marks (")

• Backslash ()

• NULL

In this example, we want to add a backslash to the predefined characters in the string:

Note: When the command is on, the PHP command magic_quotes_gpc automatically runs addslashes () on all GET, POST, and COOKIE data (). do not use addslashes () for strings that have been escaped by magic_quotes_gpc, because this causes double-layer escape. in this case, you can use the get_magic_quotes_gpc () function for detection.

Instance code:

1. /**
2. * Determine whether to use addslashes () for processing
3. *
4. * @ Param String $ str
5. *
6. */
7. Function str_addslashes ($ str, $ db_type = 'mysql '){
8. If (get_magic_quotes_gpc ()){
9. Switch ($ db_type ){
10. Case "access ":
11. $ Str = stripslashes ($ str );
12. $ Str = str_replace ("'", "'' ", $ str );
13. Break;
14. }
15. } Else {
16. Switch ($ db_type ){
17. Case "mysql ":
18. $ Str = addslashes ($ str );
19. Break;
20. Case "access ":
21. $ Str = str_replace ("'", "'' ", $ str );
22. Break;
23. }
24. }
25. Return $ str;
26. }

Custom function str_addslashes description: If you do not know whether magic_quotes_gpc is enabled during the submission process, you can use this method. if you are on, the mysql database will not process it, however, the access database must be removed first, and then the single quotation marks must be replaced with double quotation marks. when it is off, add the mysql database

Stripslashes ()

The stripslashes () function deletes the backslash added by the addslashes () function.

Instance code:

1. // Submit data or prepare variables:
2. $ Content = addslashes ("This is data, no matter whether there are single quotes or variables ");
3. // Insert data to the database. the code is omitted.
4. // Start displaying data
5. $ Content = "data read from the database ";
6. If (get_magic_quotes_gpc ()){
7. $ Content = stripslashes ($ Content );
8. }
9. Echo $ Content;

Difference summary

When magic_quotes_gpc = On, data processed using addslashes () will be saved in the database as '. if the data is output directly at this time, the stripslashes () is displayed, which can be removed (different from str_replace ("," ", $ Str )).

When magic_quotes_gpc = Off, the data processed with addslashes () will be saved in the database in the form of '. there is no problem mentioned above, addslashes () it does not cause data insertion errors. if data is output directly at this time, the data is normal. no need to use stripslashes (). addslashes () and stripslashes () are the opposite. direct memory: add addslashes (), and remove stripslashes ().