Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Disable X-Powered-By and Server headers in Apache/PHP
Answer:
Add the following lines to the Apache configuration (httpd.conf)
Header always unset "X-Powered-By"
ServerTokens Prod
ServerSignature Off
Restart Apache to take effect
apachectl -k graceful
Assume the module mod_headers is enabled
Increase PHP memory limit
Answer:
If you experienced error such as "Fatal error: Allowed memory size of 16777216 bytes exhausted ", you would need to increase the memory limit of your PHP, by editing the php.ini
vi /etc/php.ini
Locate and set
memory_limit = 32M ;
Try it with the number you need.
Turn off PHP error messages?
Answer:
In a production server, you should always turn off PHP error messages to be displayed for public, to do so, edit the php.ini
E.g.
vi /etc/php.ini
And turn off display_errors
display_errors = Off
How to avoid SQL injection in PHP?
Answer:
The easiest method is to use the mysql_real_escape_string function
Example:
$query = sprintf("SELECT * FROM users WHERE user='%s' AND password='%s'",
mysql_real_escape_string($user),
mysql_real_escape_string($password));
Reference: http://php.net/manual/en/function.mysql-real-escape-string.php
Should I always use single-quotes for PHP strings?
Answer:
Some people say single-quotes string is faster than double-quotes string in PHP. But this have been rejected by the PHP's developer
Benchmarks run against PHP 5.2 and 5.3 show that parsing double-quoted
strings with interpolation is no slower (and often faster) than single-
quoted strings using concatenation. When simple strings with no
variables in them are used, the performance is clearly better with
double-quoted strings due to implementation details in the engine. See
the benchmark posted at . Reference: http://groups.google.com/group/make-the-web-faster/browse_thread/thread/ddfbe82dd80408cc?pli=1
