8.15.1 Problem
8.15.2 Solution
Set the following values in your php.ini or web server configuration file:
display_errors =off log_errors =on
These settings tell PHP not to display errors as HTML to the
browser but to put them in the server's error log.
8.15.3 Discussion
When log_errors is set to on, error messages are written to the server's error log. If you
want PHP errors to be written to a separate file, set the error_log
configuration directive with the name of that file:
error_log = /var/log/php.error.log
If error_log is set to syslog, PHP error
messages are sent to the system logger using syslog(3) on Unix and to the Event Log on
Windows NT.
There are lots of error messages you want to show your users,
such as telling them they've filled in a form incorrectly, but you should shield
your users from internal errors that may reflect a problem with your code. There
are two reasons for this. First, these errors appear unprofessional (to expert
users) and confusing (to novice users). If something goes wrong when saving form
input to a database, check the return code from the database query and display a
message to your users apologizing and asking them to come back later. Showing
them a cryptic error message straight from PHP doesn't inspire confidence in
your web site.
Second, displaying these errors to users is a security risk.
Depending on your database and the type of error, the error message may contain
information about how to log in to your database or server and how it is
structured. Malicious users can use this information to mount an attack on your
web site.
For example, if your database server is down, and you attempt
to connect to it with mysql_connect( ), PHP generates the following
warning:
<br> <b>Warning</b>: Can't connect to MySQL server on 'db.example.com' (111) in <b>/www/docroot/example.php</b> on line <b>3</b><br>
If this warning message is sent to a user's browser, he learns
that your database server is called db.example.com and can mount an attack on it.
