Recipe 8.17 Using a Custom Error Handler
8.17.1 Problem
You want to create a
custom error handler that lets you
control how PHP reports errors.
8.17.2 Solution
To set up your own error function, use set_error_handler(
):
set_error_handler('pc_error_handler');
function pc_error_handler($errno, $error, $file, $line) {
$message = "[ERROR][$errno][$error][$file:$line]";
error_log($message);
}
8.17.3 Discussion
A custom error handling function can parse errors based on their type
and take the appropriate action. See Table 8-2 in
Recipe 8.16 for a list of error types.
Pass set_error_handler( ) the name of a function,
and PHP forwards all errors to that function. The error handling
function can take up to five parameters. The first parameter is the
error type, such as 8 for
E_NOTICE. The second is the message thrown by the
error, such as "Undefined variable:
html". The third and fourth arguments are the name
of the file and the line number in which PHP detected the error. The
final parameter is an array holding all the variables defined in the
current scope and their values.
For example, in this code $html is appended to
without first being assigned an initial value:
error_reporting(E_ALL);
set_error_handler('pc_error_handler');
function pc_error_handler($errno, $error, $file, $line, $context) {
$message = "[ERROR][$errno][$error][$file:$line]";
print "$message";
print_r($context);
}
$form = array('one','two');
foreach ($form as $line) {
$html .= "<b>$line</b>";
}
When the "Undefined variable" error
is generated, pc_error_handler(
) prints:
[ERROR][8][Undefined variable: html][err-all.php:16]
After the initial error message, pc_error_handler(
) also prints a large array containing all the globals,
environment, request, and session variables.
Errors labeled catchable in Table 8-2 can be
processed by the function registered using
set_error_handler( ). The others indicate such a
serious problem that they're not safe to be handled
by users and PHP must take care of them.
8.17.4 See Also
Recipe 8.16 lists the different error types;
documentation on set_error_handler( ) at
http://www.php.net/set-error-handler.
|
