-debugging,-and-reporting","Elefant has a default error handler setting that points to admin/error, but that you can alternately point to your own custom error handler. The handler must accept 3 data values: code, title, and message. Here's how to trigger an error in your other handlers:
<?php
// some logic
if (! $do->something ()) {
// trigger an error
echo $this->error (404, 'Page not found', 'How embarrassing, we could not find the page you wanted.');
return;
}
?>
Make sure to echo the output and return after, or the error message body will not be displayed. The above will display a 404 error message to the end user.
By default, we set the error_reporting level to E_ALL & ~E_NOTICE and turn display_errors off. This is ideal for production servers, but less so for development. You can enable debugging in the conf/config.php file and Elefant will display a detailed trace of errors including highlights of the relevant source code.
To enable debugging, change this line in conf/config.php:
; For development, turn debugging on and Elefant will output
; helpful information on errors.
debug = On
Now, any time there's an error or exception, Elefant will show helpful trace output of where the error occurred, including highlighting the relevant lines of code, and a trace of all data in the system at that time.
Similarly, you can change the display_errors setting in conf/config.php to enable PHP's display_errors setting:
; For development, turn display_errors on and Elefant will
; output fatal error messages in addition to the debugger.
display_errors = On
To trigger an error and see what your code is doing at any point, use trigger_error() like this:
<?php
$obj = new stdClass;
$obj->value = 'Some value';
if ($obj->value != 'Expected value') {
trigger_error ('Uh oh, something went wrong');
}
?>
This will print the following trace:
At the bottom of the context output, you'll find $obj described like this:
<?php
$obj = stdClass (
$value = ""Some value"";
);
?>
What I often do for debugging is leave the settings alone and instead have a command terminal open listening to the Apache error log for updates, like this:
$ tail -F /var/log/apache2/error_log
The -F switch will cause it to update the terminal window with any new errors as they're logged, so you can see them as they happen.
To log a custom error to the error log for debugging, use:
error_log ('Error message');
For much more customizable error reporting, including logging to FirePHP and other sources, see the Logging page."