How to Fix PHP Errors That Affect More Your Applications By Giving Priority to the Most Important Bugs

To find the most frequent errors, you need to process the lines of the PHP error log and count how many times the same error appears in the record, pointing to the same line of the PHP source code causing the PHP errors.

3. How to Find the Most Frequent PHP Errors

You can process the PHP errors at run time using the PHP set_error_handler function, but that is not advisable because you may need to handle too many errors, which may slow down your PHP application.

It is better to configure PHP to send the PHP error logs to an error log file. This way, you can process the error logs with a separate script or application on a computer that is not the same as running PHP. You can achieve this by setting the error_log option in the php.ini configuration file like this:

error_log = logs/php-errors.log

Then you can develop a parser for the php-errors.log file that will extract the PHP error log lines and parses them to extract the source code file name and the line number of each error found in the log file.

Here is an example of PHP code that can parse a line of a PHP error log to extract the source file name and line number.

<?php
	$error_log_line = 'PHP Warning:  Use of undefined constant sdfsdf - assumed \'sdfsdf\' (this wil throw an Error in a future version of PHP) in /home/mlemos/garbage/x.php on line 3';
	if(preg_match('/([^ ]+) on line ([0-9]+)/', $error_log_line, $m))
	{
		print_r($m);
	}

If you run the example code above, it will output this:

Array
(
    [0] => /home/mlemos/garbage/x.php on line 3
    [1] => /home/mlemos/garbage/x.php
    [2] => 3
)

As you may see, the code creates an array with the name of the PHP source file and the line number of the code that caused the error.

A complete error log processing script would be more elaborated. It would also traverse all error log file lines and count the number of times an error happened in the same line of the source code file.

I will leave that part for you as an exercise to keep this article brief.

4. How to Find the Most Frequent PHP Errors Faster

As you may understand by now, creating a basic script to process errors to find the most frequent errors to fix first may not be so simple.

Fortunately, there are several PHP error monitoring solutions available in the market that you can use, so you do not have to developer your key.

For instance, you can use a tool like Scout Application Monitoring to monitor the errors of PHP applications and show excellent charts that help you figure out the most frequent mistakes you should fix.

Below is an example screenshot of the Scout APM tool showing a report of recent errors in an application sorted by frequency.

Maybe in the future, I will write more about Demo of Scout in PHP. For now, I invite you to watch this video of a Scout Application Monitoring. By watching this video, you can learn to monitor the errors of PHP applications and sort the errors to find the most frequent mistakes.

Then you can also try this tool for free during a trial period so you can use it in simple PHP applications you developed.