500 internal server error, how to debug

Question

I have internal server errors on my POST requests. How can I debug them ? Is it something to set up in php.ini ? THe file is really big and the word 'error' is met there many-many times.

Start from up to down and resolve with first error you encounter. — Rohit Awasthi, Mar 04 '14 at 11:39
Check the above link. It has almost all in it what you need. — Rikesh, Mar 04 '14 at 11:39
For me its not a PHP error, for some reasons its showing server error of 500. — Duke, Mar 23 '17 at 05:18

score 80 · Answer 1 · edited Sep 27 '18 at 17:57

80

You can turn on your PHP errors with error_reporting:

error_reporting(E_ALL);
ini_set('display_errors', 'on');

Edit: It's possible that even after putting this, errors still don't show up. This can be caused if there is a fatal error in the script. From PHP Runtime Configuration:

Although display_errors may be set at runtime (with ini_set()), it won't have any affect if the script has fatal errors. This is because the desired runtime action does not get executed.

You should set display_errors = 1 in your php.ini file and restart the server.

edited Sep 27 '18 at 17:57

Devon Bessemer

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answered Mar 04 '14 at 11:40

Philippe Signoret

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And I will see errors in the browser console, right ? I think I dont see them now, though i managed my php.ini file. – myadmins Mar 04 '14 at 11:50
1

You will see them in the browser itself, not in a console. – Philippe Signoret Mar 04 '14 at 11:51
What platform/stack are you using? (Windows/Linux? Apache/IIS?) – Philippe Signoret Mar 04 '14 at 11:51
I'm using linux + apache + firefox. No errors in the browser yet. Only error 500 in console. – myadmins Mar 04 '14 at 11:53
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Does a blank page also generate an error?: ` – Philippe Signoret Mar 04 '14 at 11:54
No, blank page is fine, as fine as some non-blank pages. – myadmins Mar 04 '14 at 11:57
Then you probably have an error in the script preventing runtime from even getting to these lines. You should update you `php.ini` file to include `display_errors = 1`, and restart the server. (Answer updated to show this.) – Philippe Signoret Mar 04 '14 at 12:04
OOPS I forgot to restart the server, guys, reaally thank you, topic is closed. PS I never expected to recieve so fast flash help. – myadmins Mar 04 '14 at 12:07
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If you cannot modify php.ini, just add this in a .htaccess file: `php_flag display_errors 1` – Tom Jan 16 '19 at 10:56

score 29 · Answer 2 · answered Mar 04 '14 at 11:39

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Try writing all the errors to a file.

error_reporting(-1); // reports all errors
ini_set("display_errors", "1"); // shows all errors
ini_set("log_errors", 1);
ini_set("error_log", "/tmp/php-error.log");

Something like that.

answered Mar 04 '14 at 11:39

James Elliott

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So I write this lines in my php scripts, at the top of them ? – myadmins Mar 04 '14 at 11:48
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@myadmins yes, before anything else. You could also set this in php.ini. – James Elliott Mar 04 '14 at 11:49

500 internal server error, how to debug

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