PHP's white screen of death

Question

Now that I'm starting to get back into PHP, I'm starting to remember why I gave it up in the first place. The most annoying thing on my plate at the moment is what I've come to term "PHP's white screen of death". When PHP gets a fatal error due to syntax or whatever, it seems like it will always die without actually sending anything to the browser. I've added the following to my .htaccess, and it seems to work most of the time, but it doesn't work in these cases.

php_value display_errors 1
php_value display_startup_errors 1
php_value error_reporting 2147483647 # E_ALL

Am I missing something? At the moment I feel like I need to hit refresh every few lines of code I write, lest I make a mistake and have to search through many pages trying to track down that one little mistake I made...

EDIT: For example, given the two lines of code below:

$foo = array(':language' => $languageId;
$foo = array(':language' => $languageId);

The first will exhibit the white screen of death (ie, nothing at all printed to the browser), while the second will execute happily.

Answer 1

Try catching exceptions and errors and logging them to a file.

Answer 2

Errors and warnings usually appear in ....\logs\php_error.log or ....\logs\apache_erroe.log depending on your php.ini settings.

Also useful errors are often directed to the browser, but as they are not valid html they are not displayed.

So "tail -f" your log files and when you get a blank screen use IEs "view" -> "source" menu options to view the raw output.

Answer 3

Try setting your error reporting level in your actual php files. Or, as others have suggested, check your server settings--it could be something in php.ini, or some restriction as regards your host. Don't just rely on .htaccess. Also, when troubleshooting, print_r any variables you might think fishy.

Answer 4

Are you sure PHP is actually picking up the 'display_errors' setting from .htaccess? Check the output of the phpinfo() function to make sure.

Also, you should check to make sure that you haven't used '@', it could be silencing your errors if you have used '@include ...' or '@some_function(...)', somewhere up the stack trace.

Answer 5

If every setting is proper did you use any set_error_handler() call?

The set_error_handler() function can make PHP to behave like this.

It can't handle fatal errors because they make the script stop immediatly.

Answer 6

are you using output buffering? sometimes php will not flush the buffer in case of an error and you only get a white screen

Answer 7

If the error is in PHP code, you can use error_reporting() function within your code to set to the report all.

However, this does not handle the situation when PHP crashes. Information about that is only available in server logs. Maybe you don't have access to those, but many hosting providers I've worked with have some way to let you access it. For example, the approach I like best is that it creates the error_log file in the current directory where .php resides. Try searching there or contact your hosting provider about this.

Answer 8

Some applications do handle these instructions themselves, by calling something like this:

error_reporting(E_ALL & ~E_DEPRECATED); or error_reporting(0);

And thus overriding your .htaccess settings.

Answer 9

I'm always using this syntax at the very top of the php script.

ini_set('error_reporting', E_ALL);
ini_set('display_errors', 'On');  //On or Off

Answer 10

Dunno if it will help, but here is a piece of my standard config file for php projects. I tend not to depend too much on the apache configs even on my own server.

I never have the disappearing error problem, so perhaps something here will give you an idea.

**Edited to show APPLICATON_LIVE **

/*
APPLICATION_LIVE will be used in process to tell if we are in a development or production environment.  It's generally set as early as possible (often the first code to run), before any config, url routing, etc.
*/

if ( preg_match( "%^(www.)?livedomain.com$%", $_SERVER["HTTP_HOST"]) ) {
    define('APPLICATION_LIVE', true);
} elseif ( preg_match( "%^(www.)?devdomain.net$%", $_SERVER["HTTP_HOST"]) ) {
    define('APPLICATION_LIVE', false);
} else {
    die("INVALID HOST REQUEST (".$_SERVER["HTTP_HOST"].")");
    // Log or take other appropriate action.
}


/*
--------------------------------------------------------------------
DEFAULT ERROR HANDLING
--------------------------------------------------------------------
Default error logging.  Some of these may be changed later based on APPLICATION_LIVE.
*/
error_reporting(E_ALL & ~E_STRICT);
ini_set ( "display_errors", "0");
ini_set ( "display_startup_errors", "0");
ini_set ( "log_errors", 1);
ini_set ( "log_errors_max_len", 0);
ini_set ( "error_log", APPLICATION_ROOT."logs/php_error_log.txt");
ini_set ( "display_errors", "0");
ini_set ( "display_startup_errors", "0");

if ( ! APPLICATION_LIVE ) {
    // A few changes to error handling for development.
    // We will want errors to be visible during development.
    ini_set ( "display_errors", "1");
    ini_set ( "display_startup_errors", "1");
    ini_set ( "html_errors", "1");
    ini_set ( "docref_root", "http://www.php.net/");
    ini_set ( "error_prepend_string", "<div style='color:red; font-family:verdana; border:1px solid red; padding:5px;'>");
    ini_set ( "error_append_string", "</div>");
}

Answer 11

using @inexistent_function_call(); in your code will cause the intepreter to quietly die and abort the script parsing. You should check for invalid functions and try not to use the error-supressing operator(the @ char )