Question

I’m trying to read a file when ever an error occurs within my scripts so I can throw a custom error page.

When using ob_start/set_error_handler I am unable to use file_get_contents or ob_start within the callback to get the contents of my error template.

Does anyone know how I can output my custom template (and using eval) within the callback?

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Edit: Some code

error_reporting(E_ALL);
ini_set("display_errors", 1); 

function fatal_error_handler($buffer) {
  if (ereg("(error</b>:)(.+)(<br)", $buffer, $regs) ) {
    $ErrorString = preg_replace("/<.*?>/","",$regs[2]);
    error_log($ErrorString);

    $template = file_get_contents(sprintf('%s/errors/Error.php', TEMPLATES));
    return eval(sprintf('?>%s<?', $template);
    //return "ERROR CAUGHT check log file";
  }
  return $buffer;
}

function handle_error ($errno, $errstr, $errfile, $errline)
{
    error_log("$errstr in $errfile on line $errline");
    if($errno == FATAL || $errno == ERROR){
        ob_end_flush();
        echo "ERROR CAUGHT check log file";
        exit(0);
    }
}

ob_start("fatal_error_handler");
set_error_handler("handle_error");

The above just displays an empty page.

error_reporting(E_ALL);
ini_set("display_errors", 1); 

function fatal_error_handler($buffer) {
  if (ereg("(error</b>:)(.+)(<br)", $buffer, $regs) ) {
    $ErrorString = preg_replace("/<.*?>/","",$regs[2]);
    error_log($ErrorString);

    ob_start();
    include(sprintf('%s/errors/Error.php', TEMPLATES));
    $template = ob_get_contents();
    ob_end_clean();
    return eval(sprintf('?>%s<?', $template));
    //return "ERROR CAUGHT check log file";
  }
  return $buffer;
}

function handle_error ($errno, $errstr, $errfile, $errline)
{
    error_log("$errstr in $errfile on line $errline");
    if($errno == FATAL || $errno == ERROR){
        ob_end_flush();
        echo "ERROR CAUGHT check log file";
        exit(0);
    }
}

ob_start("fatal_error_handler");
set_error_handler("handle_error");

and the above gives the following:

Fatal error: ob_start() [<a href='ref.outcontrol'>ref.outcontrol</a>]: Cannot use output buffering in output buffering display handlers in /var/www/index.php on line 16

Answer 1

You have to :

• know that file_get_contents returns false when it encounters an error.
  • which means you can test its return value,
  • and if it returned false, you can display your template
• also be careful : when there’s a problem, it generates an error, and you don’t want that one displayed
  • this is the kind of situation for which you can use the @ operator,
  • to “mask” the error — you test if it returned false, anyway

It would give that kind of code :

$result = @file_get_contents('non-existing-file');
if ($result === false) {
    echo "An error has occured";
}

Which, in my case, displays :

An error has occured

Now, up to you to display your error template, depending on the Framework you might be using and all that 😉