Examples
Below we can see an example of using the error handling capabilities in
PHP. We define an error handling function which logs the information into
a file (using an XML format), and e-mails the developer in case a critical
error in the logic happens.
Example #1 Using error handling in a script
<?php // we will do our own error handling error_reporting(0);
// user defined error handling function function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars) { // timestamp for the error entry $dt = date("Y-m-d H:i:s (T)");
// define an assoc array of error string // in reality the only entries we should // consider are E_WARNING, E_NOTICE, E_USER_ERROR, // E_USER_WARNING and E_USER_NOTICE $errortype = array ( E_ERROR => 'Error', E_WARNING => 'Warning', E_PARSE => 'Parsing Error', E_NOTICE => 'Notice', E_CORE_ERROR => 'Core Error', E_CORE_WARNING => 'Core Warning', E_COMPILE_ERROR => 'Compile Error', E_COMPILE_WARNING => 'Compile Warning', E_USER_ERROR => 'User Error', E_USER_WARNING => 'User Warning', E_USER_NOTICE => 'User Notice', E_STRICT => 'Runtime Notice', E_RECOVERABLE_ERROR => 'Catchable Fatal Error' ); // set of errors for which a var trace will be saved $user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE); $err = "<errorentry>\n"; $err .= "\t<datetime>" . $dt . "</datetime>\n"; $err .= "\t<errornum>" . $errno . "</errornum>\n"; $err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n"; $err .= "\t<errormsg>" . $errmsg . "</errormsg>\n"; $err .= "\t<scriptname>" . $filename . "</scriptname>\n"; $err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";
if (in_array($errno, $user_errors)) { $err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n"; } $err .= "</errorentry>\n\n"; // for testing // echo $err;
// save to the error log, and e-mail me if there is a critical user error error_log($err, 3, "/usr/local/php4/error.log"); if ($errno == E_USER_ERROR) { mail("[email protected]", "Critical User Error", $err); } }
function distance($vect1, $vect2) { if (!is_array($vect1) || !is_array($vect2)) { trigger_error("Incorrect parameters, arrays expected", E_USER_ERROR); return NULL; }
if (count($vect1) != count($vect2)) { trigger_error("Vectors need to be of the same size", E_USER_ERROR); return NULL; }
for ($i=0; $i<count($vect1); $i++) { $c1 = $vect1[$i]; $c2 = $vect2[$i]; $d = 0.0; if (!is_numeric($c1)) { trigger_error("Coordinate $i in vector 1 is not a number, using zero", E_USER_WARNING); $c1 = 0.0; } if (!is_numeric($c2)) { trigger_error("Coordinate $i in vector 2 is not a number, using zero", E_USER_WARNING); $c2 = 0.0; } $d += $c2*$c2 - $c1*$c1; } return sqrt($d); }
$old_error_handler = set_error_handler("userErrorHandler");
// undefined constant, generates a warning $t = I_AM_NOT_DEFINED;
// define some "vectors" $a = array(2, 3, "foo"); $b = array(5.5, 4.3, -1.6); $c = array(1, -3);
// generate a user error $t1 = distance($c, $b) . "\n";
// generate another user error $t2 = distance($b, "i am not an array") . "\n";
// generate a warning $t3 = distance($a, $b) . "\n";
?>
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