Diese Seite bei php.net
The PHP manual text and comments are covered by the Creative Commons Attribution 3.0 License © the PHP Documentation Group - Impressum - mail("TO:Reinhard Neidl",...)
(PHP 5)
debug_print_backtrace — Druckt die Daten für eine Ablaufverfolgung
debug_print_backtrace() gibt eine PHP Ablaufverfolgung aus. Diese enthält Ausgaben zu allen Funktionsaufrufen, mit include() oder require() eingebundenen Dateien und mit eval() ausgeführtem Kode.
Diese Funktion hat keine Parameter.
Es wird kein Wert zurückgegeben.
Beispiel #1 debug_print_backtrace() Beispiel
<?php
// include.php Datei
function a() {
b();
}
function b() {
c();
}
function c(){
debug_print_backtrace();
}
a();
?>
<?php
// test.php Datei
// Dies ist die Datei die Sie ausführen sollten
include 'include.php';
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
#0 eval() called at [/tmp/include.php:5] #1 a() called at [/tmp/include.php:17] #2 include(/tmp/include.php) called at [/tmp/test.php:3] #0 c() called at [/tmp/include.php:10] #1 b() called at [/tmp/include.php:6] #2 a() called at [/tmp/include.php:17] #3 include(/tmp/include.php) called at [/tmp/test.php:3]
Here's a function that returns a string with the same information shown in debug_print_backtrace(), with the option to exclude a certain amount of traces (by altering the $traces_to_ignore argument).
I've done a couple of tests to ensure that it prints exactly the same information, but I might have missed something.
This solution is a nice workaround to get the debug_print_backtrace() information if you're already using ob_start() in your PHP code.
<?php
function get_debug_print_backtrace($traces_to_ignore = 1){
$traces = debug_backtrace();
$ret = array();
foreach($traces as $i => $call){
if ($i < $traces_to_ignore ) {
continue;
}
$object = '';
if (isset($call['class'])) {
$object = $call['class'].$call['type'];
if (is_array($call['args'])) {
foreach ($call['args'] as &$arg) {
get_arg($arg);
}
}
}
$ret[] = '#'.str_pad($i - $traces_to_ignore, 3, ' ')
.$object.$call['function'].'('.implode(', ', $call['args'])
.') called at ['.$call['file'].':'.$call['line'].']';
}
return implode("\n",$ret);
}
function get_arg(&$arg) {
if (is_object($arg)) {
$arr = (array)$arg;
$args = array();
foreach($arr as $key => $value) {
if (strpos($key, chr(0)) !== false) {
$key = ''; // Private variable found
}
$args[] = '['.$key.'] => '.get_arg($value);
}
$arg = get_class($arg) . ' Object ('.implode(',', $args).')';
}
}
?>
Another way to manipulate and print a backtrace, without using output buffering:
<?php
// print backtrace, getting rid of repeated absolute path on each file
$e = new Exception();
print_r(str_replace('/path/to/code/', '', $e->getTraceAsString()));
?>
I was using the function by dany dot dylan at gmail dot com and found that preg_replace had string length limits. So here is yet another output format function.
<?php
if ( !function_exists ( "mydie" ) ) {
function mydie ( ) { $this_file = __FILE__ ; $this_line = __LINE__ ;
$buffer = array ( ) ;
$trace_calls = "" ;
ob_start ( ) ;
debug_print_backtrace ( ) ;
$buffer[ "0" ] = ob_get_contents ( ) ;
ob_end_clean ( ) ;
$buffer[ "0" ] = array_slice ( explode ( "#" , $buffer[ "0" ] ) , 1 , -1 , false ) ;
foreach ( $buffer[ "0" ] as $key => $value ) {
$value = explode ( ") called at [" , $value ) ;
if ( $key == 0 ) {
$value[ "0" ] = "0 " . __FUNCTION__ . "(see above vars)" ;
}
$trace_calls .= "#" . implode ( ")\n\tcalled at [" , $value ) ;
}
unset ( $buffer , $key , $value ) ;
echo "<pre>function " . __FUNCTION__ . " lives here:{$this_file}:{$this_line}</pre>" ;
echo ( "<pre>" . print_r( func_get_args ( ) , true ) . "</pre>" ) ;
if ( $trace_calls == "" ) $trace_calls = "No functions were called." ;
echo ( "<pre>" . $trace_calls . "</pre>" ) ;
die ;
}
}
function a ( ) {
b ( func_get_args ( ) , 2 ) ;
}
function b ( ) {
c ( func_get_args ( ) , 3 ) ;
}
function c ( ) {
mydie ( func_get_args ( ) , 4 ) ;
}
a ( 1 ) ;
?>
## outputs
function mydie lives here:/path/file.php:4
Array
(
[0] => Array
(
[0] => Array
(
[0] => Array
(
[0] => 1
)
[1] => 2
)
[1] => 3
)
[1] => 4
)
#0 mydie(see above vars))
called at [/path/file.php:54]
#1 c(Array ([0] => Array ([0] => 1),[1] => 2), 3)
called at [/path/file.php:49]
#2 b(Array ([0] => 1), 2)
called at [/path/file.php:43]
I like the output of debug_print_backtrace() but I sometimes want it as a string.
bortuzar's solution to use output buffering is great, but I'd like to factorize that into a function. Doing that however always results in whatever function name I use appearing at the top of the stack which is redundant.
Below is my noddy (simple) solution. If you don't care for renumbering the call stack, omit the second preg_replace().
<?php
function debug_string_backtrace() {
ob_start();
debug_print_backtrace();
$trace = ob_get_contents();
ob_end_clean();
// Remove first item from backtrace as it's this function which
// is redundant.
$trace = preg_replace ('/^#0\s+' . __FUNCTION__ . "[^\n]*\n/", '', $trace, 1);
// Renumber backtrace items.
$trace = preg_replace ('/^#(\d+)/me', '\'#\' . ($1 - 1)', $trace);
return $trace;
}
?>
Input (Using: PHP Version 5.2.5-pl1-gentoo):
<?php
class CTest
{
public static function say($a_szVar)
{
debug_print_backtrace();
echo '<br />';
}
}
CTest::say('static call');
$obj = new CTest;
$obj->say('object call');
?>
Output:
#0 CTest::say(static call) called at [C:\PHPDocument4.php:11]
#0 CTest::say(object call) called at [C:\PHPDocument4.php:15]
Notice that the second line of the output outputs "::" instead of "->" when calling the function using an object.
bortuzar: a simpler version, w/o output buffering:
<?php
$query = sprintf("INSERT INTO EventLog (Trace) VALUES ('%s')",
mysql_real_escape_string(join("\n", debug_backtrace())) );
mysql_query($query);
?>
If you want to get the trace into a variable or DB, I suggest to do the following:
<?php
ob_start();
debug_print_backtrace();
$trace = ob_get_contents();
ob_end_clean();
$query = sprintf("INSERT INTO EventLog (Trace) VALUES ('%s')",
mysql_real_escape_string($trace));
mysql_query($query);
?>
A cleaner example:
<?php
function a() {
b();
}
function b() {
c();
}
function c(){
debug_print_backtrace();
}
a();
?>
outputs:
#0 c() called at [C:\debugbacktracetest.php:7]
#1 b() called at [C:\debugbacktracetest.php:3]
#2 a() called at [C:\debugbacktracetest.php:14]
This functionality is now implemented in the PEAR package PHP_Compat.
More information about using this function without upgrading your version of PHP can be found on the below link:
http://pear.php.net/package/PHP_Compat
Diese Seite bei php.net