dotancohen dotancohen - 2 years ago 62
PHP Question

Trace where code is coming from (PHP)

I'm going through a customer's server, running crazy proprietary forum
software (vBulletin) and even worse SEO mods (vbseo). I cannot figure
out where the php code for a page is coming from! How to trace this
URL back to a PHP page:
I just joined a project with the code based on a heavily modified vBullitin install with the VBSEO plugin. This particular plugin is horrific spaghetti code with tens of include()s, .htaccess redirects and possibly .httpd.conf changes. Then it pulls strings from a database so I cannot even use grep to find the code file!

Is there any way to stack-trace PHP to log all the code that runs to produce a page? I have root access but I am not supposed to stop or restart the server. A simple list of the include() hierarchy of files that went into producing the page would suffice.

Note that I cannot use debug_backtrace because I don't know where the code I'm looking for is! The debug_backtrace function is the exact opposite of what I need.


Answer Source

Sounds like you need to step through it with Xdebug. Most common IDE's support it such as Netbeans and PHPStorm.


In both the above mentioned IDE's, you can CTRL+Click a function/method and it will take you to the line in the file where it is defined. You can also track usages for both functions and variables.

Tracing code is built-in to xdebug. Here's an example from Zend:



  print fac(7);

  function fac($x)
    if (0 == $x) return 1;
    return $x * fac($x - 1);



Trace file output:

TRACE START [2007-10-26 12:18:48]
    0.0068      53384     -> fac() C:\www\fac.php:5
    0.0069      53584       -> fac() C:\www\fac.php:10
    0.0069      53840         -> fac() C:\www\fac.php:10
    0.0070      54096           -> fac() C:\www\fac.php:10
    0.0070      54376             -> fac() C:\www\fac.php:10
    0.0071      54656               -> fac() C:\www\fac.php:10
    0.0072      54936                 -> fac() C:\www\fac.php:10
    0.0072      55216                   -> fac() C:\www\fac.php:10
    0.0073      55392     -> xdebug_stop_trace() C:\www\fac.php:13
    0.0237      55392
TRACE END   [2007-10-26 12:18:48]
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