1. { Debugging PHP with Xdebug Stephanie Russell Zachary Klink

2.  Free and open source Swiss army knife for PHP developers.  Developed by Derick Rethans  Written in C  Initial release date: May 2, 2002  Stable Release: 2.1.2; July 28, 2011 Xdebug

3.  Stack and function traces in error messages  Full param display for user defined functions  Function name, file name and line number  Support for member functions  Memory allocation  Protection for infinite recursions  Profiling information for PHP scripts  Code coverage analysis  Debugger front-end to interactively debug Features

4.  DBG  FirePHP  Gubed  PHP_Debug  MacGDBp Competition

5.  Performance  Pause program execution  Usable with Eclipse, Netbeans, Notepad++, Chrome, Firefox, etc. Why Xdebug?

6. { Let’s dive a little deeper… How to Xdebug

7.  php.ini  When enabled, xdebug controls program execution.  As a server  GDB and DBGp  Remote control for PHP  Embedded into editor (no direct dealing with protocol itself) How to Xdebug

8.  Modes:  Default: req. Makes xdebug always connect to client when a script is started.  Second mode: jit. Only connect to the client on a breakpoint or error in script.  No setting in xdebug.remote_mode = default How to Xdebug

9.  Negatives  Potential install/configuration nightmare  Compatibility issues Drawbacks

10. { How it works! Internals

11.  With remote debugging, embedded Xdebug in PHP acts as a client, and the IDE acts as a server. Internals – single dev  The IP of the server is 10.0.1.2 with HTTP on port 80  The IDE is on IP 10.0.1.42, so xdebug.remote_host is set to 10.0.1.42 xdebug.remote_host  The IDE listens on port 9000, so xdebug.remote_port is set to 9000 xdebug.remote_port  The HTTP request is started on the machine running the IDE  Xdebug connects to 10.0.1.42:9000  Debugging runs, HTTP Response provided

12.  Setup is only slightly different: Internals – multiple dev  The IP of the server is 10.0.1.2 with HTTP on port 80  The IDE is on an unknown IP, so xdebug.remote_connect_back is set to 1 xdebug.remote_connect_back  The IDE listens on port 9000, so xdebug.remote_port is set to 9000 xdebug.remote_port  The HTTP request is made, Xdebug detects the IP address from the HTTP headers  Xdebug connects to the detected IP (10.0.1.42) on port 9000  Debugging runs, HTTP Response provided

13. Internals – Debug session  Tracks debug session through brower: cookies  URL variable XDEBUG_SESSION_START=name appended to URL  Xdebug emits cookie with name “XDEBUG_SESSION” with value “name.”  This expires in an hour.  DBGp protocol also passes this value to the init packet when connecting to debug client

14. Internals – Debug session  When there is a GET or POST, the cookie is set, xdebug connects to a debug client.  To stop debug session (and destroy the cookie), add URL parameter XDEBUG_SESSION_STOP.  Xdebug not longer tries to connect to debug client.

15. Internals – Multiple Users  Can specify one IP or multiple users  xdebug.remote_host or  If IP not known: xdebug.remote_connect_back

16. { Be sure to wear your helmet. Installation

17.  PHP 5  Apache2 First

18.  Apt-get  Compatibility with PHP release  Find installed xdebug.so  Edit php.ini file to add zend extension.  Remote host/port  Known IP (edit 09/22 or for multiple developers)  Port open Install

19.  Netbeans Tools > Options > PHP  Set debug port = remote_port Integrate with Netbeans

20. { Valiantly attempting to avoid Murphy’s law Demo

21. { Research is key to success Resources

22.  http://www.firephp.org/HQ/Use.htm http://www.firephp.org/HQ/Use.htm  http://sixrevisions.com/web-development/how- to-debug-php-using-firefox-with-firephp/ http://sixrevisions.com/web-development/how- to-debug-php-using-firefox-with-firephp/ http://sixrevisions.com/web-development/how- to-debug-php-using-firefox-with-firephp/  http://www.php-debugger.com/dbg/ http://www.php-debugger.com/dbg/  http://gubed.mccabe.nu/ http://gubed.mccabe.nu/  http://coding.smashingmagazine.com/2009/01/2 0/50-extremely-useful-php-tools/ http://coding.smashingmagazine.com/2009/01/2 0/50-extremely-useful-php-tools/ http://coding.smashingmagazine.com/2009/01/2 0/50-extremely-useful-php-tools/  http://www.bluestatic.org/software/macgdbp/ http://www.bluestatic.org/software/macgdbp/ Competition Resources

23.  http://xdebug.org/docs/remote http://xdebug.org/docs/remote  http://ubuntuforums.org/showthread.php?t=525257 http://ubuntuforums.org/showthread.php?t=525257  http://scottfaisal.com/installing-xdebug-on-ubuntu- 10-04/ http://scottfaisal.com/installing-xdebug-on-ubuntu- 10-04/ http://scottfaisal.com/installing-xdebug-on-ubuntu- 10-04/  http://2bits.com/articles/setting-up-xdebug-dbgp- for-php-on-debian-ubuntu.html http://2bits.com/articles/setting-up-xdebug-dbgp- for-php-on-debian-ubuntu.html http://2bits.com/articles/setting-up-xdebug-dbgp- for-php-on-debian-ubuntu.html  http://netbeans.org/kb/docs/php/configure-php- environment-ubuntu.html http://netbeans.org/kb/docs/php/configure-php- environment-ubuntu.html http://netbeans.org/kb/docs/php/configure-php- environment-ubuntu.html  http://wiki.netbeans.org/HowToConfigureXDebug http://wiki.netbeans.org/HowToConfigureXDebug  http://stackoverflow.com/questions/693074/how-to- debug-php-with-netbeans-and-xdebug http://stackoverflow.com/questions/693074/how-to- debug-php-with-netbeans-and-xdebug http://stackoverflow.com/questions/693074/how-to- debug-php-with-netbeans-and-xdebug  http://blogs.oracle.com/netbeansphp/entry/howto_c heck_xdebug_installation http://blogs.oracle.com/netbeansphp/entry/howto_c heck_xdebug_installation http://blogs.oracle.com/netbeansphp/entry/howto_c heck_xdebug_installation Installation Resources

24.  http://xdebug.org http://xdebug.org Everything Else Resources