Debugging in PHP can be tedious and prone to error when using var_dump and echo statements. Learn how to debug more effectively and get better insight into an application by using Xdebug. See how to setup PHPStorm, Xdebug, and the browser to enable debugging that will let you step into code and see variable values live. Extend those debugging capabilities into REST and SOAP clients to increase the code that can be debugged with ease.

1. D E B U G G I N G P H P W I T H
X D E B U G
M A R K N I E B E R G A L L
https://joind.in/talk/14128

2. A B O U T M A R K N I E B E R G A L L
• PHP since 2005
• Masters degree in MIS
• Senior Software Engineer
• Team Lead
• Drug screening project
• President of Utah PHP User Group (UPHPU)
• SSCP, CSSLP Certified and SME for (ISC)2
• PHP, databases, JavaScript
• Drones, fishing, skiing, father, husband

3. A B O U T M A R K N I E B E R G A L L

4. D E B U G G I N G P H P W I T H X D E B U G
UPHPU
• Third Thursday of each month at 7pm
• Venue is Vivint in Lehi (3401 Ashton Blvd)
• Variety of PHP related topics
• Mostly local speakers, occasional traveling speaker
• Networking with other developers, companies
• Professional development
• uphpu.org

5. D E B U G G I N G P H P W I T H
D E B U G

6. D E B U G G I N G P H P W I T H X D E B U G
Overview
• What is Xdebug
• Why use Xdebug
• Setting up Xdebug
• Using Xdebug

7. W H AT I S X D E B U G

8. W H AT I S X D E B U G

9. W H AT I S X D E B U G
Xdebug
• Available since 2002
• Developed initially by Derick Rethans
• PHP extension
• Written in C
• Open source
• Used for debugging and profiling
• Uses DeBugGer Protocol (DBGp) for communication

10. W H Y U S E X D E B U G

11. W H Y U S E X D E B U G
Debugging without Xdebug

12. W H Y U S E X D E B U G
Debugging without Xdebug
• echo $something;
• var_dump($other);
• print_r($data);
• error_log(__FILE__ . ‘ line ‘ . __LINE__);

13. W H Y U S E X D E B U G
Debugging without Xdebug
• Add outputs
• Load page
• Look for output
• Change some code
• Add more outputs
• Repeat
• Cleanup outputs without missing any
• Load page

14. W H Y U S E X D E B U G
Debugging with Xdebug

15. W H Y U S E X D E B U G
Debugging with Xdebug
• Add breakpoint(s)
• Load page
• Step into the code

16. W H Y U S E X D E B U G
Debugging with Xdebug
• Live values
• Follow actual code path
• Full stacktrace

17. W H Y U S E X D E B U G
Debugging with Xdebug
• Supported by most IDEs
• Faster development time
• Better understanding of what code is actually doing
• Does not require code changes to interrogate values

18. S E T T I N G U P X D E B U G

19. S E T T I N G U P X D E B U G
Fire up you development environment

20. S E T T I N G U P X D E B U G
Documentation from JetBrain for PhpStorm
https://confluence.jetbrains.com/display/PhpStorm/Zero-configuration+Web
+Application+Debugging+with+Xdebug+and+PhpStorm
1. Install Xdebug
2. Prepare PhpStorm
3. Set a breakpoint in the source code
4. Activate debugger on server
5. Start a debug session in browser
6. Reload the current page
7. Set initial path mappings

21. S E T T I N G U P X D E B U G
1. Install Xdebug

22. S E T T I N G U P X D E B U G
1. Install Xdebug
• https://xdebug.org/docs/install

23. S E T T I N G U P X D E B U G
1. Install Xdebug
• Download (if applicable)
• Install or compile
• Configure PHP
• Restart webserver

24. S E T T I N G U P X D E B U G
1. Install Xdebug
• Windows:
- Xdebug website has a wizard, dll downloads
• Mac:
- sudo pecl install xdebug
- brew install php70-xdebug
• Linux:
- wget http://xdebug.org/files/xdebug-2.4.0.tgz
- sudo pecl install xdebug

25. S E T T I N G U P X D E B U G
1. Install Xdebug
• Windows: download dll
- Xdebug website has a wizard, downloads
- Paste php -i or phpinfo() (ex: C:phpphp -i > C:
phpphpinfo.txt or <?php phpinfo();)
- dll download link provided
- Add a line to your php.ini file
- Restart webserver

26. S E T T I N G U P X D E B U G
1. Install Xdebug
• apt-get install php5-xdebug
• wget http://xdebug.org/files/xdebug-2.4.0.tgz
tar -xzvf xdebug-2.4.0.tgz
cd xdebug-2.4.0
phpize
./configure --enable-xdebug
make
make install

27. S E T T I N G U P X D E B U G
1. Install Xdebug
• yum install php-devel
yum install php-pear
pecl install xdebug
• dnf install php-devel
dnf install php-pear
pecl install xdebug

28. S E T T I N G U P X D E B U G
1. Install Xdebug
• Update php.ini by adding lines:
zend_extension = php_xdebug-2.4.0-5.5-vc11.dll
[xdebug]
xdebug.remote_enable = 1
xdebug.remote_port = 9000
xdebug.remote_host = localhost
xdebug.idekey = PHPSTORM

29. S E T T I N G U P X D E B U G
1. Install Xdebug
• Update php.ini by adding lines:
zend_extension = /usr/lib64/php/modules/xdebug.so
[xdebug]
xdebug.remote_enable = 1
xdebug.remote_port = 9000
xdebug.remote_host = localhost
xdebug.idekey = PHPSTORM

30. S E T T I N G U P X D E B U G
1. Install Xdebug
• Restart webserver
- Windows:
Services
Apache Monitor
- Linux:
sudo apachectl restart
sudo service nginx restart

31. S E T T I N G U P X D E B U G
1. Install Xdebug
• Verify via phpinfo
- <?php phpinfo();
- php -i | grep xdebug

32. S E T T I N G U P X D E B U G
1. Install Xdebug
• Verify via phpinfo

33. S E T T I N G U P X D E B U G
2. Prepare PhpStorm

34. S E T T I N G U P X D E B U G
2. Prepare PhpStorm
• Start Listening for PHP Debug Connections

35. S E T T I N G U P X D E B U G
2. Prepare PhpStorm

36. S E T T I N G U P X D E B U G
2. Prepare PhpStorm

37. S E T T I N G U P X D E B U G
2. Prepare PhpStorm
• Setup debug settings

39. S E T T I N G U P X D E B U G
2. Prepare PhpStorm
• Setup project path mapping

40. S E T T I N G U P X D E B U G
2. Prepare PhpStorm

41. S E T T I N G U P X D E B U G
3. Set a breakpoint in the source code

42. S E T T I N G U P X D E B U G
3. Set a breakpoint in the source code
• Line you know will be hit
• Or break on first line

44. S E T T I N G U P X D E B U G
4. Activate debugger on server

45. S E T T I N G U P X D E B U G
4. Activate debugger on server
• Browser plugin, add-on
- The easiest Xdebug (Firefox)
- Xdebug Helper (Chrome)
- Xdebug Toggler (Safari)
- Xdebug launcher (Opera)

46. S E T T I N G U P X D E B U G
4. Activate debugger on server

47. S E T T I N G U P X D E B U G
4. Activate debugger on server

48. S E T T I N G U P X D E B U G
4. Activate debugger on server
• URL
- GET: &XDEBUG_SESSION_START=PHPSTORM
- POST: XDEBUG_SESSION_START=PHPSTORM
• Headers
- Name: Cookie
- Value: XDEBUG_SESSION=PHPSTORM
• Bookmarklet

49. S E T T I N G U P X D E B U G
4. Activate debugger on server

50. S E T T I N G U P X D E B U G
4. Activate debugger on server

51. S E T T I N G U P X D E B U G
4. Activate debugger on server

52. S E T T I N G U P X D E B U G
4. Activate debugger on server

53. S E T T I N G U P X D E B U G
4. Activate debugger on server

54. S E T T I N G U P X D E B U G
4. Activate debugger on server

55. S E T T I N G U P X D E B U G
4. Activate debugger on server

56. S E T T I N G U P X D E B U G
5. Start a debug session in browser

57. S E T T I N G U P X D E B U G
5. Start a debug session in browser
• Click the debug button in toolbar
• Add GET, POST, or COOKIE

58. S E T T I N G U P X D E B U G
6. Reload the current page

59. S E T T I N G U P X D E B U G
6. Reload the current page

60. S E T T I N G U P X D E B U G
7. Set initial path mappings

61. S E T T I N G U P X D E B U G
7. Set initial path mappings

62. U S I N G X D E B U G

63. U S I N G X D E B U G

64. U S I N G X D E B U G
• Breakpoints
• Stepping through code
• Watches
• Console

65. U S I N G X D E B U G

66. U S I N G X D E B U G
Breakpoints
• Pause code execution at specific line
• Allowed multiple breakpoints
• Conditional breakpoints

67. U S I N G X D E B U G
Breakpoints
• Place strategically
• Not too early
• Not too late
• Not too many
• Remember time limit, increase if needed
• Use conditional breakpoints in loops

68. U S I N G X D E B U G
Breakpoints

69. U S I N G X D E B U G
Breakpoints

70. U S I N G X D E B U G
Stepping through code

71. U S I N G X D E B U G
Stepping through code
• Resume Program (Play)
• Stop
• View Breakpoints
• Disable All Breakpoints

72. U S I N G X D E B U G
Stepping through code
• Step Over
• Step Into
• Force Step Into
• Step Out
• Run to Cursor

73. U S I N G X D E B U G
Stepping through code
• Evaluate Expression
• Show value addresses
• Hide empty superglobal variables (on by default)
• Add method to skip list

74. U S I N G X D E B U G
Watches

75. U S I N G X D E B U G
Watches
• Live updates
• Values
• Expressions

76. U S I N G X D E B U G
Console

77. U S I N G X D E B U G
Console
• Output from debugging expressions
• Enter expressions to be evaluated

78. S U M M A RY

79. S U M M A RY
• More efficient way to debug
• Visibility into code
• Ability to change code on the fly
• Watch values change line by line
• Better understanding of code path

80. Q U E S T I O N S ?
https://joind.in/talk/14128

81. S O U R C E S
• JetBrains documentation https://confluence.jetbrains.com/display/PhpStorm/Zero-
configuration+Web+Application+Debugging+with+Xdebug+and+PhpStorm
• Xdebug documentation https://xdebug.org/docs/install
• David Stockton, php[architect], January 2015, https://www.phparch.com/wp-
content/uploads/2015/01/levelup-xdebug-phparchitect-jan2015.pdf