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The most difficult part of setting up MacGDBp is setting up the Xdebug extension. You cannot use the
built-in web server because that version of PHP will not properly execute Xdebug. Instead, the
easiest method is to download MAMP.
After installing Mamp, you have to install Xdebug.
- Download a compiled version of the Xdebug extension from Komodo. Select
either “Mac OS X / PowerPC” or “Mac OS X / x86” under “PHP Remote
- Copy the xdebug.so file from the folder that matches your MAMP PHP version to
- Open /Applications/MAMP/conf/php5/php.ini and add a semicolon (;) at the beginning of this line:
If you have Xdebug installed or you just installed it using the above steps, it is time to edit your
php.ini file to configure Xdebug.
Open up /Applications/MAMP/conf/php5/php.ini for editing in a text editor. Add these lines at the
top of the file:
zend_extension: This is the path to the xdebug.so extension file. The path to this file is
given as the last line of output from the installation process (see above).
remote_enable: Enables the remote debugging functionality.
remote_host: The address of your computer. If you are running a local web server,
“localhost” means the same machine as the web server. However, if you are debugging from a
hosting environment, this will be your IP address or hostname.
remote_port: The port to connect to. Set this to be the same as the port number in the
MacGDBp preferences. If you are using a remote_host other than “localhost,” make sure your
router will forward the port to your computer!
remote_autostart: This tells the server to try and connect to a debugger on every page load.
This is not recommended in production environments! With this setting enabled, every time that
MacGDBp is open, the server will connect to it and debug any PHP page.
For a list of more settings and deeper explanations, see
the Xdebug website.
To debug on a PHP installation that is running on a machine other than your local computer
(localhost), you will need to edit php.ini on the server. MacGDBp will merely listen for any
connection coming into your computer on port 9000. The Xdebug extension works by connecting
to the specified host and port in php.ini; if MacGDBp is running on the specified host, then the two
will connect. In order for this to work, particularly if your server is not on your local network,
you will need to have your home router forward all data coming in on port 9000 to your computer.
Make sure that your Mac’s firewall also allows this. See the above configuration section for more
Using Remote Paths
If you do not debug PHP scripts locally, but on a remote server, the file paths of your scripts will
likely be different. This means that setting breakpoints will not work as expeted; MacGDBp will tell
Xdebug (running on the remote server) to set a breakpoint for a file that’s on your local machine.
The only time this happens is when breakpoints are set; all other operations that involve source
code are done via Xdebug (including viewing source). To use breakpoints with a remote instance, you
will need to keep two copies of the source code: one on the remote server and one locally (or you
can mount the remote server). Then open MacGDBp –> Preferences –> Paths. The path
replacement system works by transforming a path on your local computer into the one on the remote
server. When you add a breakpoint path, it will replace all the “local paths” from the replacements
pane to create the remote path of the source code.
For example, if I were debugging a remote website where the local source was on my computer, this is
how I’d set it up:
- Local Path (OS X): /Users/robert/htdocs/mywebsite
- Remote Path (Linux web host): /home/hosting_company/public_html
Perpetually Disconnected Status or Socket Errors
The “could not bind to socket” error means that MacGDBp cannot bind to port 9000, which
means something else is already using that port. If you got this upon the first launch of MacGDBp,
check if another application is using this port. Also, check your firewall. If you had opened
MacGDBp and then this error happened, try closing and reopening the application, and restart if all
If you use PHP with FastCGI, many default configurations use port 9000 to communicate with the web
server (e.g., Apache). This will conflict with the default Xdebug port, so you should resolve the
conflict by changing one of the ports. The port that MacGDBp tries to connect to is set in