Scripting Sunny Side Up

I ran into an interesting problem with PHP on my Mac today.  I have been dealing with this issue for a while where connecting to MySQL with PHP only seems to work if I use 127.0.0.1 as the hostname and not if use localhost.  If I use localhost I was getting this errror:

Warning: mysql_connect() [function.mysql-connect]: Can't connect to local MySQL server through socket '/var/mysql/mysql.sock'

Well today I decided to figure out why this was happening.  After researching a bit with Google I found a few references to the problem but no specific solution.  Then I saw a mention of using sockets vs TCP/IP to make the connection.  So it appears that when I specify the IP address (127.0.0.1), we are using TCP/IP to connect to MySQL.  But if I use the hostname localhost then we are using sockets.  Now apparently the MySQL default socket location is /var/mysql/mysql.sock but this is not the case on Leopard.  The actual location on Leopard is /tmp/mysql.sock.  There are several options to fix this and the easiest for me was to edit my /private/etc/php.ini and set the mysql.default_socket:

; Default socket name for local MySQL connects.  If empty, uses the built-in
; MySQL defaults.
mysql.default_socket = /tmp/mysql.sock

Now, after restarting Apache, I can connect to MySQL with PHP using localhost instead of 127.0.0.1.  If you are looking for other solutions in case you can't edit your php.ini, here are the other options:

Taken from here.

   1. Create the /var/mysql directory (sudo mkdir /var/mysql) and then create a symbolic link from /tmp/mysql.sock to /var/mysql/mysql.sock (with: sudo ln -s /tmp/mysql.sock /var/mysql/mysql.sock).
   2. Edit /etc/my.cnf adding the following lines:
      [mysqld]
      socket=/var/mysql/mysql.sock
      [client]
      socket=/var/mysql/mysql.sock
      This will tell MySQL to create its socket where Leopard’s default PHP is looking for it. Next, you also need to create the /var/mysql directory and sudo chown mysql /var/mysql it or MySQL won’t start since it wont be able to create the socket.
   3. Recompile php for your version of MySQL (a PIA, but not a terrible idea at all).

Of these #1 is easiest, but a bit of a hack. #2 isn’t to bad, but could cause issues with other MySQL clients that look for the socket in /tmp/mysql.sock. #3 is ultimately the best fix, but is clearly neither very fast nor particularly easy