How to let PHP connect to database by using UNIX socket (Joomla)

Question

I'd like to have my PHP applications such as Joomla make use of the UNIX socket to connect to the local mysql database.

I've already configured the php.ini with:

mysqli.default_socket = /var/run/mysqld/mysqld.sock mysql.default_socket = /var/run/mysqld/mysqld.sock pdo_mysql.default_socket=/var/run/mysqld/mysqld.sock 

But in Joomla I can only set localhost or 127.0.0.1 as database, is it possible to override this? How can I test the UNIX socket is actually being used?

My MySQL/MariaDB is configured like:

[client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp lc_messages_dir = /usr/share/mysql lc_messages = en_US skip-external-locking bind-address = 127.0.0.1 max_connections = 500 connect_timeout = 10 wait_timeout = 600 max_allowed_packet = 16M thread_cache_size = 1000 sort_buffer_size = 512M bulk_insert_buffer_size = 16M tmp_table_size = 8G max_heap_table_size = 8G myisam_recover = FORCE,BACKUP key_buffer_size = 128M open-files-limit = 65535 table_open_cache = 10240 table_open_cache_instances = 8 table-definition-cache = 4096 myisam_sort_buffer_size = 512M key-cache-segments=8 concurrent_insert = 2 read_buffer_size = 32M read_rnd_buffer_size = 64M query_cache_limit = 96M query_cache_size = 128M query_cache_min_res_unit=7108 query_cache_type = 1 log_warnings = 2 slow_query_log_file = /var/log/mysql/mariadb-slow.log long_query_time = 10 log_slow_verbosity = query_plan log_bin = /var/log/mysql/mariadb-bin log_bin_index = /var/log/mysql/mariadb-bin.index sync_binlog = 1 expire_logs_days = 14 max_binlog_size = 100M default_storage_engine = InnoDB innodb_log_file_size = 50M innodb_buffer_pool_size = 6G innodb_buffer_pool_instances=8 innodb_log_buffer_size = 32M innodb_file_per_table = 1 innodb_concurrency_tickets=5000 innodb_open_files = 240000 innodb_io_capacity = 240000 innodb_flush_method = O_DIRECT innodb-log-files-in-group = 2 innodb-flush-log-at-trx-commit = 1 [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 512M !includedir /etc/mysql/conf.d/ 

Answer 1

127.0.0.1 is used for TCP socket.

'localhost' is used for Unix filesystem socket.

We can use netstat -ln | grep 'mysql' to determine the connection method.And explore option to enforce a particular type

shell> mysql --host=127.0.0.1 shell> mysql --protocol=TCP shell> mysql --host=localhost shell> mysql --host=localhost --protocol=TCP 

The connection parameters should be like this

$link = mysql_connect('localhost:/var/run/mysqld/mysqld.sock', 'mysql_user', 'mysql_password');

var $host = ':/var/run/mysqld/mysqld.sock'; var $user = 'your_user_db_name'; var $db = 'your_db_name'; var $password = 'your_db_password'; 

Answer 2

In libraries/joomla/database/database.php is defined the abstract class JDatabase, which then is implemented for different database types in libraries/joomla/database/driver/, in this case mysql or mysqli..

In mysqli.php (Joomla! 3.3.6) __construct($options) sets defaults if nothing specified in configuration.php, which will change it into 'localhost'. From line 64:

public function __construct($options) { // Get some basic values from the options. $options['host'] = (isset($options['host'])) ? $options['host'] : 'localhost'; $options['user'] = (isset($options['user'])) ? $options['user'] : 'root'; $options['password'] = (isset($options['password'])) ? $options['password'] : ''; $options['database'] = (isset($options['database'])) ? $options['database'] : ''; $options['select'] = (isset($options['select'])) ? (bool) $options['select'] : true; $options['port'] = null; $options['socket'] = null; // Finalize initialisation. parent::__construct($options); } 

Then, function connect(), finally uses them to create connection on lines 163-165:

 $this->connection = @mysqli_connect( $this->options['host'], $this->options['user'], $this->options['password'], null, $this->options['port'], $this->options['socket'] ); 

If nothing else given, mysqli_connect() uses defaults from php.ini for hostname, port and socket

mysqli mysqli_connect ([ string $host = ini_get("mysqli.default_host") [, string $username = ini_get("mysqli.default_user") [, string $passwd = ini_get("mysqli.default_pw") [, string $dbname = "" [, int $port = ini_get("mysqli.default_port") [, string $socket = ini_get("mysqli.default_socket") ]]]]]] ) 

Now you know the whole track affecting these connection parameters. By editing mysqli.php you should be able to enforce settings the configuration.php doesn't allow you to change. However, you should be careful and consider documenting these modifications well, since

1. configuration.php doesn't work like documented anymore
2. Joomla updates can (and eventually will) override your modifications
3. Something else may be depending on this particular configuration