Add support for MySQL socket connection

composer.json

@@ -22,7 +22,7 @@
     },
     "require-dev": {
         "wp-cli/db-command": "^1.3 || ^2",
-        "wp-cli/wp-cli-tests": "^4"
+        "wp-cli/wp-cli-tests": "^4.2.8"
     },
     "config": {
         "process-timeout": 7200,

features/config-create.feature

@@ -160,6 +160,62 @@ Feature: Create a wp-config file
       Error: Database connection error
       """
 
+  @require-mysql
+  Scenario: Configure with database credentials using socket path
+    Given an empty directory
+    And WP files
+    And a find-socket.php file:
+      """
+      <?php
+      // The WP_CLI_TEST_DBSOCKET variable can be set in the environment to
+      // override the default locations and will take precedence.
+      if ( ! empty( getenv( 'WP_CLI_TEST_DBSOCKET' ) ) ) {
+        echo getenv( 'WP_CLI_TEST_DBSOCKET' );
+        exit(0);
+      }
+      // From within Behat, the WP_CLI_TEST_DBSOCKET will be mapped to the internal
+      // DB_SOCKET variable, as Behat pushes a new environment context.
+      $locations = [
+        '{DB_SOCKET}',
+        '/var/run/mysqld/mysqld.sock',
+        '/tmp/mysql.sock',
+      ];
+      foreach ( $locations as $location ) {
+        if ( ! empty( $location ) && file_exists( $location ) ) {
+          echo $location;
+          exit(0);
+        }
+      }
+      echo 'No socket found';
+      exit(1);
+      """
+
+    When I run `php find-socket.php`
+    Then save STDOUT as {SOCKET}
+    And STDOUT should not be empty
+
+    When I try `wget -O {RUN_DIR}/install-package-tests https://raw.githubusercontent.com/wp-cli/wp-cli-tests/main/bin/install-package-tests`
+    Then STDERR should contain:
+      """
+      install-package-tests' saved
+      """
+
+    When I run `chmod +x {RUN_DIR}/install-package-tests`
+    Then STDERR should be empty
+
+    # We try to account for the warnings we get for passing the password on the command line.
+    When I try `MYSQL_HOST=localhost WP_CLI_TEST_DBHOST='localhost:{SOCKET}' WP_CLI_TEST_DBROOTPASS='root' {RUN_DIR}/install-package-tests`
+    Then STDOUT should contain:
+      """
+      Detected MySQL
+      """
+
+    When I run `wp config create --dbname='{DB_NAME}' --dbuser='{DB_USER}' --dbpass='{DB_PASSWORD}' --dbhost='localhost:{SOCKET}'`
+    Then the wp-config.php file should contain:
+      """
+      define( 'DB_HOST', 'localhost:{SOCKET}' );
+      """
+
   @require-php-7.0
   Scenario: Configure with salts generated
     Given an empty directory

src/Config_Command.php

@@ -163,7 +163,22 @@ public function create( $_, $assoc_args ) {
 			$mysql = mysqli_init();
 			mysqli_report( MYSQLI_REPORT_STRICT );
 			try {
-				mysqli_real_connect( $mysql, $assoc_args['dbhost'], $assoc_args['dbuser'], $assoc_args['dbpass'] );
+				// Accept similar format to one used by parse_db_host() e.g. 'localhost:/tmp/mysql.sock'
+				$socket     = '';
+				$host       = $assoc_args['dbhost'];
+				$socket_pos = strpos( $host, ':/' );
+				if ( false !== $socket_pos ) {
+					$socket = substr( $host, $socket_pos + 1 );
+					$host   = substr( $host, 0, $socket_pos );
+				}
+
+				if ( file_exists( $socket ) ) {
+					// If dbhost is a path to a socket
+					mysqli_real_connect( $mysql, null, $assoc_args['dbuser'], $assoc_args['dbpass'], null, null, $socket );
+				} else {
+					// If dbhost is a hostname or IP address
+					mysqli_real_connect( $mysql, $host, $assoc_args['dbuser'], $assoc_args['dbpass'] );
+				}
 			} catch ( mysqli_sql_exception $exception ) {
 				WP_CLI::error( 'Database connection error (' . $exception->getCode() . ') ' . $exception->getMessage() );
 			}