Extract Client::listDatabases() to an operation class

src/Client.php

@@ -7,9 +7,8 @@ use MongoDB\Driver\Cursor;
 use MongoDB\Driver\Manager;
 use MongoDB\Driver\ReadPreference;
 use MongoDB\Driver\WriteConcern;
-use MongoDB\Exception\UnexpectedValueException;
 use MongoDB\Model\DatabaseInfoIterator;
-use MongoDB\Model\DatabaseInfoLegacyIterator;
+use MongoDB\Operation\ListDatabases;
 
 class Client
 {
@@ -53,29 +52,15 @@ class Client
     /**
      * List databases.
      *
-     * @see http://docs.mongodb.org/manual/reference/command/listDatabases/
+     * @see ListDatabases::__construct() for supported options
      * @return DatabaseInfoIterator
-     * @throws UnexpectedValueException if the command result is malformed
      */
-    public function listDatabases()
+    public function listDatabases(array $options = array())
     {
-        $command = new Command(array('listDatabases' => 1));
+        $operation = new ListDatabases($options);
+        $server = $this->manager->selectServer(new ReadPreference(ReadPreference::RP_PRIMARY));
 
-        $cursor = $this->manager->executeCommand('admin', $command);
-        $cursor->setTypeMap(array('document' => 'array'));
-        $result = current($cursor->toArray());
-
-        if ( ! isset($result['databases']) || ! is_array($result['databases'])) {
-            throw new UnexpectedValueException('listDatabases command did not return a "databases" array');
-        }
-
-        /* Return an Iterator instead of an array in case listDatabases is
-         * eventually changed to return a command cursor, like the collection
-         * and index enumeration commands. This makes the "totalSize" command
-         * field inaccessible, but users can manually invoke the command if they
-         * need that value.
-         */
-        return new DatabaseInfoLegacyIterator($result['databases']);
+        return $operation->execute($server);
     }
 
     /**

src/Operation/ListDatabases.php

+<?php
+
+namespace MongoDB\Operation;
+
+use MongoDB\Driver\Command;
+use MongoDB\Driver\Server;
+use MongoDB\Exception\RuntimeException;
+use MongoDB\Exception\UnexpectedValueException;
+use MongoDB\Model\DatabaseInfoIterator;
+use MongoDB\Model\DatabaseInfoLegacyIterator;
+
+/**
+ * Operation for the ListDatabases command.
+ *
+ * @api
+ * @see MongoDB\Client::listDatabases()
+ * @see http://docs.mongodb.org/manual/reference/command/ListDatabases/
+ */
+class ListDatabases implements Executable
+{
+    private $options;
+
+    /**
+     * Constructs a listDatabases command.
+     *
+     * Supported options:
+     *
+     *  * maxTimeMS (integer): The maximum amount of time to allow the query to
+     *    run.
+     *
+     * @param array $options Command options
+     */
+    public function __construct(array $options = array())
+    {
+        if (isset($options['maxTimeMS']) && ! is_integer($options['maxTimeMS'])) {
+            throw new InvalidArgumentTypeException('"maxTimeMS" option', $options['maxTimeMS'], 'integer');
+        }
+
+        $this->options = $options;
+    }
+
+    /**
+     * Execute the operation.
+     *
+     * @see Executable::execute()
+     * @param Server $server
+     * @return DatabaseInfoIterator
+     */
+    public function execute(Server $server)
+    {
+        $cmd = array('listDatabases' => 1);
+
+        if (isset($this->options['maxTimeMS'])) {
+            $cmd['maxTimeMS'] = $this->options['maxTimeMS'];
+        }
+
+        $cursor = $server->executeCommand('admin', new Command($cmd));
+        $cursor->setTypeMap(array('document' => 'array'));
+        $result = current($cursor->toArray());
+
+        if (empty($result['ok'])) {
+            throw new RuntimeException(isset($result['errmsg']) ? $result['errmsg'] : 'Unknown error');
+        }
+
+        if ( ! isset($result['databases']) || ! is_array($result['databases'])) {
+            throw new UnexpectedValueException('listDatabases command did not return a "databases" array');
+        }
+
+        /* Return an Iterator instead of an array in case listDatabases is
+         * eventually changed to return a command cursor, like the collection
+         * and index enumeration commands. This makes the "totalSize" command
+         * field inaccessible, but users can manually invoke the command if they
+         * need that value.
+         */
+        return new DatabaseInfoLegacyIterator($result['databases']);
+    }
+}