Extract Collection::distinct() to an operation class

Author: jmikola

src/Collection.php

@@ -16,6 +16,7 @@
 use MongoDB\Model\IndexInfoIteratorIterator;
 use MongoDB\Model\IndexInput;
 use MongoDB\Operation\Aggregate;
+use MongoDB\Operation\Distinct;
 use Traversable;
 
 class Collection
@@ -358,30 +359,19 @@ public function deleteOne(array $filter)
     }
 
     /**
-     * Finds the distinct values for a specified field across the collection
+     * Finds the distinct values for a specified field across the collection.
      *
-     * @see http://docs.mongodb.org/manual/reference/command/distinct/
-     * @see Collection::getDistinctOptions() for supported $options
-     *
-     * @param string $fieldName  The fieldname to use
-     * @param array $filter      The find query to execute
-     * @param array $options     Additional options
-     * @return integer
+     * @param string $fieldName Field for which to return distinct values
+     * @param array  $filter    Query by which to filter documents
+     * @param array  $options   Command options
+     * @return array
      */
     public function distinct($fieldName, array $filter = array(), array $options = array())
     {
-        $options = array_merge($this->getDistinctOptions(), $options);
-        $cmd = array(
-            "distinct" => $this->collname,
-            "key"      => $fieldName,
-            "query"    => (object) $filter,
-        ) + $options;
+        $operation = new Distinct($this->dbname, $this->collname, $fieldName, $filter, $options);
+        $server = $this->manager->selectServer(new ReadPreference(ReadPreference::RP_PRIMARY));
 
-        $doc = current($this->_runCommand($this->dbname, $cmd)->toArray());
-        if ($doc["ok"]) {
-            return $doc["values"];
-        }
-        throw $this->_generateCommandException($doc);
+        return $operation->execute($server);
     }
 
     /**

src/Operation/Distinct.php

@@ -0,0 +1,90 @@
+<?php
+
+namespace MongoDB\Operation;
+
+use MongoDB\Driver\Command;
+use MongoDB\Driver\Server;
+use MongoDB\Exception\InvalidArgumentException;
+use MongoDB\Exception\InvalidArgumentTypeException;
+use MongoDB\Exception\RuntimeException;
+use MongoDB\Exception\UnexpectedValueException;
+use ArrayIterator;
+use stdClass;
+
+/**
+ * Operation for the distinct command.
+ *
+ * @api
+ * @see MongoDB\Collection::distinct()
+ * @see http://docs.mongodb.org/manual/reference/command/distinct/
+ */
+class Distinct implements Executable
+{
+    private $databaseName;
+    private $collectionName;
+    private $fieldName;
+    private $filter;
+    private $options;
+
+    /**
+     * Constructs a distinct command.
+     *
+     * Supported options:
+     *
+     *  * maxTimeMS (integer): The maximum amount of time to allow the query to
+     *    run.
+     *
+     * @param string $databaseName   Database name
+     * @param string $collectionName Collection name
+     * @param string $fieldName      Field for which to return distinct values
+     * @param array  $filter         Query by which to filter documents
+     * @param array  $options        Command options
+     * @throws InvalidArgumentException
+     */
+    public function __construct($databaseName, $collectionName, $fieldName, array $filter = array(), array $options = array())
+    {
+        if (isset($options['maxTimeMS']) && ! is_integer($options['maxTimeMS'])) {
+            throw new InvalidArgumentTypeException('maxTimeMS option', $options['maxTimeMS'], 'integer');
+        }
+
+        $this->databaseName = (string) $databaseName;
+        $this->collectionName = (string) $collectionName;
+        $this->fieldName = (string) $fieldName;
+        $this->filter = $filter;
+        $this->options = $options;
+    }
+
+    /**
+     * Execute the operation.
+     *
+     * @see Executable::execute()
+     * @param Server $server
+     * @return array
+     */
+    public function execute(Server $server)
+    {
+        $cmd = array(
+            'distinct' => $this->collectionName,
+            'key' => $this->fieldName,
+        );
+
+        if ( ! empty($this->filter)) {
+            $cmd['query'] = (object) $this->filter;
+        }
+
+        $cmd += $this->options;
+
+        $cursor = $server->executeCommand($this->databaseName, new Command($cmd));
+        $result = current($cursor->toArray());
+
+        if (empty($result['ok'])) {
+            throw new RuntimeException(isset($result['errmsg']) ? $result['errmsg'] : 'Unknown error');
+        }
+
+        if ( ! isset($result['values']) || ! is_array($result['values'])) {
+            throw new UnexpectedValueException('distinct command did not return a "values" array');
+        }
+
+        return $result['values'];
+    }
+}