Merge pull request #503

src/Operation/Explain.php

@@ -18,7 +18,9 @@
 namespace MongoDB\Operation;
 
 use MongoDB\Driver\Command;
+use MongoDB\Driver\ReadPreference;
 use MongoDB\Driver\Server;
+use MongoDB\Driver\Session;
 use MongoDB\Exception\UnsupportedException;
 use MongoDB\Exception\InvalidArgumentException;
 use MongoDB\Model\BSONDocument;
@@ -49,11 +51,15 @@ class Explain implements Executable
      *
      * Supported options:
      *
-     *  * verbosity (string): The mode in which the explain command will be run.
+     *  * readPreference (MongoDB\Driver\ReadPreference): Read preference.
+     *
+     *  * session (MongoDB\Driver\Session): Client session.
      *
      *  * typeMap (array): Type map for BSON deserialization. This will be used
      *    used for the returned command result document.
      *
+     *  * verbosity (string): The mode in which the explain command will be run.
+     *
      * @param string $databaseName      Database name
      * @param Explainable $explainable  Operation to explain
      * @param array  $options           Command options
@@ -61,14 +67,22 @@ class Explain implements Executable
      */
     public function __construct($databaseName, Explainable $explainable, array $options = [])
     {
-        if (isset($options['verbosity']) && ! is_string($options['verbosity'])) {
-            throw InvalidArgumentException::invalidType('"verbosity" option', $options['verbosity'], 'string');
+        if (isset($options['readPreference']) && ! $options['readPreference'] instanceof ReadPreference) {
+            throw InvalidArgumentException::invalidType('"readPreference" option', $options['readPreference'], 'MongoDB\Driver\ReadPreference');
+        }
+
+        if (isset($options['session']) && ! $options['session'] instanceof Session) {
+            throw InvalidArgumentException::invalidType('"session" option', $options['session'], 'MongoDB\Driver\Session');
         }
 
         if (isset($options['typeMap']) && ! is_array($options['typeMap'])) {
             throw InvalidArgumentException::invalidType('"typeMap" option', $options['typeMap'], 'array');
         }
 
+        if (isset($options['verbosity']) && ! is_string($options['verbosity'])) {
+            throw InvalidArgumentException::invalidType('"verbosity" option', $options['verbosity'], 'string');
+        }
+
         $this->databaseName = $databaseName;
         $this->explainable = $explainable;
         $this->options = $options;
@@ -94,7 +108,7 @@ class Explain implements Executable
             $cmd['verbosity'] = $this->options['verbosity'];
         }
 
-        $cursor = $server->executeCommand($this->databaseName, new Command($cmd));
+        $cursor = $server->executeCommand($this->databaseName, new Command($cmd), $this->createOptions());
 
         if (isset($this->options['typeMap'])) {
             $cursor->setTypeMap($this->options['typeMap']);
@@ -103,6 +117,27 @@ class Explain implements Executable
         return current($cursor->toArray());
     }
 
+    /**
+     * Create options for executing the command.
+     *
+     * @see http://php.net/manual/en/mongodb-driver-server.executecommand.php
+     * @return array
+     */
+    private function createOptions()
+    {
+        $options = [];
+
+        if (isset($this->options['readPreference'])) {
+            $options['readPreference'] = $this->options['readPreference'];
+        }
+
+        if (isset($this->options['session'])) {
+            $options['session'] = $this->options['session'];
+        }
+
+        return $options;
+    }
+
     private function isFindAndModify($explainable)
     {
         if ($explainable instanceof FindAndModify || $explainable instanceof FindOneAndDelete || $explainable instanceof FindOneAndReplace || $explainable instanceof FindOneAndUpdate) {

tests/Operation/ExplainTest.php

@@ -22,6 +22,14 @@ class ExplainTest extends TestCase
     {
         $options = [];
 
+        foreach ($this->getInvalidReadPreferenceValues() as $value) {
+            $options[][] = ['readPreference' => $value];
+        }
+
+        foreach ($this->getInvalidSessionValues() as $value) {
+            $options[][] = ['session' => $value];
+        }
+
         foreach ($this->getInvalidStringValues() as $value) {
             $options[][] = ['verbosity' => $value];
         }