Support Query readPreference (#446)

Author: dplewis

src/Parse/ParseQuery.php

@@ -78,6 +78,27 @@ class ParseQuery
      */
     private $limit = -1;
 
+    /**
+     * The read preference for the main query.
+     *
+     * @var string
+     */
+    private $readPreference;
+
+    /**
+     * The read preference for the queries to include pointers.
+     *
+     * @var string
+     */
+    private $includeReadPreference;
+
+    /**
+     * The read preference for the sub queries.
+     *
+     * @var string
+     */
+    private $subqueryReadPreference;
+
     /**
      * Create a Parse Query for a given Parse Class.
      *
@@ -176,6 +197,18 @@ public function _setConditions($conditions)
                     $this->limit = $entry;
                     break;
 
+                case 'readPreference':
+                    $this->readPreference = $entry;
+                    break;
+
+                case 'includeReadPreference':
+                    $this->includeReadPreference = $entry;
+                    break;
+
+                case 'subqueryReadPreference':
+                    $this->subqueryReadPreference = $entry;
+                    break;
+
                 // skip
                 case 'skip':
                     $this->skip = $entry;
@@ -491,6 +524,15 @@ public function _getOptions()
         if ($this->count) {
             $opts['count'] = $this->count;
         }
+        if ($this->readPreference) {
+            $opts['readPreference'] = $this->readPreference;
+        }
+        if ($this->includeReadPreference) {
+            $opts['includeReadPreference'] = $this->includeReadPreference;
+        }
+        if ($this->subqueryReadPreference) {
+            $opts['subqueryReadPreference'] = $this->subqueryReadPreference;
+        }
 
         return $opts;
     }
@@ -1375,4 +1417,22 @@ public function relatedTo($key, $value)
 
         return $this;
     }
+
+    /**
+     * Changes the read preference that the backend will use when performing the query to the database.
+     *
+     * @param string $readPreference The read preference for the main query.
+     * @param string $includeReadPreference The read preference for the queries to include pointers.
+     * @param string $subqueryReadPreference The read preference for the sub queries.
+     *
+     * @return ParseQuery Returns the query, so you can chain this call.
+     */
+    public function readPreference($readPreference, $includeReadPreference = null, $subqueryReadPreference = null)
+    {
+        $this->readPreference = $readPreference;
+        $this->includeReadPreference = $includeReadPreference;
+        $this->subqueryReadPreference = $subqueryReadPreference;
+
+        return $this;
+    }
 }

tests/Parse/ParseQueryTest.php

@@ -2499,6 +2499,7 @@ public function testGetAndSetConditions()
         $query->notEqualTo('key2', 'value2');
         $query->includeKey(['include1','include2']);
         $query->excludeKey(['excludeMe','excludeMeToo']);
+        $query->readPreference('PRIMARY', 'SECONDARY', 'SECONDARY_PREFERRED');
         $query->contains('container', 'item');
         $query->addDescending('desc');
         $query->addAscending('asc');
@@ -2528,7 +2529,10 @@ public function testGetAndSetConditions()
             'limit'     => 42,
             'skip'      => 24,
             'order'     => '-desc,asc',
-            'count'     => 1
+            'count'     => 1,
+            'readPreference'            => 'PRIMARY',
+            'includeReadPreference'     => 'SECONDARY',
+            'subqueryReadPreference'    => 'SECONDARY_PREFERRED',
         ], $conditions, 'Conditions were different than expected');
 
         $query2 = new ParseQuery('TestObject');