Added count() support

Author: hschimpf

src/Kitar/Dynamodb/Model/Model.php

@@ -343,6 +343,7 @@ public function __call($method, $parameters)
     {
         $allowedBuilderMethods = [
             "select",
+            "count",
             "take",
             "limit",
             "index",

src/Kitar/Dynamodb/Query/Builder.php

@@ -120,6 +120,12 @@ class Builder extends BaseBuilder
      */
     protected $key_condition_query;
 
+    /**
+     * The attributes to be returned in the result
+     * @var string
+     */
+    protected $selectAttributes = 'ALL_ATTRIBUTES';
+
     /**
      * Create a new query builder instance.
      *
@@ -260,6 +266,27 @@ public function getWhereAs()
         return $this->where_as;
     }
 
+    /**
+     * Set select attributes
+     *
+     * @param  string  $selectAttributes
+     * @return $this
+     */
+    protected function selectAttributes(string $selectAttributes) {
+        $this->selectAttributes = $selectAttributes;
+
+        return $this;
+    }
+
+    /**
+     * Get the selectAttributes attribute.
+     *
+     * @return string
+     */
+    public function getSelectAttributes() {
+        return $this->selectAttributes;
+    }
+
     /**
      * Get item.
      *
@@ -368,6 +395,13 @@ public function batchWriteItem($request_items = [])
         return $this->process('batchWriteItem', null);
     }
 
+    public function count($columns = '*') {
+        // reset columns selection
+        $this->select([])->selectAttributes('COUNT');
+
+        return (int) $this->process('scan', 'processCount');
+    }
+
     /**
      * @inheritdoc
      */
@@ -604,14 +638,15 @@ public function newQuery()
      * @param string $processor_method
      * @return array|\Illuminate\Support\Collection|\Aws\Result
      */
-    protected function process($query_method, $processor_method)
+    protected function process($query_method, $processor_method = null)
     {
         $table_name = $this->connection->getTablePrefix() . $this->from;
 
         // Compile columns and wheres attributes.
         // These attributes needs to interact with ExpressionAttributes during compile,
         // so it need to run before compileExpressionAttributes.
         $params = array_merge(
+            $this->grammar->compileSelectAttributes($this->selectAttributes),
             $this->grammar->compileProjectionExpression($this->columns, $this->expression_attributes),
             $this->grammar->compileConditions($this->filter_query),
             $this->grammar->compileConditions($this->condition_query),

src/Kitar/Dynamodb/Query/Grammar.php

@@ -46,6 +46,22 @@ public function __construct()
         $this->marshaler = new Marshaler;
     }
 
+    /**
+     * Compile the Select attribute.
+     *
+     * @param $select_attributes
+     * @return array
+     */
+    public function compileSelectAttributes($select_attributes) {
+        if ($select_attributes === 'ALL_ATTRIBUTES') {
+            return [];
+        }
+
+        return [
+            'Select' => $select_attributes,
+        ];
+    }
+
     /**
      * Compile the TableName attribute.
      *

src/Kitar/Dynamodb/Query/Processor.php

@@ -45,6 +45,18 @@ protected function unmarshal(Result $res)
         return $responseArray;
     }
 
+    public function processCount(Result $awsResponse, $modelClass = null) {
+        $response = $this->unmarshal($awsResponse);
+
+        if (empty($modelClass)) {
+            return $response;
+        }
+
+        if (! empty($response['Count'])) {
+            return $response['Count'];
+        }
+    }
+
     public function processSingleItem(Result $awsResponse, $modelClass = null)
     {
         $response = $this->unmarshal($awsResponse);