From 1d93ba703f63c0423c36bf42bc8dd66b35a25dbb Mon Sep 17 00:00:00 2001
From: Nick Volgas <nvolgas@ark.org>
Date: Tue, 7 Oct 2014 11:36:36 -0500
Subject: [PATCH] Adding in a query preview for seeing query before actually
 running it.

---
 src/Database.php        | 39 +++++++++++++++++++++++++++++++++++++++
 tests/DatabaseTests.php | 12 ++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/src/Database.php b/src/Database.php
index 8ce14ec..740ddde 100644
--- a/src/Database.php
+++ b/src/Database.php
@@ -3,6 +3,7 @@
 namespace werx\Core;
 
 use Illuminate\Database\Capsule\Manager as Capsule;
+use Illuminate\Database\Eloquent\Builder as QueryBuilder;
 use Prelude\Dsn\DsnParser;
 
 class Database
@@ -66,6 +67,12 @@ public static function init($config = null)
 		$capsule->bootEloquent();
 	}
 
+	/**
+	 * Return the name of the random function based on the SQL dialect being used.
+	 *
+	 * @param string $connection_name
+	 * @return string
+	 */
 	public static function random($connection_name = 'default')
 	{
 		if (self::$driver[$connection_name] == 'sqlite') {
@@ -75,6 +82,12 @@ public static function random($connection_name = 'default')
 		}
 	}
 
+	/**
+	 * Take a string DSN and parse it into an array of its pieces
+	 *
+	 * @param null $string
+	 * @return array|null
+	 */
 	public static function parseDsn($string = null)
 	{
 		$opts = null;
@@ -94,6 +107,32 @@ public static function parseDsn($string = null)
 		return $opts;
 	}
 
+	/**
+	 * Get a preview of what query will be run from a query builder.
+	 *
+	 * This DOES NOT run the query so it can be used for debugging potentially memory-intensive queries.
+	 *
+	 * @param QueryBuilder $query
+	 * @return string
+	 */
+	public static function getQueryPreview(QueryBuilder $query = null)
+	{
+		if (empty($query)) {
+			return "";
+		}
+
+		$sql        = str_replace('?', "'%s'", $query->toSql());
+		$bindings   = $query->getBindings();
+
+		return vsprintf($sql, $bindings);
+	}
+
+	/**
+	 * Get the last query that was run with data that was used bound to it.
+	 *
+	 * @param string $connection
+	 * @return string
+	 */
 	public static function getLastQuery($connection = "")
 	{
 		$last_query = "";
diff --git a/tests/DatabaseTests.php b/tests/DatabaseTests.php
index 05804dd..28120d5 100644
--- a/tests/DatabaseTests.php
+++ b/tests/DatabaseTests.php
@@ -183,6 +183,18 @@ public function testGetLastQueryNoQueryRun()
 		$this->assertEquals($expected, $query);
 	}
 
+	public function testPreviewQuery()
+	{
+		$this->databaseInitSimple();
+
+		$query = \werx\Core\Tests\App\Models\Captain::where('first_name', 'James');
+
+		$sql = Database::getQueryPreview($query);
+		$expected = 'select * from "captains" where "first_name" = \'James\'';
+
+		$this->assertEquals($expected, $sql);
+	}
+
 	protected function getTestDsnSimple()
 	{
 		return ['driver' => 'sqlite','database' => __DIR__ . '/resources/storage/example.sqlite'];