Merge pull request box#50 from kormoc/17-QDUI-Rewriter

Use QDUI Query Rewriter which supports a much wider set of queries to ex...

lib/QueryExplain.php

@@ -43,6 +43,8 @@
  */
 
 require "QueryTableParser.php";
+require_once "QueryRewrite.php";
+
 class QueryExplain {
 
     private $get_connection_func;
@@ -143,20 +145,18 @@ public function explain() {
         if (!isset($this->mysqli)) {
             return null;
         }
-
-        if (!preg_match("/^\s*\(?\s*(EXPLAIN)?\s*SELECT/i", $this->query)) {
-            return null;
-        }
-
+
         try {
             $result = $this->explain_query($this->query);
+
             if ($this->mysqli->errno) {
                 return $this->mysqli->error . " (" . $this->mysqli->errno . ")";
             }
 
             if (!$result) {
                 return "unknown error getting explain plan\n";
             }
+
             return $this->result_as_table($result);
         } catch (Exception $e) {
             return $e->getMessage();
@@ -177,7 +177,7 @@ private function connect() {
                 throw new Exception("Missing field {$r}");
             }
         }
-
+		
         try {
             $this->mysqli = new mysqli();
             $this->mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, self::$CONNECT_TIMEOUT);
@@ -202,11 +202,13 @@ private function connect() {
      * @return MySQLi_Result    the result handle
      */
     private function explain_query() {
-		if (preg_match("/^\s*EXPLAIN/i", $this->query))
-		{
-			return $this->mysqli->query($this->query);
-		}
-        return $this->mysqli->query("EXPLAIN " . $this->query);
+		$Query = new QueryRewrite($this->query);
+		$explain = $Query->asExplain();
+
+		if (is_null($explain))
+			return null;
+
+        return $this->mysqli->query($explain);
     }
 
     /**

lib/QueryRewrite.php

@@ -0,0 +1,117 @@
+<?php
+
+    class QueryRewrite{
+		public $sql 	  	= null;
+		public $type 	  	= 0;
+
+		const UNKNOWN     	= 0;
+		const SELECT      	= 1;
+		const DELETE      	= 2;
+		const INSERT      	= 3;
+		const UPDATE      	= 4;
+		const ALTER       	= 5;
+		const DROP        	= 6;
+		const CREATE      	= 7;
+		const DELETEMULTI 	= 8;
+		const UNION       	= 9;
+		const INSERTSELECT	= 10;
+
+// Valid Table Regex
+		const TABLEREF      = '`?[A-Za-z0-9_]+`?(\.`?[A-Za-z0-9_]+`?)?';
+// Comment Regexs
+		const COMMENTS_C    = '/\s*\/\*.*?\*\/\s*/';
+		const COMMENTS_HASH = '/#.*$/';
+		const COMMENTS_SQL  = '/--\s+.*$/';
+
+        public function __construct($sql = null) {
+			$this->setQuery($sql);
+        }
+
+		public function setQuery($sql = null) {
+			$this->type = self::UNKNOWN;
+			$this->sql  = $sql;
+            if (is_null($this->sql))
+                return;
+        // Remove comments
+            $this->sql  = preg_replace(self::COMMENTS_C,    '', $this->sql);
+            $this->sql  = preg_replace(self::COMMENTS_HASH, '', $this->sql);
+            $this->sql  = preg_replace(self::COMMENTS_SQL,  '', $this->sql);
+        // Remove whitespace
+			$this->sql  = trim($this->sql);
+            $this->sql  = str_replace("\n", " ", $this->sql);
+			$this->figureOutType();    
+		}
+
+		private function figureOutType(){
+			if (preg_match('/^SELECT\s/i', $this->sql))
+				$this->type = self::SELECT;
+			elseif (preg_match('/^DELETE\s+FROM\s/i', $this->sql))
+				$this->type = self::DELETE;
+			elseif (preg_match('/^DELETE\s+'.self::TABLEREF.'\s+FROM\s/i', $this->sql))
+				$this->type = self::DELETEMULTI;
+			elseif (preg_match('/^INSERT\s+INTO\s'.self::TABLEREF.'[\s\(]*SELECT\s+/i', $this->sql))
+				$this->type = self::INSERTSELECT;
+			elseif (preg_match('/^INSERT\s+INTO\s/i', $this->sql))
+				$this->type = self::INSERT;
+			elseif (preg_match('/^(.*)\s+UNION\s+(.*)$/i', $this->sql))
+				$this->type = self::UNION;
+			elseif (preg_match('/^UPDATE\s/i', $this->sql))
+				$this->type = self::UPDATE;
+			elseif (preg_match('/^ALTER\s/i', $this->sql))
+				$this->type = self::ALTER;
+			elseif (preg_match('/^CREATE\s/i', $this->sql))
+				$this->type = self::CREATE;
+			elseif (preg_match('/^DROP\s/i', $this->sql))
+				$this->type = self::DROP;
+			else
+				$this->type = self::UNKNOWN;
+		}
+
+		public function getType() {
+			return $this->type;
+		}
+
+		public function toSelect() {
+			$select = '';
+			switch ($this->type) {
+				case self::SELECT:
+				case self::UNION:
+					$select = $this->sql;
+					break;
+				case self::DELETE:
+					$select = preg_replace('/^DELETE\s+FROM\s/i', 'SELECT 0 FROM ', $this->sql);
+					break;
+				case self::DELETEMULTI:
+					$select = preg_replace('/^DELETE\s+'.self::TABLEREF.'\s+FROM\s/i', 'SELECT 0 FROM ', $this->sql);
+					break;
+				case self::UPDATE:
+					preg_match('/^UPDATE\s+(.*)\s+SET\s+(.*)\s+WHERE\s+(.*)$/i', $this->sql, $subpatterns);
+					$select = "SELECT {$subpatterns[2]} FROM {$subpatterns[1]} WHERE {$subpatterns[3]}";
+					break;
+				case self::INSERTSELECT:
+					if (preg_match('/\(\s*(SELECT\s+.*)\)/', $this->sql, $subpatterns))
+						$select = trim("{$subpatterns[1]}");
+					else
+						preg_match('/^INSERT\s+INTO\s+\w+\s+(SELECT.*)/i', $this->sql, $subpatterns);
+						$select = trim("{$subpatterns[1]}");
+					break;
+				default:
+					return null;
+			}
+			return trim($select);
+		}
+
+		public function asExplain() {
+			$sql = $this->toSelect();
+			if (is_null($sql))
+				return null;
+			return "EXPLAIN $sql";
+		}
+
+		public function asExtendedExplain() {
+			$sql = $this->toSelect();
+			if (is_null($sql))
+				return null;
+			return "EXPLAIN EXTENDED $sql";
+		}
+	}