在files文件类中增加了单个附件信息读取函数，增加了图片附件的mime类型判断函数

application/models/files.php

@@ -142,6 +142,73 @@ class files{
 		}
 	}//文件上传
 	
+	/**
+	* getOne()
+	*
+	* 从数据库获取单个文件的信息
+	*
+	* @param int id
+	*
+	* return array
+	*/
+	static function getOne($db,$id){
+		//下载单个附件
+		$sql = $db->quoteInto("select a.* from attachments a where a.id=? order by a.ts_created desc",$id);
+		$att = $db->fetchRow($sql);
+		if(empty($att['id']))
+		{	$att['error']=='文件不存在';}
+		return $att;
+	}
+	
+	
+	static  function getImageType($filename)
+	 {
+	  
+	  //通过mime判断是否是真正的图片
+	  
+	  $finfo = finfo_open(FILEINFO_MIME_TYPE);
+	  $mime = finfo_file($finfo, $filename); 
+	  finfo_close($finfo);
+	  $type = $mime;
+	  if(!in_array($type,array('image/jpeg','image/png')))
+	  {
+		  return array('error'=>'F');
+	  }else{
+	  switch ($type){
+	   case 'image/jpeg':
+	   $image_create_func = 'imagecreatefromjpeg';
+	   $image_save_func = 'imagejpeg';
+	   $new_image_ext='jpg';
+	   $quality = 100;
+	   break;
+	   case 'image/gif':
+	   $image_create_func = 'imagecreatefromgif';
+	   $image_save_func = 'imagegif';
+	   $new_image_ext = 'gif';
+	   break;
+	   case 'image/png':
+	   $image_create_func = 'imagecreatefrompng';
+	   $image_save_func = 'imagepng';
+	   $new_image_ext = 'png';
+	   $quality = 100;
+	   break;
+	   default:
+	   $image_create_func = 'imagecreatefromjpeg';
+	   $image_save_func = 'imagejpeg';
+	   $new_image_ext='jpg';
+	   $quality = 100;
+	   }
+	   
+	   $downloadcfg = array('creatfunc'=>$image_create_func,
+			 'savefunc'=>$image_save_func,
+			 'ext'=>$new_image_ext,
+			 'mime'=>$mime,
+			 'quality'=>$quality);
+	   
+	   return $downloadcfg;
+	  }
+	   
+	 }//function getimagetype
 	
 	
 	/**