前些時間看了玉開兄的“如此高效通用的分頁存儲過程是帶有sql注入漏洞的”這篇文章,才突然想起 某個項目也是使用了累似的通用分頁存儲過程。使用這種通用的存儲過程進行分頁查詢,想要防SQL注入 ,只能對輸入的參數進行過濾,例如將一個單引號“'”轉換成兩個單引號“''”,但這種做法是不安全 的,厲害的黑客可以通過編碼的方式繞過單引號的過濾,要想有效防SQL注入,只有參數化查詢才是最終 的解決方案。但問題就出在這種通用分頁存儲過程是在存儲過程內部進行SQL語句拼接,根本無法修改為 參數化的查詢語句,因此這種通用分頁存儲過程是不可取的。但是如果不用通用的分頁存儲過程,則意味 著必須為每個具體的分頁查詢寫一個分頁存儲過程,這會增加不少的工作量。
經過幾天的時間考慮之後,想到了一個用代碼來生成參數化的通用分頁查詢語句的解決方案。代碼如 下:
public class PagerQuery
{
private int _pageIndex;
private int _pageSize = 20;
private string _pk;
private string _fromClause;
private string _groupClause;
private string _selectClause;
private string _sortClause;
private StringBuilder _whereClause;
public DateTime DateFilter = DateTime.MinValue;
protected QueryBase()
{
_whereClause = new StringBuilder();
}
/**//// <summary>
/// 主鍵
/// </summary>
public string PK
{
get { return _pk; }
set { _pk = value; }
}
public string SelectClause
{
get { return _selectClause; }
set { _selectClause = value; }
}
public string FromClause
{
get { return _fromClause; }
set { _fromClause = value; }
}
public StringBuilder WhereClause
{
get { return _whereClause; }
set { _whereClause = value; }
}
public string GroupClause
{
get { return _groupClause; }
set { _groupClause = value; }
}
public string SortClause
{
get { return _sortClause; }
set { _sortClause = value; }
}
/**//// <summary>
/// 當 前頁數
/// </summary>
public int PageIndex
{
get { return _pageIndex; }
set { _pageIndex = value; }
}
/**//// <summary>
/// 分頁大小
/// </summary>
public int PageSize
{
get { return _pageSize; }
set { _pageSize = value; }
}
/**//// <summary>
/// 生成緩存Key
/// </summary>
/// <returns></returns>
public override string GetCacheKey()
{
const string keyFormat = "Pager-SC:{0}-FC:{1}-WC:{2}-GC:{3}-SC:{4}";
return string.Format(keyFormat, SelectClause, FromClause, WhereClause, GroupClause, SortClause);
}
/**//// <summary>
/// 生成查詢記錄總數的SQL語句
/// </summary>
/// <returns></returns>
public string GenerateCountSql()
{
StringBuilder sb = new StringBuilder();
sb.AppendFormat(" from {0}", FromClause);
if (WhereClause.Length > 0)
sb.AppendFormat(" where 1=1 {0}", WhereClause);
if (! string.IsNullOrEmpty(GroupClause))
sb.AppendFormat(" group by {0}", GroupClause);
return string.Format("Select count(0) {0}", sb);
}
/**//// <summary>
/// 生成分頁查詢語句,包含記錄總數
/// </summary>
/// <returns></returns>
public string GenerateSqlIncludeTotalRecords()
{
StringBuilder sb = new StringBuilder();
if (string.IsNullOrEmpty(SelectClause))
SelectClause = "*";
if (string.IsNullOrEmpty(SortClause))
SortClause = PK;
int start_row_num = (PageIndex - 1)*PageSize + 1;
sb.AppendFormat(" from {0}", FromClause);
if (WhereClause.Length > 0)
sb.AppendFormat(" where 1=1 {0}", WhereClause);
if (!string.IsNullOrEmpty(GroupClause))
sb.AppendFormat(" group by {0}", GroupClause);
string countSql = string.Format("Select count(0) {0};", sb);
string tempSql =
string.Format(
"WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY {0}) as row_number,{1}{2}) Select * from t where row_number BETWEEN {3} and {4};",
SortClause, SelectClause, sb, start_row_num, (start_row_num + PageSize - 1));
return tempSql + countSql;
}
/**//// <summary>
/// 生成分頁查詢語句
/// </summary>
/// <returns></returns>
public override string GenerateSql()
{
StringBuilder sb = new StringBuilder();
if (string.IsNullOrEmpty(SelectClause))
SelectClause = "*";
if (string.IsNullOrEmpty(SortClause))
SortClause = PK;
int start_row_num = (PageIndex - 1)*PageSize + 1;
sb.AppendFormat(" from {0}", FromClause);
if (WhereClause.Length > 0)
sb.AppendFormat(" where 1=1 {0}", WhereClause);
if (! string.IsNullOrEmpty(GroupClause))
sb.AppendFormat(" group by {0}", GroupClause);
return
string.Format(
"WITH t AS (SELECT ROW_NUMBER() OVER(ORDER BY {0}) as row_number,{1}{2}) Select * from t where row_number BETWEEN {3} and {4}",
SortClause, SelectClause, sb, start_row_num, (start_row_num + PageSize - 1));
}
}