sqlFileStream System.ComponentModel.Win32Exception:不支持该请求

Question

我在windows7(版本6.1版本7601: Service pack1)和visual studio 2010上安装了SQL server express 2008 SP1。

我正在尝试使用以下代码创建一个存储过程CLR，用于将文件插入到文件流中。

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.IO;
using System.Security.Principal;

public partial class StoredProcedures
{
     [Microsoft.SqlServer.Server.SqlProcedure]
     public static void sp_fileController(String friendlyName, String filePath)
{
    SqlParameter fDataParam = new System.Data.SqlClient.SqlParameter("@fData", SqlDbType.VarBinary, -1);
    SqlParameter fNameParam = new System.Data.SqlClient.SqlParameter("@fName", SqlDbType.NVarChar, 300);

    WindowsIdentity newId = SqlContext.WindowsIdentity;
    WindowsImpersonationContext impersonatedUser = newId.Impersonate();

    try
    {
        string cs = @"Server=[myservername];Integrated Security=true";
        using (SqlConnection con = new SqlConnection(cs))
        {
            con.Open();
            SqlTransaction objSqlTran = con.BeginTransaction();

            //string sql = "INSERT INTO fileStreamTest VALUES ((Cast('' As varbinary(Max))), @fName, default); Select fData.PathName() As Path From fileStreamTest Where fId = SCOPE_IDENTITY()";//OUTPUT inserted.fid 
            SqlCommand insertFileCommand = con.CreateCommand();

            insertFileCommand.Transaction = objSqlTran;

            insertFileCommand.CommandText = "INSERT INTO fileStreamTest.dbo.fileStreamTest (RowGuid, fData) VALUES (@FileID, CAST ('' as varbinary(max)))";

            Guid newFileID = Guid.NewGuid();

            insertFileCommand.Parameters.Add("@FileID", SqlDbType.UniqueIdentifier).Value = newFileID;

            insertFileCommand.ExecuteNonQuery();

            SqlCommand getPathAndTokenCommand = con.CreateCommand();

            getPathAndTokenCommand.Transaction = objSqlTran;

            getPathAndTokenCommand.CommandText =
                "SELECT fData.PathName(), GET_FILESTREAM_TRANSACTION_CONTEXT() " +
                "FROM   fileStreamTest.dbo.fileStreamTest " +
                "WHERE  rowGuid = @FileID";

            getPathAndTokenCommand.Parameters.Add("@FileID", SqlDbType.UniqueIdentifier).Value = newFileID;

            SqlDataReader tokenReader = getPathAndTokenCommand.ExecuteReader(CommandBehavior.SingleRow);

            tokenReader.Read();

            SqlString filePathName = tokenReader.GetSqlString(0);

            SqlBinary fileToken = tokenReader.GetSqlBinary(1);

            tokenReader.Close();

            SqlFileStream sqlFile = new SqlFileStream(filePathName.Value, fileToken.Value, System.IO.FileAccess.ReadWrite);
            sqlFile.Close();

            objSqlTran.Rollback();
            //objSqlTran.Commit();
            con.Close();

        }
    }
    finally
    {
        impersonatedUser.Undo();
    }
}
};

然而，当它到达一行时：

SqlFileStream sqlFile = new SqlFileStream(filePathName.Value, fileToken.Value, System.IO.FileAccess.ReadWrite);

我得到了：

执行用户定义的例程或聚合“sp_fileController”时出现.NET框架错误：

System.ComponentModel.Win32Exception: The request is not supported
System.ComponentModel.Win32Exception: 
   at System.Data.SqlTypes.SqlFileStream.OpenSqlFileStream(String path, Byte[] transactionContext, FileAccess access, FileOptions options, Int64 allocationSize)
   at System.Data.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess access, FileOptions options, Int64 allocationSize)
   at System.Data.SqlTypes.SqlFileStream..ctor(String path, Byte[] transactionContext, FileAccess access)
   at StoredProcedures.sp_fileController(String friendlyName, String filePath)

有人能告诉我如何解决这个问题吗？简单地说，我不能用SQL2008 express edition以这种方式执行代码？

Answer 1

我想我已经在这里找到了可行的解决方案：

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/f49def09-3b47-4e54-8a53-2dd47762821e/filestream-on-windows-server-2012-the-request-is-not-supported?forum=sqldatabaseengine

综上所述:添加注册表项解决了SQL Server 11.0.7001上的问题：

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters\FsctlAllowlist]
"FSCTL_SQL_FILESTREAM_FETCH_OLD_CONTENT"=dword:0x00092560

Answer 2

听起来很奇怪，但微软故意阻止在SQL CLR程序集中使用SqlFileStream类用法(即使您授予EXTERNAL_ACCESS或将程序集声明为UNSAFE)，因为您可以在Microsoft Connect issue 768308中读取。

但是，您可以通过SqlBytes类型(在blog post上找到的一个非常好的技巧)将FILESTREAM作为流访问。至少对于只读使用，我从来没有尝试过写。

我复制了代码，以防博客消失(在适当处理对象的略微改进的版本中)：

using System;
using System.IO;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Security.Cryptography;

public partial class UserDefinedFunctions
{
    [Microsoft.SqlServer.Server.SqlFunction(DataAccess = DataAccessKind.None, IsDeterministic = true, SystemDataAccess = SystemDataAccessKind.None)]
    public static SqlBinary Hash(SqlBytes source, SqlString hashAlgorithmName)
    {
        if (Source.IsNull) 
        {
            return null;
        }

        using (HashAlgorithm ha = GetHashAlgotithm(hashAlgorithmName.Value)) 
        using (Stream stream = Source.Stream) 
        {
            return new SqlBinary(ha.ComputeHash(source.Stream));
        }
    }
}

我可以确认这绝对适用于只读访问。我从未尝试过写访问(我正在从外部的C# Windows Service或Web应用程序写入FILESTREAM数据)。