使用Sql FILESTREAM学习和测试Web应用程序。客户端从网页上传一个大文件，该文件占用“X”时间，完全上传时显示100％完成。但是，非常大的文件也需要时间让SqlFileStream写入文件系统，因此我想分离一个线程来完成该部分。我得到的代码似乎工作正常，但文件流文件中没有数据结束。
我将初始记录创建包装在它自己的事务范围中，并在线程中使用单独的事务范围。在线程例程中，我有适当的PathName（）和TransactionContext但我假设我在使用线程时遗漏了一些东西。
我已经注释掉了正常的SqlFileStream调用，它运行正常。你能看到我在这里做的事情有什么问题吗？
Public Function StoreFileStream()
Dim json As New Dictionary(Of String, Object)
Dim parms As New FileStreamThreadParameters
If HttpContext.Current.Request.Files.Count > 0 Then
Dim file As HttpPostedFile = HttpContext.Current.Request.Files(0)
If "contentType" <> String.Empty Then
Dim fs As Stream = file.InputStream
Dim br As New BinaryReader(fs)
Dim noBytes As New Byte()
Try
Dim filePath As String = ""
Dim trxContext As Byte() = {}
Dim baseFileId As Integer
Using trxScope As New TransactionScope
Using dbConn As New SqlConnection(DigsConnStr)
Using dbCmd As New SqlCommand("ADD_FileStreamFile", dbConn)
dbConn.Open()
Using dbRdr As SqlDataReader = dbCmd.ExecuteReader(CommandBehavior.SingleRow)
dbRdr.Read()
If dbRdr.HasRows Then
filePath = dbRdr("Path")
trxContext = dbRdr("TrxContext")
baseFileId = dbRdr("BaseFileID")
End If
dbRdr.Close()
End Using
' Code below writes to file, but trying to offload this to a separate thread so user is not waiting
'Using dest As New SqlFileStream(filePath, trxContext, FileAccess.Write)
' fs.CopyTo(dest, 4096)
' dest.Close()
'End Using
End Using
dbConn.Close()
End Using
trxScope.Complete()
End Using ' transaction commits here, not in line above
parms.baseFileId = baseFileId
parms.fs = New MemoryStream
fs.CopyTo(parms.fs)
Dim fileUpdateThread As New Threading.Thread(Sub()
UpdateFileStreamThreaded(parms)
End Sub)
fileUpdateThread.Start()
json.Add("status", "success")
Catch ex As Exception
Elmah.ErrorSignal.FromCurrentContext().Raise(ex)
json.Add("status", "failure")
json.Add("msg", ex.Message)
json.Add("procedure", System.Reflection.MethodBase.GetCurrentMethod.Name)
End Try
Else
json.Add("status", "failure")
json.Add("msg", "Invalid file type")
json.Add("procedure", System.Reflection.MethodBase.GetCurrentMethod.Name)
End If
End If
Return json
End Function
Public Class FileStreamThreadParameters
Public Property baseFileId As Integer
Public fs As Stream
End Class
Private Sub UpdateFileStreamThreaded(parms As FileStreamThreadParameters)
Dim filePath As String = ""
Dim trxContext As Byte() = {}
Try
Using trxScope As New TransactionScope
Using dbConn As New SqlConnection(DigsConnStr)
Using dbCmd As New SqlCommand("SELECT FileBytes.PathName() 'Path', GET_FILESTREAM_TRANSACTION_CONTEXT() 'TrxContext' FROM FileStreamFile WHERE Id = " & parms.baseFileId, dbConn)
dbConn.Open()
Using dbRdr As SqlDataReader = dbCmd.ExecuteReader(CommandBehavior.SingleRow)
dbRdr.Read()
If dbRdr.HasRows Then
filePath = dbRdr("Path")
trxContext = dbRdr("TrxContext")
End If
dbRdr.Close()
Using dest As New SqlFileStream(filePath, trxContext, FileAccess.Write)
parms.fs.CopyTo(dest, 4096)
dest.Close()
End Using
End Using
End Using
dbConn.Close()
End Using
trxScope.Complete()
End Using
Catch ex As Exception
'Elmah.ErrorSignal.FromCurrentContext().Raise(ex)
End Try
End Sub
答案 0 :(得分：0)
显然这是一个复杂的问题。我实际上让它使用下面的代码。但是我最终完全放弃了使用SQL FILESTREAM，因为设置过程太复杂了。
这是一个现有的Web应用程序，其中sql server位于不同的框中。在我完成文件流工作之后，下一个障碍是身份验证设置。 Filestream要求您的连接字符串具有集成安全性。即使在我们的Intranet应用程序上使用Windows身份验证，我也无法在连接到数据库时让Web应用程序使用Windows凭据。它似乎总是使用计算机名称或应用程序池服务。我尝试了很多我在网上找到的例子，这里无济于事。即使我让它工作，然后我想使用Active Directory组而不是单个登录，这看起来是另一个障碍。
此应用程序将文档存储在varbinary列中，以便可以在某个时刻启用全文搜索。问题在于大文件，通常是图片或视频。既然你无法在那些上搜索文本，那么现在的策略是将它们存储在文件系统上，所有其他可搜索的文档（.docx，.pptx等）仍将存储在varbinary中。我真的很伤心，我无法让文件流工作，因为它似乎是理想的解决方案。我有一天会回到它，但它真的不应该那么复杂。 ： - （
我工作的代码是：
Dim filePath As String = ""
Dim trxContext As Byte() = {}
Dim baseFileId As Integer
Using trxScope As New TransactionScope
Using dbConn As New SqlConnection(DigsFSConnStr)
Using dbCmd As New SqlCommand("NEW_FileStreamBaseFile", dbConn)
dbCmd.CommandType = CommandType.StoredProcedure
dbCmd.Parameters.AddWithValue("@Title", fileDesc)
dbCmd.Parameters.AddWithValue("@Summary", summary)
dbCmd.Parameters.AddWithValue("@Comments", comments)
dbCmd.Parameters.AddWithValue("@FileName", uploadedFileName)
dbCmd.Parameters.AddWithValue("@ContentType", contentType)
dbCmd.Parameters.AddWithValue("@FileExt", ext)
'dbCmd.Parameters.AddWithValue("@FileBytes", noBytes) ' now that were offloading the file byte storage to a thread
dbCmd.Parameters.AddWithValue("@UploadedByResourceID", uploadedByResourceID)
dbCmd.Parameters.AddWithValue("@UploadedByShortName", uploadedByShortName)
dbCmd.Parameters.AddWithValue("@FileAuthor", fileAuthor)
dbCmd.Parameters.AddWithValue("@TagRecID", tagRecID)
dbCmd.Parameters.AddWithValue("@UserID", samAccountName)
dbCmd.Parameters.AddWithValue("@FileDate", fileDate)
dbCmd.Parameters.AddWithValue("@FileType", fileType)
dbCmd.Parameters.AddWithValue("@FileTypeRecID", fileTypeRecId)
' Save to file system too for xod conversion
file.SaveAs(HttpContext.Current.Server.MapPath("~/files/uploaded/") & uploadedFileName)
dbConn.Open()
Using dbRdr As SqlDataReader = dbCmd.ExecuteReader(CommandBehavior.SingleRow)
dbRdr.Read()
If dbRdr.HasRows Then
filePath = dbRdr("Path")
trxContext = dbRdr("TrxContext")
json.Add("baseFileId", dbRdr("BaseFileID"))
virtualFileRecId = dbRdr("VirtualFileRecID")
dbStatus = dbRdr("status")
If dbStatus = "failure" Then
json.Add("msg", dbRdr("msg"))
End If
End If
dbRdr.Close()
End Using
' Prepare and start Task thread to write the file
If dbStatus = "success" Then
bytes = br.ReadBytes(fs.Length)
Dim task As New System.Threading.Tasks.Task(
Sub()
UpdateNewFileStreamBytes(virtualFileRecId, bytes)
End Sub)
task.Start()
json.Add("status", "success")
Else
json.Add("status", "failure")
End If
End Using
dbConn.Close()
End Using
trxScope.Complete()
End Using ' transaction commits here, not in line above
使用以下任务程序：
Private Sub UpdateNewFileStreamBytes(virtualFileRecId As Integer, fileBytes As Byte())
Dim filePath As String = ""
Dim trxContext As Byte() = {}
Try
Using trxScope As New TransactionScope
Using dbConn As New SqlConnection(DigsFSConnStr)
Using dbCmd As New SqlCommand("UPD_FileStreamBaseFile", dbConn)
dbCmd.CommandType = CommandType.StoredProcedure
dbCmd.Parameters.AddWithValue("@VirtualFileRecID", virtualFileRecId)
dbConn.Open()
Using dbRdr As SqlDataReader = dbCmd.ExecuteReader(CommandBehavior.SingleRow)
dbRdr.Read()
If dbRdr.HasRows Then
filePath = dbRdr("Path")
trxContext = dbRdr("TrxContext")
End If
dbRdr.Close()
Using dest As New SqlFileStream(filePath, trxContext, FileAccess.Write)
dest.Write(fileBytes, 0, fileBytes.Length)
dest.Close()
End Using
End Using
End Using
dbConn.Close()
End Using
trxScope.Complete()
End Using
Catch ex As Exception
Elmah.ErrorSignal.FromCurrentContext().Raise(ex)
End Try