Question

我使用SOAP Extensions在服务器和客户端之间加密/解密SOAP消息消耗WebService。

一般流程是，在发送soap消息之前，1。提取消息的正文，2。加密它，3。将客户端信息添加到它，4。将其重新发送到消息，最后发送修改后的soap消息给服务器

它与小请求完美配合。但是当发送大量请求时，当我尝试将加密的字节数组转换为人类可读的字符串（Base64String），然后将其重新发送回SOAP消息时，会抛出OutOfMemory Exception。在调试器中我可以看到消息太大，当在Stackoverflow上查找该异常时，我已经知道Convert.ToBase64String(bytearr)在转换整个大字节数组时会抛出OOM异常，我应该按块转换块

但是当我将这个字节数组的块改为转换块时，我仍然会得到OOM异常，如下面的代码

请给我一些处理这个问题的建议。

SOAP Message修改方法：

Private Shared Function EncryptSoap(ByVal streamToEncrypt As Stream, ByVal clientInfo As String, ByVal encryptKey As String) As MemoryStream
        streamToEncrypt.Position = 0

        'read the soap stream into a xml doc
        Dim reader As XmlTextReader = New XmlTextReader(streamToEncrypt)
        Dim xmlDoc As XmlDocument = New XmlDocument()
        xmlDoc.Load(reader)

        '' Select soap body to encrypt
        Dim targetNode As XmlNode = xmlDoc.SelectSingleNode(SOAPConstraints.c_strSOAP_BODY_STR, nsmgr)

        '' Encrypt SOAP Body
        Dim encryptedString As String = Utilities.Rfc2898Encrypt(targetNode.InnerXml, encryptKey)

        ' build soap body string = clientInfo + Encrypted Request
        Dim strbld As StringBuilder = New StringBuilder(clientInfo, clientInfo.Length + encryptedString.Length)
        strbld.Append(encryptedString)

        'now save the encrypted xml doc to the returning stream
        targetNode.InnerXml = strbld.ToString

        'now save the encrypted xml doc to the returning stream
        Dim ms As MemoryStream = New MemoryStream()
        xmlDoc.Save(ms)
        ms.Position = 0

        Return ms
    End Function

以下是加密方法：

Public Shared Function Rfc2898Encrypt(ByVal p_strInput As String, ByVal p_strEncryptKey As String) As String
        Try
            '' Encrypt Object initialization
            Dim rijndael As New System.Security.Cryptography.RijndaelManaged()
            Dim encrypter As System.Security.Cryptography.ICryptoTransform = rijndael.CreateEncryptor()

            Dim buffer As Byte() = System.Text.Encoding.Unicode.GetBytes(p_strInput)
            Dim bytearr As Byte() = encrypter.TransformFinalBlock(buffer, 0, buffer.Length)
            '' Convert to human readable string (Base64String)

            '' Convert all at one  => THROW OUT OF MEM EXCEPTION
            'Return Convert.ToBase64String(bytearr) ''

            Dim chunkSize As Integer = 3 * 1024
            '' Convert  chunk by chunk
            ''**ADD** Init MemoryStream with predicted capacity
            Using ms As New MemoryStream((bytearr.Length / 3 + 1) * 4)
                Dim sw As New StreamWriter(ms)
                Dim intConvertCount As Integer = bytearr.Length \ chunkSize
                For idx As Integer = 0 To intConvertCount - 1
                    sw.Write(Convert.ToBase64String(bytearr, idx * chunkSize, chunkSize)) '' => STILL THROW OUT OF MEM EXCEPTION
                    sw.Flush()
                Next
                '' convert last block
                sw.Write(Convert.ToBase64String(bytearr, intConvertCount * chunkSize, bytearr.Length - intConvertCount * chunkSize))
                sw.Flush()
                ms.Position = 0
                Dim sr As New StreamReader(ms)

                Return sr.ReadToEnd
            End Using
        Catch ex As Exception
            Throw ex
        End Try
        Return String.Empty
    End Function

附加信息

异常StackTrace：

System.String.GetStringForStringBuilder(String value, Int32 startIndex, Int32 length, Int32 capacity)  
System.Text.StringBuilder.GetNewString(String currentString, Int32 requiredLength)  
System.Text.StringBuilder.Append(Char[] value, Int32 startIndex, Int32 charCount)  
System.IO.StreamReader.ReadToEnd()

消息长度：

加密前（p_strInput长度）：2748763210
加密后（bytearr长度）：54975280

.NET Convert.To/FromBase64String导致SOAP消息中的OutOfMemory异常

0 个答案: