Thrift.Transport.TTransportException:无法写入null outputstream

Question

我正在与Cassandra和Thrift库做一些工作.我意识到这些是非常早期的库,并且(毫无疑问)会在某些时候发生变化.

我一直在使用以下链接来帮助设置我的C#代码来写入和读取我的Cassandra服务器(我在本地VirtualBox中的Ubuntu Server实例中运行).我已经确认了简单的读/写功能.

我遇到问题的地方是执行以下方法(使用Cassandra附带的thrift.definition文件为我生成):

public void send_get_count(string keyspace, string key, ColumnParent column_parent, ConsistencyLevel consistency_level)

这是我的设置代码:

TTransport _transport;
TProtocol _protocol;
Cassandra.Client _client;

public Test()
{
    _transport = new TSocket("192.168.56.101", 9160);
    _protocol = new TBinaryProtocol(_transport);
    _client = new Cassandra.Client(_protocol);
}

我的调用代码如下所示:

public void GetAllBlogEntries()
    {
        var timestamp = DateTime.Now.Millisecond;
        var keyspace = "Keyspace1";

        var utf8Encoding = System.Text.Encoding.UTF8;

        var columnParent = new ColumnParent() {Column_family = "BlogEntries"};
        var predicate = new SlicePredicate()
        {
            Slice_range = new SliceRange()
                          {
                              Start = new byte[0],
                              Finish = new byte[0],
                              Count = 10,
                              Reversed = false
                          }
        };

        var results = _client.get_range_slice(keyspace, columnParent, predicate, "", "", 5, ConsistencyLevel.ONE);

        foreach(var slice in results)
        {
            Console.WriteLine("Found Key: {0}", slice.Key);
            foreach(var resultColumn in slice.Columns)
            {
                var column = resultColumn.Column;
                Console.WriteLine("\tName: {0}, value: {1}",
                                  utf8Encoding.GetString(column.Name),
                                  utf8Encoding.GetString(column.Value));                        
            }
        }
    } 

这个方法的第一行是我得到异常的地方:

oprot_.WriteMessageBegin(new TMessage("get_count", TMessageType.Call, seqid_));

以下是例外情况:

Thrift.Transport.TTransportException:不能写在Thrift.Transport.TStreamTransport.Write为空的OutputStream(字节[] buf中,关闭的Int32,的Int32 LEN)在Thrift.Protocol.TBinaryProtocol.WriteI32(的Int32 123-132)在Thrift.Protocol.TBinaryProtocol. WriteMessageBegin(TMessage消息)在Apache.Cassandra.Cassandra.Client.send_get_range_slice(字符串密钥空间,ColumnParent column_parent,SlicePredicate谓词,字符串start_key,字符串finish_key,的Int32 ROW_COUNT,ConsistencyLevel consistency_level)在Cassandra.cs:线341在Apache.Cassandra.Cassandra .Client.get_range_slice(字符串密钥空间,ColumnParent column_parent,SlicePredicate谓词,字符串start_key,字符串finish_key,的Int32 ROW_COUNT,ConsistencyLevel consistency_level)在Cassandra.cs:在test.cs中线335在CassandraDemo.Models.Test.GetAllBlogEntries():线212在TestTest.cs中的CassandraDemo.Tests.Models.TestTest.Test_GetAllBlogEntries_Success():第42行

有任何想法吗？

Answer 1

您需要在传输上调用Open().