Boost.Asio：从SSL-Socket读取输入会导致不完整的数据 [英] Boost.Asio: Reading input from SSL-Socket results in incomplete data

问题描述

我有一个名为 NIUserSession 的类，它处理与客户端的SSL加密连接。这是它，虽然我删除了与我的问题不相关的一切：

I have a class called NIUserSession which handles a SSL-encrypted connection with a client. This is it, although I removed everything which is not relevant for my question:

typedef boost::asio::ssl::stream<boost::asio::ip::tcp::socket> ssl_socket;


class NIUserSession
{
public:

    /*....*/
    void readUntil(std::string until);
    /*....*/

private:

    /*....*/
    void readHandler(const boost::system::error_code& error, std::size_t bytes_transferred);
    ssl_socket socket_;
    boost::asio::streambuf readBuffer;
    /*....*/

};

void NIUserSession::readUntil(std::string until)
{
    boost::asio::async_read_until(this->socket_, this->readBuffer, until, boost::bind(&NIUserSession::readHandler,
                                                                                      this,
                                                                                      boost::asio::placeholders::error(),
                                                                                      boost::asio::placeholders::bytes_transferred()));
}

void NIUserSession::readHandler(const boost::system::error_code &error, std::size_t bytes_transferred)
{
    if(!error)
    {
        std::cout << "Bytes transfered: " << bytes_transferred << std::endl;
        this->readBuffer.commit(bytes_transferred);
        std::istream istrm(&this->readBuffer);
        std::string message;
        istrm >> message;

        std::cout << "Message: " << message << std::endl;
    } else {
        // ...
    }
}

现在客户端连接，ssl握手等，然后从 NIUserSession 内执行此行：

Now a client connects, ssl handshake, etc., and then this line is executed from within NIUserSession:

this-> readUntil（< EOF>）;

等待客户端发送消息并以< EOF> 结束。

The server should now wait until the client sends a message and ends it with <EOF>.

从我的客户端应用程序，我发送以下（JSON）数据：

From my client application, I send the following (JSON) data:

服务器输出：

Bytes transfered: 169
Message: {

可以看到，169个字节被传输， strong> 1 字符出现在输出中。我想我做错了与 boost :: asio :: streambuf （我从来没有使用它之前）。

As you can see, 169 bytes are transfered but only 1 character appears in the output. I think I am doing something wrong with the boost::asio::streambuf (I never used it before).

推荐答案

此行：

istrm >> message;

从流中读取由空格分隔的字符串。第一个{是由空格分隔的字符串。您只需要继续阅读 istrm 。

reads a string delimited by whitespace from the stream. That first "{" is a string delimited by whitespace. You just need to keep reading from istrm.

而不是使用 operator> ，您可以使用 boost :: asio :: buffers_begin（） 获取一个随机访问迭代器，然后使用两个迭代器。这看起来像这样（未测试）：

Instead of using operator>>, you can copy the indicated number of bytes to a string by using boost::asio::buffers_begin() to get a random access iterator, and then constructing the string with two iterators. That would look something like this (untested):

const auto bufferIterator = boost::asio::buffers_begin(this->readBuffer.data());
const std::string message(bufferIterator, bufferIterator + bytes_transferred);
this->readBuffer.consume(bytes_transferred);

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