c++ - boost 序列化: see whether a stream is "good"

Question

我目前正在开发一个服务器应用程序，它必须从客户端接收序列化数据，反序列化并最终处理它。序列化数据以字符数组的形式发送。我的问题是我的应用程序很容易通过向它发送无效数据而被破坏。所以我想问一下是否有可能在尝试从中获取数据之前检查一个字符串(-stream)并查看它是否适合(反)序列化(例如它是否具有有效签名)。

顺便说一句:正如标题所说，我的应用程序使用了 boost.serialization。

提前致谢:)

Answer 1

我假设您想进行轻量级检查，而不需要读取所有数据(在这种情况下处理异常会尽可能高效)。

我刚刚用这个简单的函数测试成功:

bool can_deserialize(std::istream& is)
{
    bool ok = false;
    is.seekg(0, std::ios_base::beg);

    try
    {
        boost::archive::binary_iarchive ia(is);
        unsigned test = ia.get_library_version();
        ok = true;
    } catch (...) { }

    is.seekg(0, std::ios_base::beg);
    is.clear();
    return ok;
}

这是我使用的一个简单测试工具(在反序列化之前操作 data.bin 中的数据以检查“坏流”):

#include <boost/archive/binary_iarchive.hpp>
#include <boost/archive/binary_oarchive.hpp>
#include <boost/serialization/vector.hpp>
#include <fstream>
#include <iostream>

bool can_deserialize(std::istream& is)
{
    bool ok = false;
    is.seekg(0, std::ios_base::beg);

    try
    {
        boost::archive::binary_iarchive ia(is);
        unsigned test = ia.get_library_version();
        ok = true;
    } catch (...) { }

    is.seekg(0, std::ios_base::beg);
    is.clear();
    return ok;
}

int main()
{
    std::vector<int> data = { 19415, -2611, 12092, -3942, -2535, 12105, 21079, 4660, 3,
        27131, 13647, 24428, 15159, 9029, 24827, -979, 17194, 25102, -3631,
        20914, -3223, 25801, 6652, 26208, -77, 15606, 8764, 1896, 7430, 24323,
        -152, 23805, -4259, 11243, 13367, 23559, 19293, 18581, 1639, 15671,
        7929, 18386, 5168, 13816, 465, 15801, 16750, -3340, -202, 10412, 11068,
        13458, 24304, 14814, 6530, 1178, -974, 12882, 757, 583, 4897, 24541,
        12490, -119, 2240, -4833, 569, 24700, 24522, 8708, 9760, 26837, 26060,
        20914, -3223, 25801, 6652, 26208, -77, 15606, 8764, 1896, 7430, 24323,
        3377, 6972, 25689, 2334, 1567, 21670, 23233, 14711, 4650, -4703, 25057,
        16057, 19488, 14575, 18936, 13346, 2779, 5644, 17165, 4526, 4390,
        9616, 2413, 14459, -1070, -4079, 22126, 9063, 4362, 8182, 24439, 23625,
        7929, 18386, 5168, 13816, 465, 15801, 16750, -3340, -202, 10412, 11068,
        4184, 25930, 24767, 2785, 17361, 18033, 12366, 20548, -3831, -4101,
        16841, -193, 23217, 6351, 19077, 23565, 10482, 4100, 27488, 15956,
        -2577, 7161, 20943, 25708, -2877, 7900, -4564, -3647, 12008, 1648,
        10533 };

    {
        std::ofstream ofs("data.bin", std::ios::out | std::ios::binary);
        boost::archive::binary_oarchive oa(ofs);

        oa & data;
        ofs.flush();
        ofs.close();
    }

    {
        std::ifstream ifs("data.bin", std::ios::in | std::ios::binary);
        if (can_deserialize(ifs))
        {
            std::cout << "OK! going to read..." << std::endl;

            boost::archive::binary_iarchive ia(ifs);
            std::vector<int> cloned;
            ia & cloned;

            std::cout << "Read " << cloned.size() << " records" << std::endl;
        }
        else
            std::cout << "not OK! -- skipping data read" << std::endl;
    }

}