DTO.md

How to create a custom DTO

DTO definition

You will need to create your custom DTO to transfer data over network.
A DTO is a simple structure that contains all the fields you want to transfer.

Note : The structure need to be packed to be sent over the network. No padding must be left over so any client programmed in a different language can read the data correctly.

//packing start for MSVC compiler
#ifdef _WIN32
    #pragma pack(push, 1)
#endif

// DTO definition
struct SampleDto {
    std::string value;
}

#ifdef _WIN32
    // packing end for MSVC compiler
    ;
    #pragma pack(pop)
#else
    // packing for linux compilers
    __attribute__((packed));
#endif

DTO serialization

The library provides a SerializerTrait trait to serialize your DTO. There is already a specialization for all standard layout types.
If your DTO has only standard layout types, you can use the SerializerTrait trait as is. Otherwise, you will need to specialize it for your DTO.

// Specialization of the SerializerTrait for the SampleDto
namespace polymorph::network
{
    template<>
    struct SerializerTrait<SampleDto>
    {
        static std::vector<std::byte> serialize(const SampleDto &data)
        {
            std::vector<std::byte> buffer(data.value.size());

            std::memcpy(buffer.data(), data.value.data(), data.value.size());
            return buffer;
        }

        static SampleDto deserialize(const std::vector<std::byte> &buffer)
        {
            SampleDto dto;

            dto.value = std::string(reinterpret_cast<const char *>(buffer.data()), buffer.size());
            return dto;
        }
    };
}

It is recommended to define the specialization of the SerializerTrait in the same file as the DTO definition.