WebSocketUtil.hpp

#pragma once
#include <samchon/API.hpp>

#include <string>
#include <random>
#include <boost/uuid/sha1.hpp>

#include <samchon/ByteArray.hpp>
#include <samchon/library/Base64.hpp>
#include <samchon/library/Date.hpp>

namespace samchon
{
namespace protocol
{
    class WebSocketUtil
    {
    public:
        enum OpCode : unsigned char
        {
            TEXT = 129,
            BINARY = 130,
            DISCONNECT = 136
        };

        enum SizeCode : unsigned char
        {
            TWO_BYTES = 126,
            EIGHT_BYTES = 127
        };

        static const unsigned char MASK = 128;

        static auto GUID() -> std::string
        {
            return "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
        };
        
        static auto generate_base64_certification_key() -> std::string
        {
            static std::uniform_int_distribution<unsigned short> distribution(0, 255);
            static std::random_device device;

            std::string certification_key(16, NULL);
            for (size_t i = 0; i < certification_key.size(); i++)
                certification_key[i] = (unsigned char)distribution(device);

            ByteArray byte_array;
            byte_array.assign(certification_key.begin(), certification_key.end());

            return library::Base64::encode(byte_array);
        };

        static auto encode_certification_key(const std::string &base64) -> std::string
        {
            std::string acceptKey = base64 + GUID();

            boost::uuids::detail::sha1 hash;
            hash.process_bytes(acceptKey.c_str(), acceptKey.size());

            ByteArray bytes;
            unsigned int digest[5];
            hash.get_digest(digest);

            for (size_t index = 0; index < 5; index++)
                bytes.writeReversely(digest[index]); //ENDIAN REVERSING

            return library::Base64::encode(bytes);
        };
    };
};
};