c++ - Boost-beast websocket握手问题

Question

我正在尝试与远程服务器建立 websocket 连接，但出现以下错误:WebSocket 握手被远程端拒绝

我正在关注这个例子:https://www.boost.org/doc/libs/1_70_0/libs/beast/example/websocket/client/sync/websocket_client_sync.cpp

对于以下服务器:https://api.hitbtc.com/#socket-api-reference

提前感谢您的帮助!

int main(int argc, char** argv) {
    try
    {
        auto const host = "api.hitbtc.com";
        auto const port = "443";

        net::io_context ioc;
        tcp::resolver resolver{ ioc };
        websocket::stream<tcp::socket> ws{ ioc };

        auto const results = resolver.resolve(host, port);

        net::connect(ws.next_layer(), results.begin(), results.end());

        // Perform the websocket handshake - this is where i presume the issue is.
        ws.handshake(host, "/api/2/ws");

        beast::flat_buffer buffer;
        ws.read(buffer);
        ws.close(websocket::close_code::normal);
        std::cout << beast::make_printable(buffer.data()) << std::endl;
    }
    catch (std::exception const& e)
    {
        std::cerr << "Error: " << e.what() << std::endl;
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

Answer 1

您必须提供 ssl 上下文。这是 example来自 boost.org，

这里是 api.hitbtc 握手和通过 JSON-RPC 获取货币信息的示例(我省略了证书加载):

#include <boost/beast/core.hpp>
#include <boost/beast/ssl.hpp>
#include <boost/beast/websocket.hpp>
#include <boost/beast/websocket/ssl.hpp>
#include <boost/asio/connect.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/ssl/stream.hpp>
#include <cstdlib>
#include <iostream>
#include <string>

namespace beast = boost::beast;         // from <boost/beast.hpp>
namespace http = beast::http;           // from <boost/beast/http.hpp>
namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
namespace net = boost::asio;            // from <boost/asio.hpp>
namespace ssl = boost::asio::ssl;       // from <boost/asio/ssl.hpp>
using tcp = boost::asio::ip::tcp;       // from <boost/asio/ip/tcp.hpp>

// Sends a WebSocket message and prints the response
int main(int argc, char** argv)
{
    try
    {
        // Check command line arguments.
        auto const host = "api.hitbtc.com";
        auto const port = "443";
        auto const rpcJson = R"({"method":"getCurrency", "params":{"currency":"ETH"},"id":0})";

        // The io_context is required for all I/O
        net::io_context ioc;

        // The SSL context is required, and holds certificates
        ssl::context ctx{ssl::context::tlsv12_client};

        // This holds the root certificate used for verification
        //load_root_certificates(ctx);

        // These objects perform our I/O
        tcp::resolver resolver{ioc};
        websocket::stream<beast::ssl_stream<tcp::socket>> ws{ioc, ctx};

        // Look up the domain name
        auto const results = resolver.resolve(host, port);

        // Make the connection on the IP address we get from a lookup
        net::connect(ws.next_layer().next_layer(), results.begin(), results.end());

        // Perform the SSL handshake
        ws.next_layer().handshake(ssl::stream_base::client);

        // Set a decorator to change the User-Agent of the handshake
        ws.set_option(websocket::stream_base::decorator(
            [](websocket::request_type& req)
            {
                req.set(http::field::user_agent,
                    std::string(BOOST_BEAST_VERSION_STRING) +
                        " websocket-client-coro");
            }));

        // Perform the websocket handshake
        ws.handshake(host, "/api/2/ws");

        // Our message in this case should be stringified JSON-RPC request
        ws.write(net::buffer(std::string(rpcJson)));

        // This buffer will hold the incoming message
        beast::flat_buffer buffer;

        // Read a message into our buffer
        ws.read(buffer);

        // Close the WebSocket connection
        ws.close(websocket::close_code::normal);

        // If we get here then the connection is closed gracefully

        // The make_printable() function helps print a ConstBufferSequence
        std::cout << beast::make_printable(buffer.data()) << std::endl;
    }
    catch(std::exception const& e)
    {
        std::cerr << "Error: " << e.what() << std::endl;
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

您应该得到字符串化的 JSON-RPC 响应。在这种情况下，对于 getCurrency("ETH") 请求，响应将是:

{"jsonrpc":"2.0","result":{"id":"ETH","fullName":"Ethereum","crypto":true,"payinEnabled":true,"payinPaymentId":false,"payinConfirmations":2,"payoutEnabled":true,"payoutIsPaymentId":false,"transferEnabled":true,"delisted":false,"payoutFee":"0.0428"},"id":null}