Question

我使用优秀的websocketpp库在C ++应用程序中提供Websockets（和HTTP）服务器。我还需要在同一个应用程序中的HTTP客户端连接到REST API。我也一直在websocketpp尝试这个，但到目前为止我没有成功。以下初步尝试为我提供了这个日志输出：

[2015-03-06 18:01:18] [connect] Successful connection
[2015-03-06 18:01:18] [error] Server handshake response error: websocketpp.processor:20 (Invalid HTTP status.)
[2015-03-06 18:01:18] [disconnect] Failed: Invalid HTTP status.

这表明我的http_处理程序方法可能需要更多内容。任何意见，将不胜感激。 websocketpp文档和示例似乎不包括简单的HTTP客户端。

#define _WEBSOCKETPP_CPP11_STL_
#include <websocketpp/config/asio_client.hpp>
#include <websocketpp/client.hpp>
#include <websocketpp/common/thread.hpp>

namespace {

using namespace websocketpp;
typedef client<websocketpp::config::asio_client> client;

class Client {
public:

    Client(void){
        client_.init_asio();
        client_.set_http_handler(bind(&Client::http_,this,_1));
    }

    std::string get(const std::string& url) {
        websocketpp::lib::error_code error;
        client::connection_ptr con = client_.get_connection(url,error);
        if(error) std::runtime_error("Unable to connnect.\n  url: "+url+"\n  message: "+error.message());
        client_.connect(con);
        websocketpp::lib::thread asio_thread(&client::run, &client_);
        asio_thread.join();
        return data_;
    }

private:

    void http_(connection_hdl hdl){
        std::cout<<"Connected\n";
        data_ = "http payload";
    }

    client client_;
    std::string data_;
};

}

int main(void){
    Client client;
    client.get("http://google.com/");
}

Answer 1

WebSocket ++的HTTP处理功能是一种便利功能，旨在允许WebSocket服务器以有限的容量提供HTTP响应。 WebSocket ++不适合用作通用HTTP库，也不包含扮演（非WebSocket）HTTP客户端角色的能力。

为HTTP客户端功能使用单独的库（例如cpp-netlib）是一个很好的解决方案。

Answer 2

如果您正在尝试在C ++中同时执行WebSocket和HTTP，那么有一个名为Beast的伟大库，其中包含这些东西！它的开源并建立在Boost.Asio上： https://github.com/vinniefalco/Beast/

以下是一些示例代码：

使用HTTP从网站请求根页并打印响应：

#include <beast/http.hpp>
#include <boost/asio.hpp>
#include <iostream>
#include <string>

int main()
{
    // Normal boost::asio setup
    std::string const host = "boost.org";
    boost::asio::io_service ios;
    boost::asio::ip::tcp::resolver r(ios);
    boost::asio::ip::tcp::socket sock(ios);
    boost::asio::connect(sock,
        r.resolve(boost::asio::ip::tcp::resolver::query{host, "http"}));

    // Send HTTP request using beast
    beast::http::request_v1<beast::http::empty_body> req;
    req.method = "GET";
    req.url = "/";
    req.version = 11;
    req.headers.replace("Host", host + ":" + std::to_string(sock.remote_endpoint().port()));
    req.headers.replace("User-Agent", "Beast");
    beast::http::prepare(req);
    beast::http::write(sock, req);

    // Receive and print HTTP response using beast
    beast::streambuf sb;
    beast::http::response_v1<beast::http::streambuf_body> resp;
    beast::http::read(sock, sb, resp);
    std::cout << resp;
}

建立WebSocket连接，发送消息并收到回复：

#include <beast/to_string.hpp>
#include <beast/websocket.hpp>
#include <boost/asio.hpp>
#include <iostream>
#include <string>

int main()
{
    // Normal boost::asio setup
    std::string const host = "echo.websocket.org";
    boost::asio::io_service ios;
    boost::asio::ip::tcp::resolver r(ios);
    boost::asio::ip::tcp::socket sock(ios);
    boost::asio::connect(sock,
        r.resolve(boost::asio::ip::tcp::resolver::query{host, "80"}));

    // WebSocket connect and send message using beast
    beast::websocket::stream<boost::asio::ip::tcp::socket&> ws(sock);
    ws.handshake(host, "/");
    ws.write(boost::asio::buffer("Hello, world!"));

    // Receive WebSocket message, print and close using beast
    beast::streambuf sb;
    beast::websocket::opcode op;
    ws.read(op, sb);
    ws.close(beast::websocket::close_code::normal);
    std::cout << to_string(sb.data()) << "\n";
}

Answer 3

我不知道如何阻止websocketpp客户端要求Upgrade: connection，所以我最终使用cpp-netlib代替HTTP客户端。

Websocketpp简单的HTTP客户端

3 个答案: