如何通过boost beast提交登录请求？

Question

我试图使用boost beast登录该站点，但在结果中只能得到字段已更改的页面

#include <iostream>

#include "boost/asio.hpp"
#include "boost/beast.hpp"

namespace beast = boost::beast;
namespace http = beast::http;
namespace asio = boost::asio;
using tcp = asio::ip::tcp;

int main() {
    asio::io_context context;

    beast::tcp_stream stream(context);
    stream.connect(tcp::resolver(context).resolve("site.com", "http"));

    http::request<http::string_body> request;
    request.version(11);
    request.method(http::verb::post);
    request.target("/login.php?redirect=somepage");
    request.set(http::field::host, "site.com");
    request.set(http::field::content_type, "application/x-www-form-urlencoded");
    request.body() = "fusername=USERNAME&fpassword=PASSWORD";
    request.prepare_payload();

    boost::beast::http::write(stream, request);

    boost::beast::flat_buffer buffer;
    boost::beast::http::response<boost::beast::http::dynamic_body> res;

    boost::beast::http::read(stream, buffer, res);

    std::cout << res;
}

这个站点的方法部分看起来像这样

<form action="./login.php" method="post">
    <input type="hidden" name="redirect" value="somepage">
    <div><b>Enter your username and password to log in.</b></div>
    <div class="input-prepend">
        <span class="add-on" style="width:100px;text-align:right;">Username:</span>
        <input type="text" class="post input" name="fusername" size="25" maxlength="40" value="" tabindex="101">
    </div>
    <div class="input-prepend">
        <span class="add-on" style="width:100px;text-align:right;">Password:</span>
        <input type="password" class="post input" name="fpassword" value="" tabindex="102" size="25" maxlength="32">
    </div>
    <input type="submit" name="login" class="bold long btn" value="Log in" style="margin:0 auto;">

</form>

res与页面相同，只是值字段看起来像value="USERNAME"

Answer 1

重定向实际上也是在正文中发送的输入值，而不是用作URL参数。尝试更改：

request.target("/login.php");

和

request.body() = "fusername=USERNAME&fpassword=PASSWORD&redirect=somepage";

Answer 2

好了，我找到答案了，希望能对你有所帮助。

在作为参数发送时，您需要对字符串“

• ”使用转义序列

• 如果站点有名称和值的按钮，则需要将其作为参数传递给POST too

• POST将更改状态，但不会返回页面使用GET after this

• 如果站点向您发送应答中的cookie，则需要将其添加到GET请求

是的，如果你不能创建HTTP请求，你可以直接在浏览器(比如Firefox)中登录，然后从浏览器中获取原始请求。

#include <iostream>
#include <fstream>

#include "boost/asio.hpp"
#include "boost/beast.hpp"

namespace beast = boost::beast;
namespace http = beast::http;
namespace asio = boost::asio;
using tcp = asio::ip::tcp;

static std::string const host = "site.com";
static std::string const redirected = "/somepage=1";
static std::string const redirected_escaped = "somepage%3D1";

static std::string const username = "USERNAME";
static std::string const password = "PASSWORD";

int main() {
    try {
        std::ofstream output("../output.html");

        asio::io_context context;

        beast::tcp_stream stream(context);
        stream.connect(tcp::resolver(context).resolve(host, "http"));

        std::string cookie;

        {
            http::request<http::string_body> request(http::verb::post, "/login.php", 11);
            request.set(http::field::host, host);
            request.set(http::field::content_type, "application/x-www-form-urlencoded");

            request.body() =
                    "redirect=" + redirected_escaped +
                    "&login_username=" + username +
                    "&login_password=" + password +
                    "&login=Log+in";
            request.prepare_payload();

            std::cout << request << std::endl;

            boost::beast::http::write(stream, request);

            boost::beast::flat_buffer buffer;
            boost::beast::http::response<boost::beast::http::dynamic_body> res;

            boost::beast::http::read(stream, buffer, res);

            cookie = std::string(res.base().at(http::field::set_cookie));

            std::cout << "Cookie: " << cookie << std::endl;
        }

        {
            http::request<http::string_body> request(http::verb::get, redirected, 11);
            request.set(http::field::host, host);
            request.set(http::field::cookie, cookie);

            std::cout << request << std::endl;

            boost::beast::http::write(stream, request);

            boost::beast::flat_buffer buffer;
            boost::beast::http::response<boost::beast::http::dynamic_body> res;

            boost::beast::http::read(stream, buffer, res);

            output << beast::buffers_to_string(res.body().data());
        }

    } catch (boost::wrapexcept<boost::system::system_error> const &wrapexcept) {
        std::cout << wrapexcept.what();
    }

}