HTTP POST 请求不允许我定义上下文类型

Question

我正在使用 Ubuntu 18.04 和 boost.asio 发送 POST 请求休息一下 API。当服务器收到请求时，它会捕获它，但我似乎无法定义它的内容类型。我有一个函数 collectRequestData 应该解析请求的主体，然后将其 return 保存到 MySQL 数据库中。当我打印函数 returns 时，它打印 null 而它应该是它发送的 JSON 文本。当我在调用函数之前打印 "Content-Type" 时，当我认为它应该是 "application/json" 时它打印未定义。我的最终目标是当我运行我的客户端代码 ./file.o localhost 8080 /licence '{JSON formatted text}' 它连接到本地主机端口 8080 路径 /licence （它正确执行）然后将 JSON 文本保存到 MySQL 数据库。它没有正确执行，我很确定原因是 "Content-Type" 我是使用服务器和 JavaScript 的新手，所以如果有人看到我做错了什么，请指出。另外，如果您能提供额外的细节以帮助我理解建议，我们将不胜感激。

下面是我发送 POST 请求的客户端代码

#include <iostream>
#include <istream>
#include <ostream>
#include <string>
#include <boost/asio.hpp>

using boost::asio::ip::tcp;
using namespace std;

int main(int argc, char* argv[])
{
    cout << "main -start" << endl;
    try
    {
        boost::asio::io_service io_service;
        string ipAddress = argv[1]; //"localhost" for loop back or ip address otherwise, i.e.- www.boost.org;       
        string portNum = argv[2]; //"8000" for instance;
        string hostAddress;
        if (portNum.compare("80") != 0) // add the ":" only if the port number is not 80 (proprietary port number).
        {
            hostAddress = ipAddress + ":" + portNum;
        }
        else 
        { 
            hostAddress = ipAddress;
        }
        string wordToQuery = "";//this will be used for entry indexing
        string queryStr = argv[3]; //"/api/v1/similar?word=" + wordToQuery;
        string json = argv[4];

        // Get a list of endpoints corresponding to the server name.
        tcp::resolver resolver(io_service);
        tcp::resolver::query query(ipAddress, portNum);
        tcp::resolver::iterator endpoint_iterator = resolver.resolve(query);

        // Try each endpoint until we successfully establish a connection.
        tcp::socket socket(io_service);
        boost::asio::connect(socket, endpoint_iterator);

        // Form the request. We specify the "Connection: close" header so that the
        // server will close the socket after transmitting the response. This will
        // allow us to treat all data up until the EOF as the content.
        string typeJSON = application/json;
        boost::asio::streambuf request;
        std::ostream request_stream(&request);
        request_stream << "POST " << queryStr << " HTTP/1.1\r\n";  // note that you can change it if you wish to HTTP/1.0
        request_stream << "Host: " << hostAddress << "\r\n";
        request_stream << "User-Agent: C/1.0";
        request_stream << "Content-Type: application/json; charset=utf-8\r\n";
        request_stream << "Accept: */*\r\n";
        request_stream << "Content-Length: " << json.length() << "\r\n"; 
        request_stream << "Connection: close\r\n\r\n";
        request_stream << json;

        // Send the request.
        boost::asio::write(socket, request);

        // Read the response status line. The response streambuf will automatically
        // grow to accommodate the entire line. The growth may be limited by passing
        // a maximum size to the streambuf constructor.
        boost::asio::streambuf response;
        boost::asio::read_until(socket, response, "\r\n");

        // Check that response is OK.
        std::istream response_stream(&response);
        std::string http_version;
        response_stream >> http_version;
        unsigned int status_code;
        response_stream >> status_code;
        std::string status_message;
        std::getline(response_stream, status_message);
        if (!response_stream || http_version.substr(0, 5) != "HTTP/")
        {
            std::cout << "Invalid response\n";
            return 1;
        }
        if (status_code != 200)
        {
            std::cout << "Response returned with status code " << status_code << "\n";
            return 1;
        }

        // Read the response headers, which are terminated by a blank line.
        boost::asio::read_until(socket, response, "\r\n\r\n");

        // Process the response headers.
        std::string header;
        while (std::getline(response_stream, header) && header != "\r")
        {
            std::cout << header << "\n";
        }

        std::cout << "\n";

        // Write whatever content we already have to output.
        if (response.size() > 0)
        {
            std::cout << &response;
        }

        // Read until EOF, writing data to output as we go.
        boost::system::error_code error;
        while (boost::asio::read(socket, response,boost::asio::transfer_at_least(1), error))
        {
            std::cout << &response;
        }

        if (error != boost::asio::error::eof)
        {
            throw boost::system::system_error(error);
        }
    }
    catch (std::exception& e)
    {
        std::cout << "Exception: " << e.what() << "\n";
    }

    return 0;
}

下面是我的服务器处理 POST 请求的部分

app.post('/licence', function (req, res) {
    collectRequestData(req, result => {
        //console.log(request.headers['Content-Type']);
        console.log(result);
        sleep(5000);
        connection.query('INSERT INTO licence SET ?', result, function (error, results) {
            if (error) throw error;
            res.end(JSON.stringify(results));
        });
        //res.end(`Parsed data belonging to ${result.fname}`);
    });
});

function collectRequestData(request, callback) {
    console.log(request.headers['Content-Type']);
    const FORM_URLENCODED = 'application/json';
    if(request.headers['Content-Type'] === FORM_URLENCODED) {
        let body = '';
        request.on('data', chunk => {
            body += chunk.toString();
        });
        request.on('end', () => {
            callback(JSON.parse(body));
        });
    }
    else {
        callback(null);
    }
}

Answer 1

您缺少行尾

request_stream << "User-Agent: C/1.0";

应该是

request_stream << "User-Agent: C/1.0\r\n";

表示您的内容类型 header 永远不会被识别，因为它不在单独的行上

Answer 2

我假设您正在为服务器使用 nodeJS

nodejs 给你小写的请求头

所以

function collectRequestData(request, callback) {
    console.log(request.headers['content-type']);
    const FORM_URLENCODED = 'application/json';
    if(request.headers['content-type'] === FORM_URLENCODED) {
        let body = '';

一旦您解决了@john 指出的其他问题，当然

即

You are missing an end of line

request_stream << "User-Agent: C/1.0";

should be

request_stream << "User-Agent: C/1.0\r\n";

Answer 3

感觉是网络服务器的问题，你可能不符合http协议规范。尝试使用 boost::beast，在 boost 1.66 及以上版本中可用。它是 boost::asio 的包装器，添加了高级网络服务器和网络套接字功能。您无需为低级 HTTP 实现而烦恼。

sample code

Answer 4

首先，我认为你应该仔细检查服务器是否正确。提供一种方法：

curl "http://localhost:8080/licence" --data "{json format text}" -v

如果此命令返回的结果与您的相同，则为服务器问题。如果不行，请尝试assemble你代码中的请求包内容与curl相同，尤其是“\r\n”等。

Answer 5

正确的解决方案是@john 和@Jaromanda X 所说的组合，我还必须将 const FORM_URLENCODED = 'application/json'; 更改为 const FORM_URLENCODED = 'application/json; charset=utf-8'

HTTP POST 请求不允许我定义上下文类型

HTTP POST request won't let me define context type

javascript

c++

rest

http

asio