C++ : Poco라이브러리로 REST API 서버 만들기(1)

 

1. POCO 라이브러리를 설치합니다.

https://pocoproject.org/download.html

POCO C++ Libraries - Simplify C++ Development

 

2. vcpkg를 이용하여 쉽게 설치할 수 있습니다.

    - vcpkg를 설치합니다.

    - vcpkg search poco를 실행한다.

    - vcpkg install poco[core,json,net]:x64-windows으로 필요한 라이브러리를 설치한다.

    - vcpkg install mariadb-connector-cpp:x64-windows로 mariaDB C++ Connector를

      설치한다.(SQL Server로 mariaDB Server를 사용합니다)

 

3. Database.h 파일을 추가합니다.

#pragma once

#include <mariadb/conncpp.hpp>

#include <memory>

class Database
{
public:
    static std::unique_ptr<sql::Connection> GetConnection();

private:
    static constexpr const char* URL = "jdbc:mariadb://127.0.0.1:3306/database1";    
    static constexpr const char* USER = "user1";

    static constexpr const char* PASSWORD = "password1";
};

 

4. Database.cpp 파일을 추가합니다.

#include "Database.h"
#include <iostream>
#include <cstdlib>

std::unique_ptr<sql::Connection>
Database::GetConnection()
{
 
    sql::SQLString url(URL);
    sql::Properties properties(
        {
            {"user", USER},
            {"password", PASSWORD},
        });

    _putenv_s("MARIADB_TLS_DISABLE_PEER_VERIFICATION", "1");

    sql::Driver* driver = sql::mariadb::get_driver_instance();

    std::unique_ptr<sql::Connection> conn;
    try {
        conn.reset(driver->connect(url, properties));
    }
    catch (sql::SQLException& e)
    {
        std::cerr << "Connection error: " << e.what() << std::endl;
        return nullptr;
		}
    return conn;
}

 

5. MemberHandler.h 파일을 추가합니다.

#pragma once

#include <Poco/Net/HTTPRequestHandler.h>
#include <Poco/Net/HTTPServerRequest.h>
#include <Poco/Net/HTTPServerResponse.h>

class MemberHandler : public Poco::Net::HTTPRequestHandler
{
public:
    void handleRequest(Poco::Net::HTTPServerRequest& request, Poco::Net::HTTPServerResponse& response) override;
};

 

6. MemberHandler.cpp 파일을 추가합니다.

#include "MemberHandler.h"
#include "Database.h"

#include <Poco/JSON/Object.h>
#include <Poco/JSON/Array.h>
#include <Poco/JSON/Stringifier.h>
#include <Poco/Dynamic/Var.h>
#include <Poco/JSON/Parser.h>

#include <mariadb/conncpp.hpp>
#include <sstream>

using namespace Poco::JSON;
using namespace Poco::Net;

void MemberHandler::handleRequest(HTTPServerRequest& request, HTTPServerResponse& response)
{
    if (request.getMethod() == "GET")
    {
		std::cout << "GET request received" << std::endl;

        std::string uri = request.getURI();

        if (uri == "/")
        {
            Poco::JSON::Object result;

			result.set("success", false);
            result.set("message","POCO REST Server Running");

            std::stringstream ss;

            result.stringify(ss);

			response.setStatus(Poco::Net::HTTPResponse::HTTP_BAD_REQUEST);
			response.setContentType("application/json");

            response.send() << ss.str();
        }
        else if (uri == "/members")
        {
            auto conn = Database::GetConnection();

            std::unique_ptr<sql::PreparedStatement> pstmt{ conn->prepareStatement("SELECT id, forename, surname, email FROM member") };

            std::unique_ptr<sql::ResultSet> rs{ pstmt->executeQuery() };

            Array arr;

            while (rs->next())
            {
                Object::Ptr obj = new Object;
                auto setStringOrNull = [&](const std::string& key)
                    {
                        auto value = rs->getString(key);
                        if (rs->wasNull())
                            obj->set(key, Poco::Dynamic::Var());
                        else
                            obj->set(key, std::string(value.c_str()));
                    };

                obj->set("id", rs->getInt("id"));
                setStringOrNull("forename");
                setStringOrNull("surname");
                setStringOrNull("email");
                
                arr.add(obj);
            }

            response.setStatus(Poco::Net::HTTPResponse::HTTP_OK);
            response.setContentType("application/json");
            arr.stringify(response.send());
        }
    }

    if (request.getMethod() == "POST")
    {
		std::cout << "POST request received" << std::endl;

        std::string uri = request.getURI();

        if (uri == "/members")
        {
            std::istream& in = request.stream();

            std::string body(std::istreambuf_iterator<char>(in), {});

            Parser parser;
            Poco::Dynamic::Var result = parser.parse(body);
            Object::Ptr j = result.extract<Object::Ptr>();

            auto conn = Database::GetConnection();

            auto pstmt =
                conn->prepareStatement(
                    "INSERT INTO member (forename, surname, email) VALUES (?, ?, ?)");

            pstmt->setString(1, j->getValue<std::string>("forename"));
            pstmt->setString(2, j->getValue<std::string>("surname"));
            pstmt->setString(3, j->getValue<std::string>("email"));

            pstmt->executeUpdate();

            Object obj;

            obj.set("success", true);
            obj.set("message", "member created");

            response.setStatus(Poco::Net::HTTPResponse::HTTP_CREATED);
            response.setContentType("application/json");

            std::stringstream ss;

            obj.stringify(ss);

            //response.send() << result.dump();
            response.send() << ss.str();
        }
        else
        {
            Poco::JSON::Object error;

            error.set("success",false);

            error.set("message","invalid uri");

            std::stringstream out;

            error.stringify(out);

            response.setStatus(Poco::Net::HTTPResponse::HTTP_BAD_REQUEST);
            response.setContentType("application/json");

            response.send() << out.str();
        }
    }

    if (request.getMethod() == "PUT")
    {
		std::cout << "PUT request received" << std::endl;

        std::string uri = request.getURI();

        std::vector<std::string> parts;

        std::stringstream ss(uri);

        std::string part;

        while (std::getline(ss, part, '/'))
        {
            if (!part.empty())
            {
                parts.push_back(part);
            }
        }

        if (parts.size() == 2 && parts[0] == "members")
        {
            int id = std::stoi(parts[1]);

            std::istream& in = request.stream();

            std::string body(std::istreambuf_iterator<char>(in), {});

            Poco::JSON::Parser parser;

            auto parsed = parser.parse(body);

            auto obj = parsed.extract<Poco::JSON::Object::Ptr>();

            std::string forename = obj->getValue<std::string>("forename");

            std::string surname = obj->getValue<std::string>("surname");

            std::string email = obj->getValue<std::string>("email");

            auto conn = Database::GetConnection();

            auto pstmt = conn->prepareStatement("UPDATE member SET forename=?, surname=?, email=? WHERE id=?");

            pstmt->setString(1, forename);
            pstmt->setString(2, surname);
            pstmt->setString(3, email);

            pstmt->setInt(4, id);

            pstmt->executeUpdate();

            Poco::JSON::Object result;

            result.set("success", true);
            result.set("message","member updated");

            result.set("id",id);

            response.setStatus(Poco::Net::HTTPResponse::HTTP_OK);
            response.setContentType("application/json");

            std::stringstream out;

            result.stringify(out);

            response.send() << out.str();
        }
        else
        {
            Poco::JSON::Object error;

            error.set("success", false);

            error.set("message", "invalid uri");

            std::stringstream out;

            error.stringify(out);

            response.setStatus(Poco::Net::HTTPResponse::HTTP_BAD_REQUEST);
            response.setContentType("application/json");

            response.send() << out.str();
        }
    }

    if (request.getMethod() == "DELETE")
    {
		std::cout << "DELETE request received" << std::endl;

		std::string uri = request.getURI(); // e.g. "/members/123"

        std::vector<std::string> parts;

        std::stringstream ss(uri);

        std::string part;

        while (std::getline(ss, part, '/'))
        {
            if (!part.empty())
            {
                parts.push_back(part);
            }
        }

        if (parts.size() == 2 && parts[0] == "members")
        {
            int id = std::stoi(parts[1]);

            auto conn = Database::GetConnection();

            auto pstmt = conn->prepareStatement("DELETE FROM member WHERE id=?");

            pstmt->setInt(1, id);

            pstmt->executeUpdate();

            Poco::JSON::Object result;

            result.set("success",true);

            result.set("message","member deleted");

            std::stringstream out;

            result.stringify(out);
            
            response.setStatus(Poco::Net::HTTPResponse::HTTP_OK);
            response.setContentType("application/json");

            response.send() << out.str();
        }
        else
        {
            Poco::JSON::Object error;

            error.set("success", false);

            error.set("message", "invalid uri");

            std::stringstream out;

            error.stringify(out);

            response.setStatus(Poco::Net::HTTPResponse::HTTP_BAD_REQUEST);
            response.setContentType("application/json");

            response.send() << out.str();
        }

	}
}

 

7. maim.cpp 파일을 추가합니다.

#include "MemberHandler.h"

#include <Poco/Net/HTTPServer.h>
#include <Poco/Net/HTTPRequestHandlerFactory.h>
#include <Poco/Net/ServerSocket.h>

#include <iostream>

using namespace Poco::Net;

class Factory : public HTTPRequestHandlerFactory
{
public:
    HTTPRequestHandler* createRequestHandler(const HTTPServerRequest&) override
    {
        return new MemberHandler();
    }
};

int main()
{
    ServerSocket socket(8080);

    HTTPServer server(
        new Factory(),
        socket,
        new HTTPServerParams);

    server.start();

    std::cout << "REST Server Start : 8080\n";

    getchar();

    server.stop();

    return 0;
}

 

8. 프로젝트를 실행합니다.

 

* 참고

- C++ : Poco라이브러리로 REST API 서버 만들기(2)

https://taekho.tistory.com/42

C++ : Poco라이브러리로 REST API 서버 만들기(2)

 

- C++ : Poco라이브러리로 REST API 서버 만들기(3)

https://taekho.tistory.com/43

 

- REST API Client는 다음을 참고하세요

  C++ GUI : wxWidgets의 webRequest로 REST API Client 만들기

https://taekho.tistory.com/46