C++ Web Framework Oat++ Controller

前面的例子中，每一个请求的 URL 都对应了一个 HttpRequestHandler 类，并实现该类中 handle 函数，如下代码：

class Handler1 : public oatpp::web::server::HttpRequestHandler {
public:
    std::shared_ptr<OutgoingResponse> handle(const std::shared_ptr<IncomingRequest>& request) override {
        (void)request;
        return ResponseFactory::createResponse(Status::CODE_200, "Hello Handler1");
    }
};


class Handler2 : public oatpp::web::server::HttpRequestHandler {
public:
    std::shared_ptr<OutgoingResponse> handle(const std::shared_ptr<IncomingRequest>& request) override {
        (void)request;
        return ResponseFactory::createResponse(Status::CODE_200, "Hello Handler2");
    }
};

如果我们设计更多的 URL 就需要写更多的 HttpRequestHandler 类，比较麻烦。控制器（Cotroller）可以简化这部分代码。先增加一个 Controller.hpp 文件，代码如下:

#ifndef CONTROLLER_HPP
#define CONTROLLER_HPP

#include "oatpp/web/server/api/ApiController.hpp"
#include "oatpp/core/macro/codegen.hpp"
#include "oatpp/parser/json/mapping/ObjectMapper.hpp"

// 1. 必须增加这一行代码
#include OATPP_CODEGEN_BEGIN(ApiController)


class Controller : public oatpp::web::server::api::ApiController {
public:
    Controller(const std::shared_ptr<ObjectMapper>& object_mapper) : oatpp::web::server::api::ApiController(object_mapper) {}
public:
    // 注意: 定义多个处理函数时，第三个参数名字不能重复
    ENDPOINT("GET", "/hello", root) {
        return ResponseFactory::createResponse(Status::CODE_200, "hello oat++");
    }

    // 获得 PATH 参数
    ENDPOINT("GET", "/path/{param}", get_path_param, PATH(String, param)) {
        String message = "hello " + param;
        return ResponseFactory::createResponse(Status::CODE_200, message);
    }

    // 获得 QUERY 参数
    ENDPOINT("GET", "/query", get_query_param, QUERY(Int32, age), QUERY(String, name)) {
        // QUERY 第二个参数名对应 ? 后的请求参数名
        String message = "name=" + name + ", age=" + std::to_string(age);
        return ResponseFactory::createResponse(Status::CODE_200, message);
    }

    // 获得 HEADER
    ENDPOINT("GET", "/header", get_header_param, HEADER(String, user_agent, "User-Agent")) {
        // QUERY 第二个参数名对应 ? 后的请求参数名
        String message = user_agent;
        return ResponseFactory::createResponse(Status::CODE_200, message);
    }

};

// 2. 必须增加这一行代码
#include OATPP_CODEGEN_END(ApiController)


#endif

run 函数代码如下:

#include "oatpp/web/server/HttpConnectionHandler.hpp"
#include "oatpp/network/Server.hpp"
#include "oatpp/network/tcp/server/ConnectionProvider.hpp"
#include "oatpp/web/server/HttpRouter.hpp"
#include "oatpp/parser/json/mapping/ObjectMapper.hpp"
#include "Cotroller.hpp"


void run() {

    // 1. 创建路由对象
    auto router = oatpp::web::server::HttpRouter::createShared();
    auto object_mapper = oatpp::parser::json::mapping::ObjectMapper::createShared();
    // 构建控制器对象
    auto controller = std::make_shared<Controller>(object_mapper);
    // 设置控制器到路由器
    router->addController(controller);

    // 2. 连接处理对象
    // 服务器接受得到连接之后，交给 HttpConnectionHandler 来处理连接
    auto conn_handler = oatpp::web::server::HttpConnectionHandler::createShared(router);

    // 3. 套接字监听参数
    auto address = oatpp::network::Address({"localhost", 8000, oatpp::network::Address::IP_4});
    auto conn_provider = oatpp::network::tcp::server::ConnectionProvider::createShared(address);

    // 4. 构建服务对象
    oatpp::network::Server server(conn_provider, conn_handler);

    // 5. 服务启动信息
    const void* host = conn_provider->getProperty("host").getData();
    const void* port = conn_provider->getProperty("port").getData();
    OATPP_LOGI("url1", "http://%s:%s/hello", host, port);
    OATPP_LOGI("url2", "http://%s:%s/path/abc", host, port);
    OATPP_LOGI("url3", "http://%s:%s/query?age=18&name=obama", host, port);
    OATPP_LOGI("url4", "http://%s:%s/header", host, port);

    // 6. 启动服务等待连接
    server.run();
}

int main() {

    oatpp::base::Environment::init();
    run();
    oatpp::base::Environment::destroy();

    return 0;
}

程序输出结果:

 I |2023-02-11 00:31:47 1676046707449597| url1:http://localhost:8000/hello
 I |2023-02-11 00:31:47 1676046707449817| url2:http://localhost:8000/path/abc
 I |2023-02-11 00:31:47 1676046707449825| url3:http://localhost:8000/query?age=18&name=obama
 I |2023-02-11 00:31:47 1676046707449832| url4:http://localhost:8000/header