C++实现轻量级极简httpserver和httpclient(转)

xiaoxiao2025-02-14 33

一般来说，C++的项目多是偏底层，不怎么需要跟http打交道，但有时候又需要在C++后端项目中加入一些简单 http接口，比如游戏运营服务器，金融交易监控服务等。

但是传统的实现方法比如采用libcurl，asio等较为重型的框架来做有没有必要，因此，这里采用mongoose这个库来实现基本的httpserver和httpclient功能，非常简单，包含一个h文件，一个cpp文件到工程中就行了，无需编译，无需链接库。

本文实现了一个project，将mongoose中提供的http相关api封装成了httpserver类和httpclient类，方便调用，目录结构如下：

├─common ├─mongoose.h └─mongoose.cpp ├─httpclient ├─http_client.h ├─http_client.cpp └─main.cpp └─httpserver └─web └─index.html ├─http_server.h ├─http_server.cpp └─main.cpp

编译环境：win10，vs2015， C++11 （其实是跨平台的）

http_server.h

#pragma once #include <string> #include <unordered_map> #include <functional> #include "../common/mongoose.h"

// 定义http返回callback typedef void OnRspCallback(mg_connection *c, std::string); // 定义http请求handler using ReqHandler = std::function<bool (std::string, std::string, mg_connection *c, OnRspCallback)>;

class HttpServer { public: HttpServer() {} ~HttpServer() {} void Init(const std::string &port); // 初始化设置 bool Start(); // 启动httpserver bool Close(); // 关闭 void AddHandler(const std::string &url, ReqHandler req_handler); // 注册事件处理函数 void RemoveHandler(const std::string &url); // 移除时间处理函数 static std::string s_web_dir; // 网页根目录 static mg_serve_http_opts s_server_option; // web服务器选项 static std::unordered_map<std::string, ReqHandler> s_handler_map; // 回调函数映射表

private: // 静态事件响应函数 static void OnHttpEvent(mg_connection *connection, int event_type, void *event_data); static void HandleEvent(mg_connection *connection, http_message *http_req); static void SendRsp(mg_connection *connection, std::string rsp);

std::string m_port; // 端口 mg_mgr m_mgr; // 连接管理器 };

http_server.cpp

#include <utility> #include "http_server.h"

void HttpServer::Init(const std::string &port) { m_port = port; s_server_option.enable_directory_listing = "yes"; s_server_option.document_root = s_web_dir.c_str(); // TODO：其他设置 }

bool HttpServer::Start() { mg_mgr_init(&m_mgr, NULL); mg_connection *connection = mg_bind(&m_mgr, m_port.c_str(), OnHttpEvent); if (connection == NULL) return false; mg_set_protocol_http_websocket(connection);

printf("starting http server at port: %s\n", m_port.c_str()); // loop while (true) mg_mgr_poll(&m_mgr, 500); // ms

return true; }

void HttpServer::OnHttpEvent(mg_connection *connection, int event_type, void *event_data) { http_message *http_req = (http_message *)event_data; switch (event_type) { case MG_EV_HTTP_REQUEST: HandleEvent(connection, http_req); break; default: break; } }

static bool route_check(http_message *http_msg, char *route_prefix) { if (mg_vcmp(&http_msg->uri, route_prefix) == 0) return true; else return false;

// TODO: 还可以判断 GET, POST, PUT, DELTE等方法 //mg_vcmp(&http_msg->method, "GET"); //mg_vcmp(&http_msg->method, "POST"); //mg_vcmp(&http_msg->method, "PUT"); //mg_vcmp(&http_msg->method, "DELETE"); }

void HttpServer::AddHandler(const std::string &url, ReqHandler req_handler) { if (s_handler_map.find(url) != s_handler_map.end()) return;

s_handler_map.insert(std::make_pair(url, req_handler)); }

void HttpServer::RemoveHandler(const std::string &url) { auto it = s_handler_map.find(url); if (it != s_handler_map.end()) s_handler_map.erase(it); }

void HttpServer::SendRsp(mg_connection *connection, std::string rsp) { // 必须先发送header mg_printf(connection, "%s", "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\n\r\n"); // 以json形式返回 mg_printf_http_chunk(connection, "{ \"result\": %s }", rsp.c_str()); // 发送空白字符快，结束当前响应 mg_send_http_chunk(connection, "", 0); }

void HttpServer::HandleEvent(mg_connection *connection, http_message *http_req) { std::string req_str = std::string(http_req->message.p, http_req->message.len); printf("got request: %s\n", req_str.c_str());

// 先过滤是否已注册的函数回调 std::string url = std::string(http_req->uri.p, http_req->uri.len); std::string body = std::string(http_req->body.p, http_req->body.len); auto it = s_handler_map.find(url); if (it != s_handler_map.end()) { ReqHandler handle_func = it->second; handle_func(url, body, connection, SendRsp); }

// 其他请求 if (route_check(http_req, "/")) // index page mg_serve_http(connection, http_req, s_server_option); else if (route_check(http_req, "/api/hello")) { // 直接回传 SendRsp(connection, "welcome to httpserver"); } else if (route_check(http_req, "/api/sum")) { // 简单post请求，加法运算测试 char n1[100], n2[100]; double result;

/* Get form variables */ mg_get_http_var(&http_req->body, "n1", n1, sizeof(n1)); mg_get_http_var(&http_req->body, "n2", n2, sizeof(n2));

/* Compute the result and send it back as a JSON object */ result = strtod(n1, NULL) + strtod(n2, NULL); SendRsp(connection, std::to_string(result)); } else { mg_printf( connection, "%s", "HTTP/1.1 501 Not Implemented\r\n" "Content-Length: 0\r\n\r\n"); } }

bool HttpServer::Close() { mg_mgr_free(&m_mgr); return true; }

index.html

<!DOCTYPE html> <html> <head> <title>RESTful API demo</title>

$(document).ready(function(){ $("button").click(function(){ $.get("/api/hello",function(data, status){ console.log("get rsp: ", data); $('#result1').html(data); }); }); });

$(document).on('keyup', '#n1, #n2', function() { $.ajax({ url: '/api/sum', method: 'POST', dataType: 'json', data: { n1: $('#n1').val(), n2: $('#n2').val() }, success: function(json) { console.log("post rsp: ", json); $('#result2').html(json.result); } }); });

</script> </head> <body> <h1>c++ httpserver demo</h1>

<p> front end request </p>

<h2>GET</h2> <div> <button id="btn">get request</button> </div> <div> <label>Result1:</label> <span id="result1"> </span> </div>

<h2>POST</h2> <div> <label>Number 1:</label> <input type="text" id="n1" /> </div> <div> <label>Number 2:</label> <input type="text" id="n2" /> </div> <div> <label>Result2:</label> <span id="result2"> </span> </div>

</body> </html>

main.cpp

#include <iostream> #include <memory> #include "http_server.h"

// 初始化HttpServer静态类成员 mg_serve_http_opts HttpServer::s_server_option; std::string HttpServer::s_web_dir = "./web"; std::unordered_map<std::string, ReqHandler> HttpServer::s_handler_map;

bool handle_fun1(std::string url, std::string body, mg_connection *c, OnRspCallback rsp_callback) { // do sth std::cout << "handle fun1" << std::endl; std::cout << "url: " << url << std::endl; std::cout << "body: " << body << std::endl;

rsp_callback(c, "rsp1");

return true; }

bool handle_fun2(std::string url, std::string body, mg_connection *c, OnRspCallback rsp_callback) { // do sth std::cout << "handle fun2" << std::endl; std::cout << "url: " << url << std::endl; std::cout << "body: " << body << std::endl;

rsp_callback(c, "rsp2");

return true; }

int main(int argc, char *argv[]) { std::string port = "7999"; auto http_server = std::shared_ptr<HttpServer>(new HttpServer); http_server->Init(port); // add handler http_server->AddHandler("/api/fun1", handle_fun1); http_server->AddHandler("/api/fun2", handle_fun2); http_server->RemoveHandler("/api/fun3"); // http_server->RemoveHandler("/api/fun3"); http_server->Start(); return 0; }

服务器支持host静态页面资源，也支持rest api调用需要手动设置loop polling的时间间隔可以自定义静态页面根路径，注册和解注册自定义api函数回调某些变量必须声明定义成全局或者静态变量

http客户端

http_client.h

#pragma once #include <string> #include <functional> #include "../common/mongoose.h"

// 此处必须用function类，typedef再后面函数指针赋值无效 using ReqCallback = std::function<void (std::string)>;

class HttpClient { public: HttpClient() {} ~HttpClient() {}

static void SendReq(const std::string &url, ReqCallback req_callback); static void OnHttpEvent(mg_connection *connection, int event_type, void *event_data); static int s_exit_flag; static ReqCallback s_req_callback; };

http_client.cpp

#include "http_client.h"

// 初始化client静态变量 int HttpClient::s_exit_flag = 0; ReqCallback HttpClient::s_req_callback;

// 客户端的网络请求响应 void HttpClient::OnHttpEvent(mg_connection *connection, int event_type, void *event_data) { http_message *hm = (struct http_message *)event_data; int connect_status;

switch (event_type) { case MG_EV_CONNECT: connect_status = *(int *)event_data; if (connect_status != 0) { printf("Error connecting to server, error code: %d\n", connect_status); s_exit_flag = 1; } break; case MG_EV_HTTP_REPLY: { printf("Got reply:\n%.*s\n", (int)hm->body.len, hm->body.p); std::string rsp = std::string(hm->body.p, hm->body.len); connection->flags |= MG_F_SEND_AND_CLOSE; s_exit_flag = 1; // 每次收到请求后关闭本次连接，重置标记 // 回调处理 s_req_callback(rsp); } break; case MG_EV_CLOSE: if (s_exit_flag == 0) { printf("Server closed connection\n"); s_exit_flag = 1; }; break; default: break; } }

// 发送一次请求，并回调处理，然后关闭本次连接 void HttpClient::SendReq(const std::string &url, ReqCallback req_callback) { // 给回调函数赋值 s_req_callback = req_callback; mg_mgr mgr; mg_mgr_init(&mgr, NULL); auto connection = mg_connect_http(&mgr, OnHttpEvent, url.c_str(), NULL, NULL); mg_set_protocol_http_websocket(connection);

printf("Send http request %s\n", url.c_str());

// loop while (s_exit_flag == 0) mg_mgr_poll(&mgr, 500);

mg_mgr_free(&mgr); }

client每次请求都是一个独立的请求请求函数中加入回调用于处理网络返回

测试可以用浏览器、或者其他工具提交url，查看网络请求返回 GET请求 http://localhost:7999/api/hello

结果 { "result": welcome to httpserver }

POST请求 http://localhost:7999/api/sum?n1=20&n2=18 结果 { "result": 38 }https://www.cnblogs.com/cnxkey/articles/8777975.html(转自这里)

https://blog.csdn.net/u012234115/article/details/79596826(原作者)

最新回复(0)