说明：
cpp-httplib 是个开源的库，是一个c++封装的http库，使用这个库可以在linux、windows平台下完成http客户端、http服务端的搭建，这是一个多线程“阻塞”HTTP 库。
使用起来非常方便，只需要包含头文件httplib.h即可。
源码库地址：https://github.com/yhirose/cpp-httplib
httplib 库基本结构：
发送请求Request类的组成：
class Request
{
std::string method; // 请求方法
std::string path; // 请求路径
map<std::string, std::string> param; // 查询字符串(查询字符串中)
map<std::string, std::string> headers;// 键值对头部
std::string body; //正文
};
响应数据类Response的组成：
class Response
{
int status; //返回的状态码
map<std::string,std::string> headers; //返回的价值对头部
std::string body; //正文
};
服务端Server 类的组成：
class Server {
public:
using Handler = std::function<void(const Request &, Response &)>;
using HandlerWithContentReader = std::function<void(
const Request &, Response &, const ContentReader &content_reader)>;
using Expect100ContinueHandler =
std::function<int(const Request &, Response &)>;
Server();
virtual ~Server();
virtual bool is_valid() const;
Server &Get(const char *pattern, Handler handler);
Server &Post(const char *pattern, Handler handler);
Server &Post(const char *pattern, HandlerWithContentReader handler);
Server &Put(const char *pattern, Handler handler);
Server &Put(const char *pattern, HandlerWithContentReader handler);
Server &Patch(const char *pattern, Handler handler);
Server &Patch(const char *pattern, HandlerWithContentReader handler);
Server &Delete(const char *pattern, Handler handler);
Server &Delete(const char *pattern, HandlerWithContentReader handler);
Server &Options(const char *pattern, Handler handler);
客户端Client 类的组成：
class Client
{
//创建client
Client(host,port);
Get()
Post()
Put()
...
};
简单实例：
Server：
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// HTTP
httplib::Server svr;
// HTTPS
httplib::SSLServer svr;
svr.Get("/hi", [](const httplib::Request &, httplib::Response &res) {
res.set_content("Hello World!", "text/plain");
});
svr.listen("0.0.0.0", 8080);
Client：
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// HTTP
httplib::Client cli("http://cpp-httplib-server.yhirose.repl.co");
// HTTPS
httplib::Client cli("https://cpp-httplib-server.yhirose.repl.co");
auto res = cli.Get("/hi");
res->status;
res->body;
SSL Support：
SSL support 要用到 CPPHTTPLIB_OPENSSL_SUPPORT. libssl and libcrypto 的支持。
现在只有 httplib 1.1.1 支持ssl 服务器。
#define CPPHTTPLIB_OPENSSL_SUPPORT
#include "path/to/httplib.h"
// Server
httplib::SSLServer svr("./cert.pem", "./key.pem");
// Client
httplib::Client cli("https://localhost:1234"); // scheme + host
httplib::SSLClient cli("localhost:1234"); // host
// Use your CA bundle
cli.set_ca_cert_path("./ca-bundle.crt");
// Disable cert verification
cli.enable_server_certificate_verification(false);
g++ -o service service.cpp -I/usr/local/openssl/include -L/usr/local/openssl/lib -lssl -lcrypto -pthread
完整简单web例子：
#include <stdio.h>
#include <iostream>
#include <jsoncpp/json/json.h>
#include "httplib.h"
using namespace httplib;
using namespace std;
int g_val = 100;
void Get_CallBackFunc(const Request& req, Response& resp)
{
printf("%d\n", g_val);
cout << req.method << endl;
printf("i am Get_CallBackFunc\n");
const char* lp = "<html><h2>hello bite!</h2></html>";
resp.set_content(lp, strlen(lp), "text/html");
}
int main()
{
Server http_svr;
int a = 10;
http_svr.Get("/abc", Get_CallBackFunc);
http_svr.Post("/login", [](const Request& req, Response& resp){
cout << req.body << endl;
Json::Value resp_json;
resp_json["login_status"] = true;
Json::FastWriter w;
resp.body = w.write(resp_json);
resp.set_header("Content-Type", "application/json");
});
http_svr.set_mount_point("/", "./web");
http_svr.listen("0.0.0.0", 21010);
return 0;
}
完整简单upload例子：
#include "httplib.h"
#include <iostream>
#include <fstream>
using namespace httplib;
using namespace std;
int main(void)
{
Server svr;
svr.Post("/post", [](const Request &req, Response &res) {
auto music_file = req.get_file_value("music_file");
cout << "image file length: " << music_file.content.length() << endl
<< "image file name: " << music_file.filename << endl;
{
ofstream ofs(music_file.filename, ios::binary);
ofs << music_file.content;
}
res.set_content("done", "text/plain");
});
svr.set_mount_point("/", "./www");
/// listen
svr.listen("0.0.0.0", 9089);
}