cpp-httplib

#include <httplib.h>

int main(void)
{
    using namespace httplib;

    Server svr;

    svr.Get("/hi", [](const Request& req, Response& res) {
        res.set_content("Hello World!", "text/plain");
    });

    svr.Get(R"(/numbers/(\d+))", [&](const Request& req, Response& res) {
        auto numbers = req.matches[1];
        res.set_content(numbers, "text/plain");
    });

    svr.listen("localhost", 1234);
}

int port = svr.bind_to_any_port("0.0.0.0");
svr.listen_after_bind();

svr.Get("/get", [](const auto& req, auto& res) {
        res.set_content("get", "text/plain");
    })
    .Post("/post", [](const auto& req, auto& res) {
        res.set_content(req.body(), "text/plain");
    })
    .listen("localhost", 1234);

svr.set_base_dir("./www");

svr.set_logger([](const auto& req, const auto& res) {
    your_logger(req, res);
});

svr.set_error_handler([](const auto& req, auto& res) {
    const char* fmt = "<p>Error Status: <span style='color:red;'>%d</span></p>";
    char buf[BUFSIZ];
    snprintf(buf, sizeof(buf), fmt, res.status);
    res.set_content(buf, "text/html");
});

svr.Post("/multipart", [&](const auto& req, auto& res) {
    auto size = req.files.size();
    auto ret = req.has_file("name1"));
    const auto& file = req.get_file_value("name1");
    // file.filename;
    // file.content_type;
    auto body = req.body.substr(file.offset, file.length));
})

#include <httplib.h>
#include <iostream>

int main(void)
{
    httplib::Client cli("localhost", 1234);

    auto res = cli.Get("/hi");
    if (res && res->status == 200) {
        std::cout << res->body << std::endl;
    }
}

res = cli.Post("/post", "text", "text/plain");
res = cli.Post("/person", "name=john1&note=coder", "application/x-www-form-urlencoded");

httplib::Params params;
params.emplace("name", "john");
params.emplace("note", "coder");

auto res = cli.Post("/post", params);

httplib::Params params{
  { "name", "john" },
  { "note", "coder" }
};

auto res = cli.Post("/post", params);

res = cli.Put("/resource/foo", "text", "text/plain");

res = cli.Delete("/resource/foo");

res = cli.Options("*");
res = cli.Options("/resource/foo");

httplib::Client cli("localhost", 8080, 5); // timeouts in 5 seconds

httplib::Client client(url, port);

// prints: 0 / 000 bytes => 50% complete
std::shared_ptr<httplib::Response> res =
    cli.Get("/", [](uint64_t len, uint64_t total) {
        printf("%lld / %lld bytes => %d%% complete\n",
            len, total,
            (int)((len/total)*100));
        return true; // return 'false' if you want to cancel the request.
    }
);

httplib::Client cli("httpbin.org", 80);

// 'Range: bytes=1-10'
httplib::Headers headers = { httplib::make_range_header(1, 10) };

auto res = cli.Get("/range/32", headers);
// res->status should be 206.
// res->body should be "bcdefghijk".

#define CPPHTTPLIB_OPENSSL_SUPPORT

SSLServer svr("./cert.pem", "./key.pem");

SSLClient cli("localhost", 8080);