router.h

#pragma once

#include <functional>
#include <string>
#include <string_view>
#include <unordered_map>

#include "request.h"
#include "response.h"

class Router {
public:
  using Handler = std::function<Response(const Request &)>;

  void add(std::string method, std::string path, Handler h) {
    routes_[method + " " + path] = std::move(h);
  }

  Response handle(const Request &req) const {
    std::string_view route_path = req.path;
    if (auto q = route_path.find('?'); q != std::string_view::npos)
      route_path = route_path.substr(0, q);

    std::string key;
    key.reserve(req.method.size() + 1 + route_path.size());
    key.append(req.method);
    key.push_back(' ');
    key.append(route_path);

    if (auto it = routes_.find(key); it != routes_.end())
      return it->second(req);

    return not_found(req);
  }

private:
  std::unordered_map<std::string, Handler> routes_;

  static Response not_found(const Request &) {
    Response r;
    r.status_code = 404;
    r.status_text = "Not Found";
    r.body = "404 Not Found\n";
    r.headers["Content-Type"] = "text/plain";
    return r;
  }
};