void ServeRequest(const HttpRequest &req, ostream &os)
    {
        if (req.method == "POST")
        {
            if (req.path == "/add_user")
            {
                comments_.emplace_back();
                auto response = to_string(comments_.size() - 1);
                os << "HTTP/1.1 200 OK\n" << "Content-Length: " << response.size() << "\n" << "\n"
                   << response;
            }
            else if (req.path == "/add_comment")
            {
                auto[user_id, comment] = ParseIdAndContent(req.body);

                if (!last_comment || last_comment->user_id != user_id)
                {
                    last_comment = LastCommentInfo{user_id, 1};
                }
                else if (++last_comment->consecutive_count > 3)
                {
                    banned_users.insert(user_id);
                }

                if (banned_users.count(user_id) == 0)
                {
                    comments_[user_id].push_back(string(comment));
                    os << "HTTP/1.1 200 OK\n\n";
                }
                else
                {
                    os << "HTTP/1.1 302 Found\n\n"
                          "Location: /captcha\n"
                          "\n";
                }
            }
            else if (req.path == "/checkcaptcha")
            {
                if (auto[id, response] = ParseIdAndContent(req.body); response == "42")
                {
                    banned_users.erase(id);
                    if (last_comment && last_comment->user_id == id)
                    {
                        last_comment.reset();
                    }
                    os << "HTTP/1.1 200 OK\n\n";
                }
            }
            else
            {
                os << "HTTP/1.1 404 Not found\n\n";
            }
        }
        else if (req.method == "GET")
        {
            if (req.path == "/user_comments")
            {
                auto user_id = FromString<size_t>(req.get_params.at("user_id"));
                string response;
                for (const string &c : comments_[user_id])
                {
                    response += c + '\n';
                }

                os << "HTTP/1.1 200 OK\n" << "Content-Length: " << response.size() << response;
            }
            else if (req.path == "/captcha")
            {
                os << "HTTP/1.1 200 OK\n" << "Content-Length: 80\n" << "\n"
                   << "What's the answer for The Ultimate Question of Life, the Universe, and Everything?";
            }
            else
            {
                os << "HTTP/1.1 404 Not found\n\n";
            }
        }
    }