Routing без фреймворків · fullstack.org.ua

fullstack.org.ua

Routing без фреймворків · fullstack.org.ua

javascript

const http = require("node:http");

const users = [
  { id: 1, name: "Olena" },
  { id: 2, name: "Andrii" },
];

function sendJson(res, statusCode, data) {
  res.writeHead(statusCode, {
    "Content-Type": "application/json; charset=utf-8",
  });

  res.end(JSON.stringify(data));
}

function readJsonBody(req) {
  return new Promise((resolve, reject) => {
    let body = "";

    req.setEncoding("utf8");

    req.on("data", (chunk) => {
      body += chunk;
    });

    req.on("end", () => {
      if (body.trim() === "") {
        resolve({});
        return;
      }

      try {
        resolve(JSON.parse(body));
      } catch {
        reject(new Error("Некоректний JSON"));
      }
    });

    req.on("error", reject);
  });
}

function homeHandler(req, res) {
  sendJson(res, 200, {
    message: "API працює",
  });
}

function listUsersHandler(req, res, params, url) {
  const limit = Number(url.searchParams.get("limit"));

  if (Number.isInteger(limit) && limit > 0) {
    sendJson(res, 200, users.slice(0, limit));
    return;
  }

  sendJson(res, 200, users);
}

function getUserHandler(req, res, params) {
  const userId = Number(params.id);
  const user = users.find((item) => item.id === userId);

  if (!user) {
    sendJson(res, 404, {
      error: "Користувача не знайдено",
    });
    return;
  }

  sendJson(res, 200, user);
}

async function createUserHandler(req, res) {
  let data;

  try {
    data = await readJsonBody(req);
  } catch (error) {
    sendJson(res, 400, {
      error: error.message,
    });
    return;
  }

  if (typeof data.name !== "string" || data.name.trim() === "") {
    sendJson(res, 400, {
      error: "Поле name є обов'язковим",
    });
    return;
  }

  const user = {
    id: users.length === 0 ? 1 : users[users.length - 1].id + 1,
    name: data.name.trim(),
  };

  users.push(user);

  sendJson(res, 201, user);
}

const routes = [
  {
    method: "GET",
    pattern: /^\/$/,
    handler: homeHandler,
  },
  {
    method: "GET",
    pattern: /^\/users\/?$/,
    handler: listUsersHandler,
  },
  {
    method: "GET",
    pattern: /^\/users\/(?<id>[^/]+)\/?$/,
    handler: getUserHandler,
  },
  {
    method: "POST",
    pattern: /^\/users\/?$/,
    handler: createUserHandler,
  },
];

function findRoute(method, pathname) {
  for (const route of routes) {
    if (route.method !== method) {
      continue;
    }

    const match = pathname.match(route.pattern);

    if (match) {
      return {
        route,
        params: match.groups ?? {},
      };
    }
  }

  return null;
}

function getAllowedMethods(pathname) {
  return [
    ...new Set(
      routes
        .filter((route) => route.pattern.test(pathname))
        .map((route) => route.method),
    ),
  ];
}

const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, `http://${req.headers.host}`);
  const { pathname } = url;

  const matchedRoute = findRoute(req.method, pathname);

  if (!matchedRoute) {
    const allowedMethods = getAllowedMethods(pathname);

    if (allowedMethods.length > 0) {
      res.setHeader("Allow", allowedMethods.join(", "));
      sendJson(res, 405, {
        error: "Метод не дозволений для цього маршруту",
      });
      return;
    }

    sendJson(res, 404, {
      error: "Маршрут не знайдено",
    });
    return;
  }

  try {
    await matchedRoute.route.handler(
      req,
      res,
      matchedRoute.params,
      url,
    );
  } catch (error) {
    console.error(error);

    if (!res.headersSent) {
      sendJson(res, 500, {
        error: "Внутрішня помилка сервера",
      });
    }
  }
});

const port = 3000;

server.listen(port, () => {
  console.log(`Сервер запущено на http://localhost:${port}`);
});