Step 11

Let's refactor our code and store all the middlewares in a separate module.

Add a file, middleware.js, to server/util folder:

const ApiError = require("../model/ApiError");
const { verifyToken, decodeToken, parseBearer } = require("./token");

const checkAdmin = async (req, res, next) => {
  const { authorization } = req.headers;
  const token = authorization ? parseBearer(authorization) : "";
  const valid = await verifyToken(token);
  const user = decodeToken(token);
  if (!valid || user.role !== "ADMIN") {
    next(new ApiError(403, "You are not authorized to perform this action."));
  }
  next();
};

const checkToken = async (req, res, next) => {
  const { authorization } = req.headers;
  const token = authorization ? parseBearer(authorization) : "";
  const valid = await verifyToken(token);
  if (!valid) {
    next(new ApiError(403, "You are not authorized to perform this action."));
  }
  req.user = decodeToken(token);
  next();
};

const globalErrorHandler = (err, req, res, next) => {
  if (err) {
    // debug(err);
    return res
      .status(err.status || 500)
      .json({ message: err.message || "Internal server error!" });
  }
  next();
};

module.exports = {
  checkToken,
  checkAdmin,
  globalErrorHandler,
};

Make the following updates:

1. Remove checkAdmin from server/routes/users.js (and related import stataments). Instead, import checkAdmin from ../util/middleware.
2. Remove checkToken from server/routes/notes.js (and related import stataments). Instead, import checkToken from ../util/middleware.
3. Update server/index.js (and related import stataments). Instead, import checkToken from ../util/middleware.

+ const { globalErrorHandler } = require("./util/middleware");

- // Global error handler!
- app.use((err, req, res, next) => {
-   if (err) {
-     // debug(err);
-     return res
-       .status(err.status || 500)
-       .json({message: err.message || "Internal server error!"});
-   }
-   next();
- });

+ app.use(globalErrorHandler);

Save the changes and rerun the tests to ensure the refactoring has not intriduced a defect.