middleware.js

const multer = require("multer");
const { multerConfig } = require("./config/general.config");
const upload = multer(multerConfig);
const fs = require("fs");

module.exports.isLoggedIn = (req, res, next) => {
  if (!req.isAuthenticated()) {
    req.session.returnTo = req.originalUrl;
    req.user = false;
    req.flash("error", "You must be logged in to view this page!");
    return res.redirect("/");
  } else {
    next();
  }
};

module.exports.isAdminAuthenticated = (req, res, next) => {
  if (process.env.NODE_ENV === "development") {
    // bypass admin auth in development mode
    next();
  } else {
    if (
      req.user === undefined ||
      !req.user.is_admin ||
      !req.isAuthenticated()
    ) {
      req.session.returnTo = req.originalUrl;
      req.user = false;
      req.flash("error", "You do not have permission to view this page!");
      return res.redirect("/");
    } else {
      next();
    }
  }
};

module.exports.upload = (id) => {
  const impl = upload.single(id);
  return async (req, res, next) => {
    impl(req, res, async (err) => {
      if (err instanceof multer.MulterError) {
        req.flash(
          "error",
          "Please upload a valid image. Only JPEG, JPG, and PNG files are allowed, and they must be under 5MB.",
        );
        res.redirect(req.url);
      } else if (err) {
        req.flash(
          "error",
          "An error occurred while trying to upload your image! Please try again. If the issue persists, contact us.",
        );
        res.redirect(req.url);
      } else {
        next();
      }
    });
  };
};

module.exports.fallible = (block) => {
  return async (req, res, next) => {
    try {
      await block(req, res);
    } catch (e) {
      // If any upload middleware was used, we will need to remove the
      // newly-uploaded image as it's unlikely to be referenced anywhere
      // in the database.
      if (req.file) {
        try {
          fs.unlinkSync("uploads/" + req.file.filename);
        } catch (e) {
          // Letting this error be thrown would crash the server, and
          // routing it to next would override the original error we
          // wanted to catch and make debugging more difficult. Thus,
          // we ignore the error.
        }
      }
      next(e);
    }
  };
};