improve error handling

lib/middlewares.js

@@ -0,0 +1,33 @@
+const FBURLError = () => new Error('Not a valid Facebook URL!')
+
+const genericErrorHandler = (err, req, res, next) => {
+  console.error(err.stack)
+  res
+    .status(500)
+    .render('error', { error: err.toString() })
+}
+
+const checkFBURL = (req, res, next) => {
+  const { url } = req.body
+
+  if (!url) {
+    return next(FBURLError())
+  }
+
+  try {
+    const FBURL = new URL(url)
+    if (!(/facebook/.test(FBURL.hostname))) {
+      return next(FBURLError())
+    }
+  } catch (err) {
+    return next(err)
+  }
+
+
+  return next()
+}
+
+module.exports = {
+  genericErrorHandler,
+  checkFBURL,
+}