improve error handling

lib/index.js

@@ -5,6 +5,7 @@ const path = require('path')
 const crawl = require('./crawler')
 const parseHTML = require('./parser')
 const generateICS = require('./ics')
+const { genericErrorHandler, checkFBURL } = require('./middlewares')
 
 const port = process.env.PORT
 const app = express()
@@ -21,18 +22,16 @@ app.get('*', (req, res) => {
   res.status(400).render('404')
 })
 
+app.get('/error', (req, res) => {
+  res
+    .status(500)
+    .render('error', { error: req.error || '' })
+})
+
+app.use('/download', checkFBURL)
 app.post('/download', async (req, res) => {
   const { url } = req.body
 
-  if (!/facebook/.test(url)) {
-    return res
-      .status(500)
-      .render(
-        'error',
-        { error: 'Not Facebook URL!' }
-      )
-  }
-
   try {
     const html = await crawl(url)
     const data = parseHTML(html)
@@ -44,15 +43,12 @@ app.post('/download', async (req, res) => {
         .send(200, new Buffer(ics, 'utf8'))
     }
   } catch (err) {
-    console.error(err)
+    return next(err)
-    return res
-      .status(500)
-      .render('error', { error: err.toString() })
   }
-
-  return res.render('download', { url })
 })
 
+app.use(genericErrorHandler)
+
 app.listen(port, () => {
   console.log(`App running on port ${port}`)
 })

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,
+}

lib/parser.js

@@ -84,7 +84,6 @@ const parseHTML = (html) => {
       {}
     const data = parseEventData(eventData)
 
-    console.log(data)
     return data
   } catch (err) {
     throw err