From 4297d5aa64ecf9982f2cc695ee2721f80f142742 Mon Sep 17 00:00:00 2001
From: Ondrej Synacek <ondrejsynacek@fastmail.com>
Date: Thu, 17 Oct 2019 22:36:29 +0200
Subject: [PATCH] improve error handling

---
 lib/index.js       | 26 +++++++++++---------------
 lib/middlewares.js | 33 +++++++++++++++++++++++++++++++++
 lib/parser.js      |  1 -
 3 files changed, 44 insertions(+), 16 deletions(-)
 create mode 100644 lib/middlewares.js

diff --git a/lib/index.js b/lib/index.js
index 2479979..40951c6 100644
--- a/lib/index.js
+++ b/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 res
-      .status(500)
-      .render('error', { error: err.toString() })
+    return next(err)
   }
-
-  return res.render('download', { url })
 })
 
+app.use(genericErrorHandler)
+
 app.listen(port, () => {
   console.log(`App running on port ${port}`)
 })
diff --git a/lib/middlewares.js b/lib/middlewares.js
new file mode 100644
index 0000000..41758ef
--- /dev/null
+++ b/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,
+}
diff --git a/lib/parser.js b/lib/parser.js
index 5e3506e..aff473a 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -84,7 +84,6 @@ const parseHTML = (html) => {
       {}
     const data = parseEventData(eventData)
 
-    console.log(data)
     return data
   } catch (err) {
     throw err