Closes #665 - Correctly handle user not granting auth permissions, display friendly error

server/auth/slack.js

@@ -78,8 +78,13 @@ router.get('slack.callback', async ctx => {
 });
 
 router.get('slack.commands', async ctx => {
-  const { code } = ctx.request.query;
-  ctx.assertPresent(code, 'code is required');
+  const { code, error } = ctx.request.query;
+  ctx.assertPresent(code || error, 'code is required');
+
+  if (error) {
+    ctx.redirect(`/settings/integrations/slack?error=${error}`);
+    return;
+  }
 
   const endpoint = `${process.env.URL || ''}/auth/slack.commands`;
   const data = await Slack.oauthAccess(code, endpoint);
@@ -108,8 +113,13 @@ router.get('slack.commands', async ctx => {
 });
 
 router.get('slack.post', async ctx => {
-  const { code, state } = ctx.request.query;
-  ctx.assertPresent(code, 'code is required');
+  const { code, error, state } = ctx.request.query;
+  ctx.assertPresent(code || error, 'code is required');
+
+  if (error) {
+    ctx.redirect(`/settings/integrations/slack?error=${error}`);
+    return;
+  }
 
   const collectionId = state;
   ctx.assertUuid(collectionId, 'collectionId must be an uuid');

server/pages/Home.js

@@ -4,6 +4,7 @@ import { Helmet } from 'react-helmet';
 import styled from 'styled-components';
 import Grid from 'styled-components-grid';
 import breakpoint from 'styled-components-breakpoint';
+import Notice from '../../shared/components/Notice';
 import Hero from './components/Hero';
 import SigninButtons from './components/SigninButtons';
 import { developers, githubUrl } from '../../shared/utils/routeHelpers';
@@ -120,13 +121,6 @@ function Home(props: Props) {
   );
 }
 
-const Notice = styled.p`
-  background: #ffd95c;
-  color: hsla(46, 100%, 20%, 1);
-  padding: 10px;
-  border-radius: 4px;
-`;
-
 const Screenshot = styled.img`
   width: 100%;
   box-shadow: 0 0 80px 0 rgba(124, 124, 124, 0.5),