Decode IDNA in PreviewCard (#2781)

app/javascript/mastodon/features/status/components/card.js

 import React from 'react';
 import ImmutablePropTypes from 'react-immutable-proptypes';
+import punycode from 'punycode'
 
-const hostStyle = {
-  display: 'block',
-  marginTop: '5px',
-  fontSize: '13px'
-};
+const IDNA_PREFIX = 'xn--';
+
+const decodeIDNA = domain => {
+  return domain
+    .split('.')
+    .map(part => part.indexOf(IDNA_PREFIX) === 0 ? punycode.decode(part.slice(IDNA_PREFIX.length)) : part)
+    .join('.');
+}
 
 const getHostname = url => {
   const parser = document.createElement('a');
@@ -30,7 +34,7 @@ class Card extends React.PureComponent {
     }
 
     if (provider.length < 1) {
-      provider = getHostname(card.get('url'))
+      provider = decodeIDNA(getHostname(card.get('url')));
     }
 
     return (
@@ -40,7 +44,7 @@ class Card extends React.PureComponent {
         <div className='status-card__content'>
           <strong className='status-card__title' title={card.get('title')}>{card.get('title')}</strong>
           <p className='status-card__description'>{(card.get('description') || '').substring(0, 50)}</p>
-          <span className='status-card__host' style={hostStyle}>{provider}</span>
+          <span className='status-card__host'>{provider}</span>
         </div>
       </a>
     );

app/javascript/styles/components.scss

@@ -1818,6 +1818,12 @@ button.icon-button.active i.fa-retweet {
   color: $color3;
 }
 
+.status-card__host {
+  display: block;
+  margin-top: 5px;
+  font-size: 13px;
+}
+
 .status-card__image {
   flex: 0 0 100px;
   background: lighten($color1, 8%);

app/services/fetch_link_card_service.rb

@@ -11,6 +11,7 @@ class FetchLinkCardService < BaseService
 
     return if url.nil?
 
+    url = Addressable::URI.parse(url).normalize.to_s
     card = PreviewCard.where(status: status).first_or_initialize(status: status, url: url)
     attempt_opengraph(card, url) unless attempt_oembed(card, url)
   end

package.json

@@ -63,6 +63,7 @@
     "postcss-smart-import": "^0.6.12",
     "precss": "^1.4.0",
     "prop-types": "^15.5.8",
+    "punycode": "^2.1.0",
     "rails-erb-loader": "^5.0.0",
     "react": "^15.5.4",
     "react-addons-perf": "^15.4.2",

yarn.lock

@@ -5343,6 +5343,10 @@ punycode@^1.2.4, punycode@^1.4.1:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.4.1.tgz#c0d5a63b2718800ad8e1eb0fa5269c84dd41845e"
 
+punycode@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.0.tgz#5f863edc89b96db09074bad7947bf09056ca4e7d"
+
 q@^1.1.2:
   version "1.4.1"
   resolved "https://registry.yarnpkg.com/q/-/q-1.4.1.tgz#55705bcd93c5f3673530c2c2cbc0c2b3addc286e"