From 52763f5115a7fa7f8c592d373800b2d34ea20125 Mon Sep 17 00:00:00 2001
From: Erick Guan <fantasticfears@gmail.com>
Date: Mon, 5 Dec 2016 13:31:43 +0100
Subject: [PATCH] FEATURE: Allow posting a link with topics

---
 .../discourse/components/composer-body.js.es6 |  5 +-
 .../discourse/controllers/history.js.es6      |  3 ++
 .../discourse/controllers/topic.js.es6        |  8 ++++
 .../helpers/topic-featured-link.js.es6        |  6 +++
 .../lib/render-topic-featured-link.js.es6     | 46 +++++++++++++++++++
 .../discourse/models/category.js.es6          | 12 +++++
 .../discourse/models/composer.js.es6          | 40 ++++++++++++----
 .../components/edit-category-settings.hbs     | 11 +++++
 .../templates/components/topic-category.hbs   | 20 ++++----
 .../discourse/templates/composer.hbs          |  6 ++-
 .../templates/list/topic-list-item.raw.hbs    |  3 ++
 .../discourse/templates/modal/history.hbs     |  7 +++
 .../javascripts/discourse/templates/topic.hbs |  3 ++
 .../widgets/header-topic-info.js.es6          | 10 +++-
 .../stylesheets/common/base/compose.scss      |  4 ++
 .../stylesheets/common/base/tagging.scss      | 33 ++-----------
 app/assets/stylesheets/common/base/topic.scss | 21 ++++++++-
 .../common/components/badges.css.scss         |  4 ++
 app/assets/stylesheets/desktop/compose.scss   |  9 ++++
 .../stylesheets/desktop/topic-post.scss       | 24 +++++++++-
 app/controllers/posts_controller.rb           |  1 -
 app/helpers/application_helper.rb             | 11 +++++
 app/models/topic.rb                           | 13 ++++++
 app/models/topic_list.rb                      |  2 +
 app/serializers/post_revision_serializer.rb   |  4 ++
 app/serializers/site_serializer.rb            | 11 ++++-
 app/serializers/suggested_topic_serializer.rb | 10 +++-
 app/serializers/topic_list_item_serializer.rb | 11 ++++-
 app/serializers/topic_view_serializer.rb      | 12 ++++-
 app/views/user_notifications/digest.html.erb  |  6 +++
 config/locales/client.en.yml                  |  2 +
 config/locales/server.en.yml                  |  8 ++++
 config/site_settings.yml                      | 10 ++++
 lib/discourse_featured_link.rb                | 27 +++++++++++
 lib/email/styles.rb                           |  5 ++
 lib/guardian/category_guardian.rb             |  5 ++
 lib/guardian/topic_guardian.rb                |  5 ++
 lib/post_creator.rb                           | 20 +++++++-
 lib/post_revisor.rb                           | 17 +++++++
 lib/topic_creator.rb                          |  4 ++
 lib/validators/post_validator.rb              | 11 +++--
 spec/components/guardian_spec.rb              | 23 ++++++++++
 spec/components/post_creator_spec.rb          |  9 ++++
 .../validators/post_validator_spec.rb         | 10 ++++
 spec/controllers/posts_controller_spec.rb     |  8 +---
 .../fabricators/embeddable_host_fabricator.rb |  4 ++
 spec/models/category_spec.rb                  | 10 ++--
 spec/models/topic_spec.rb                     | 36 ++++++++++++++-
 spec/support/helpers.rb                       |  4 +-
 test/javascripts/models/composer-test.js.es6  |  6 ++-
 50 files changed, 503 insertions(+), 77 deletions(-)
 create mode 100644 app/assets/javascripts/discourse/helpers/topic-featured-link.js.es6
 create mode 100644 app/assets/javascripts/discourse/lib/render-topic-featured-link.js.es6
 create mode 100644 lib/discourse_featured_link.rb

diff --git a/app/assets/javascripts/discourse/components/composer-body.js.es6 b/app/assets/javascripts/discourse/components/composer-body.js.es6
index d3c1e96d2eb..aba22cf7284 100644
--- a/app/assets/javascripts/discourse/components/composer-body.js.es6
+++ b/app/assets/javascripts/discourse/components/composer-body.js.es6
@@ -13,7 +13,8 @@ export default Ember.Component.extend({
                       'composer.canEditTitle:edit-title',
                       'composer.createdPost:created-post',
                       'composer.creatingTopic:topic',
-                      'composer.whisper:composing-whisper'],
+                      'composer.whisper:composing-whisper',
+                      'composer.showComposerEditor::topic-featured-link-only'],
 
   @computed('composer.composeState')
   composeState(composeState) {
@@ -27,7 +28,7 @@ export default Ember.Component.extend({
     this.appEvents.trigger("composer:resized");
   },
 
-  @observes('composeState', 'composer.action')
+  @observes('composeState', 'composer.action', 'composer.canEditTopicFeaturedLink')
   resize() {
     Ember.run.scheduleOnce('afterRender', () => {
       if (!this.element || this.isDestroying || this.isDestroyed) { return; }
diff --git a/app/assets/javascripts/discourse/controllers/history.js.es6 b/app/assets/javascripts/discourse/controllers/history.js.es6
index 42550be8803..e94852cf3ec 100644
--- a/app/assets/javascripts/discourse/controllers/history.js.es6
+++ b/app/assets/javascripts/discourse/controllers/history.js.es6
@@ -21,6 +21,9 @@ export default Ember.Controller.extend(ModalFunctionality, {
     if (this.site.mobileView) { this.set("viewMode", "inline"); }
   }.on("init"),
 
+  previousFeaturedLink: Em.computed.alias('model.featured_link_changes.previous'),
+  currentFeaturedLink: Em.computed.alias('model.featured_link_changes.current'),
+
   previousTagChanges: customTagArray('model.tags_changes.previous'),
   currentTagChanges: customTagArray('model.tags_changes.current'),
 
diff --git a/app/assets/javascripts/discourse/controllers/topic.js.es6 b/app/assets/javascripts/discourse/controllers/topic.js.es6
index 377aebd76d5..4b9650fd98c 100644
--- a/app/assets/javascripts/discourse/controllers/topic.js.es6
+++ b/app/assets/javascripts/discourse/controllers/topic.js.es6
@@ -160,6 +160,14 @@ export default Ember.Controller.extend(SelectedPostsCount, BufferedContent, {
     return post => this.postSelected(post);
   }.property(),
 
+  @computed('model.isPrivateMessage', 'model.category.id')
+  canEditTopicFeaturedLink(isPrivateMessage, categoryId) {
+    if (!this.siteSettings.topic_featured_link_enabled || isPrivateMessage) { return false; }
+
+    const categoryIds = this.site.get('topic_featured_link_allowed_category_ids');
+    return categoryIds === undefined || !categoryIds.length || categoryIds.indexOf(categoryId) !== -1;
+  },
+
   @computed('model.isPrivateMessage')
   canEditTags(isPrivateMessage) {
     return !isPrivateMessage && this.site.get('can_tag_topics');
diff --git a/app/assets/javascripts/discourse/helpers/topic-featured-link.js.es6 b/app/assets/javascripts/discourse/helpers/topic-featured-link.js.es6
new file mode 100644
index 00000000000..686599e2b1f
--- /dev/null
+++ b/app/assets/javascripts/discourse/helpers/topic-featured-link.js.es6
@@ -0,0 +1,6 @@
+import { registerUnbound } from 'discourse-common/lib/helpers';
+import renderTopicFeaturedLink from 'discourse/lib/render-topic-featured-link';
+
+export default registerUnbound('topic-featured-link', function(topic, params) {
+  return new Handlebars.SafeString(renderTopicFeaturedLink(topic, params));
+});
diff --git a/app/assets/javascripts/discourse/lib/render-topic-featured-link.js.es6 b/app/assets/javascripts/discourse/lib/render-topic-featured-link.js.es6
new file mode 100644
index 00000000000..c8c3d640f80
--- /dev/null
+++ b/app/assets/javascripts/discourse/lib/render-topic-featured-link.js.es6
@@ -0,0 +1,46 @@
+import { extractDomainFromUrl } from 'discourse/lib/utilities';
+import { h } from 'virtual-dom';
+
+const _decorators = [];
+
+export function addFeaturedLinkMetaDecorator(decorator) {
+  _decorators.push(decorator);
+}
+
+function extractLinkMeta(topic) {
+  const href = topic.featured_link, target = Discourse.SiteSettings.open_topic_featured_link_in_external_window ? '_blank' : '';
+  if (!href) { return; }
+
+  let domain = extractDomainFromUrl(href);
+  if (!domain) { return; }
+
+  // www appears frequently, so we truncate it
+  if (domain && domain.substr(0, 4) === 'www.') {
+    domain = domain.substring(4);
+  }
+
+  const meta = { target, href, domain, rel: 'nofollow' };
+  if (_decorators.length) {
+    _decorators.forEach(cb => cb(meta));
+  }
+  return meta;
+}
+
+export default function renderTopicFeaturedLink(topic) {
+  const meta = extractLinkMeta(topic);
+  if (meta) {
+    return `<a class="topic-featured-link" rel="${meta.rel}" target="${meta.target}" href="${meta.href}">${meta.domain}</a>`;
+  } else {
+    return '';
+  }
+};
+
+export function topicFeaturedLinkNode(topic) {
+  const meta = extractLinkMeta(topic);
+  if (meta) {
+    return h('a.topic-featured-link', {
+      attributes: { href: meta.href, rel: meta.rel, target: meta.target }
+    }, meta.domain);
+  }
+}
+
diff --git a/app/assets/javascripts/discourse/models/category.js.es6 b/app/assets/javascripts/discourse/models/category.js.es6
index b77a4abdf33..fc56790194d 100644
--- a/app/assets/javascripts/discourse/models/category.js.es6
+++ b/app/assets/javascripts/discourse/models/category.js.es6
@@ -169,6 +169,18 @@ const Category = RestModel.extend({
   @computed("id")
   isUncategorizedCategory(id) {
     return id === Discourse.Site.currentProp("uncategorized_category_id");
+  },
+
+  @computed('custom_fields.topic_featured_link_allowed')
+  topicFeaturedLinkAllowed: {
+    get(allowed) {
+      return allowed === "true";
+    },
+    set(value) {
+      value = value ? "true" : "false";
+      this.set("custom_fields.topic_featured_link_allowed", value);
+      return value;
+    }
   }
 });
 
diff --git a/app/assets/javascripts/discourse/models/composer.js.es6 b/app/assets/javascripts/discourse/models/composer.js.es6
index e782c4074ae..52d8cde6aef 100644
--- a/app/assets/javascripts/discourse/models/composer.js.es6
+++ b/app/assets/javascripts/discourse/models/composer.js.es6
@@ -32,13 +32,15 @@ const CLOSED = 'closed',
         target_usernames: 'targetUsernames',
         typing_duration_msecs: 'typingTime',
         composer_open_duration_msecs: 'composerTime',
-        tags: 'tags'
+        tags: 'tags',
+        featured_link: 'featuredLink'
       },
 
       _edit_topic_serializer = {
         title: 'topic.title',
         categoryId: 'topic.category.id',
-        tags: 'topic.tags'
+        tags: 'topic.tags',
+        featuredLink: 'topic.featured_link'
       };
 
 const Composer = RestModel.extend({
@@ -136,6 +138,14 @@ const Composer = RestModel.extend({
   canEditTitle: Em.computed.or('creatingTopic', 'creatingPrivateMessage', 'editingFirstPost'),
   canCategorize: Em.computed.and('canEditTitle', 'notCreatingPrivateMessage'),
 
+  @computed('canEditTitle', 'creatingPrivateMessage', 'categoryId')
+  canEditTopicFeaturedLink(canEditTitle, creatingPrivateMessage, categoryId) {
+    if (!this.siteSettings.topic_featured_link_enabled || !canEditTitle || creatingPrivateMessage) { return false; }
+
+    const categoryIds = this.site.get('topic_featured_link_allowed_category_ids');
+    return categoryIds === undefined || !categoryIds.length || categoryIds.indexOf(categoryId) !== -1;
+  },
+
   // Determine the appropriate title for this action
   actionTitle: function() {
     const topic = this.get('topic');
@@ -180,6 +190,10 @@ const Composer = RestModel.extend({
 
   }.property('action', 'post', 'topic', 'topic.title'),
 
+  @computed('canEditTopicFeaturedLink')
+  showComposerEditor(canEditTopicFeaturedLink) {
+    return canEditTopicFeaturedLink ? !this.siteSettings.topic_featured_link_onebox : true;
+  },
 
   // whether to disable the post button
   cantSubmitPost: function() {
@@ -269,11 +283,12 @@ const Composer = RestModel.extend({
     }
   }.property('privateMessage'),
 
-  missingReplyCharacters: function() {
-    const postType = this.get('post.post_type');
-    if (postType === this.site.get('post_types.small_action')) { return 0; }
-    return this.get('minimumPostLength') - this.get('replyLength');
-  }.property('minimumPostLength', 'replyLength'),
+  @computed('minimumPostLength', 'replyLength', 'canEditTopicFeaturedLink')
+  missingReplyCharacters(minimumPostLength, replyLength, canEditTopicFeaturedLink) {
+    if (this.get('post.post_type') === this.site.get('post_types.small_action') ||
+        canEditTopicFeaturedLink && this.siteSettings.topic_featured_link_onebox) { return 0; }
+    return minimumPostLength - replyLength;
+  },
 
   /**
     Minimum number of characters for a post body to be valid.
@@ -492,6 +507,14 @@ const Composer = RestModel.extend({
 
   save(opts) {
     if (!this.get('cantSubmitPost')) {
+
+      // change category may result in some effect for topic featured link
+      if (this.get('canEditTopicFeaturedLink')) {
+        if (this.siteSettings.topic_featured_link_onebox) { this.set('reply', null); }
+      } else {
+        this.set('featuredLink', null);
+      }
+
       return this.get('editingPost') ? this.editPost(opts) : this.createPost(opts);
     }
   },
@@ -512,7 +535,8 @@ const Composer = RestModel.extend({
       stagedPost: false,
       typingTime: 0,
       composerOpened: null,
-      composerTotalOpened: 0
+      composerTotalOpened: 0,
+      featuredLink: null
     });
   },
 
diff --git a/app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs b/app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs
index 72883cba5ad..790e61e9390 100644
--- a/app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs
+++ b/app/assets/javascripts/discourse/templates/components/edit-category-settings.hbs
@@ -19,6 +19,17 @@
   </label>
 </section>
 
+{{#if siteSettings.topic_featured_link_enabled}}
+  <section class='field'>
+    <div class="allowed-topic-featured-link-category">
+      <label class="checkbox-label">
+        {{input type="checkbox" checked=category.topicFeaturedLinkAllowed}}
+        {{i18n 'category.topic_featured_link_allowed'}}
+      </label>
+    </div>
+  </section>
+{{/if}}
+
 <section class="field">
   <label>
     {{i18n "category.sort_order"}}
diff --git a/app/assets/javascripts/discourse/templates/components/topic-category.hbs b/app/assets/javascripts/discourse/templates/components/topic-category.hbs
index c3114225607..cf717a09922 100644
--- a/app/assets/javascripts/discourse/templates/components/topic-category.hbs
+++ b/app/assets/javascripts/discourse/templates/components/topic-category.hbs
@@ -2,12 +2,16 @@
   {{bound-category-link topic.category.parentCategory}}
 {{/if}}
 {{bound-category-link topic.category hideParent=true}}
-{{#if siteSettings.tagging_enabled}}
-  <div class="list-tags">
-    {{#each topic.tags as |t|}}
-      {{discourse-tag t}}
-    {{/each}}
-  </div>
-{{/if}}
-
+<div class="topic-header-extra">
+  {{#if siteSettings.tagging_enabled}}
+    <div class="list-tags">
+      {{#each topic.tags as |t|}}
+        {{discourse-tag t}}
+      {{/each}}
+    </div>
+  {{/if}}
+  {{#if siteSettings.topic_featured_link_enabled}}
+    {{topic-featured-link topic}}
+  {{/if}}
+</div>
 {{plugin-outlet "topic-category"}}
diff --git a/app/assets/javascripts/discourse/templates/composer.hbs b/app/assets/javascripts/discourse/templates/composer.hbs
index ffed59d239c..bf40be927c1 100644
--- a/app/assets/javascripts/discourse/templates/composer.hbs
+++ b/app/assets/javascripts/discourse/templates/composer.hbs
@@ -80,9 +80,13 @@
                     {{/if}}
                     {{render "additional-composer-buttons" model}}
                   {{/if}}
+                  {{#if model.canEditTopicFeaturedLink}}
+                    <div class="topic-featured-link-input">
+                      {{text-field tabindex="4" type="url" value=model.featuredLink id='topic-featured-link' placeholderKey="composer.topic_featured_link_placeholder"}}
+                    </div>
+                  {{/if}}
                 </div>
               {{/if}}
-
               {{plugin-outlet "composer-fields"}}
             </div>
 
diff --git a/app/assets/javascripts/discourse/templates/list/topic-list-item.raw.hbs b/app/assets/javascripts/discourse/templates/list/topic-list-item.raw.hbs
index bc21dfd6a7d..da825c4774b 100644
--- a/app/assets/javascripts/discourse/templates/list/topic-list-item.raw.hbs
+++ b/app/assets/javascripts/discourse/templates/list/topic-list-item.raw.hbs
@@ -7,6 +7,9 @@
 <td class='main-link clearfix' colspan="{{titleColSpan}}">
   {{raw "topic-status" topic=topic}}
   {{topic-link topic}}
+  {{#if topic.featured_link}}
+    {{topic-featured-link topic}}
+  {{/if}}
   {{plugin-outlet "topic-list-after-title"}}
   {{#if showTopicPostBadges}}
     {{raw "topic-post-badges" unread=topic.unread newPosts=topic.displayNewPosts unseen=topic.unseen url=topic.lastUnreadUrl}}
diff --git a/app/assets/javascripts/discourse/templates/modal/history.hbs b/app/assets/javascripts/discourse/templates/modal/history.hbs
index eac25480d52..ce860fefcbf 100644
--- a/app/assets/javascripts/discourse/templates/modal/history.hbs
+++ b/app/assets/javascripts/discourse/templates/modal/history.hbs
@@ -86,6 +86,13 @@
         {{/each}}
       </div>
     {{/if}}
+    {{#if model.featured_link_changes}}
+      <div class='row'>
+        {{model.featured_link_changes.previous}}
+        &rarr;
+        {{model.featured_link_changes.current}}
+      </div>
+    {{/if}}
 
     {{plugin-outlet "post-revisions"}}
 
diff --git a/app/assets/javascripts/discourse/templates/topic.hbs b/app/assets/javascripts/discourse/templates/topic.hbs
index 65c0f3f6a81..aed888a39f8 100644
--- a/app/assets/javascripts/discourse/templates/topic.hbs
+++ b/app/assets/javascripts/discourse/templates/topic.hbs
@@ -25,6 +25,9 @@
                 {{category-chooser valueAttribute="id" value=buffered.category_id}}
               {{/if}}
 
+              {{#if canEditTopicFeaturedLink}}
+                {{text-field type="url" value=buffered.featured_link id='topic-featured-link' placeholderKey="composer.topic_featured_link_placeholder"}}
+              {{/if}}
               {{#if canEditTags}}
                 <br>
                 {{tag-chooser tags=buffered.tags categoryId=buffered.category_id}}
diff --git a/app/assets/javascripts/discourse/widgets/header-topic-info.js.es6 b/app/assets/javascripts/discourse/widgets/header-topic-info.js.es6
index 8704830bbde..a3d5ad585d7 100644
--- a/app/assets/javascripts/discourse/widgets/header-topic-info.js.es6
+++ b/app/assets/javascripts/discourse/widgets/header-topic-info.js.es6
@@ -4,6 +4,7 @@ import { iconNode } from 'discourse/helpers/fa-icon-node';
 import DiscourseURL from 'discourse/lib/url';
 import RawHtml from 'discourse/widgets/raw-html';
 import { tagNode } from 'discourse/lib/render-tag';
+import { topicFeaturedLinkNode } from 'discourse/lib/render-topic-featured-link';
 
 export default createWidget('header-topic-info', {
   tagName: 'div.extra-info-wrapper',
@@ -44,12 +45,19 @@ export default createWidget('header-topic-info', {
         title.push(this.attach('category-link', { category }));
       }
 
+      const extra = [];
       if (this.siteSettings.tagging_enabled) {
         const tags = topic.get('tags') || [];
         if (tags.length) {
-          title.push(h('div.list-tags', tags.map(tagNode)));
+          extra.push(h('div.list-tags', tags.map(tagNode)));
         }
       }
+      if (this.siteSettings.topic_featured_link_enabled) {
+        extra.push(topicFeaturedLinkNode(attrs.topic));
+      }
+      if (extra) {
+        title.push(h('div.topic-header-extra', extra));
+      }
     }
 
     const contents = h('div.title-wrapper', title);
diff --git a/app/assets/stylesheets/common/base/compose.scss b/app/assets/stylesheets/common/base/compose.scss
index dfadbd6fb80..4e53da0fc26 100644
--- a/app/assets/stylesheets/common/base/compose.scss
+++ b/app/assets/stylesheets/common/base/compose.scss
@@ -187,6 +187,10 @@ div.ac-wrap {
   }
 }
 
+#reply-control.topic-featured-link-only.open {
+  .wmd-controls { display: none; }
+}
+
 #cancel-file-upload {
   font-size: 1.6em;
 }
diff --git a/app/assets/stylesheets/common/base/tagging.scss b/app/assets/stylesheets/common/base/tagging.scss
index 70b971c4229..2a32c29d3b0 100644
--- a/app/assets/stylesheets/common/base/tagging.scss
+++ b/app/assets/stylesheets/common/base/tagging.scss
@@ -27,18 +27,11 @@
   }
 }
 
-.extra-info-wrapper {
-  .list-tags {
-    padding-top: 5px;
-  }
-
-  .discourse-tag {
-    -webkit-animation: fadein .7s;
-    animation: fadein .7s;
-  }
+.topic-header-extra .discourse-tag {
+  -webkit-animation: fadein .7s;
+  animation: fadein .7s;
 }
 
-
 .add-tags .select2 {
   margin: 0;
 }
@@ -139,8 +132,8 @@ $tag-color: scale-color($primary, $lightness: 40%);
 header .discourse-tag {color: $tag-color }
 
 .list-tags {
+  margin-right: 3px;
   display: inline;
-  margin: 0 0 0 5px;
   font-size: 0.857em;
 }
 
@@ -171,24 +164,6 @@ header .discourse-tag {color: $tag-color }
   left: auto;
 }
 
-.bullet + .list-tags {
-  display: block;
-  line-height: 15px;
-}
-
-.bar + .list-tags {
-  line-height: 1.25;
-  .discourse-tag {
-    vertical-align: middle;
-  }
-}
-
-.box + .list-tags {
-  display: inline-block;
-  margin: 5px 0 0 5px;
-  padding-top: 2px;
-}
-
 .tag-sort-options {
   margin-bottom: 20px;
   a {
diff --git a/app/assets/stylesheets/common/base/topic.scss b/app/assets/stylesheets/common/base/topic.scss
index 38e17a48da1..def557e03e7 100644
--- a/app/assets/stylesheets/common/base/topic.scss
+++ b/app/assets/stylesheets/common/base/topic.scss
@@ -9,6 +9,10 @@
     .badge-wrapper {
       float: left;
     }
+
+    a.topic-featured-link {
+      display: inline-block;
+    }
   }
 
   a.badge-category {
@@ -47,7 +51,7 @@
   display: inline;
 }
 
-#suggested-topics h3 .badge-wrapper.bullet span.badge-category, {
+#suggested-topics h3 .badge-wrapper.bullet span.badge-category {
   // Override vertical-align: text-top from `badges.css.scss`
   vertical-align: baseline;
   line-height: 1.2;
@@ -133,3 +137,18 @@
     }
   }
 }
+
+a.topic-featured-link {
+  display: inline-block;
+  text-transform: lowercase;
+  color: #858585;
+  font-size: 0.875rem;
+
+  &::before {
+    position: relative;
+    top: 0.1em;
+    padding-right: 3px;
+    font-family: FontAwesome;
+    content: "\f08e";
+  }
+}
diff --git a/app/assets/stylesheets/common/components/badges.css.scss b/app/assets/stylesheets/common/components/badges.css.scss
index ed145348943..8273d97c8b4 100644
--- a/app/assets/stylesheets/common/components/badges.css.scss
+++ b/app/assets/stylesheets/common/components/badges.css.scss
@@ -133,6 +133,10 @@
   }
 }
 
+.extra-info-wrapper .title-wrapper .badge-wrapper.bar {
+  margin-top: 6px;
+}
+
 .autocomplete, td.category {
   .badge-wrapper {
     max-width: 230px;
diff --git a/app/assets/stylesheets/desktop/compose.scss b/app/assets/stylesheets/desktop/compose.scss
index 738fb583e83..fbfcd4e874c 100644
--- a/app/assets/stylesheets/desktop/compose.scss
+++ b/app/assets/stylesheets/desktop/compose.scss
@@ -298,6 +298,11 @@
         background-color: dark-light-diff($primary, $secondary, 90%, -60%);
       }
     }
+    #topic-featured-link {
+      padding: 7px 10px;
+      margin: 6px 10px 3px 0;
+      width: 400px;
+    }
     .d-editor-input:disabled {
       background-color: dark-light-diff($primary, $secondary, 90%, -60%);
     }
@@ -465,6 +470,10 @@
   }
 }
 
+#reply-control.topic-featured-link-only.open {
+  height: 200px;
+}
+
 .control-row.reply-area {
   padding-left: 20px;
   padding-right: 20px;
diff --git a/app/assets/stylesheets/desktop/topic-post.scss b/app/assets/stylesheets/desktop/topic-post.scss
index a53b90f9ba6..2c0c57e4fd1 100644
--- a/app/assets/stylesheets/desktop/topic-post.scss
+++ b/app/assets/stylesheets/desktop/topic-post.scss
@@ -505,13 +505,13 @@ video {
 .extra-info-wrapper {
   overflow: hidden;
 
-  .badge-wrapper, i,  .topic-link {
+  .badge-wrapper, i, .topic-link {
     -webkit-animation: fadein .7s;
     animation: fadein .7s;
   }
 
   .topic-statuses {
-    i  { color: $header_primary; }
+    i { color: $header_primary; }
     i.fa-envelope { color: $danger; }
     .unpinned { color: $header_primary; }
   }
@@ -523,6 +523,26 @@ video {
     overflow: hidden;
     text-overflow: ellipsis;
   }
+
+  .topic-header-extra {
+    margin: 0 0 0 5px;
+    padding-top: 5px;
+  }
+}
+
+.bullet + .topic-header-extra {
+  display: block;
+  line-height: 12px;
+}
+
+.bar + .topic-header-extra {
+  line-height: 1.25;
+}
+
+.box + .topic-header-extra {
+  display: inline-block;
+  margin: 0 0 0 5px;
+  padding-top: 5px;
 }
 
 /* default docked header CSS for all topics, including those without categories */
diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index b2c3c85a3fb..7f68a648eff 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -574,7 +574,6 @@ class PostsController < ApplicationController
 
     end
 
-    params.require(:raw)
     result = params.permit(*permitted).tap do |whitelisted|
       whitelisted[:image_sizes] = params[:image_sizes]
       # TODO this does not feel right, we should name what meta_data is allowed
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index e3689036be3..e13539e6471 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -282,4 +282,15 @@ module ApplicationHelper
     result.html_safe
   end
 
+  def topic_featured_link_domain(link)
+    begin
+      uri = URI.encode(link)
+      uri = URI.parse(uri)
+      uri = URI.parse("http://#{uri}") if uri.scheme.nil?
+      host = uri.host.downcase
+      host.start_with?('www.') ? host[4..-1] : host
+    rescue
+      ''
+    end
+  end
 end
diff --git a/app/models/topic.rb b/app/models/topic.rb
index 567f0d4e6b5..a5117113238 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -7,6 +7,7 @@ require_dependency 'text_cleaner'
 require_dependency 'archetype'
 require_dependency 'html_prettify'
 require_dependency 'discourse_tagging'
+require_dependency 'discourse_featured_link'
 
 class Topic < ActiveRecord::Base
   include ActionView::Helpers::SanitizeHelper
@@ -73,6 +74,10 @@ class Topic < ActiveRecord::Base
                    (!t.user_id || !t.user.staff?)
             }
 
+  validates :featured_link, allow_nil: true, format: URI::regexp(%w(http https))
+  validate if: :featured_link do
+    errors.add(:featured_link, :invalid_category) unless Guardian.new.can_edit_featured_link?(category_id)
+  end
 
   before_validation do
     self.title = TextCleaner.clean_title(TextSentinel.title_sentinel(title).text) if errors[:title].empty?
@@ -378,6 +383,14 @@ class Topic < ActiveRecord::Base
     featured_topic_ids ? topics.where("topics.id NOT IN (?)", featured_topic_ids) : topics
   end
 
+  def featured_link
+    custom_fields[DiscourseFeaturedLink::CUSTOM_FIELD_NAME]
+  end
+
+  def featured_link=(link)
+    custom_fields[DiscourseFeaturedLink::CUSTOM_FIELD_NAME] = link.strip
+  end
+
   def meta_data=(data)
     custom_fields.replace(data)
   end
diff --git a/app/models/topic_list.rb b/app/models/topic_list.rb
index e0b3fd8353b..f758a358afb 100644
--- a/app/models/topic_list.rb
+++ b/app/models/topic_list.rb
@@ -1,4 +1,5 @@
 require_dependency 'avatar_lookup'
+require_dependency 'discourse_featured_link'
 
 class TopicList
   include ActiveModel::Serialization
@@ -27,6 +28,7 @@ class TopicList
     end
 
     preloaded_custom_fields << DiscourseTagging::TAGS_FIELD_NAME if SiteSetting.tagging_enabled
+    preloaded_custom_fields << DiscourseFeaturedLink::CUSTOM_FIELD_NAME if SiteSetting.topic_featured_link_enabled
   end
 
   def tags
diff --git a/app/serializers/post_revision_serializer.rb b/app/serializers/post_revision_serializer.rb
index 4df9012e8d3..8ff8b1826e3 100644
--- a/app/serializers/post_revision_serializer.rb
+++ b/app/serializers/post_revision_serializer.rb
@@ -193,6 +193,10 @@ class PostRevisionSerializer < ApplicationSerializer
         end
       end
 
+      if SiteSetting.topic_featured_link_enabled
+        latest_modifications["featured_link"] = [post.topic.featured_link]
+      end
+
       if SiteSetting.tagging_enabled
         latest_modifications["tags"] = [post.topic.tags.map(&:name)]
       end
diff --git a/app/serializers/site_serializer.rb b/app/serializers/site_serializer.rb
index 718cb1221aa..d43c165a96e 100644
--- a/app/serializers/site_serializer.rb
+++ b/app/serializers/site_serializer.rb
@@ -23,7 +23,8 @@ class SiteSerializer < ApplicationSerializer
              :can_tag_topics,
              :tags_filter_regexp,
              :top_tags,
-             :wizard_required
+             :wizard_required,
+             :topic_featured_link_allowed_category_ids
 
   has_many :categories, serializer: BasicCategorySerializer, embed: :objects
   has_many :trust_levels, embed: :objects
@@ -121,4 +122,12 @@ class SiteSerializer < ApplicationSerializer
   def include_wizard_required?
     Wizard.user_requires_completion?(scope.user)
   end
+
+  def include_topic_featured_link_allowed_category_ids?
+    SiteSetting.topic_featured_link_enabled
+  end
+
+  def topic_featured_link_allowed_category_ids
+    scope.topic_featured_link_allowed_category_ids
+  end
 end
diff --git a/app/serializers/suggested_topic_serializer.rb b/app/serializers/suggested_topic_serializer.rb
index 3d4b8f380fd..a0817917f5b 100644
--- a/app/serializers/suggested_topic_serializer.rb
+++ b/app/serializers/suggested_topic_serializer.rb
@@ -7,7 +7,7 @@ class SuggestedTopicSerializer < ListableTopicSerializer
     has_one :user, serializer: BasicUserSerializer, embed: :objects
   end
 
-  attributes :archetype, :like_count, :views, :category_id, :tags
+  attributes :archetype, :like_count, :views, :category_id, :tags, :featured_link
   has_many :posters, serializer: SuggestedPosterSerializer, embed: :objects
 
   def posters
@@ -21,4 +21,12 @@ class SuggestedTopicSerializer < ListableTopicSerializer
   def tags
     object.tags.map(&:name)
   end
+
+  def include_featured_link?
+    SiteSetting.topic_featured_link_enabled
+  end
+
+  def featured_link
+    object.featured_link
+  end
 end
diff --git a/app/serializers/topic_list_item_serializer.rb b/app/serializers/topic_list_item_serializer.rb
index a04c1eeae3c..9e1e642a159 100644
--- a/app/serializers/topic_list_item_serializer.rb
+++ b/app/serializers/topic_list_item_serializer.rb
@@ -10,7 +10,8 @@ class TopicListItemSerializer < ListableTopicSerializer
              :pinned_globally,
              :bookmarked_post_numbers,
              :liked_post_numbers,
-             :tags
+             :tags,
+             :featured_link
 
   has_many :posters, serializer: TopicPosterSerializer, embed: :objects
   has_many :participants, serializer: TopicPosterSerializer, embed: :objects
@@ -72,4 +73,12 @@ class TopicListItemSerializer < ListableTopicSerializer
     object.tags.map(&:name)
   end
 
+  def include_featured_link?
+    SiteSetting.topic_featured_link_enabled
+  end
+
+  def featured_link
+    object.featured_link
+  end
+
 end
diff --git a/app/serializers/topic_view_serializer.rb b/app/serializers/topic_view_serializer.rb
index e9e308b5dfc..780d2b80c37 100644
--- a/app/serializers/topic_view_serializer.rb
+++ b/app/serializers/topic_view_serializer.rb
@@ -56,7 +56,8 @@ class TopicViewSerializer < ApplicationSerializer
              :chunk_size,
              :bookmarked,
              :message_archived,
-             :tags
+             :tags,
+             :featured_link
 
   # TODO: Split off into proper object / serializer
   def details
@@ -243,8 +244,17 @@ class TopicViewSerializer < ApplicationSerializer
   def include_tags?
     SiteSetting.tagging_enabled
   end
+
   def tags
     object.topic.tags.map(&:name)
   end
 
+  def include_featured_link?
+    SiteSetting.topic_featured_link_enabled
+  end
+
+  def featured_link
+    object.topic.featured_link
+  end
+
 end
diff --git a/app/views/user_notifications/digest.html.erb b/app/views/user_notifications/digest.html.erb
index 28036ce8ad7..d551dfe2d29 100644
--- a/app/views/user_notifications/digest.html.erb
+++ b/app/views/user_notifications/digest.html.erb
@@ -117,6 +117,9 @@ body, table, td, th, h1, h2, h3 {font-family: Helvetica, Arial, sans-serif !impo
             <strong><%= t.title -%></strong>
           </a>
         </h2>
+        <%- if SiteSetting.show_topic_featured_link_in_digest && t.featured_link %>
+          <a class='topic-featured-link' href='<%= t.featured_link %>'><%= raw topic_featured_link_domain(t.featured_link) %></a>
+        <%- end %>
       </td>
     </tr>
   </tbody>
@@ -328,6 +331,9 @@ body, table, td, th, h1, h2, h3 {font-family: Helvetica, Arial, sans-serif !impo
         <a href="<%= Discourse.base_url_no_prefix + t.relative_url %>" style="color:#2F70AC;font-weight:400;line-height:1.3;margin:0;padding:0;text-decoration:none">
           <strong><%= t.title -%></strong>
         </a>
+        <%- if SiteSetting.show_topic_featured_link_in_digest && t.featured_link %>
+          <a class='topic-featured-link' href='<%= t.featured_link %>'><%= raw topic_featured_link_domain(t.featured_link) %></a>
+        <%- end %>
         <p style="color:#0a0a0a;line-height:1.3;margin:0 0 10px 0;padding:0;text-align:left">
           <%= category_badge(t.category, inline_style: true, absolute_url: true) %>
         </p>
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index 9cb484ec7d1..60c676becfd 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -1074,6 +1074,7 @@ en:
       title_placeholder: "What is this discussion about in one brief sentence?"
       edit_reason_placeholder: "why are you editing?"
       show_edit_reason: "(add edit reason)"
+      topic_featured_link_placeholder: "Enter link shown with title."
       reply_placeholder: "Type here. Use Markdown, BBCode, or HTML to format. Drag or paste images."
       view_new_post: "View your new post."
       saving: "Saving"
@@ -1875,6 +1876,7 @@ en:
       tags_allowed_tag_groups: "Tag groups that can only be used in this category:"
       tags_placeholder: "(Optional) list of allowed tags"
       tag_groups_placeholder: "(Optional) list of allowed tag groups"
+      topic_featured_link_allowed: "Restricts editing the topic featured link in this category. Require site setting topic_featured_link_enabled is checked."
       delete: 'Delete Category'
       create: 'New Category'
       create_long: 'Create a new category'
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index a9048c3a738..3c1d84d8338 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -320,6 +320,7 @@ en:
         name: "Category Name"
       topic:
         title: 'Title'
+        featured_link: 'Featured Link'
       post:
         raw: "Body"
       user_profile:
@@ -336,6 +337,9 @@ en:
               too_many_users: "You can only send warnings to one user at a time."
               cant_send_pm: "Sorry, you cannot send a private message to that user."
               no_user_selected: "You must select a valid user."
+            featured_link:
+              invalid: "is invalid. URL should include http:// or https://."
+              invalid_category: "can't be edited in this category."
         user:
           attributes:
             password:
@@ -846,6 +850,10 @@ en:
     min_first_post_length: "Minimum allowed first post (topic body) length in characters"
     min_private_message_post_length: "Minimum allowed post length in characters for messages"
     max_post_length: "Maximum allowed post length in characters"
+    topic_featured_link_enabled: "Enable posting a link with topics."
+    topic_featured_link_onebox: "Show an onebox in the post body if possible and prevent editing post content."
+    open_topic_featured_link_in_external_window: "Open topic featured link in a external window."
+    show_topic_featured_link_in_digest: "Show the topic featured link in the digest email."
     min_topic_title_length: "Minimum allowed topic title length in characters"
     max_topic_title_length: "Maximum allowed topic title length in characters"
     min_private_message_title_length: "Minimum allowed title length for a message in characters"
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 5899f29c66c..aae34135a64 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -433,6 +433,15 @@ posting:
   max_post_length:
     client: true
     default: 32000
+  topic_featured_link_enabled:
+    client: true
+    default: false
+  topic_featured_link_onebox:
+    client: true
+    default: false
+  open_topic_featured_link_in_external_window:
+    client: true
+    default: true
   body_min_entropy: 7
   min_topic_title_length:
     client: true
@@ -596,6 +605,7 @@ email:
   disable_digest_emails:
     default: false
     client: true
+  show_topic_featured_link_in_digest: true
   email_custom_headers: 'Auto-Submitted: auto-generated'
   email_subject: '[%{site_name}] %{optional_pm}%{optional_cat}%{topic_title}'
   reply_by_email_enabled:
diff --git a/lib/discourse_featured_link.rb b/lib/discourse_featured_link.rb
new file mode 100644
index 00000000000..304383e9234
--- /dev/null
+++ b/lib/discourse_featured_link.rb
@@ -0,0 +1,27 @@
+module DiscourseFeaturedLink
+  CUSTOM_FIELD_NAME = 'featured_link'.freeze
+
+  AdminDashboardData::GLOBAL_REPORTS << CUSTOM_FIELD_NAME
+
+  Report.add_report(CUSTOM_FIELD_NAME) do |report|
+    report.data = []
+    link_topics = TopicCustomField.where(name: CUSTOM_FIELD_NAME)
+    link_topics = link_topics.joins(:topic).where("topics.category_id = ?", report.category_id) if report.category_id
+    link_topics.where("topic_custom_fields.created_at >= ?", report.start_date)
+               .where("topic_custom_fields.created_at <= ?", report.end_date)
+               .group("DATE(topic_custom_fields.created_at)")
+               .order("DATE(topic_custom_fields.created_at)")
+               .count
+               .each { |date, count| report.data << { x: date, y: count } }
+    report.total = link_topics.count
+    report.prev30Days = link_topics.where("topic_custom_fields.created_at >= ?", report.start_date - 30.days)
+                                   .where("topic_custom_fields.created_at <= ?", report.start_date)
+                                   .count
+  end
+
+  def self.cache_onebox_link(link)
+    # If the link is pasted swiftly, onebox may not have time to cache it
+    Oneboxer.onebox(link, invalidate_oneboxes: false)
+    link
+  end
+end
diff --git a/lib/email/styles.rb b/lib/email/styles.rb
index db32a221d7a..39adcf88cd1 100644
--- a/lib/email/styles.rb
+++ b/lib/email/styles.rb
@@ -67,6 +67,11 @@ module Email
         add_styles(img, 'max-width: 100%;') if img['style'] !~ /max-width/
       end
 
+      # topic featured link
+      @fragment.css('a.topic-featured-link').each do |e|
+        e['style'] = "color:#858585;padding:2px 8px;border:1px solid #e6e6e6;border-radius:2px;box-shadow:0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);"
+      end
+
       # attachments
       @fragment.css('a.attachment').each do |a|
         # ensure all urls are absolute
diff --git a/lib/guardian/category_guardian.rb b/lib/guardian/category_guardian.rb
index dbe5f868194..ccebde7dbf1 100644
--- a/lib/guardian/category_guardian.rb
+++ b/lib/guardian/category_guardian.rb
@@ -68,4 +68,9 @@ module CategoryGuardian
   def topic_create_allowed_category_ids
     @topic_create_allowed_category_ids ||= @user.topic_create_allowed_category_ids
   end
+
+  def topic_featured_link_allowed_category_ids
+    @topic_featured_link_allowed_category_ids = CategoryCustomField.where(name: "topic_featured_link_allowed", value: "true")
+                                                                   .pluck(:category_id)
+  end
 end
diff --git a/lib/guardian/topic_guardian.rb b/lib/guardian/topic_guardian.rb
index 892a8517d9a..b107fc7e669 100644
--- a/lib/guardian/topic_guardian.rb
+++ b/lib/guardian/topic_guardian.rb
@@ -105,4 +105,9 @@ module TopicGuardian
     records
   end
 
+  def can_edit_featured_link?(category_id)
+    SiteSetting.topic_featured_link_enabled &&
+        (topic_featured_link_allowed_category_ids.empty? || # no per category restrictions
+        category_id && topic_featured_link_allowed_category_ids.include?(category_id.to_i)) # category restriction exists
+  end
 end
diff --git a/lib/post_creator.rb b/lib/post_creator.rb
index 9b4fb345dd8..6a788cf5bdb 100644
--- a/lib/post_creator.rb
+++ b/lib/post_creator.rb
@@ -5,6 +5,7 @@ require_dependency 'topic_creator'
 require_dependency 'post_jobs_enqueuer'
 require_dependency 'distributed_mutex'
 require_dependency 'has_errors'
+require_dependency 'discourse_featured_link'
 
 class PostCreator
   include HasErrors
@@ -103,6 +104,11 @@ class PostCreator
       end
     end
 
+    onebox_featured_link = SiteSetting.topic_featured_link_enabled && SiteSetting.topic_featured_link_onebox && guardian.can_edit_featured_link?(find_category_id)
+    if onebox_featured_link
+      @opts[:raw] = DiscourseFeaturedLink.cache_onebox_link(@opts[:featured_link])
+    end
+
     setup_post
 
     return true if skip_validations?
@@ -116,7 +122,7 @@ class PostCreator
     DiscourseEvent.trigger :before_create_post, @post
     DiscourseEvent.trigger :validate_post, @post
 
-    post_validator = Validators::PostValidator.new(skip_topic: true)
+    post_validator = Validators::PostValidator.new(skip_topic: true, skip_post_body: onebox_featured_link)
     post_validator.validate(@post)
 
     valid = @post.errors.blank?
@@ -338,6 +344,18 @@ class PostCreator
 
   private
 
+  # TODO: merge the similar function in TopicCreator and fix parameter naming for `category`
+  def find_category_id
+    @opts.delete(:category) if @opts[:archetype].present? && @opts[:archetype] == Archetype.private_message
+
+    category = if (@opts[:category].is_a? Integer) || (@opts[:category] =~ /^\d+$/)
+                 Category.find_by(id: @opts[:category])
+               else
+                 Category.find_by(name_lower: @opts[:category].try(:downcase))
+               end
+    category&.id
+  end
+
   def create_topic
     return if @topic
     begin
diff --git a/lib/post_revisor.rb b/lib/post_revisor.rb
index f253d3712e3..55d061ef91d 100644
--- a/lib/post_revisor.rb
+++ b/lib/post_revisor.rb
@@ -95,6 +95,23 @@ class PostRevisor
     end
   end
 
+  track_topic_field(:featured_link) do |topic_changes, featured_link|
+    if SiteSetting.topic_featured_link_enabled &&
+       featured_link.present? &&
+       topic_changes.guardian.can_edit_featured_link?(topic_changes.topic.category_id)
+
+      topic_changes.record_change('featured_link', topic_changes.topic.featured_link, featured_link)
+      topic_changes.topic.featured_link = featured_link
+
+      if SiteSetting.topic_featured_link_onebox
+        post = topic_changes.topic.first_post
+        post.raw = DiscourseFeaturedLink.cache_onebox_link(featured_link)
+        post.save!
+        post.rebake!
+      end
+    end
+  end
+
   # AVAILABLE OPTIONS:
   # - revised_at: changes the date of the revision
   # - force_new_version: bypass ninja-edit window
diff --git a/lib/topic_creator.rb b/lib/topic_creator.rb
index 9e76327a5a8..8c0621d507c 100644
--- a/lib/topic_creator.rb
+++ b/lib/topic_creator.rb
@@ -124,6 +124,10 @@ class TopicCreator
     topic_params[:pinned_at] = Time.zone.parse(@opts[:pinned_at].to_s) if @opts[:pinned_at].present?
     topic_params[:pinned_globally] = @opts[:pinned_globally] if @opts[:pinned_globally].present?
 
+    if SiteSetting.topic_featured_link_enabled && @opts[:featured_link].present? && @guardian.can_edit_featured_link?(topic_params[:category_id])
+      topic_params[:featured_link] = @opts[:featured_link]
+    end
+
     topic_params
   end
 
diff --git a/lib/validators/post_validator.rb b/lib/validators/post_validator.rb
index 32f6063596c..30e68bafad7 100644
--- a/lib/validators/post_validator.rb
+++ b/lib/validators/post_validator.rb
@@ -10,8 +10,7 @@ class Validators::PostValidator < ActiveModel::Validator
     return if record.acting_user.try(:staged?)
     return if record.acting_user.try(:admin?) && Discourse.static_doc_topic_ids.include?(record.topic_id)
 
-    stripped_length(record)
-    raw_quality(record)
+    post_body_validator(record)
     max_posts_validator(record)
     max_mention_validator(record)
     max_images_validator(record)
@@ -21,8 +20,6 @@ class Validators::PostValidator < ActiveModel::Validator
   end
 
   def presence(post)
-    post.errors.add(:raw, :blank, options) if post.raw.blank?
-
     unless options[:skip_topic]
       post.errors.add(:topic_id, :blank, options) if post.topic_id.blank?
     end
@@ -32,6 +29,12 @@ class Validators::PostValidator < ActiveModel::Validator
     end
   end
 
+  def post_body_validator(post)
+    return if options[:skip_post_body]
+    stripped_length(post)
+    raw_quality(post)
+  end
+
   def stripped_length(post)
     range = if private_message?(post)
       # private message
diff --git a/spec/components/guardian_spec.rb b/spec/components/guardian_spec.rb
index c5e637f189a..bf51aadfe4d 100644
--- a/spec/components/guardian_spec.rb
+++ b/spec/components/guardian_spec.rb
@@ -2280,4 +2280,27 @@ describe Guardian do
       end
     end
   end
+
+  context 'topic featured link category restriction' do
+    before { SiteSetting.topic_featured_link_enabled = true }
+    let(:guardian) { Guardian.new }
+
+    it 'returns true if no category restricts editing link' do
+      expect(guardian.can_edit_featured_link?(nil)).to eq(true)
+      expect(guardian.can_edit_featured_link?(5)).to eq(true)
+    end
+
+    context 'when exist' do
+      let!(:category) { Fabricate(:category) }
+      let!(:link_category) { Fabricate(:link_category) }
+
+      it 'returns true if the category is listed' do
+        expect(guardian.can_edit_featured_link?(link_category.id)).to eq(true)
+      end
+
+      it 'returns false if the category is not listed' do
+        expect(guardian.can_edit_featured_link?(category.id)).to eq(false)
+      end
+    end
+  end
 end
diff --git a/spec/components/post_creator_spec.rb b/spec/components/post_creator_spec.rb
index a428bb03b81..197e6be9d40 100644
--- a/spec/components/post_creator_spec.rb
+++ b/spec/components/post_creator_spec.rb
@@ -20,6 +20,7 @@ describe PostCreator do
     let(:creator_with_category) { PostCreator.new(user, basic_topic_params.merge(category: category.id )) }
     let(:creator_with_meta_data) { PostCreator.new(user, basic_topic_params.merge(meta_data: {hello: "world"} )) }
     let(:creator_with_image_sizes) { PostCreator.new(user, basic_topic_params.merge(image_sizes: image_sizes)) }
+    let(:creator_with_featured_link) { PostCreator.new(user, title: "featured link topic", archetype_id: 1, featured_link: "http://discourse.org") }
 
     it "can create a topic with null byte central" do
       post = PostCreator.create(user, title: "hello\u0000world this is title", raw: "this is my\u0000 first topic")
@@ -243,6 +244,14 @@ describe PostCreator do
         end
       end
 
+      it 'creates a post without raw' do
+        SiteSetting.topic_featured_link_enabled = true
+        SiteSetting.topic_featured_link_onebox = true
+        post = creator_with_featured_link.create
+        expect(post.topic.featured_link).to eq('http://discourse.org')
+        expect(post.raw).to eq('http://discourse.org')
+      end
+
       describe "topic's auto close" do
 
         it "doesn't update topic's auto close when it's not based on last post" do
diff --git a/spec/components/validators/post_validator_spec.rb b/spec/components/validators/post_validator_spec.rb
index b497d4454c7..093cff9ff52 100644
--- a/spec/components/validators/post_validator_spec.rb
+++ b/spec/components/validators/post_validator_spec.rb
@@ -5,6 +5,16 @@ describe Validators::PostValidator do
   let(:post) { build(:post) }
   let(:validator) { Validators::PostValidator.new({}) }
 
+  context "when empty raw can bypass post body validation" do
+    let(:validator) { Validators::PostValidator.new(skip_post_body: true) }
+
+    it "should be allowed for empty raw based on site setting" do
+      post.raw = ""
+      validator.post_body_validator(post)
+      expect(post.errors).to be_empty
+    end
+  end
+
   context "stripped_length" do
     it "adds an error for short raw" do
       post.raw = "abc"
diff --git a/spec/controllers/posts_controller_spec.rb b/spec/controllers/posts_controller_spec.rb
index 99af04c81ab..9f29a456393 100644
--- a/spec/controllers/posts_controller_spec.rb
+++ b/spec/controllers/posts_controller_spec.rb
@@ -579,10 +579,6 @@ describe PostsController do
       let(:moderator) { log_in(:moderator) }
       let(:new_post) { Fabricate.build(:post, user: user) }
 
-      it "raises an exception without a raw parameter" do
-	      expect { xhr :post, :create }.to raise_error(ActionController::ParameterMissing)
-      end
-
       context "fast typing" do
         before do
           SiteSetting.min_first_post_typing_time = 3000
@@ -771,8 +767,8 @@ describe PostsController do
         end
 
         it "passes category through" do
-          xhr :post, :create, {raw: 'hello', category: 'cool'}
-          expect(assigns(:manager_params)['category']).to eq('cool')
+          xhr :post, :create, {raw: 'hello', category: 1}
+          expect(assigns(:manager_params)['category']).to eq('1')
         end
 
         it "passes target_usernames through" do
diff --git a/spec/fabricators/embeddable_host_fabricator.rb b/spec/fabricators/embeddable_host_fabricator.rb
index a37f5b4c8ba..9f589d389e0 100644
--- a/spec/fabricators/embeddable_host_fabricator.rb
+++ b/spec/fabricators/embeddable_host_fabricator.rb
@@ -25,3 +25,7 @@ Fabricator(:private_category, from: :category) do
     cat.category_groups.build(group_id: transients[:group].id, permission_type: CategoryGroup.permission_types[:full])
   end
 end
+
+Fabricator(:link_category, from: :category) do
+  before_validation { |category, transients| category.custom_fields['topic_featured_link_allowed'] = 'true' }
+end
diff --git a/spec/models/category_spec.rb b/spec/models/category_spec.rb
index d603077ebf9..efe28cb6be7 100644
--- a/spec/models/category_spec.rb
+++ b/spec/models/category_spec.rb
@@ -421,14 +421,14 @@ describe Category do
   describe 'latest' do
     it 'should be updated correctly' do
       category = Fabricate(:category)
-      post = create_post(category: category.name)
+      post = create_post(category: category.id)
 
       category.reload
       expect(category.latest_post_id).to eq(post.id)
       expect(category.latest_topic_id).to eq(post.topic_id)
 
-      post2 = create_post(category: category.name)
-      post3 = create_post(topic_id: post.topic_id, category: category.name)
+      post2 = create_post(category: category.id)
+      post3 = create_post(topic_id: post.topic_id, category: category.id)
 
       category.reload
       expect(category.latest_post_id).to eq(post3.id)
@@ -451,7 +451,7 @@ describe Category do
 
     context 'with regular topics' do
       before do
-        create_post(user: @category.user, category: @category.name)
+        create_post(user: @category.user, category: @category.id)
         Category.update_stats
         @category.reload
       end
@@ -491,7 +491,7 @@ describe Category do
 
     context 'with revised post' do
       before do
-        post = create_post(user: @category.user, category: @category.name)
+        post = create_post(user: @category.user, category: @category.id)
 
         SiteSetting.stubs(:editing_grace_period).returns(1.minute.to_i)
         post.revise(post.user, { raw: 'updated body' }, revised_at: post.updated_at + 2.minutes)
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index f2ac723e6ec..0f35c714483 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -1725,7 +1725,6 @@ describe Topic do
     expect(@topic_status_event_triggered).to eq(true)
   end
 
-
   it 'allows users to normalize counts' do
 
     topic = Fabricate(:topic, last_posted_at: 1.year.ago)
@@ -1741,4 +1740,39 @@ describe Topic do
     expect(topic.last_posted_at).to be_within(1.second).of (post1.created_at)
   end
 
+  context 'featured link' do
+    before { SiteSetting.topic_featured_link_enabled = true }
+    let(:topic) { Fabricate(:topic) }
+
+    it 'can validate featured link' do
+      topic.featured_link = ' invalid string'
+
+      expect(topic).not_to be_valid
+      expect(topic.errors[:featured_link]).to be_present
+    end
+
+    it 'can properly save the featured link' do
+      topic.featured_link = '  https://github.com/discourse/discourse'
+
+      expect(topic.save).to be_truthy
+      expect(topic.custom_fields['featured_link']).to eq('https://github.com/discourse/discourse')
+    end
+
+    context 'when category restricts present' do
+      let!(:link_category) { Fabricate(:link_category) }
+      let(:topic) { Fabricate(:topic) }
+      let(:link_topic) { Fabricate(:topic, category: link_category) }
+
+      it 'can save the featured link if it belongs to that category' do
+        link_topic.featured_link = 'https://github.com/discourse/discourse'
+        expect(link_topic.save).to be_truthy
+        expect(link_topic.custom_fields['featured_link']).to eq('https://github.com/discourse/discourse')
+      end
+
+      it 'can not save the featured link if it belongs to that category' do
+        topic.featured_link = 'https://github.com/discourse/discourse'
+        expect(topic.save).to be_falsey
+      end
+    end
+  end
 end
diff --git a/spec/support/helpers.rb b/spec/support/helpers.rb
index 39457073a37..36863e798d7 100644
--- a/spec/support/helpers.rb
+++ b/spec/support/helpers.rb
@@ -28,7 +28,7 @@ module Helpers
     args[:title] ||= "This is my title #{Helpers.next_seq}"
     user = args.delete(:user) || Fabricate(:user)
     guardian = Guardian.new(user)
-    args[:category] = args[:category].name if args[:category].is_a?(Category)
+    args[:category] = args[:category].id if args[:category].is_a?(Category)
     TopicCreator.create(user, guardian, args)
   end
 
@@ -37,7 +37,7 @@ module Helpers
     args[:raw] ||= "This is the raw body of my post, it is cool #{Helpers.next_seq}"
     args[:topic_id] = args[:topic].id if args[:topic]
     user = args.delete(:user) || Fabricate(:user)
-    args[:category] = args[:category].name if args[:category].is_a?(Category)
+    args[:category] = args[:category].id if args[:category].is_a?(Category)
     creator = PostCreator.new(user, args)
     post = creator.create
 
diff --git a/test/javascripts/models/composer-test.js.es6 b/test/javascripts/models/composer-test.js.es6
index d541aaeb087..1ed5a691c37 100644
--- a/test/javascripts/models/composer-test.js.es6
+++ b/test/javascripts/models/composer-test.js.es6
@@ -40,6 +40,10 @@ test('missingReplyCharacters', function() {
   missingReplyCharacters('hi', false, false, Discourse.SiteSettings.min_post_length - 2, 'too short public post');
   missingReplyCharacters('hi', false, true,  Discourse.SiteSettings.min_first_post_length - 2, 'too short first post');
   missingReplyCharacters('hi', true, false,  Discourse.SiteSettings.min_private_message_post_length - 2, 'too short private message');
+
+  Discourse.SiteSettings.topic_featured_link_onebox = true;
+  const composer = createComposer({ canEditTopicFeaturedLink: true });
+  equal(composer.get('missingReplyCharacters'), 0, "don't require any post content");
 });
 
 test('missingTitleCharacters', function() {
@@ -105,7 +109,7 @@ test("prependText", function() {
 
   composer.prependText("world ");
   equal(composer.get('reply'), "world hello", "it prepends text to existing text");
-  
+
   composer.prependText("before new line", {new_line: true});
   equal(composer.get('reply'), "before new line\n\nworld hello", "it prepends text with new line to existing text");
 });