2 files changed, 7 insertions, 1 deletions
diff --git a/app/models/custom_emoji.rb b/app/models/custom_emoji.rb
index b99ed01f0..d3cc70504 100644
--- a/app/models/custom_emoji.rb
+++ b/app/models/custom_emoji.rb
@@ -31,6 +31,8 @@ class CustomEmoji < ApplicationRecord
 
   has_attached_file :image, styles: { static: { format: 'png', convert_options: '-coalesce -strip' } }
 
+  before_validation :downcase_domain
+
   validates_attachment :image, content_type: { content_type: 'image/png' }, presence: true, size: { less_than: LIMIT }
   validates :shortcode, uniqueness: { scope: :domain }, format: { with: /\A#{SHORTCODE_RE_FRAGMENT}\z/ }, length: { minimum: 2 }
 
@@ -73,4 +75,8 @@ class CustomEmoji < ApplicationRecord
   def remove_entity_cache
     Rails.cache.delete(EntityCache.instance.to_key(:emoji, shortcode, domain))
   end
+
+  def downcase_domain
+    self.domain = domain.downcase unless domain.nil?
+  end
 end
diff --git a/app/models/custom_emoji_filter.rb b/app/models/custom_emoji_filter.rb
index c4bc310bb..7649055d2 100644
--- a/app/models/custom_emoji_filter.rb
+++ b/app/models/custom_emoji_filter.rb
@@ -26,7 +26,7 @@ class CustomEmojiFilter
     when 'remote'
       CustomEmoji.remote
     when 'by_domain'
-      CustomEmoji.where(domain: value)
+      CustomEmoji.where(domain: value.downcase)
     when 'shortcode'
       CustomEmoji.search(value)
     else