Prepare Mastodon for Rails 6 (#15911)

* Fix misuse of foreign_type

* Fix use of removed "add_template_helper"

* Use response.media_type instead of response.content_type in tests

* Fix CSV export controller test on Rails 6

Rails 6 sets a "filename*" field in the Content-Disposition header to
explicitly encode the filename as UTF-8.

This changes checks the first part of the Content-Disposition header so
it matches in both Rails 5 and Rails 6.

* Fix emoji formatting with Rails 6

* Make emoji output more idiomatic and robust

* Switch from redis-rails gem to built-in Rails redis cache storage

spec/controllers/accounts_controller_spec.rb

@@ -370,7 +370,7 @@ RSpec.describe AccountsController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it_behaves_like 'cachable response'
@@ -402,7 +402,7 @@ RSpec.describe AccountsController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns public Cache-Control header' do
@@ -428,7 +428,7 @@ RSpec.describe AccountsController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it_behaves_like 'cachable response'
@@ -446,7 +446,7 @@ RSpec.describe AccountsController, type: :controller do
           end
 
           it 'returns application/activity+json' do
-            expect(response.content_type).to eq 'application/activity+json'
+            expect(response.media_type).to eq 'application/activity+json'
           end
 
           it 'returns private Cache-Control header' do

spec/controllers/activitypub/collections_controller_spec.rb

@@ -43,7 +43,7 @@ RSpec.describe ActivityPub::CollectionsController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it_behaves_like 'cachable response'
@@ -88,7 +88,7 @@ RSpec.describe ActivityPub::CollectionsController, type: :controller do
           end
 
           it 'returns application/activity+json' do
-            expect(response.content_type).to eq 'application/activity+json'
+            expect(response.media_type).to eq 'application/activity+json'
           end
 
           it_behaves_like 'cachable response'
@@ -116,7 +116,7 @@ RSpec.describe ActivityPub::CollectionsController, type: :controller do
             end
 
             it 'returns application/activity+json' do
-              expect(response.content_type).to eq 'application/activity+json'
+              expect(response.media_type).to eq 'application/activity+json'
             end
 
             it 'returns private Cache-Control header' do
@@ -141,7 +141,7 @@ RSpec.describe ActivityPub::CollectionsController, type: :controller do
             end
 
             it 'returns application/activity+json' do
-              expect(response.content_type).to eq 'application/activity+json'
+              expect(response.media_type).to eq 'application/activity+json'
             end
 
             it 'returns private Cache-Control header' do

spec/controllers/activitypub/followers_synchronizations_controller_spec.rb

@@ -40,7 +40,7 @@ RSpec.describe ActivityPub::FollowersSynchronizationsController, type: :controll
       end
 
       it 'returns application/activity+json' do
-        expect(response.content_type).to eq 'application/activity+json'
+        expect(response.media_type).to eq 'application/activity+json'
       end
 
       it 'returns orderedItems with followers from example.com' do

spec/controllers/activitypub/outboxes_controller_spec.rb

@@ -46,7 +46,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns totalItems' do
@@ -85,7 +85,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns orderedItems with public or unlisted statuses' do
@@ -133,7 +133,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns orderedItems with public or unlisted statuses' do
@@ -159,7 +159,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns orderedItems with private statuses' do
@@ -185,7 +185,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns empty orderedItems' do
@@ -210,7 +210,7 @@ RSpec.describe ActivityPub::OutboxesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it 'returns empty orderedItems' do

spec/controllers/activitypub/replies_controller_spec.rb

@@ -73,7 +73,7 @@ RSpec.describe ActivityPub::RepliesController, type: :controller do
         end
 
         it 'returns application/activity+json' do
-          expect(response.content_type).to eq 'application/activity+json'
+          expect(response.media_type).to eq 'application/activity+json'
         end
 
         it_behaves_like 'cachable response'
@@ -120,7 +120,7 @@ RSpec.describe ActivityPub::RepliesController, type: :controller do
           end
 
           it 'returns application/activity+json' do
-            expect(response.content_type).to eq 'application/activity+json'
+            expect(response.media_type).to eq 'application/activity+json'
           end
 
           it_behaves_like 'cachable response'

spec/controllers/concerns/export_controller_concern_spec.rb

@@ -22,8 +22,8 @@ describe ApplicationController, type: :controller do
       get :index, format: :csv
 
       expect(response).to have_http_status(200)
-      expect(response.content_type).to eq 'text/csv'
-      expect(response.headers['Content-Disposition']).to eq 'attachment; filename="anonymous.csv"'
+      expect(response.media_type).to eq 'text/csv'
+      expect(response.headers['Content-Disposition']).to start_with 'attachment; filename="anonymous.csv"'
       expect(response.body).to eq user.account.username
     end
 

spec/controllers/well_known/host_meta_controller_spec.rb

@@ -8,7 +8,7 @@ describe WellKnown::HostMetaController, type: :controller do
       get :show, format: :xml
 
       expect(response).to have_http_status(200)
-      expect(response.content_type).to eq 'application/xrd+xml'
+      expect(response.media_type).to eq 'application/xrd+xml'
       expect(response.body).to eq <<XML
 <?xml version="1.0" encoding="UTF-8"?>
 <XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">

spec/controllers/well_known/keybase_proof_config_controller_spec.rb

@@ -8,7 +8,7 @@ describe WellKnown::KeybaseProofConfigController, type: :controller do
       get :show
 
       expect(response).to have_http_status(200)
-      expect(response.content_type).to eq 'application/json'
+      expect(response.media_type).to eq 'application/json'
       expect { JSON.parse(response.body) }.not_to raise_exception
     end
   end

spec/controllers/well_known/nodeinfo_controller_spec.rb

@@ -8,7 +8,7 @@ describe WellKnown::NodeInfoController, type: :controller do
       get :index
 
       expect(response).to have_http_status(200)
-      expect(response.content_type).to eq 'application/json'
+      expect(response.media_type).to eq 'application/json'
 
       json = body_as_json
 
@@ -23,7 +23,7 @@ describe WellKnown::NodeInfoController, type: :controller do
       get :show
 
       expect(response).to have_http_status(200)
-      expect(response.content_type).to eq 'application/json'
+      expect(response.media_type).to eq 'application/json'
 
       json = body_as_json
 

spec/controllers/well_known/webfinger_controller_spec.rb

@@ -25,7 +25,7 @@ describe WellKnown::WebfingerController, type: :controller do
       end
 
       it 'returns application/jrd+json' do
-        expect(response.content_type).to eq 'application/jrd+json'
+        expect(response.media_type).to eq 'application/jrd+json'
       end
 
       it 'returns links for the account' do