Fix Accept headers when fetching AP objects to match spec (#30354)

app/lib/activitypub/dereferencer.rb

@@ -44,7 +44,7 @@ class ActivityPub::Dereferencer
 
     req = Request.new(:get, uri)
 
-    req.add_headers('Accept' => 'application/activity+json, application/ld+json')
+    req.add_headers('Accept' => 'application/ld+json; profile="https://www.w3.org/ns/activitystreams", application/activity+json')
     req.add_headers(headers) if headers
     req.on_behalf_of(@signature_actor) if @signature_actor
 

app/services/fetch_resource_service.rb

@@ -3,7 +3,7 @@
 class FetchResourceService < BaseService
   include JsonLdHelper
 
-  ACCEPT_HEADER = 'application/activity+json, application/ld+json; profile="https://www.w3.org/ns/activitystreams", text/html;q=0.1'
+  ACCEPT_HEADER = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams", application/activity+json, text/html;q=0.1'
   ACTIVITY_STREAM_LINK_TYPES = ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].freeze
 
   attr_reader :response_code

app/views/accounts/show.html.haml

@@ -6,6 +6,7 @@
 
   %link{ rel: 'alternate', type: 'application/rss+xml', href: rss_url }/
   %link{ rel: 'alternate', type: 'application/activity+json', href: ActivityPub::TagManager.instance.uri_for(@account) }/
+  %link{ rel: 'alternate', type: 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"', href: ActivityPub::TagManager.instance.uri_for(@account) }/
 
   - @account.fields.select(&:verifiable?).each do |field|
     %link{ rel: 'me', type: 'text/html', href: field.value }/

app/views/statuses/show.html.haml

@@ -8,6 +8,7 @@
 
   %link{ rel: 'alternate', type: 'application/json+oembed', href: api_oembed_url(url: short_account_status_url(@account, @status), format: 'json') }/
   %link{ rel: 'alternate', type: 'application/activity+json', href: ActivityPub::TagManager.instance.uri_for(@status) }/
+  %link{ rel: 'alternate', type: 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"', href: ActivityPub::TagManager.instance.uri_for(@status) }/
 
   = opengraph 'og:site_name', site_title
   = opengraph 'og:type', 'article'

app/views/tags/show.html.haml

@@ -1,6 +1,7 @@
 - content_for :header_tags do
   %link{ rel: :alternate, type: 'application/rss+xml', href: tag_url(@tag) }/
   %link{ rel: :alternate, type: 'application/activity+json', href: tag_url(@tag) }/
+  %link{ rel: :alternate, type: 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"', href: tag_url(@tag) }/
   %meta{ name: 'robots', content: 'noindex' }/
   = render partial: 'shared/og'