Remove dependency on goldfinger gem (#14919)

There are edge cases where requests to certain hosts timeout when
using the vanilla HTTP.rb gem, which the goldfinger gem uses. Now
that we no longer need to support OStatus servers, webfinger logic
is so simple that there is no point encapsulating it in a gem, so
we can just use our own Request class. With that, we benefit from
more robust timeout code and IPv4/IPv6 resolution.

Fix #14091

app/services/activitypub/fetch_remote_account_service.rb

@@ -39,17 +39,16 @@ class ActivityPub::FetchRemoteAccountService < BaseService
     webfinger                            = webfinger!("acct:#{@username}@#{@domain}")
     confirmed_username, confirmed_domain = split_acct(webfinger.subject)
 
-    return webfinger.link('self')&.href == @uri if @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
+    return webfinger.link('self', 'href') == @uri if @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
 
     webfinger                            = webfinger!("acct:#{confirmed_username}@#{confirmed_domain}")
     @username, @domain                   = split_acct(webfinger.subject)
-    self_reference                       = webfinger.link('self')
 
     return false unless @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
-    return false if self_reference&.href != @uri
+    return false if webfinger.link('self', 'href') != @uri
 
     true
-  rescue Goldfinger::Error
+  rescue Webfinger::Error
     false
   end
 

app/services/process_mentions_service.rb

@@ -29,7 +29,7 @@ class ProcessMentionsService < BaseService
       if mention_undeliverable?(mentioned_account)
         begin
           mentioned_account = resolve_account_service.call(Regexp.last_match(1))
-        rescue Goldfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::UnexpectedResponseError
+        rescue Webfinger::Error, HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::UnexpectedResponseError
           mentioned_account = nil
         end
       end

app/services/resolve_account_service.rb

@@ -26,11 +26,10 @@ class ResolveAccountService < BaseService
 
     @account ||= Account.find_remote(@username, @domain)
 
-    return @account if @account&.local? || !webfinger_update_due?
+    return @account if @account&.local? || @domain.nil? || !webfinger_update_due?
 
     # At this point we are in need of a Webfinger query, which may
     # yield us a different username/domain through a redirect
-
     process_webfinger!(@uri)
 
     # Because the username/domain pair may be different than what
@@ -47,7 +46,7 @@ class ResolveAccountService < BaseService
     # either needs to be created, or updated from fresh data
 
     process_account!
-  rescue Goldfinger::Error, WebfingerRedirectError, Oj::ParseError => e
+  rescue Webfinger::Error, WebfingerRedirectError, Oj::ParseError => e
     Rails.logger.debug "Webfinger query for #{@uri} failed: #{e}"
     nil
   end
@@ -118,11 +117,11 @@ class ResolveAccountService < BaseService
   end
 
   def activitypub_ready?
-    !@webfinger.link('self').nil? && ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(@webfinger.link('self').type)
+    ['application/activity+json', 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"'].include?(@webfinger.link('self', 'type'))
   end
 
   def actor_url
-    @actor_url ||= @webfinger.link('self').href
+    @actor_url ||= @webfinger.link('self', 'href')
   end
 
   def actor_json