HTTP proxy support for outgoing request, manage access to hidden service (#7134)

* Add support for HTTP client proxy

* Add access control for darknet

Supress error when access to darknet via transparent proxy

* Fix the codes pointed out

* Lint

* Fix an omission + lint

* any? -> include?

* Change detection method to regexp to avoid test fail

app/lib/request.rb

@@ -11,9 +11,10 @@ class Request
   def initialize(verb, url, **options)
     @verb    = verb
     @url     = Addressable::URI.parse(url).normalize
-    @options = options.merge(socket_class: Socket)
+    @options = options.merge(use_proxy? ? Rails.configuration.x.http_client_proxy : { socket_class: Socket })
     @headers = {}
 
+    raise Mastodon::HostValidationError, 'Instance does not support hidden service connections' if block_hidden_service?
     set_common_headers!
     set_digest! if options.key?(:body)
   end
@@ -99,6 +100,14 @@ class Request
     @http_client ||= HTTP.timeout(:per_operation, timeout).follow(max_hops: 2)
   end
 
+  def use_proxy?
+    Rails.configuration.x.http_client_proxy.present?
+  end
+
+  def block_hidden_service?
+    !Rails.configuration.x.access_to_hidden_service && /\.(onion|i2p)$/.match(@url.host)
+  end
+
   module ClientLimit
     def body_with_limit(limit = 1.megabyte)
       raise Mastodon::LengthValidationError if content_length.present? && content_length > limit
@@ -129,6 +138,7 @@ class Request
   class Socket < TCPSocket
     class << self
       def open(host, *args)
+        return super host, *args if thru_hidden_service? host
         outer_e = nil
         Addrinfo.foreach(host, nil, nil, :SOCK_STREAM) do |address|
           begin
@@ -142,6 +152,10 @@ class Request
       end
 
       alias new open
+
+      def thru_hidden_service?(host)
+        Rails.configuration.x.hidden_service_via_transparent_proxy && /\.(onion|i2p)$/.match(host)
+      end
     end
   end