Remove rabl dependency

Gemfile

@@ -49,7 +49,6 @@ gem 'oj', '~> 3.3'
 gem 'ostatus2', '~> 2.0'
 gem 'ox', '~> 2.8'
 gem 'pundit', '~> 1.1'
-gem 'rabl', '~> 0.13'
 gem 'rack-attack', '~> 5.0'
 gem 'rack-cors', '~> 0.4', require: 'rack/cors'
 gem 'rack-timeout', '~> 0.4'

Gemfile.lock

@@ -334,8 +334,6 @@ GEM
     puma (3.11.0)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
-    rabl (0.13.1)
-      activesupport (>= 2.3.14)
     rack (2.0.3)
     rack-attack (5.0.1)
       rack
@@ -606,7 +604,6 @@ DEPENDENCIES
   pry-rails (~> 0.3)
   puma (~> 3.10)
   pundit (~> 1.1)
-  rabl (~> 0.13)
   rack-attack (~> 5.0)
   rack-cors (~> 0.4)
   rack-timeout (~> 0.4)

app/controllers/well_known/webfinger_controller.rb

@@ -6,12 +6,10 @@ class WebfingerController < ApplicationController
 
     def show
       @account = Account.find_local!(username_from_resource)
-      @canonical_account_uri = @account.to_webfinger_s
-      @magic_key = pem_to_magic_key(@account.keypair.public_key)
 
       respond_to do |format|
         format.any(:json, :html) do
-          render formats: :json, content_type: 'application/jrd+json'
+          render json: @account, serializer: WebfingerSerializer, content_type: 'application/jrd+json'
         end
 
         format.xml do
@@ -35,21 +33,6 @@ def username_from_resource
       WebfingerResource.new(resource_user).username
     end
 
-    def pem_to_magic_key(public_key)
-      modulus, exponent = [public_key.n, public_key.e].map do |component|
-        result = []
-
-        until component.zero?
-          result << [component % 256].pack('C')
-          component >>= 8
-        end
-
-        result.reverse.join
-      end
-
-      (['RSA'] + [modulus, exponent].map { |n| Base64.urlsafe_encode64(n) }).join('.')
-    end
-
     def resource_param
       params.require(:resource)
     end

app/models/account.rb

@@ -184,6 +184,21 @@ def keypair
     @keypair ||= OpenSSL::PKey::RSA.new(private_key || public_key)
   end
 
+  def magic_key
+    modulus, exponent = [keypair.public_key.n, keypair.public_key.e].map do |component|
+      result = []
+
+      until component.zero?
+        result << [component % 256].pack('C')
+        component >>= 8
+      end
+
+      result.reverse.join
+    end
+
+    (['RSA'] + [modulus, exponent].map { |n| Base64.urlsafe_encode64(n) }).join('.')
+  end
+
   def subscription(webhook_url)
     @subscription ||= OStatus2::Subscription.new(remote_url, secret: secret, webhook: webhook_url, hub: hub_url)
   end

app/serializers/webfinger_serializer.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+class WebfingerSerializer < ActiveModel::Serializer
+  include RoutingHelper
+
+  attributes :subject, :aliases, :links
+
+  def subject
+    object.to_webfinger_s
+  end
+
+  def aliases
+    [short_account_url(object), account_url(object)]
+  end
+
+  def links
+    [
+      { rel: 'http://webfinger.net/rel/profile-page', type: 'text/html', href: short_account_url(object) },
+      { rel: 'http://schemas.google.com/g/2010#updates-from', type: 'application/atom+xml', href: account_url(object, format: 'atom') },
+      { rel: 'self', type: 'application/activity+json', href: account_url(object) },
+      { rel: 'salmon', href: api_salmon_url(object.id) },
+      { rel: 'magic-public-key', href: "data:application/magic-public-key,#{object.magic_key}" },
+      { rel: 'http://ostatus.org/schema/1.0/subscribe', template: "#{authorize_follow_url}?acct={uri}" },
+    ]
+  end
+end

app/views/well_known/webfinger/show.xml.ruby

@@ -1,13 +1,13 @@
 Nokogiri::XML::Builder.new do |xml|
   xml.XRD(xmlns: 'http://docs.oasis-open.org/ns/xri/xrd-1.0') do
-    xml.Subject @canonical_account_uri
+    xml.Subject @account.to_webfinger_s
     xml.Alias short_account_url(@account)
     xml.Alias account_url(@account)
     xml.Link(rel: 'http://webfinger.net/rel/profile-page', type: 'text/html', href: short_account_url(@account))
     xml.Link(rel: 'http://schemas.google.com/g/2010#updates-from', type: 'application/atom+xml', href: account_url(@account, format: 'atom'))
     xml.Link(rel: 'self', type: 'application/activity+json', href: account_url(@account))
     xml.Link(rel: 'salmon', href: api_salmon_url(@account.id))
-    xml.Link(rel: 'magic-public-key', href: "data:application/magic-public-key,#{@magic_key}")
+    xml.Link(rel: 'magic-public-key', href: "data:application/magic-public-key,#{@account.magic_key}")
     xml.Link(rel: 'http://ostatus.org/schema/1.0/subscribe', template: "#{authorize_follow_url}?acct={uri}")
   end
 end.to_xml