Clean up well-known routes/controllers (mastodon#1649)

* Add request spec for host meta route returning xml

* Add routing spec for xrd routes

* Update well-known routes

* Move webfinger and host-meta actions to their own controllers

app/controllers/well_known/host_meta_controller.rb

@@ -0,0 +1,13 @@
+  # frozen_string_literal: true
+
+module WellKnown
+  class HostMetaController < ApplicationController
+    def show
+      @webfinger_template = "#{webfinger_url}?resource={uri}"
+
+      respond_to do |format|
+        format.xml { render content_type: 'application/xrd+xml' }
+      end
+    end
+  end
+end

app/controllers/well_known/webfinger_controller.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module WellKnown
+  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.xml  { render content_type: 'application/xrd+xml' }
+        format.json { render content_type: 'application/jrd+json' }
+      end
+    rescue ActiveRecord::RecordNotFound
+      head 404
+    end
+
+    private
+
+    def username_from_resource
+      WebfingerResource.new(resource_param).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
+  end
+end

config/routes.rb

@@ -15,8 +15,8 @@
     controllers authorizations: 'oauth/authorizations', authorized_applications: 'oauth/authorized_applications'
   end
 
-  get '.well-known/host-meta', to: 'xrd#host_meta', as: :host_meta
-  get '.well-known/webfinger', to: 'xrd#webfinger', as: :webfinger, defaults: { format: 'json' }
+  get '.well-known/host-meta', to: 'well_known/host_meta#show', as: :host_meta, defaults: { format: 'xml' }
+  get '.well-known/webfinger', to: 'well_known/webfinger#show', as: :webfinger, defaults: { format: 'json' }
 
   devise_for :users, path: 'auth', controllers: {
     sessions:           'auth/sessions',

spec/controllers/well_known/host_meta_controller_spec.rb

@@ -0,0 +1,13 @@
+require 'rails_helper'
+
+describe WellKnown::HostMetaController, type: :controller do
+  render_views
+
+  describe 'GET #show' do
+    it 'returns http success' do
+      get :show, format: :xml
+
+      expect(response).to have_http_status(:success)
+    end
+  end
+end

spec/controllers/well_known/webfinger_controller_spec.rb

@@ -0,0 +1,21 @@
+require 'rails_helper'
+
+describe WellKnown::WebfingerController, type: :controller do
+  render_views
+
+  describe 'GET #show' do
+    let(:alice) { Fabricate(:account, username: 'alice') }
+
+    it 'returns http success when account can be found' do
+      get :show, params: { resource: alice.to_webfinger_s }, format: :json
+
+      expect(response).to have_http_status(:success)
+    end
+
+    it 'returns http not found when account cannot be found' do
+      get :show, params: { resource: 'acct:not@existing.com' }, format: :json
+
+      expect(response).to have_http_status(:not_found)
+    end
+  end
+end

spec/requests/host_meta_request_spec.rb

@@ -0,0 +1,12 @@
+require "rails_helper"
+
+describe "The host_meta route" do
+  describe "requested without accepts headers" do
+    it "returns an xml response" do
+      get host_meta_url
+
+      expect(response).to have_http_status(:success)
+      expect(response.content_type).to eq "application/xrd+xml"
+    end
+  end
+end

spec/routing/well_known_routes_spec.rb

@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+describe 'the host-meta route' do
+  it 'routes to correct place with xml format' do
+    expect(get('/.well-known/host-meta')).
+      to route_to('well_known/host_meta#show', format: 'xml')
+  end
+end
+
+describe 'the webfinger route' do
+  it 'routes to correct place with json format' do
+    expect(get('/.well-known/webfinger')).
+      to route_to('well_known/webfinger#show', format: 'json')
+  end
+end