Default to json type for webfinger requests (mastodon#1583)

app/controllers/xrd_controller.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 class XrdController < ApplicationController
-  before_action :set_default_format_json, only: :webfinger
   before_action :set_default_format_xml, only: :host_meta
 
   def host_meta
@@ -31,10 +30,6 @@ def set_default_format_xml
     request.format = 'xml' if request.headers['HTTP_ACCEPT'].nil? && params[:format].nil?
   end
 
-  def set_default_format_json
-    request.format = 'json' if request.headers['HTTP_ACCEPT'].nil? && params[:format].nil?
-  end
-
   def username_from_resource
     if resource_param =~ /\Ahttps?:\/\//
       path_params = Rails.application.routes.recognize_path(resource_param)

config/routes.rb

@@ -15,7 +15,7 @@
   end
 
   get '.well-known/host-meta', to: 'xrd#host_meta', as: :host_meta
-  get '.well-known/webfinger', to: 'xrd#webfinger', as: :webfinger
+  get '.well-known/webfinger', to: 'xrd#webfinger', as: :webfinger, defaults: { format: 'json' }
 
   devise_for :users, path: 'auth', controllers: {
     sessions:           'auth/sessions',

spec/controllers/xrd_controller_spec.rb

@@ -14,12 +14,12 @@
     let(:alice) { Fabricate(:account, username: 'alice') }
 
     it 'returns http success when account can be found' do
-      get :webfinger, params: { resource: alice.to_webfinger_s }
+      get :webfinger, 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 :webfinger, params: { resource: 'acct:not@existing.com' }
+      get :webfinger, params: { resource: 'acct:not@existing.com' }, format: :json
       expect(response).to have_http_status(:not_found)
     end
   end

spec/requests/webfinger_request_spec.rb

@@ -0,0 +1,33 @@
+require "rails_helper"
+
+describe "The webfinger route" do
+  let(:alice) { Fabricate(:account, username: 'alice') }
+
+  describe "requested without accepts headers" do
+    it "returns a json response" do
+      get webfinger_url, params: { resource: alice.to_webfinger_s }
+
+      expect(response).to have_http_status(:success)
+      expect(response.content_type).to eq "application/jrd+json"
+    end
+  end
+
+  describe "requested with html in accepts headers" do
+    it "returns a json response" do
+      headers = { 'HTTP_ACCEPT' => 'text/html' }
+      get webfinger_url, params: { resource: alice.to_webfinger_s }, headers: headers
+
+      expect(response).to have_http_status(:success)
+      expect(response.content_type).to eq "application/jrd+json"
+    end
+  end
+
+  describe "requested with xml format" do
+    it "returns an xml response" do
+      get webfinger_url(resource: alice.to_webfinger_s, format: :xml)
+
+      expect(response).to have_http_status(:success)
+      expect(response.content_type).to eq "application/xrd+xml"
+    end
+  end
+end