Pubsub confirmation worker spec (#2974)

* Add specs for valid challenge response from pubsub confirmation worker

* Refactor the pubsub confirmation worker

app/workers/pubsubhubbub/confirmation_worker.rb

@@ -6,31 +6,85 @@ class Pubsubhubbub::ConfirmationWorker
 
   sidekiq_options queue: 'push', retry: false
 
+  attr_reader :subscription, :mode, :secret, :lease_seconds
+
   def perform(subscription_id, mode, secret = nil, lease_seconds = nil)
-    subscription = Subscription.find(subscription_id)
-    challenge    = SecureRandom.hex
+    @subscription = Subscription.find(subscription_id)
+    @mode = mode
+    @secret = secret
+    @lease_seconds = lease_seconds
+    process_confirmation
+  end
 
-    subscription.secret        = secret
-    subscription.lease_seconds = lease_seconds
-    subscription.confirmed     = true
+  private
 
-    response = HTTP.headers(user_agent: 'Mastodon/PubSubHubbub')
+  def process_confirmation
+    prepare_subscription
+
+    confirm_callback
+    logger.debug "Confirming PuSH subscription for #{subscription.callback_url} with challenge #{challenge}: #{callback_response_body}"
+
+    update_subscription
+  end
+
+  def update_subscription
+    if successful_subscribe?
+      subscription.save!
+    elsif successful_unsubscribe?
+      subscription.destroy!
+    end
+  end
+
+  def successful_subscribe?
+    subscribing? && response_matches_challenge?
+  end
+
+  def successful_unsubscribe?
+    (unsubscribing? && response_matches_challenge?) || !subscription.confirmed?
+  end
+
+  def response_matches_challenge?
+    callback_response_body == challenge
+  end
+
+  def subscribing?
+    mode == 'subscribe'
+  end
+
+  def unsubscribing?
+    mode == 'unsubscribe'
+  end
+
+  def confirm_callback
+    @_confirm_callback ||= callback_get_with_params
+  end
+
+  def callback_get_with_params
+    HTTP.headers(user_agent: 'Mastodon/PubSubHubbub')
         .timeout(:per_operation, write: 20, connect: 20, read: 50)
-                   .get(subscription.callback_url, params: {
+        .get(subscription.callback_url, params: callback_params)
+  end
+
+  def callback_response_body
+    confirm_callback.body.to_s
+  end
+
+  def callback_params
+    {
       'hub.topic' => account_url(subscription.account, format: :atom),
       'hub.mode' => mode,
       'hub.challenge' => challenge,
       'hub.lease_seconds' => subscription.lease_seconds,
-                        })
+    }
+  end
 
-    body = response.body.to_s
+  def prepare_subscription
+    subscription.secret = secret
+    subscription.lease_seconds = lease_seconds
+    subscription.confirmed = true
+  end
 
-    logger.debug "Confirming PuSH subscription for #{subscription.callback_url} with challenge #{challenge}: #{body}"
-
-    if mode == 'subscribe' && body == challenge
-      subscription.save!
-    elsif (mode == 'unsubscribe' && body == challenge) || !subscription.confirmed?
-      subscription.destroy!
-    end
+  def challenge
+    @_challenge ||= SecureRandom.hex
   end
 end

spec/workers/pubsubhubbub/confirmation_worker_spec.rb

@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Pubsubhubbub::ConfirmationWorker do
+  include RoutingHelper
+
+  subject { described_class.new }
+
+  let!(:alice) { Fabricate(:account, username: 'alice') }
+  let!(:subscription) { Fabricate(:subscription, account_id: alice.id, callback_url: 'http://example.com/api', confirmed: false, expires_at: 3.days.from_now, secret: nil) }
+
+  describe 'perform' do
+    describe 'with subscribe mode' do
+      it 'confirms and updates subscription when challenge matches' do
+        stub_random_value
+        stub_request(:get, url_for_mode('subscribe'))
+          .with(headers: http_headers)
+          .to_return(status: 200, body: challenge_value, headers: {})
+
+        seconds = 10.days.seconds.to_i
+        subject.perform(subscription.id, 'subscribe', 'asdf', seconds)
+
+        subscription.reload
+        expect(subscription.secret).to eq 'asdf'
+        expect(subscription.confirmed).to eq true
+        expect(subscription.expires_at).to be_within(5).of(10.days.from_now)
+      end
+
+      it 'does not update subscription when challenge does not match' do
+        stub_random_value
+        stub_request(:get, url_for_mode('subscribe'))
+          .with(headers: http_headers)
+          .to_return(status: 200, body: 'wrong value', headers: {})
+
+        seconds = 10.days.seconds.to_i
+        subject.perform(subscription.id, 'subscribe', 'asdf', seconds)
+
+        subscription.reload
+        expect(subscription.secret).to be_blank
+        expect(subscription.confirmed).to eq false
+        expect(subscription.expires_at).to be_within(5).of(3.days.from_now)
+      end
+    end
+
+    describe 'with unsubscribe mode' do
+      it 'confirms and destroys subscription when challenge matches' do
+        stub_random_value
+        stub_request(:get, url_for_mode('unsubscribe'))
+          .with(headers: http_headers)
+          .to_return(status: 200, body: challenge_value, headers: {})
+
+        seconds = 10.days.seconds.to_i
+        subject.perform(subscription.id, 'unsubscribe', 'asdf', seconds)
+
+        expect { subscription.reload }.to raise_error(ActiveRecord::RecordNotFound)
+      end
+
+      it 'does not destroy subscription when challenge does not match' do
+        stub_random_value
+        stub_request(:get, url_for_mode('unsubscribe'))
+          .with(headers: http_headers)
+          .to_return(status: 200, body: 'wrong value', headers: {})
+
+        seconds = 10.days.seconds.to_i
+        subject.perform(subscription.id, 'unsubscribe', 'asdf', seconds)
+
+        expect { subscription.reload }.not_to raise_error
+      end
+    end
+  end
+
+  def url_for_mode(mode)
+    "http://example.com/api?hub.challenge=#{challenge_value}&hub.lease_seconds=863999&hub.mode=#{mode}&hub.topic=https://#{Rails.configuration.x.local_domain}/users/alice.atom"
+  end
+
+  def stub_random_value
+    allow(SecureRandom).to receive(:hex).and_return(challenge_value)
+  end
+
+  def challenge_value
+    '1a2s3d4f'
+  end
+
+  def http_headers
+    { 'Connection' => 'close', 'Host' => 'example.com', 'User-Agent' => 'Mastodon/PubSubHubbub' }
+  end
+end