Spec coverage and refactor for pubsub/delivery worker (#3021)

* Framework for delivery worker spec

* Refactor of pubsub delivery worker

app/workers/pubsubhubbub/delivery_worker.rb

@@ -10,40 +10,83 @@ class Pubsubhubbub::DeliveryWorker
     5 * (count + 1)
   end
 
+  attr_reader :subscription, :payload
+
   def perform(subscription_id, payload)
-    subscription = Subscription.find(subscription_id)
-    headers      = {}
-    host         = Addressable::URI.parse(subscription.callback_url).normalize.host
+    @subscription = Subscription.find(subscription_id)
+    @payload = payload
+    process_delivery unless blocked_domain?
+  end
 
-    return if DomainBlock.blocked?(host)
+  private
 
-    headers['User-Agent']      = 'Mastodon/PubSubHubbub'
-    headers['Content-Type']    = 'application/atom+xml'
-    headers['Link']            = LinkHeader.new([[api_push_url, [%w(rel hub)]], [account_url(subscription.account, format: :atom), [%w(rel self)]]]).to_s
-    headers['X-Hub-Signature'] = signature(subscription.secret, payload) if subscription.secret?
+  def process_delivery
+    payload_delivery
 
-    response = HTTP.timeout(:per_operation, write: 50, connect: 20, read: 50)
-                   .headers(headers)
-                   .post(subscription.callback_url, body: payload)
+    if response_successful?
+      subscription.touch(:last_successful_delivery_at)
+    elsif response_failed_permanently?
+      subscription.destroy!
+    else
+      raise "Delivery failed for #{subscription.callback_url}: HTTP #{payload_delivery.code}"
+    end
+  end
 
-    return subscription.destroy! if response_failed_permanently?(response) # HTTP 4xx means error is not temporary, except for 429 (throttling)
-    raise "Delivery failed for #{subscription.callback_url}: HTTP #{response.code}" unless response_successful?(response)
+  def payload_delivery
+    @_payload_delivery ||= callback_post_payload
+  end
 
-    subscription.touch(:last_successful_delivery_at)
+  def callback_post_payload
+    HTTP.timeout(:per_operation, write: 50, connect: 20, read: 50)
+        .headers(headers)
+        .post(subscription.callback_url, body: payload)
   end
 
-  private
+  def blocked_domain?
+    DomainBlock.blocked?(host)
+  end
+
+  def host
+    Addressable::URI.parse(subscription.callback_url).normalize.host
+  end
+
+  def headers
+    {
+      'User-Agent' => 'Mastodon/PubSubHubbub',
+      'Content-Type' => 'application/atom+xml',
+      'Link' => link_headers,
+    }.merge(signature_headers.to_h)
+  end
+
+  def link_headers
+    LinkHeader.new([hub_link_header, self_link_header]).to_s
+  end
+
+  def hub_link_header
+    [api_push_url, [%w(rel hub)]]
+  end
+
+  def self_link_header
+    [account_url(subscription.account, format: :atom), [%w(rel self)]]
+  end
+
+  def signature_headers
+    { 'X-Hub-Signature' => payload_signature } if subscription.secret?
+  end
+
+  def payload_signature
+    "sha1=#{hmac_payload_digest}"
+  end
 
-  def signature(secret, payload)
-    hmac = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha1'), secret, payload)
-    "sha1=#{hmac}"
+  def hmac_payload_digest
+    OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha1'), subscription.secret, payload)
   end
 
-  def response_failed_permanently?(response)
-    response.code > 299 && response.code < 500 && response.code != 429
+  def response_failed_permanently?
+    payload_delivery.code > 299 && payload_delivery.code < 500 && payload_delivery.code != 429
   end
 
-  def response_successful?(response)
-    response.code > 199 && response.code < 300
+  def response_successful?
+    payload_delivery.code > 199 && payload_delivery.code < 300
   end
 end

spec/fabricators/subscription_fabricator.rb

@@ -1,4 +1,5 @@
 Fabricator(:subscription) do
+  account
   callback_url "http://example.com/callback"
   secret       "foobar"
   expires_at   "2016-11-28 11:30:07"

spec/workers/pubsubhubbub/confirmation_worker_spec.rb

@@ -8,7 +8,7 @@ describe Pubsubhubbub::ConfirmationWorker do
   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) }
+  let!(:subscription) { Fabricate(:subscription, account: alice, callback_url: 'http://example.com/api', confirmed: false, expires_at: 3.days.from_now, secret: nil) }
 
   describe 'perform' do
     describe 'with subscribe mode' do

spec/workers/pubsubhubbub/delivery_worker_spec.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Pubsubhubbub::DeliveryWorker do
+  include RoutingHelper
+  subject { described_class.new }
+
+  let(:payload) { 'test' }
+
+  describe 'perform' do
+    it 'raises when subscription does not exist' do
+      expect { subject.perform 123, payload }.to raise_error(ActiveRecord::RecordNotFound)
+    end
+
+    it 'does not attempt to deliver when domain blocked' do
+      _domain_block = Fabricate(:domain_block, domain: 'example.com', severity: :suspend)
+      subscription = Fabricate(:subscription, callback_url: 'https://example.com/api', last_successful_delivery_at: 2.days.ago)
+
+      subject.perform(subscription.id, payload)
+
+      expect(subscription.reload.last_successful_delivery_at).to be_within(2).of(2.days.ago)
+    end
+
+    it 'destroys subscription when request fails permanently' do
+      subscription = Fabricate(:subscription)
+
+      stub_request_to_respond_with(subscription, 404)
+      subject.perform(subscription.id, payload)
+
+      expect { subscription.reload }.to raise_error(ActiveRecord::RecordNotFound)
+    end
+
+    it 'raises when request fails' do
+      subscription = Fabricate(:subscription)
+
+      stub_request_to_respond_with(subscription, 500)
+      expect { subject.perform(subscription.id, payload) }.to raise_error(/Delivery failed/)
+    end
+
+    it 'updates subscriptions when delivery succeeds' do
+      subscription = Fabricate(:subscription)
+
+      stub_request_to_respond_with(subscription, 200)
+      subject.perform(subscription.id, payload)
+
+      expect(subscription.reload.last_successful_delivery_at).to be_within(2).of(Time.now.utc)
+    end
+
+    it 'updates subscription without a secret when delivery succeeds' do
+      subscription = Fabricate(:subscription, secret: nil)
+
+      stub_request_to_respond_with(subscription, 200)
+      subject.perform(subscription.id, payload)
+
+      expect(subscription.reload.last_successful_delivery_at).to be_within(2).of(Time.now.utc)
+    end
+
+    def stub_request_to_respond_with(subscription, code)
+      stub_request(:post, 'http://example.com/callback')
+        .with(body: payload, headers: expected_headers(subscription))
+        .to_return(status: code, body: '', headers: {})
+    end
+
+    def expected_headers(subscription)
+      {
+        'Connection' => 'close',
+        'Content-Type' => 'application/atom+xml',
+        'Host' => 'example.com',
+        'Link' => "<https://#{Rails.configuration.x.local_domain}/api/push>; rel=\"hub\", <https://#{Rails.configuration.x.local_domain}/users/#{subscription.account.username}.atom>; rel=\"self\"",
+        'User-Agent' => 'Mastodon/PubSubHubbub',
+      }.tap do |basic|
+        known_digest = OpenSSL::HMAC.hexdigest(OpenSSL::Digest.new('sha1'), subscription.secret.to_s, payload)
+        basic.merge('X-Hub-Signature' => "sha1=#{known_digest}") if subscription.secret?
+      end
+    end
+  end
+end

spec/workers/pubsubhubbub/distribution_worker_spec.rb

@@ -5,8 +5,8 @@ describe Pubsubhubbub::DistributionWorker do
 
   let!(:alice) { Fabricate(:account, username: 'alice') }
   let!(:bob) { Fabricate(:account, username: 'bob', domain: 'example2.com') }
-  let!(:anonymous_subscription) { Fabricate(:subscription, account_id: alice.id, callback_url: 'http://example1.com', confirmed: true, lease_seconds: 3600) }
-  let!(:subscription_with_follower) { Fabricate(:subscription, account_id: alice.id, callback_url: 'http://example2.com', confirmed: true, lease_seconds: 3600) }
+  let!(:anonymous_subscription) { Fabricate(:subscription, account: alice, callback_url: 'http://example1.com', confirmed: true, lease_seconds: 3600) }
+  let!(:subscription_with_follower) { Fabricate(:subscription, account: alice, callback_url: 'http://example2.com', confirmed: true, lease_seconds: 3600) }
 
   before do
     bob.follow!(alice)