Merge 8929f5251d into 8b34daf254

.env.production.sample

@@ -110,3 +110,17 @@ FETCH_REPLIES_MAX_SINGLE=500
 
 # Max number of replies Collection pages to fetch - total
 FETCH_REPLIES_MAX_PAGES=500
+
+
+# Account Backfill Behavior
+# --------------------------
+# When the first person from your instance follows a remote account,
+# backfill their most recent n statuses.
+# (default: true if unset, set explicitly to ``false`` to disable)
+ACCOUNT_BACKFILL_ENABLED=true
+
+# Max statuses to fetch when backfilling a new account
+ACCOUNT_BACKFILL_MAX_STATUSES=1000
+
+# Max number of replies Collection pages to fetch
+ACCOUNT_BACKFILL_MAX_PAGES=200

app/helpers/json_ld_helper.rb

@@ -203,6 +203,85 @@ module JsonLdHelper
     end
   end
 
+  # Iterate through the pages of an activitypub collection,
+  # returning the collected items and the number of pages that were fetched.
+  #
+  # @param collection_or_uri [String, Hash]
+  #   either the URI or an already-fetched AP object
+  # @param max_pages [Integer, nil]
+  #   Max pages to fetch, if nil, fetch until no more pages
+  # @param max_items [Integer, nil]
+  #   Max items to fetch, if nil, fetch until no more items
+  # @param reference_uri [String, nil]
+  #   If not nil, a URI to compare to the collection URI.
+  #   If the host of the collection URI does not match the reference URI,
+  #   do not fetch the collection page.
+  # @param on_behalf_of [Account, nil]
+  #   Sign the request on behalf of the Account, if not nil
+  # @return [Array<Array<Hash>, Integer>, nil]
+  #   The collection items and the number of pages fetched
+  def collection_items(collection_or_uri, max_pages: 1, max_items: nil, reference_uri: nil, on_behalf_of: nil)
+    collection = fetch_collection(collection_or_uri, reference_uri: reference_uri, on_behalf_of: on_behalf_of)
+    return unless collection.is_a?(Hash)
+
+    collection = fetch_collection(collection['first'], reference_uri: reference_uri, on_behalf_of: on_behalf_of) if collection['first'].present?
+    return unless collection.is_a?(Hash)
+
+    items = []
+    n_pages = 1
+    while collection.is_a?(Hash)
+      items.concat(as_array(collection_page_items(collection)))
+
+      break if !max_items.nil? && items.size >= max_items
+      break if !max_pages.nil? && n_pages >= max_pages
+
+      collection = collection['next'].present? ? fetch_collection(collection['next'], reference_uri: reference_uri, on_behalf_of: on_behalf_of) : nil
+      n_pages += 1
+    end
+
+    [items, n_pages]
+  end
+
+  def collection_page_items(collection)
+    case collection['type']
+    when 'Collection', 'CollectionPage'
+      collection['items']
+    when 'OrderedCollection', 'OrderedCollectionPage'
+      collection['orderedItems']
+    end
+  end
+
+  # Fetch a single collection page
+  # To get the whole collection, use collection_items
+  #
+  # @param collection_or_uri [String, Hash]
+  # @param reference_uri [String, nil]
+  #   If not nil, a URI to compare to the collection URI.
+  #   If the host of the collection URI does not match the reference URI,
+  #   do not fetch the collection page.
+  # @param on_behalf_of [Account, nil]
+  #   Sign the request on behalf of the Account, if not nil
+  # @return [Hash, nil]
+  def fetch_collection(collection_or_uri, reference_uri: nil, on_behalf_of: nil)
+    return collection_or_uri if collection_or_uri.is_a?(Hash)
+    return if !reference_uri.nil? && non_matching_uri_hosts?(reference_uri, collection_or_uri)
+
+    # NOTE: For backward compatibility reasons, Mastodon signs outgoing
+    # queries incorrectly by default.
+    #
+    # While this is relevant for all URLs with query strings, this is
+    # the only code path where this happens in practice.
+    #
+    # Therefore, retry with correct signatures if this fails.
+    begin
+      fetch_resource_without_id_validation(collection_or_uri, on_behalf_of, raise_on_error: :temporary)
+    rescue Mastodon::UnexpectedResponseError => e
+      raise unless e.response && e.response.code == 401 && Addressable::URI.parse(collection_or_uri).query.present?
+
+      fetch_resource_without_id_validation(collection_or_uri, on_behalf_of, raise_on_error: :temporary, request_options: { omit_query_string: false })
+    end
+  end
+
   def valid_activitypub_content_type?(response)
     return true if response.mime_type == 'application/activity+json'
 

app/models/follow_request.rb

@@ -32,6 +32,7 @@ class FollowRequest < ApplicationRecord
   validates :languages, language: true
 
   def authorize!
+    is_first_follow = first_follow?
     follow = account.follow!(target_account, reblogs: show_reblogs, notify: notify, languages: languages, uri: uri, bypass_limit: true)
 
     if account.local?
@@ -40,6 +41,7 @@ class FollowRequest < ApplicationRecord
       MergeWorker.push_bulk(List.where(account: account).joins(:list_accounts).where(list_accounts: { account_id: target_account.id }).pluck(:id)) do |list_id|
         [target_account.id, list_id, 'list']
       end
+      ActivityPub::AccountBackfillWorker.perform_async(target_account.id) if is_first_follow & ActivityPub::AccountBackfillService::ENABLED
     end
 
     destroy!
@@ -51,6 +53,10 @@ class FollowRequest < ApplicationRecord
     false # Force uri_for to use uri attribute
   end
 
+  def first_follow?
+    !target_account.followers.local.exists?
+  end
+
   before_validation :set_uri, only: :create
   after_commit :invalidate_follow_recommendations_cache
 

app/services/activitypub/account_backfill_service.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+class ActivityPub::AccountBackfillService < BaseService
+  include JsonLdHelper
+
+  ENABLED = ENV['ACCOUNT_BACKFILL_ENABLED'].nil? || ENV['ACCOUNT_BACKFILL_ENABLED'] == 'true'
+  MAX_STATUSES = (ENV['ACCOUNT_BACKFILL_MAX_STATUSES'] || 1000).to_i
+  MAX_PAGES = (ENV['ACCOUNT_BACKFILL_MAX_PAGES'] || 200).to_i
+
+  def call(account, on_behalf_of: nil, request_id: nil)
+    return unless ENABLED
+
+    @account = account
+    return if @account.nil? || @account.outbox_url.nil?
+
+    @items, = collection_items(@account.outbox_url, max_items: MAX_STATUSES, max_pages: MAX_PAGES, on_behalf_of: on_behalf_of)
+    @items = filter_items(@items)
+    return if @items.nil?
+
+    on_behalf_of_id = on_behalf_of&.id
+
+    FetchReplyWorker.push_bulk(@items) do |status_uri_or_body|
+      if status_uri_or_body.is_a?(Hash) && status_uri_or_body.key?('object') && status_uri_or_body.key?('id')
+        # Re-add the minimally-acceptable @context, which gets stripped because this object comes inside a collection
+        status_uri_or_body['@context'] = ActivityPub::TagManager::CONTEXT unless status_uri_or_body.key?('@context')
+        [status_uri_or_body['id'], { prefetched_body: status_uri_or_body, request_id: request_id, on_behalf_of: on_behalf_of_id }]
+      else
+        [status_uri_or_body, { request_id: request_id, on_behalf_of: on_behalf_of_id }]
+      end
+    end
+
+    @items
+  end
+
+  private
+
+  # Reject any non-public statuses.
+  # Since our request may have been signed on behalf of the follower,
+  # we may have received followers-only statuses.
+  #
+  # Formally, a followers-only status is addressed to the account's followers collection.
+  # We were not in that collection at the time that the post was made,
+  # so followers-only statuses fetched by backfilling are not addressed to us.
+  # Public and unlisted statuses are send to the activitystreams "Public" entity.
+  # We are part of the public, so those posts *are* addressed to us.
+  #
+  # @param items [Array<Hash>]
+  # @return [Array<Hash>]
+  def filter_items(items)
+    allowed = [:public, :unlisted]
+    items.filter { |item| item.is_a?(String) || allowed.include?(ActivityPub::Parser::StatusParser.new(item).visibility) }
+  end
+end

app/services/activitypub/fetch_featured_collection_service.rb

@@ -12,30 +12,12 @@ class ActivityPub::FetchFeaturedCollectionService < BaseService
 
     return unless supported_context?(@json)
 
-    process_items(collection_items(@json))
+    @items, = collection_items(@json, max_pages: 1, reference_uri: @account.uri, on_behalf_of: local_follower)
+    process_items(@items)
   end
 
   private
 
-  def collection_items(collection)
-    collection = fetch_collection(collection['first']) if collection['first'].present?
-    return unless collection.is_a?(Hash)
-
-    case collection['type']
-    when 'Collection', 'CollectionPage'
-      as_array(collection['items'])
-    when 'OrderedCollection', 'OrderedCollectionPage'
-      as_array(collection['orderedItems'])
-    end
-  end
-
-  def fetch_collection(collection_or_uri)
-    return collection_or_uri if collection_or_uri.is_a?(Hash)
-    return if non_matching_uri_hosts?(@account.uri, collection_or_uri)
-
-    fetch_resource_without_id_validation(collection_or_uri, local_follower, raise_on_error: :temporary)
-  end
-
   def process_items(items)
     return if items.nil?
 

app/services/activitypub/fetch_featured_tags_collection_service.rb

@@ -11,43 +11,12 @@ class ActivityPub::FetchFeaturedTagsCollectionService < BaseService
 
     return unless supported_context?(@json)
 
-    process_items(collection_items(@json))
+    @items, = collection_items(@json, max_items: FeaturedTag::LIMIT, reference_uri: @account.uri, on_behalf_of: local_follower)
+    process_items(@items)
   end
 
   private
 
-  def collection_items(collection)
-    all_items = []
-
-    collection = fetch_collection(collection['first']) if collection['first'].present?
-
-    while collection.is_a?(Hash)
-      items = case collection['type']
-              when 'Collection', 'CollectionPage'
-                collection['items']
-              when 'OrderedCollection', 'OrderedCollectionPage'
-                collection['orderedItems']
-              end
-
-      break if items.blank?
-
-      all_items.concat(items)
-
-      break if all_items.size >= FeaturedTag::LIMIT
-
-      collection = collection['next'].present? ? fetch_collection(collection['next']) : nil
-    end
-
-    all_items
-  end
-
-  def fetch_collection(collection_or_uri)
-    return collection_or_uri if collection_or_uri.is_a?(Hash)
-    return if non_matching_uri_hosts?(@account.uri, collection_or_uri)
-
-    fetch_resource_without_id_validation(collection_or_uri, local_follower, raise_on_error: :temporary)
-  end
-
   def process_items(items)
     names            = items.filter_map { |item| item['type'] == 'Hashtag' && item['name']&.delete_prefix('#') }.take(FeaturedTag::LIMIT)
     tags             = names.index_by { |name| HashtagNormalizer.new.normalize(name) }

app/services/activitypub/fetch_remote_status_service.rb

@@ -11,6 +11,9 @@ class ActivityPub::FetchRemoteStatusService < BaseService
   def call(uri, prefetched_body: nil, on_behalf_of: nil, expected_actor_uri: nil, request_id: nil)
     return if domain_not_allowed?(uri)
 
+    # load the account if given as an ID
+    on_behalf_of = Account.find(on_behalf_of) unless on_behalf_of.nil? || on_behalf_of.is_a?(Account)
+
     @request_id = request_id || "#{Time.now.utc.to_i}-status-#{uri}"
     @json = if prefetched_body.nil?
               fetch_status(uri, true, on_behalf_of)

app/services/activitypub/fetch_replies_service.rb

@@ -8,9 +8,13 @@ class ActivityPub::FetchRepliesService < BaseService
 
   def call(reference_uri, collection_or_uri, max_pages: 1, allow_synchronous_requests: true, request_id: nil)
     @reference_uri = reference_uri
-    @allow_synchronous_requests = allow_synchronous_requests
+    return if !allow_synchronous_requests && !collection_or_uri.is_a?(Hash)
 
-    @items, n_pages = collection_items(collection_or_uri, max_pages: max_pages)
+    # if given a prefetched collection while forbidding synchronous requests,
+    # process it and return without fetching additional pages
+    max_pages = 1 if !allow_synchronous_requests && collection_or_uri.is_a?(Hash)
+
+    @items, n_pages = collection_items(collection_or_uri, max_pages: max_pages, max_items: MAX_REPLIES, reference_uri: @reference_uri)
     return if @items.nil?
 
     @items = filter_replies(@items)
@@ -21,58 +25,6 @@ class ActivityPub::FetchRepliesService < BaseService
 
   private
 
-  def collection_items(collection_or_uri, max_pages: 1)
-    collection = fetch_collection(collection_or_uri)
-    return unless collection.is_a?(Hash)
-
-    collection = fetch_collection(collection['first']) if collection['first'].present?
-    return unless collection.is_a?(Hash)
-
-    items = []
-    n_pages = 1
-    while collection.is_a?(Hash)
-      items.concat(as_array(collection_page_items(collection)))
-
-      break if items.size >= MAX_REPLIES
-      break if n_pages >= max_pages
-
-      collection = collection['next'].present? ? fetch_collection(collection['next']) : nil
-      n_pages += 1
-    end
-
-    [items, n_pages]
-  end
-
-  def collection_page_items(collection)
-    case collection['type']
-    when 'Collection', 'CollectionPage'
-      collection['items']
-    when 'OrderedCollection', 'OrderedCollectionPage'
-      collection['orderedItems']
-    end
-  end
-
-  def fetch_collection(collection_or_uri)
-    return collection_or_uri if collection_or_uri.is_a?(Hash)
-    return unless @allow_synchronous_requests
-    return if non_matching_uri_hosts?(@reference_uri, collection_or_uri)
-
-    # NOTE: For backward compatibility reasons, Mastodon signs outgoing
-    # queries incorrectly by default.
-    #
-    # While this is relevant for all URLs with query strings, this is
-    # the only code path where this happens in practice.
-    #
-    # Therefore, retry with correct signatures if this fails.
-    begin
-      fetch_resource_without_id_validation(collection_or_uri, nil, raise_on_error: :temporary)
-    rescue Mastodon::UnexpectedResponseError => e
-      raise unless e.response && e.response.code == 401 && Addressable::URI.parse(collection_or_uri).query.present?
-
-      fetch_resource_without_id_validation(collection_or_uri, nil, raise_on_error: :temporary, request_options: { omit_query_string: false })
-    end
-  end
-
   def filter_replies(items)
     # Only fetch replies to the same server as the original status to avoid
     # amplification attacks.

app/services/activitypub/synchronize_followers_service.rb

@@ -63,10 +63,10 @@ class ActivityPub::SynchronizeFollowersService < BaseService
 
   # Only returns true if the whole collection has been processed
   def process_collection!(collection_uri, max_pages: MAX_COLLECTION_PAGES)
-    collection = fetch_collection(collection_uri)
+    collection = fetch_collection(collection_uri, reference_uri: @account.uri)
     return false unless collection.is_a?(Hash)
 
-    collection = fetch_collection(collection['first']) if collection['first'].present?
+    collection = fetch_collection(collection['first'], reference_uri: @account.uri) if collection['first'].present?
 
     while collection.is_a?(Hash)
       process_page!(as_array(collection_page_items(collection)))
@@ -81,20 +81,4 @@ class ActivityPub::SynchronizeFollowersService < BaseService
 
     false
   end
-
-  def collection_page_items(collection)
-    case collection['type']
-    when 'Collection', 'CollectionPage'
-      collection['items']
-    when 'OrderedCollection', 'OrderedCollectionPage'
-      collection['orderedItems']
-    end
-  end
-
-  def fetch_collection(collection_or_uri)
-    return collection_or_uri if collection_or_uri.is_a?(Hash)
-    return if non_matching_uri_hosts?(@account.uri, collection_or_uri)
-
-    fetch_resource_without_id_validation(collection_or_uri, nil, raise_on_error: :temporary)
-  end
 end

app/workers/activitypub/account_backfill_worker.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+class ActivityPub::AccountBackfillWorker
+  include Sidekiq::Worker
+  include ExponentialBackoff
+
+  def perform(account_id, options = {})
+    account = Account.find(account_id)
+    return if account.local?
+
+    ActivityPub::AccountBackfillService.new.call(account, **options.deep_symbolize_keys)
+  end
+end

app/workers/fetch_reply_worker.rb

@@ -7,6 +7,6 @@ class FetchReplyWorker
   sidekiq_options queue: 'pull', retry: 3
 
   def perform(child_url, options = {})
-    FetchRemoteStatusService.new.call(child_url, **options.deep_symbolize_keys)
+    FetchRemoteStatusService.new.call(child_url, **options.symbolize_keys)
   end
 end

spec/models/follow_request_spec.rb

@@ -20,17 +20,19 @@ RSpec.describe FollowRequest do
       end
     end
 
-    it 'calls Account#follow!, MergeWorker.perform_async, and #destroy!' do
+    it 'calls Account#follow!, MergeWorker.perform_async, ActivityPub::AccountBackfillWorker, and #destroy!' do
       allow(account).to receive(:follow!) do
         account.active_relationships.create!(target_account: target_account)
       end
       allow(MergeWorker).to receive(:perform_async)
+      allow(ActivityPub::AccountBackfillWorker).to receive(:perform_async)
       allow(follow_request).to receive(:destroy!)
 
       follow_request.authorize!
 
       expect(account).to have_received(:follow!).with(target_account, reblogs: true, notify: false, uri: follow_request.uri, languages: nil, bypass_limit: true)
       expect(MergeWorker).to have_received(:perform_async).with(target_account.id, account.id, 'home')
+      expect(ActivityPub::AccountBackfillWorker).to have_received(:perform_async).with(target_account.id)
       expect(follow_request).to have_received(:destroy!)
     end
 
@@ -47,6 +49,21 @@ RSpec.describe FollowRequest do
       target = follow_request.target_account
       expect(follow_request.account.muting_reblogs?(target)).to be true
     end
+
+    context 'when subsequent follow requests are made' do
+      before do
+        second_account = Fabricate(:account)
+        second_account.follow!(target_account)
+      end
+
+      it 'doesnt call ActivityPub::AccountBackfillWorker' do
+        allow(ActivityPub::AccountBackfillWorker).to receive(:perform_async)
+
+        follow_request.authorize!
+
+        expect(ActivityPub::AccountBackfillWorker).to_not have_received(:perform_async)
+      end
+    end
   end
 
   describe '#reject!' do

spec/services/activitypub/account_backfill_service_spec.rb

@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ActivityPub::AccountBackfillService do
+  subject { described_class.new }
+
+  before do
+    stub_const('ActivityPub::AccountBackfillService::ENABLED', true)
+  end
+
+  let!(:account) { Fabricate(:account, domain: 'other.com', outbox_url: 'http://other.com/alice/outbox') }
+
+  let!(:outbox) do
+    {
+      '@context': 'https://www.w3.org/ns/activitystreams',
+
+      id: 'http://other.com/alice/outbox',
+      type: 'OrderedCollection',
+      first: 'http://other.com/alice/outbox?page=true',
+    }.with_indifferent_access
+  end
+
+  let!(:items) do
+    [
+      {
+        '@context': 'https://www.w3.org/ns/activitystreams',
+        id: 'https://other.com/alice/1234',
+        to: ['https://www.w3.org/ns/activitystreams#Public'],
+        cc: ['https://other.com/alice/followers'],
+        type: 'Note',
+        content: 'Lorem ipsum',
+        attributedTo: 'http://other.com/alice',
+      },
+      'https://other.com/alice/5678',
+    ]
+  end
+
+  let!(:outbox_page) do
+    {
+      '@context': 'https://www.w3.org/ns/activitystreams',
+      id: 'http://example.com/alice/outbox?page=true',
+      type: 'OrderedCollectionPage',
+      orderedItems: items,
+    }
+  end
+
+  describe '#call' do
+    before do
+      stub_request(:get, 'http://other.com/alice/outbox').to_return(status: 200, body: Oj.dump(outbox), headers: { 'Content-Type': 'application/activity+json' })
+      stub_request(:get, 'http://other.com/alice/outbox?page=true').to_return(status: 200, body: Oj.dump(outbox_page), headers: { 'Content-Type': 'application/activity+json' })
+    end
+
+    it 'fetches the items in the outbox' do
+      allow(FetchReplyWorker).to receive(:push_bulk)
+      got_items = subject.call(account)
+      expect(got_items[0].deep_symbolize_keys).to eq(items[0])
+      expect(got_items[1]).to eq(items[1])
+      expect(FetchReplyWorker).to have_received(:push_bulk).with([items[0].stringify_keys, items[1]])
+    end
+
+    context 'with followers-only and private statuses' do
+      let!(:items) do
+        [
+          {
+            '@context': 'https://www.w3.org/ns/activitystreams',
+            id: 'https://other.com/alice/public',
+            type: 'Note',
+            to: ['https://www.w3.org/ns/activitystreams#Public'],
+            cc: ['https://other.com/alice/followers'],
+            content: 'Lorem ipsum',
+            attributedTo: 'http://other.com/alice',
+          },
+          {
+            '@context': 'https://www.w3.org/ns/activitystreams',
+            id: 'https://other.com/alice/unlisted',
+            to: ['https://other.com/alice/followers'],
+            cc: ['https://www.w3.org/ns/activitystreams#Public'],
+            type: 'Note',
+            content: 'Lorem ipsum',
+            attributedTo: 'http://other.com/alice',
+          },
+          {
+            '@context': 'https://www.w3.org/ns/activitystreams',
+            id: 'https://other.com/alice/followers-only',
+            to: ['https://other.com/alice/followers'],
+            type: 'Note',
+            content: 'Lorem ipsum',
+            attributedTo: 'http://other.com/alice',
+          },
+          {
+            '@context': 'https://www.w3.org/ns/activitystreams',
+            id: 'https://other.com/alice/dm',
+            to: ['https://other.com/alice/followers'],
+            type: 'Note',
+            content: 'Lorem ipsum',
+            attributedTo: 'http://other.com/alice',
+          },
+        ]
+      end
+
+      it 'only processes public and unlisted statuses' do
+        allow(FetchReplyWorker).to receive(:push_bulk)
+        got_items = subject.call(account)
+        expect(got_items.length).to eq(2)
+        expect(got_items[0].deep_symbolize_keys).to eq(items[0])
+        expect(got_items[1].deep_symbolize_keys).to eq(items[1])
+        expect(FetchReplyWorker).to have_received(:push_bulk).with([items[0].stringify_keys, items[1].stringify_keys])
+      end
+    end
+  end
+end