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mastodon/app/lib
ThibG ca56527140
Add follower synchronization mechanism (#14510)
* Add support for followers synchronization on the receiving end

Check the `collectionSynchronization` attribute on `Create` and `Announce`
activities and synchronize followers from provided collection if possible.

* Add tests for followers synchronization on the receiving end

* Add support for follower synchronization on the sender's end

* Add tests for the sending end

* Switch from AS attributes to HTTP header

Replace the custom `collectionSynchronization` ActivityStreams attribute by
an HTTP header (`X-AS-Collection-Synchronization`) with the same syntax as
the `Signature` header and the following fields:
- `collectionId` to specify which collection to synchronize
- `digest` for the SHA256 hex-digest of the list of followers known on the
   receiving instance (where “receiving instance” is determined by accounts
   sharing the same host name for their ActivityPub actor `id`)
- `url` of a collection that should be fetched by the instance actor

Internally, move away from the webfinger-based `domain` attribute and use
account `uri` prefix to group accounts.

* Add environment variable to disable followers synchronization

Since the whole mechanism relies on some new preconditions that, in some
extremely rare cases, might not be met, add an environment variable
(DISABLE_FOLLOWERS_SYNCHRONIZATION) to disable the mechanism altogether and
avoid followers being incorrectly removed.

The current conditions are:
1. all managed accounts' actor `id` and inbox URL have the same URI scheme and
   netloc.
2. all accounts whose actor `id` or inbox URL share the same URI scheme and
   netloc as a managed account must be managed by the same Mastodon instance
   as well.

As far as Mastodon is concerned, breaking those preconditions require extensive
configuration changes in the reverse proxy and might also cause other issues.

Therefore, this environment variable provides a way out for people with highly
unusual configurations, and can be safely ignored for the overwhelming majority
of Mastodon administrators.

* Only set follower synchronization header on non-public statuses

This is to avoid unnecessary computations and allow Follow-related
activities to be handled by the usual codepath instead of going through
the synchronization mechanism (otherwise, any Follow/Undo/Accept activity
would trigger the synchronization mechanism even if processing the activity
itself would be enough to re-introduce synchronization)

* Change how ActivityPub::SynchronizeFollowersService handles follow requests

If the remote lists a local follower which we only know has sent a follow
request, consider the follow request as accepted instead of sending an Undo.

* Integrate review feeback

- rename X-AS-Collection-Synchronization to Collection-Synchronization
- various minor refactoring and code style changes

* Only select required fields when computing followers_hash

* Use actor URI rather than webfinger domain in synchronization endpoint

* Change hash computation to be a XOR of individual hashes

Makes it much easier to be memory-efficient, and avoid sorting discrepancy issues.

* Marginally improve followers_hash computation speed

* Further improve hash computation performances by using pluck_each
4 years ago
..
activitypub Add follower synchronization mechanism (#14510) 4 years ago
connection_pool Add request pool to improve delivery performance (#10353) 6 years ago
nodeinfo Add a nodeinfo endpoint (#12002) 5 years ago
ostatus Remove Atom feeds and old URLs in the form of `GET /:username/updates/:id` (#11247) 6 years ago
proof_provider Fix rubocop warning (#14288) 5 years ago
rss Improve RSS entries for statuses (#13592) 5 years ago
settings Removed disabling comments for Style/MethodMissingSuper (#15014) 4 years ago
activity_tracker.rb Add a nodeinfo endpoint (#12002) 5 years ago
application_extension.rb Conditional validations no longer accept strings for if/unless (#3124) 8 years ago
delivery_failure_tracker.rb Change delivery failure tracking to work with hostnames instead of URLs (#13437) 5 years ago
entity_cache.rb Bump rubocop from 0.86.0 to 0.88.0 (#14412) 4 years ago
exceptions.rb Fix movie width and frame_rate returning nil (#14357) 5 years ago
extractor.rb Using double splat operator (#5859) 7 years ago
fast_geometry_parser.rb Fix avatar and header issues by using custom geometry detector (#6515) 7 years ago
fast_ip_map.rb Add IP-based rules (#14963) 4 years ago
feed_manager.rb Refactor feed manager (#14761) 4 years ago
formatter.rb Bump rubocop from 0.86.0 to 0.88.0 (#14412) 4 years ago
hash_object.rb Migrate from ledermann/rails-settings to rails-settings-cached which allows global settings 8 years ago
inline_renderer.rb Add E2EE API (#13820) 5 years ago
language_detector.rb Fix Thai being skipped from language detection (#13989) 5 years ago
potential_friendship_tracker.rb Create Redisable#redis (#9633) 6 years ago
proof_provider.rb Add Keybase integration (#10297) 6 years ago
rate_limiter.rb Add rate limit for reporting (#13390) 5 years ago
request.rb Add environment variable to allow requests to some private addresses (#14722) 4 years ago
request_pool.rb Add request pool to improve delivery performance (#10353) 6 years ago
response_with_limit.rb Fix remote files not using Content-Type header, streaming (#14184) 5 years ago
rss_builder.rb Add RSS feeds for end-users (#7259) 7 years ago
sanitize_config.rb Add support for Gemini urls (#15013) 4 years ago
search_query_parser.rb Fix accounts search by full/partial display name and others (#11580) 5 years ago
search_query_transformer.rb Fix error when searching for empty phrase (#12711) 5 years ago
sidekiq_error_handler.rb Bump rubocop from 0.86.0 to 0.88.0 (#14412) 4 years ago
spam_check.rb Exempt staff members from spam check (#12874) 5 years ago
status_filter.rb Fix n+1 queries in StatusThreadingConcern (#7321) 7 years ago
status_finder.rb Remove Atom feeds and old URLs in the form of `GET /:username/updates/:id` (#11247) 6 years ago
tag_manager.rb Refactor domain block checks (#11268) 6 years ago
themes.rb Add support for multiple themes (#4959) 7 years ago
toc_generator.rb Add fallback section ID with ToC (#11941) 5 years ago
user_settings_decorator.rb Add option to disable swiping motions across the WebUI (#13885) 4 years ago
webfinger.rb Remove dependency on goldfinger gem (#14919) 4 years ago
webfinger_resource.rb Fix webfinger returning wrong status code on malformed or missing param (#13759) 5 years ago