diff --git a/FEDERATION.md b/FEDERATION.md new file mode 100644 index 000000000..dd0c917e2 --- /dev/null +++ b/FEDERATION.md @@ -0,0 +1,333 @@ +# Federation + +BookWyrm uses the [ActivityPub](http://activitypub.rocks/) protocol to send and receive user activity between other BookWyrm instances and other services that implement ActivityPub. To handle book data, BookWyrm has a handful of extended Activity types which are not part of the standard, but are legible to other BookWyrm instances. + +## Activities and Objects + +### Users and relationships +User relationship interactions follow the standard ActivityPub spec. + +- `Follow`: request to receive statuses from a user, and view their statuses that have followers-only privacy +- `Accept`: approves a `Follow` and finalizes the relationship +- `Reject`: denies a `Follow` +- `Block`: prevent users from seeing one another's statuses, and prevents the blocked user from viewing the actor's profile +- `Update`: updates a user's profile and settings +- `Delete`: deactivates a user +- `Undo`: reverses a `Follow` or `Block` + +### Activities +- `Create/Status`: saves a new status in the database. +- `Delete/Status`: Removes a status +- `Like/Status`: Creates a favorite on the status +- `Announce/Status`: Boosts the status into the actor's timeline +- `Undo/*`,: Reverses a `Like` or `Announce` + +### Collections +User's books and lists are represented by [`OrderedCollection`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-orderedcollection) + +### Statuses + +BookWyrm is focused on book reading activities - it is not a general-purpose messaging application. For this reason, BookWyrm only accepts status `Create` activities if they are: + +- Direct messages (i.e., `Note`s with the privacy level `direct`, which mention a local user), +- Related to a book (of a custom status type that includes the field `inReplyToBook`), +- Replies to existing statuses saved in the database + +All other statuses will be received by the instance inbox, but by design **will not be delivered to user inboxes or displayed to users**. + +### Custom Object types + +With the exception of `Note`, the following object types are used in Bookwyrm but are not currently provided with a custom JSON-LD `@context` extension IRI. This is likely to change in future to make them true deserialisable JSON-LD objects. + +##### Note + +Within BookWyrm a `Note` is constructed according to [the ActivityStreams vocabulary](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-note), however `Note`s can only be created as direct messages or as replies to other statuses. As mentioned above, this also applies to incoming `Note`s. + +##### Review + +A `Review` is a status in response to a book (indicated by the `inReplyToBook` field), which has a title, body, and numerical rating between 0 (not rated) and 5. + +Example: + +```json +{ + "id": "https://example.net/user/library_lurker/review/2", + "type": "Review", + "published": "2023-06-30T21:43:46.013132+00:00", + "attributedTo": "https://example.net/user/library_lurker", + "content": "

This is an enjoyable book with great characters.

", + "to": ["https://example.net/user/library_lurker/followers"], + "cc": [], + "replies": { + "id": "https://example.net/user/library_lurker/review/2/replies", + "type": "OrderedCollection", + "totalItems": 0, + "first": "https://example.net/user/library_lurker/review/2/replies?page=1", + "last": "https://example.net/user/library_lurker/review/2/replies?page=1", + "@context": "https://www.w3.org/ns/activitystreams" + }, + "summary": "Spoilers ahead!", + "tag": [], + "attachment": [], + "sensitive": true, + "inReplyToBook": "https://example.net/book/1", + "name": "What a cracking read", + "rating": 4.5, + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +##### Comment + +A `Comment` on a book mentions a book and has a message body, reading status, and progress indicator. + +Example: + +```json +{ + "id": "https://example.net/user/library_lurker/comment/9", + "type": "Comment", + "published": "2023-06-30T21:43:46.013132+00:00", + "attributedTo": "https://example.net/user/library_lurker", + "content": "

This is a very enjoyable book so far.

", + "to": ["https://example.net/user/library_lurker/followers"], + "cc": [], + "replies": { + "id": "https://example.net/user/library_lurker/comment/9/replies", + "type": "OrderedCollection", + "totalItems": 0, + "first": "https://example.net/user/library_lurker/comment/9/replies?page=1", + "last": "https://example.net/user/library_lurker/comment/9/replies?page=1", + "@context": "https://www.w3.org/ns/activitystreams" + }, + "summary": "Spoilers ahead!", + "tag": [], + "attachment": [], + "sensitive": true, + "inReplyToBook": "https://example.net/book/1", + "readingStatus": "reading", + "progress": 25, + "progressMode": "PG", + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +##### Quotation + +A quotation (aka "quote") has a message body, an excerpt from a book including position as a page number or percentage indicator, and mentions a book. + +Example: + +```json +{ + "id": "https://example.net/user/mouse/quotation/13", + "url": "https://example.net/user/mouse/quotation/13", + "inReplyTo": null, + "published": "2020-05-10T02:38:31.150343+00:00", + "attributedTo": "https://example.net/user/mouse", + "to": [ + "https://www.w3.org/ns/activitystreams#Public" + ], + "cc": [ + "https://example.net/user/mouse/followers" + ], + "sensitive": false, + "content": "I really like this quote", + "type": "Quotation", + "replies": { + "id": "https://example.net/user/mouse/quotation/13/replies", + "type": "Collection", + "first": { + "type": "CollectionPage", + "next": "https://example.net/user/mouse/quotation/13/replies?only_other_accounts=true&page=true", + "partOf": "https://example.net/user/mouse/quotation/13/replies", + "items": [] + } + }, + "inReplyToBook": "https://example.net/book/1", + "quote": "To be or not to be, that is the question.", + "position": 50, + "positionMode": "PCT", + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +### Custom Objects + +##### Work +A particular book, a "work" in the [FRBR](https://en.wikipedia.org/wiki/Functional_Requirements_for_Bibliographic_Records) sense. + +Example: + +```json +{ + "id": "https://bookwyrm.social/book/5988", + "type": "Work", + "authors": [ + "https://bookwyrm.social/author/417" + ], + "first_published_date": null, + "published_date": null, + "title": "Piranesi", + "sort_title": null, + "subtitle": null, + "description": "**From the *New York Times* bestselling author of *Jonathan Strange & Mr. Norrell*, an intoxicating, hypnotic new novel set in a dreamlike alternative reality.", + "languages": [], + "series": null, + "series_number": null, + "subjects": [ + "English literature" + ], + "subject_places": [], + "openlibrary_key": "OL20893680W", + "librarything_key": null, + "goodreads_key": null, + "attachment": [ + { + "url": "https://bookwyrm.social/images/covers/10226290-M.jpg", + "type": "Image" + } + ], + "lccn": null, + "editions": [ + "https://bookwyrm.social/book/5989" + ], + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +##### Edition +A particular _manifestation_ of a Work, in the [FRBR](https://en.wikipedia.org/wiki/Functional_Requirements_for_Bibliographic_Records) sense. + +Example: + +```json +{ + "id": "https://bookwyrm.social/book/5989", + "lastEditedBy": "https://example.net/users/rat", + "type": "Edition", + "authors": [ + "https://bookwyrm.social/author/417" + ], + "first_published_date": null, + "published_date": "2020-09-15T00:00:00+00:00", + "title": "Piranesi", + "sort_title": null, + "subtitle": null, + "description": "Piranesi's house is no ordinary building; its rooms are infinite, its corridors endless, its walls are lined with thousands upon thousands of statues, each one different from all the others.", + "languages": [ + "English" + ], + "series": null, + "series_number": null, + "subjects": [], + "subject_places": [], + "openlibrary_key": "OL29486417M", + "librarything_key": null, + "goodreads_key": null, + "isfdb": null, + "attachment": [ + { + "url": "https://bookwyrm.social/images/covers/50202953._SX318_.jpg", + "type": "Image" + } + ], + "isbn_10": "1526622424", + "isbn_13": "9781526622426", + "oclc_number": null, + "asin": null, + "pages": 272, + "physical_format": null, + "publishers": [ + "Bloomsbury Publishing Plc" + ], + "work": "https://bookwyrm.social/book/5988", + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +#### Shelf + +A user's book collection. By default, every user has a `to-read`, `reading`, `read`, and `stopped-reading` shelf which are used to track reading progress. Users may create an unlimited number of additional shelves with their own ids. + +Example + +```json +{ + "id": "https://example.net/user/avid_reader/books/extraspecialbooks-5", + "type": "Shelf", + "totalItems": 0, + "first": "https://example.net/user/avid_reader/books/extraspecialbooks-5?page=1", + "last": "https://example.net/user/avid_reader/books/extraspecialbooks-5?page=1", + "name": "Extra special books", + "owner": "https://example.net/user/avid_reader", + "to": [ + "https://www.w3.org/ns/activitystreams#Public" + ], + "cc": [ + "https://example.net/user/avid_reader/followers" + ], + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +#### List + +A collection of books that may have items contributed by users other than the one who created the list. + +Example: + +```json +{ + "id": "https://example.net/list/1", + "type": "BookList", + "totalItems": 0, + "first": "https://example.net/list/1?page=1", + "last": "https://example.net/list/1?page=1", + "name": "My cool list", + "owner": "https://example.net/user/avid_reader", + "to": [ + "https://www.w3.org/ns/activitystreams#Public" + ], + "cc": [ + "https://example.net/user/avid_reader/followers" + ], + "summary": "A list of books I like.", + "curation": "curated", + "@context": "https://www.w3.org/ns/activitystreams" +} +``` + +#### Activities + +- `Create`: Adds a shelf or list to the database. +- `Delete`: Removes a shelf or list. +- `Add`: Adds a book to a shelf or list. +- `Remove`: Removes a book from a shelf or list. + +## Alternative Serialization +Because BookWyrm uses custom object types that aren't listed in [the standard ActivityStreams Vocabulary](https://www.w3.org/TR/activitystreams-vocabulary), some statuses are transformed into standard types when sent to or viewed by non-BookWyrm services. `Review`s are converted into `Article`s, and `Comment`s and `Quotation`s are converted into `Note`s, with a link to the book and the cover image attached. + +In future this may be done with [JSON-LD type arrays](https://www.w3.org/TR/json-ld/#specifying-the-type) instead. + +## Other extensions + +### Webfinger + +Bookwyrm uses the [Webfinger](https://datatracker.ietf.org/doc/html/rfc7033) standard to identify and disambiguate fediverse actors. The [Webfinger documentation on the Mastodon project](https://docs.joinmastodon.org/spec/webfinger/) provides a good overview of how Webfinger is used. + +### HTTP Signatures + +Bookwyrm uses and requires HTTP signatures for all `POST` requests. `GET` requests are not signed by default, but if Bookwyrm receives a `403` response to a `GET` it will re-send the request, signed by the default server user. This usually will have a user id of `https://example.net/user/bookwyrm.instance.actor` + +#### publicKey id + +In older versions of Bookwyrm the `publicKey.id` was incorrectly listed in request headers as `https://example.net/user/username#main-key`. As of v0.6.3 the id is now listed correctly, as `https://example.net/user/username/#main-key`. In most ActivityPub implementations this will make no difference as the URL will usually resolve to the same place. + +### NodeInfo + +Bookwyrm uses the [NodeInfo](http://nodeinfo.diaspora.software/) standard to provide statistics and version information for each instance. + +## Further Documentation + +See [docs.joinbookwyrm.com/](https://docs.joinbookwyrm.com/) for more documentation. \ No newline at end of file