Bring your lists in

Somebody arriving from Mastodon, Misskey or another Anahita brings who they follow, block and mute, and what they saved, in a file: another Anahita's download, or a single CSV of Mastodon's or Misskey's. The file is read at once and what is in it shown; nothing is done until they start it; then a worker goes through it a line at a time, doing each as they would by hand. Roadmap row 124, part 1 (Moving (opens in a new tab)).

Its routes are in the API reference: import-export-service.

What a file may be

File	Read as
Another Anahita's download, the zip of Download your data	Its data/following.json, blocked.json, muted.json and saved.json, which say the most: a mute's length and whether it hides notifications, and the groups and events followed. Its mastodon/ folder is read only when there is no data/
following_accounts.csv	Mastodon's: Account address,Show boosts,Notify on new posts,Languages. People to follow
blocked_accounts.csv	One address a line, no header. People to block
muted_accounts.csv	Account address,Hide notifications. People to mute
bookmarks.csv	One post's address a line, no header, or under #uri. Posts to save
Misskey's, or any list	One address a line, with or without its first @. Its kind by its name, or as the person says (kind)

A CSV is known as Mastodon knows one: by its first header, or, with none, by its name. One whose kind cannot be told is refused with kind_unknown, and the person is asked which it is. Lists (List name,Account address) and blocked servers (#domain) are refused with not_supported: Anahita has neither yet. A list of somebody's followers is not read: their followers come by moving (Moving (opens in a new tab), part 3).

How each line is done

As the person, by the rules the same thing has when done by hand (anahita-libs/permissions):

1. Who or what is found first. Somebody here by their username, from a handle on this site's domain; somebody elsewhere by their handle, found on their own server and kept, by activitypub-service, or by atproto-service for a Bluesky handle; a post by its ActivityPub id or its at:// address, the same way. Those two are asked on their internal port (Internal calls).
2. Follow: followed, or asked to be followed when they approve their followers; a group or an event whose rules are to be agreed first is not followed, and is listed. Nobody is followed across a block.
3. Block: not twice, and not somebody who blocks the person already.
4. Mute: a person only, not across a block, with what the file said of its notifications and its end. One that has ended is not made.
5. Save: a post the person may see.
6. Nothing is undone. An import adds: it unfollows, unblocks, unmutes and unsaves nothing. What the person has already is counted as such (already), so importing a file twice does nothing twice.

What a line does is told as it would be by hand: a follow to the person's server, a block to the fediverse and to Bluesky for somebody connected. A mute and a save are told to nobody.

What could not be done

Each line ends done, already, skipped (a kind not chosen, or the import given up) or failed, with why in a word, listed in a CSV the person can download (GET /imports/:id/failed):

Reason	Means
not_found	Nobody, or nothing, at that address
not_on_fediverse	A group or an event on another Anahita: groups are not on the fediverse, and it is followed by hand there
refused	On a server, or an account, this site refuses
not_federating	This site does not take part in that network
unreachable	Their server could not be reached: importing the file again later may do
blocked	One of them blocks the other
not_allowed	Not theirs to follow, or to see
rules_not_agreed	A group or an event whose rules are to be agreed first
ended	A mute that ended since the file was made
failed	Something here went wrong

Limits

1. Mastodon's own: at most 20,000 lines and 20 MB a file.
2. One import at a time for each person, waiting or running: a rule of the database (data_imports.active_person_id).
3. A line a second, whoever's: several people's imports go forward together, a line each in turn. 20,000 lines take about five and a half hours.
4. A line left by a worker that stopped is taken again ten minutes on.

Endpoints

Request	Does
GET /imports	The viewer's latest five imports, newest first
POST /imports (form: file, and kind for a CSV with no header)	Reads the file and keeps it, ready, with how many of each kind
GET /imports/:id	How it is getting on: for each kind, how many in all, done, already, failed, skipped and left
POST /imports/:id/start { "kinds": ["follow", "block", "mute", "save"] }	Starts it with the kinds chosen; the others are skipped
GET /imports/:id/failed	What could not be done, as a CSV
DELETE /imports/:id	Gives it up: what it has not done is not done

Every route is the viewer's own; reading a file asks for the socialgraph:write scope. The gateway lets a request to /imports be as large as 21 MB.

The parts

Part	Does
import-export-service (/imports)	Reads a file and keeps its lines; says how an import is getting on
import-export-worker	Goes through the started imports, a line a second, beside the downloads it makes
activitypub-service, atproto-service (port 8443)	Find somebody or a post elsewhere and keep it, for the worker
graph-grpc-service	Follows, blocks, mutes and saves, as for a person's own request

Where the code is

What	Where
Reading a file	import-export-service/importfile/importfile.go (Read), tested in importfile_test.go
The imports and their lines	import-export-service/data/repositories/imports.go, tables data_imports and data_import_lines in migration-job/schema/init.sql
The endpoints	import-export-service/cmd/api/handlers/imports.go
Going through the lines	import-export-service/worker/importer.go (Importer), the acts in worker/acts.go (GraphActs)
Finding somebody elsewhere	anahita-libs/servicecalls, activitypub-service/cmd/api/handlers/internal.go, atproto-service/cmd/api/handlers/internal.go

What is not built

1. Lists, one's own blocked servers, filters, Misskey's antennas: the features are not here yet.
2. Replacing one's lists with a file's, as Mastodon's "overwrite" does.
3. Posts, between two Anahitas (Moving (opens in a new tab), part 4).