How Plume Federates

A summary of the standards Plume uses to federate, how they are implemented, and which parts of these standards are available or not in Plume.

To federate with other Fediverse software (and itself), Plume uses various protocols:

Currently, the following aspects are federated:

And these parts are not federated, but may be in the future:

WebFinger

WebFinger is used to discover remote profiles. When you open the page of an unknown user (/@/username@instance.tld), Plume will send a WebFinger request to the other instance, on the standard /.well-known/webfinger endpoint. Plume will ignore the /.well-known/host-meta endpoint (that can normally be used to define another WebFinger endpoint), and always use the standard URL.

Plume uses the webfinger crate to serve WebFinger informations and fetch them.

HTTP Signatures

Plume checks that each incoming Activity has been signed with the actor‘s keypair.

To achieve that, it uses the Signature HTTP header. For more details on how this header is generated, please refer to the HTTP Signatures Specification.

The Digest header should be present too, and used to generate the signature, so that we can verify the body of the request too.

NodeInfo

Plume exposes instance metadata with NodeInfo on the /nodeinfo URL.

Example output

{
  "version": "2.0",
  "software": {
    "name": "Plume",
    "version": "0.2.0"
  },
  "protocols": ["activitypub"],
  "services": {
    "inbound": [],
    "outbound": []
  },
  "openRegistrations": true,
  "usage": {
    "users": {
      "total": 42
    },
    "localPosts": 7878,
    "localComments": 1312
  },
  "metadata": {}
}

ActivityPub

Each user has a personal inbox at /@/username/inbox, and each instance has a shared inbox at /inbox.

If available, Plume will use the shared inbox to deliver activities.

Object representation

Supported Activities

Plume 0.2.0 supports the following activity types.

Accept

Accepts a follow request.

It will be ignored when received, as Plume considers follow requests to be immediatly approved in all cases (however, this will change in the future).

When a Follow activity is received, Plume will respond with this activity.

Announce

Reshares an article (not available for other objects).

Makes an user (actor) reshare a post (object).

Create

Creates a new article or comment.

If object is an Article:

If object is a Note:

Delete

Deletes an object that was first created with a Create activity.

object is a Tombstone, and object.id the ID of the object to delete (either an Article ID, or a Note ID).

Follow

When received, the actor is added to the follower list of the target.

These activities are immediatly accepted (see Accept) by Plume.

For blogs, they won’t actually do anything else than sending back an Accept activity: following a blog is not yet implemented.

Like

Can be used to add a like to an article.

Update

Updates an article.

Undo

Cancels a previous action (either a like, reshare or follow).