Snapshots of Replaceable Events

draft optional

Kind 1349 preserves one version of a replaceable or addressable event by wrapping it in a regular event, which relays keep.

Motivation#

Relays keep only the latest replaceable or addressable event, so an author can rewrite a document and leave no trace of what it said before. Approvals and highlights point at a coordinate rather than at an id, so they silently transfer to whatever replaces the text they were given to.

The event#

content is the wrapped event, serialized as JSON exactly as it appeared on the wire. Anyone may publish a snapshot: the inner signature proves who wrote the document, the outer one proves only who archived it.

Tag	Description
e	Id of the wrapped event.
k	Kind of the wrapped event.
p	Pubkey of the wrapped event's author.
a	Coordinate of the wrapped event, with an empty d for kinds 10000 to 19999.

{
  "kind": 1349,
  "content": "{\"id\":\"a1b2...\",\"pubkey\":\"9f8e...\",\"created_at\":1771547830,\"kind\":30817,\"tags\":[[\"d\",\"my-spec\"]],\"content\":\"# My Spec\",\"sig\":\"c3d4...\"}",
  "tags": [
    ["e", "a1b2..."],
    ["k", "30817"],
    ["p", "9f8e..."],
    ["a", "30817:9f8e...:my-spec"]
  ]
}

Validation#

The tags are written by the publisher, who may be anyone. Without checking them, anyone could attach arbitrary events to another document's history.

Clients MUST discard a snapshot unless:

1. content parses as an event and its signature verifies;
2. e, k, p and a agree with the wrapped event;
3. the wrapped kind is replaceable or addressable.

Order versions by the wrapped event's created_at, not the snapshot's, which is only the time of archival. Deduplicate on the wrapped event's id; several archivers wrapping the same version is expected.

Querying#

{ "kinds": [1349], "#a": ["30817:<pubkey>:<d>"] }

A snapshot proves a version existed. It never proves a set of them is complete, so a history is what was observed, not what happened.