nips/C7.md

NIP-C7

Chats

draft optional

This NIP describes simple chat messages.

These messages behave like kind:1 notes syntactically, but are intended to be used in the compĺetely different circumstance of sequential and localized group chats in which ordered consistency is expected, such as, for example, NIP-29 rooms, in which a shared relay acts as the (temporary) single source of truth for all the chat messages.

Definition

A chat message is a kind 9 event.

{
  "kind": 9,
  "content": "GM",
  "tags": []
}

Reply

A reply to a kind 9 is an additional kind 9 which quotes the parent using a q tag.

{
  "kind": 9,
  "content": "nostr:nevent1...\nyes",
  "tags": [
    ["q", <event-id>, <relay-url>, <pubkey>]
  ]
}

Edit

Because these messages are always received in order, an edit can just be another message in the stream that refers to a previous message.

The only difference between an edit and a normal message is that it will have a special "edit" tag (and an EDIT label prefixing the content) that allows clients to optionally parse it as a special edit action and have its changes applied to a previous message in the chat state. For that it uses a simple human-readable text-diff syntax in order to encode a "patch".

Simpler clients that do not want to support this can be just fine with just displaying the edits as normal text messages.

{
  "kind": 9,
  "content": "EDIT\n<patch-content>",
  "tags": [
    ["e", <event-id-being-edited>],
    ["edit"]
  ]
}

In which <patch-content> is formed by one or more lines of

<index> -<number-of-characters-deleted> +<number-of-characters-inserted> <actual-characters-inserted>

For example, if the original text was Their should hire more internets to help them and was edited to They should hire more interns to help the patch will be:

0 -5 +4 They
23 -9 +7 interns
40 -5 +0

The indexes and amounts refer to unicode characters, not bytes.

When generating these diffs clients should prefer to do it over full words instead of over characters, for readability.