Add NIP-C7 support

[SubatomicPlanets]

nostr: add NIP-C7 support

Added a new ChatMessage kind and 2 new builders: chat_message and chat_message_reply.
The code is structured similarly to text_note and text_note_reply.

[TheAwiteb]

Also update crates/nostr/CHANGELOG.md

[TheAwiteb]

Also I think you should parse the content using NostrParser and return an error if it doesn't contains the quoted event.

Or maybe add it if it doesn't contains it? the NIP-C7 shows it should be the first line. I'm not sure.

@yukibtc what do you think?

[SubatomicPlanets]

Okay @TheAwiteb, I updated the changelog and code. I am new to Rust and Nostr so thanks for the help. I think it should automatically add the event to the context if it's not there already. I played around with NostrParser a bit but I think something like this could be simpler:

pub fn chat_message_reply<S>(content: S, reply_to: &Event, relay_url: Option<RelayUrl>) -> Self
where
    S: Into<String>,
{
    let mut content_string: String = content.into();

    let nevent = Nip19Event {
        event_id: reply_to.id,
        author: None,
        kind: None,
        relays: vec![],
    }.to_bech32().unwrap();
	
    if !content_string.starts_with(&format!("nostr:{}", nevent)) {
        content_string = format!("nostr:{}\n{}", nevent, content_string);
    }

    Self::new(Kind::ChatMessage, content_string).tag(Tag::from_standardized_without_cell(
        TagStandard::Quote {
            event_id: reply_to.id,
            relay_url,
            public_key: Some(reply_to.pubkey),
        },
    ))
}

I don't think we need NostrParser here since all we need to do is check the start of a string. Using NostrParser would be very similar to this with the only difference being that instead of checking the start of a string we parse the whole string, get the first element, and check if its the correct nevent. So let me know what you think, maybe I have overlooked something.

[TheAwiteb]

I am new to Rust and Nostr so thanks for the help

Apologies for the delay in responding! You're absolutely welcome, happy to help.

I don't think we need NostrParser here since all we need to do is check the start of a string

We do need the NostrParser here because the Nip19Event you've constructed might not align with the existing one, as it could include additional details like the author, kind, or extra relays. It might also just be a note rather than a nevent. Using NostrParser simplifies the process, you can check if the event ID is present, and if not, you can add it while ensuring the provided relays are included.

[TheAwiteb]

Also you can write this

content_string = format!("nostr:{}\n{}", nevent, content_string);

like this

content_string = format!("nostr:{nevent}\n{content_string}");

in your new change, it's more readable.

[SubatomicPlanets]

Okay so something like this would work, right?

pub fn chat_message_reply<S>(content: S, reply_to: &Event, relay_url: Option<RelayUrl>) -> Self
where
    S: Into<String>,
{
    let mut content_string: String = content.into();

    let nevent = Nip19Event {
        event_id: reply_to.id,
        author: Some(reply_to.pubkey),
        kind: Some(reply_to.kind),
        relays: vec![],
    };
    let nevent_uri = nevent.to_nostr_uri().unwrap();

    let parsed = NostrParser::new().parse(&content_string).next();
    if !matches!(parsed, Some(Token::Nostr(nip21)) if nip21.event_id() == Some(reply_to.id)) {
        content_string = format!("{nevent_uri}\n{content_string}");
    }

    Self::new(Kind::ChatMessage, content_string).tag(Tag::from_standardized_without_cell(
        TagStandard::Quote {
            event_id: reply_to.id,
            relay_url,
            public_key: Some(reply_to.pubkey),
        },
    ))
}

It basically just parses the content, gets the first token, checks if it is an nevent and if it has the same event id as the reply_to event, and then it adds the nostr uri to the content based on those conditions. What should I do with the relays in Nip19Event though? Should I leave them empty, add only the optional relay_url (if it is not None), or add a third parameter (a vec of RelayUrls) for it? Thanks!

[TheAwiteb]

What should I do with the relays in Nip19Event though? Should I leave them empty, add only the optional relay_url (if it is not None), or add a third parameter (a vec of RelayUrls) for it? Thanks!

Instead of an empty Vec make it the provided relay if it's not None.

Also remove the author and kind from your nevent, they are useless.

And don't just check the first token, the nevent may be in the end of the content, instead of .next() use any function and check each token if it match the event id.

And don't unwrap the to_nostr_uri function, it can return an error if the relay url are very long :)

Thank you for your contribution.

[yukibtc]

Also I think you should parse the content using NostrParser and return an error if it doesn't contains the quoted event.

Or maybe add it if it doesn't contains it? the NIP-C7 shows it should be the first line. I'm not sure.

@yukibtc what do you think?

Yeah, I think make sense to automatically add it in the content if it doesn't exist.

[yukibtc]

@SubatomicPlanets, I would rewrite it like this, for better readability:

impl EventBuilder {
    // ...

    /// Chat message reply
    ///
    /// <https://github.com/nostr-protocol/nips/blob/master/C7.md>
    pub fn chat_message_reply<S>(
        content: S,
        reply_to: &Event,
        relay_url: Option<RelayUrl>,
    ) -> Result<Self, Error>
    where
        S: Into<String>,
    {
        let mut content: String = content.into();

        // Check if the content starts with a `nostr:` event uri
        if !starts_with_nostr_event_uri(&content, &reply_to.id)? {
            let nevent = Nip19Event {
                event_id: reply_to.id,
                author: Some(reply_to.pubkey),
                kind: Some(reply_to.kind),
                relays: relay_url.clone().into_iter().collect(),
            };
            let nevent_uri: String = nevent.to_nostr_uri()?;

            content = format!("{nevent_uri}\n{content}");
        }

        Ok(
            Self::new(Kind::ChatMessage, content).tag(Tag::from_standardized_without_cell(
                TagStandard::Quote {
                    event_id: reply_to.id,
                    relay_url,
                    public_key: Some(reply_to.pubkey),
                },
            )),
        )
    }
}

fn starts_with_nostr_event_uri(content: &str, event_id: &EventId) -> Result<bool, Error> {
    let token: Option<Token> = NostrParser::new().parse(content).next();

    if let Some(Token::Nostr(nip21)) = token {
        if let Some(id) = nip21.event_id() {
            return if &id == event_id {
                Ok(true)
            } else {
                Err(Error::) // Add an error to indicate that the event in the content is not right
            };
        }
    }

    Ok(false)
}

@SubatomicPlanets @TheAwiteb, what do you think?

[TheAwiteb]

@SubatomicPlanets @TheAwiteb, what do you think

It's cool, but I don't like assuming that the quote are in the binging, it can be in the end.

---

my previous review:

And don't just check the first token, the nevent may be in the end of the content, instead of .next() use any function and check each token if it match the event id.

[yukibtc]

@SubatomicPlanets @TheAwiteb, what do you think

It's cool, but I don't like assuming that the quote are in the binging, it can be in the end.

my previous review:

And don't just check the first token, the nevent may be in the end of the content, instead of .next() use any function and check each token if it match the event id.

Ah, I've missed it.

Otherwise, what if we specify in doc that the content must be just the message without the nostr:nevent URI, which is automatically added using the reply_to event?

[TheAwiteb]

Otherwise, what if we specify in doc that the content must be just the message without the nostr:nevent URI, which is automatically added using the reply_to event?

I think adding it if it's not exist is better, because maybe I want add a custom relays to it or the kind and the public key, or maybe not :).

We need to make it clear that if the content doesn't contains the reply_to event as a nostr-uri it will be added as the first line.

[TheAwiteb]

@SubatomicPlanets If you need any help let me know

[yukibtc]

So, instead of the start_with_nostr_event_uri, something like this could be used:

fn has_nostr_event_uri(content: &str, event_id: &EventId) -> bool {
    const OPTS: NostrParserOptions = NostrParserOptions::disable_all().nostr_uris(true);
    
    let parser = NostrParser::new().parse(content).opts(OPTS);
    
    for token in parser.into_iter() {
        if let Token::Nostr(nip21) = token {
            if let Some(id) = nip21.event_id() {
                if &id == event_id {
                    return true;
                }
            }
        }
    }

    false
}

@TheAwiteb

[TheAwiteb]

something like this could be used:

Yes, but this version is much simpler

fn has_nostr_event_uri(content: &str, event_id: &EventId) -> bool {
    const OPTS: NostrParserOptions = NostrParserOptions::disable_all().nostr_uris(true);

    NostrParser::new().parse(content).opts(OPTS).any(
        |token| matches!(token, Token::Nostr(uri) if uri.event_id().as_ref() == Some(event_id)),
    )
}

[TheAwiteb]

LGTM. Just this minor changes

[TheAwiteb]

@yukibtc Do you think the #[inline] should be removed? Because it's not a small function anymore

[TheAwiteb]

Waiting for @yukibtc about removing the #[inline] from chat_message_reply function, it's not small anymore.