WebFinger (RFC 7033) primitives for ActivityPub account discovery.

WebFinger is the discovery mechanism used across the Fediverse to map acct:user@host identifiers to ActivityPub actor URLs via a /.well-known/webfinger endpoint returning a JSON Resource Descriptor (JRD).

Example (client)

# #[cfg(feature = "client")]
# async fn example() -> Result<(), Box<dyn std::error::Error>> {
use actpub_webfinger::{Account, resolve};

let client = reqwest::Client::new();
let account = Account::parse("acct:gargron@mastodon.social")?;
let jrd = resolve(&account, &client).await?;

if let Some(link) = jrd.activitypub_actor() {
    println!("Actor URL: {}", link.href.as_ref().unwrap());
}
# Ok(()) }

Example (server)

use actpub_webfinger::{Jrd, JrdLink, rels};

let jrd = Jrd::builder("acct:alice@example.com")
    .alias("https://example.com/@alice")
    .link(
        JrdLink::builder(rels::ACTIVITYPUB_ACTOR)
            .href("https://example.com/users/alice".parse().unwrap())
            .media_type("application/activity+json")
            .build(),
    )
    .build();

let json = serde_json::to_string(&jrd).unwrap();
assert!(json.contains(r#""subject":"acct:alice@example.com""#));