lemmy/lemmy_utils/src/apub.rs

use crate::settings::Settings;
use openssl::{pkey::PKey, rsa::Rsa};
use std::io::{Error, ErrorKind};
use url::Url;

pub struct Keypair {
  pub private_key: String,
  pub public_key: String,
}

/// Generate the asymmetric keypair for ActivityPub HTTP signatures.
pub fn generate_actor_keypair() -> Result<Keypair, Error> {
  let rsa = Rsa::generate(2048)?;
  let pkey = PKey::from_rsa(rsa)?;
  let public_key = pkey.public_key_to_pem()?;
  let private_key = pkey.private_key_to_pem_pkcs8()?;
  let key_to_string = |key| match String::from_utf8(key) {
    Ok(s) => Ok(s),
    Err(e) => Err(Error::new(
      ErrorKind::Other,
      format!("Failed converting key to string: {}", e),
    )),
  };
  Ok(Keypair {
    private_key: key_to_string(private_key)?,
    public_key: key_to_string(public_key)?,
  })
}

pub enum EndpointType {
  Community,
  User,
  Post,
  Comment,
  PrivateMessage,
}

pub fn get_apub_protocol_string() -> &'static str {
  if Settings::get().federation.tls_enabled {
    "https"
  } else {
    "http"
  }
}

/// Generates the ActivityPub ID for a given object type and ID.
pub fn make_apub_endpoint(endpoint_type: EndpointType, name: &str) -> Url {
  let point = match endpoint_type {
    EndpointType::Community => "c",
    EndpointType::User => "u",
    EndpointType::Post => "post",
    EndpointType::Comment => "comment",
    EndpointType::PrivateMessage => "private_message",
  };

  Url::parse(&format!(
    "{}://{}/{}/{}",
    get_apub_protocol_string(),
    Settings::get().hostname,
    point,
    name
  ))
  .unwrap()
}