lemmy/lemmy_apub/src/objects/comment.rs

use crate::{
  check_actor_domain,
  fetcher::{
    get_or_fetch_and_insert_comment,
    get_or_fetch_and_insert_post,
    get_or_fetch_and_upsert_user,
  },
  objects::create_tombstone,
  FromApub,
  ToApub,
};
use activitystreams::{
  object::{kind::NoteType, Note, Tombstone},
  prelude::*,
};
use anyhow::Context;
use lemmy_db::{
  comment::{Comment, CommentForm},
  community::Community,
  post::Post,
  user::User_,
  Crud,
  DbPool,
};
use lemmy_structs::blocking;
use lemmy_utils::{
  location_info,
  utils::{convert_datetime, remove_slurs},
  LemmyError,
};
use lemmy_websocket::LemmyContext;
use url::Url;

#[async_trait::async_trait(?Send)]
impl ToApub for Comment {
  type Response = Note;

  async fn to_apub(&self, pool: &DbPool) -> Result<Note, LemmyError> {
    let mut comment = Note::new();

    let creator_id = self.creator_id;
    let creator = blocking(pool, move |conn| User_::read(conn, creator_id)).await??;

    let post_id = self.post_id;
    let post = blocking(pool, move |conn| Post::read(conn, post_id)).await??;

    let community_id = post.community_id;
    let community = blocking(pool, move |conn| Community::read(conn, community_id)).await??;

    // Add a vector containing some important info to the "in_reply_to" field
    // [post_ap_id, Option(parent_comment_ap_id)]
    let mut in_reply_to_vec = vec![post.ap_id];

    if let Some(parent_id) = self.parent_id {
      let parent_comment = blocking(pool, move |conn| Comment::read(conn, parent_id)).await??;

      in_reply_to_vec.push(parent_comment.ap_id);
    }

    comment
      // Not needed when the Post is embedded in a collection (like for community outbox)
      .set_context(activitystreams::context())
      .set_id(Url::parse(&self.ap_id)?)
      .set_published(convert_datetime(self.published))
      .set_to(community.actor_id)
      .set_many_in_reply_tos(in_reply_to_vec)
      .set_content(self.content.to_owned())
      .set_attributed_to(creator.actor_id);

    if let Some(u) = self.updated {
      comment.set_updated(convert_datetime(u));
    }

    Ok(comment)
  }

  fn to_tombstone(&self) -> Result<Tombstone, LemmyError> {
    create_tombstone(self.deleted, &self.ap_id, self.updated, NoteType::Note)
  }
}

#[async_trait::async_trait(?Send)]
impl FromApub for CommentForm {
  type ApubType = Note;

  /// Parse an ActivityPub note received from another instance into a Lemmy comment
  async fn from_apub(
    note: &Note,
    context: &LemmyContext,
    expected_domain: Option<Url>,
  ) -> Result<CommentForm, LemmyError> {
    let creator_actor_id = &note
      .attributed_to()
      .context(location_info!())?
      .as_single_xsd_any_uri()
      .context(location_info!())?;

    let creator = get_or_fetch_and_upsert_user(creator_actor_id, context).await?;

    let mut in_reply_tos = note
      .in_reply_to()
      .as_ref()
      .context(location_info!())?
      .as_many()
      .context(location_info!())?
      .iter()
      .map(|i| i.as_xsd_any_uri().context(""));
    let post_ap_id = in_reply_tos.next().context(location_info!())??;

    // This post, or the parent comment might not yet exist on this server yet, fetch them.
    let post = get_or_fetch_and_insert_post(&post_ap_id, context).await?;

    // The 2nd item, if it exists, is the parent comment apub_id
    // For deeply nested comments, FromApub automatically gets called recursively
    let parent_id: Option<i32> = match in_reply_tos.next() {
      Some(parent_comment_uri) => {
        let parent_comment_ap_id = &parent_comment_uri?;
        let parent_comment =
          get_or_fetch_and_insert_comment(&parent_comment_ap_id, context).await?;

        Some(parent_comment.id)
      }
      None => None,
    };
    let content = note
      .content()
      .context(location_info!())?
      .as_single_xsd_string()
      .context(location_info!())?
      .to_string();
    let content_slurs_removed = remove_slurs(&content);

    Ok(CommentForm {
      creator_id: creator.id,
      post_id: post.id,
      parent_id,
      content: content_slurs_removed,
      removed: None,
      read: None,
      published: note.published().map(|u| u.to_owned().naive_local()),
      updated: note.updated().map(|u| u.to_owned().naive_local()),
      deleted: None,
      ap_id: Some(check_actor_domain(note, expected_domain)?),
      local: false,
    })
  }
}