lemmy/crates/apub/src/fetcher/community.rs

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use crate::{
check_is_apub_id_valid,
fetcher::{
fetch::fetch_remote_object,
get_or_fetch_and_upsert_user,
is_deleted,
should_refetch_actor,
},
objects::FromApub,
ActorType,
GroupExt,
PageExt,
};
use activitystreams::{
base::{BaseExt, ExtendsExt},
collection::{CollectionExt, OrderedCollection},
object::ObjectExt,
};
use anyhow::Context;
use diesel::result::Error::NotFound;
use lemmy_db_queries::{source::community::Community_, ApubObject, Joinable};
use lemmy_db_schema::source::{
community::{Community, CommunityModerator, CommunityModeratorForm},
post::Post,
};
use lemmy_structs::blocking;
use lemmy_utils::{location_info, LemmyError};
use lemmy_websocket::LemmyContext;
use log::debug;
use url::Url;
/// Get a community from its apub ID.
///
/// If it exists locally and `!should_refetch_actor()`, it is returned directly from the database.
/// Otherwise it is fetched from the remote instance, stored and returned.
pub(crate) async fn get_or_fetch_and_upsert_community(
apub_id: &Url,
context: &LemmyContext,
recursion_counter: &mut i32,
) -> Result<Community, LemmyError> {
let apub_id_owned = apub_id.to_owned();
let community = blocking(context.pool(), move |conn| {
Community::read_from_apub_id(conn, apub_id_owned.as_str())
})
.await?;
match community {
Ok(c) if !c.local && should_refetch_actor(c.last_refreshed_at) => {
debug!("Fetching and updating from remote community: {}", apub_id);
fetch_remote_community(apub_id, context, Some(c), recursion_counter).await
}
Ok(c) => Ok(c),
Err(NotFound {}) => {
debug!("Fetching and creating remote community: {}", apub_id);
fetch_remote_community(apub_id, context, None, recursion_counter).await
}
Err(e) => Err(e.into()),
}
}
/// Request a community by apub ID from a remote instance, including moderators. If `old_community`,
/// is set, this is an update for a community which is already known locally. If not, we don't know
/// the community yet and also pull the outbox, to get some initial posts.
async fn fetch_remote_community(
apub_id: &Url,
context: &LemmyContext,
old_community: Option<Community>,
recursion_counter: &mut i32,
) -> Result<Community, LemmyError> {
let group = fetch_remote_object::<GroupExt>(context.client(), apub_id, recursion_counter).await;
if let Some(c) = old_community.to_owned() {
if is_deleted(&group) {
blocking(context.pool(), move |conn| {
Community::update_deleted(conn, c.id, true)
})
.await??;
} else if group.is_err() {
// If fetching failed, return the existing data.
return Ok(c);
}
}
let group = group?;
let community =
Community::from_apub(&group, context, apub_id.to_owned(), recursion_counter).await?;
// Also add the community moderators too
let attributed_to = group.inner.attributed_to().context(location_info!())?;
let creator_and_moderator_uris: Vec<&Url> = attributed_to
.as_many()
.context(location_info!())?
.iter()
.map(|a| a.as_xsd_any_uri().context(""))
.collect::<Result<Vec<&Url>, anyhow::Error>>()?;
let mut creator_and_moderators = Vec::new();
for uri in creator_and_moderator_uris {
let c_or_m = get_or_fetch_and_upsert_user(uri, context, recursion_counter).await?;
creator_and_moderators.push(c_or_m);
}
// TODO: need to make this work to update mods of existing communities
if old_community.is_none() {
let community_id = community.id;
blocking(context.pool(), move |conn| {
for mod_ in creator_and_moderators {
let community_moderator_form = CommunityModeratorForm {
community_id,
user_id: mod_.id,
};
CommunityModerator::join(conn, &community_moderator_form)?;
}
Ok(()) as Result<(), LemmyError>
})
.await??;
}
// fetch outbox (maybe make this conditional)
let outbox = fetch_remote_object::<OrderedCollection>(
context.client(),
&community.get_outbox_url()?,
recursion_counter,
)
.await?;
let outbox_items = outbox.items().context(location_info!())?.clone();
let mut outbox_items = outbox_items.many().context(location_info!())?;
if outbox_items.len() > 20 {
outbox_items = outbox_items[0..20].to_vec();
}
for o in outbox_items {
let page = PageExt::from_any_base(o)?.context(location_info!())?;
let page_id = page.id_unchecked().context(location_info!())?;
// The post creator may be from a blocked instance, if it errors, then skip it
if check_is_apub_id_valid(page_id).is_err() {
continue;
}
Post::from_apub(&page, context, page_id.to_owned(), recursion_counter).await?;
// TODO: we need to send a websocket update here
}
Ok(community)
}