+use crate::{
+ objects::{community::ApubCommunity, person::ApubPerson},
+ CONTEXT,
+};
+use activitypub_federation::{
+ activity_queue::send_activity,
+ config::Data,
+ fetch::object_id::ObjectId,
+ kinds::public,
+ protocol::context::WithContext,
+ traits::{ActivityHandler, Actor},
+};
+use anyhow::anyhow;
+use lemmy_api_common::context::LemmyContext;
+use lemmy_db_schema::{
+ newtypes::CommunityId,
+ source::{
+ activity::{SentActivity, SentActivityForm},
+ community::Community,
+ instance::Instance,
+ },
+};
+use lemmy_db_views_actor::structs::{CommunityPersonBanView, CommunityView};
+use lemmy_utils::error::{LemmyError, LemmyErrorExt, LemmyErrorType};
+use moka::future::Cache;
+use once_cell::sync::Lazy;
+use serde::Serialize;
+use std::{ops::Deref, sync::Arc, time::Duration};
+use tracing::info;
+use url::{ParseError, Url};
+use uuid::Uuid;
+
+pub mod block;
+pub mod community;
+pub mod create_or_update;
+pub mod deletion;
+pub mod following;
+pub mod unfederated;
+pub mod voting;
+
+/// Amount of time that the list of dead instances is cached. This is only updated once a day,
+/// so there is no harm in caching it for a longer time.
+pub static DEAD_INSTANCE_LIST_CACHE_DURATION: Duration = Duration::from_secs(30 * 60);
+
+/// Checks that the specified Url actually identifies a Person (by fetching it), and that the person
+/// doesn't have a site ban.
+#[tracing::instrument(skip_all)]
+async fn verify_person(
+ person_id: &ObjectId<ApubPerson>,
+ context: &Data<LemmyContext>,
+) -> Result<(), LemmyError> {
+ let person = person_id.dereference(context).await?;
+ if person.banned {
+ return Err(anyhow!("Person {} is banned", person_id))
+ .with_lemmy_type(LemmyErrorType::CouldntUpdateComment);
+ }
+ Ok(())
+}
+
+/// Fetches the person and community to verify their type, then checks if person is banned from site
+/// or community.
+#[tracing::instrument(skip_all)]
+pub(crate) async fn verify_person_in_community(
+ person_id: &ObjectId<ApubPerson>,
+ community: &ApubCommunity,
+ context: &Data<LemmyContext>,
+) -> Result<(), LemmyError> {
+ let person = person_id.dereference(context).await?;
+ if person.banned {
+ return Err(LemmyErrorType::PersonIsBannedFromSite)?;
+ }
+ let person_id = person.id;
+ let community_id = community.id;
+ let is_banned = CommunityPersonBanView::get(&mut context.pool(), person_id, community_id)
+ .await
+ .is_ok();
+ if is_banned {
+ return Err(LemmyErrorType::PersonIsBannedFromCommunity)?;
+ }
+
+ Ok(())
+}
+
+/// Verify that mod action in community was performed by a moderator.
+///
+/// * `mod_id` - Activitypub ID of the mod or admin who performed the action
+/// * `object_id` - Activitypub ID of the actor or object that is being moderated
+/// * `community` - The community inside which moderation is happening
+#[tracing::instrument(skip_all)]
+pub(crate) async fn verify_mod_action(
+ mod_id: &ObjectId<ApubPerson>,
+ object_id: &Url,
+ community_id: CommunityId,
+ context: &Data<LemmyContext>,
+) -> Result<(), LemmyError> {
+ let mod_ = mod_id.dereference(context).await?;
+
+ let is_mod_or_admin =
+ CommunityView::is_mod_or_admin(&mut context.pool(), mod_.id, community_id).await?;
+ if is_mod_or_admin {
+ return Ok(());
+ }
+
+ // mod action comes from the same instance as the moderated object, so it was presumably done
+ // by an instance admin.
+ // TODO: federate instance admin status and check it here
+ if mod_id.inner().domain() == object_id.domain() {
+ return Ok(());
+ }
+
+ Err(LemmyErrorType::NotAModerator)?
+}
+
+pub(crate) fn verify_is_public(to: &[Url], cc: &[Url]) -> Result<(), LemmyError> {
+ if ![to, cc].iter().any(|set| set.contains(&public())) {
+ return Err(LemmyErrorType::ObjectIsNotPublic)?;
+ }
+ Ok(())
+}
+
+pub(crate) fn verify_community_matches<T>(
+ a: &ObjectId<ApubCommunity>,
+ b: T,
+) -> Result<(), LemmyError>
+where
+ T: Into<ObjectId<ApubCommunity>>,
+{
+ let b: ObjectId<ApubCommunity> = b.into();
+ if a != &b {
+ return Err(LemmyErrorType::InvalidCommunity)?;
+ }
+ Ok(())
+}
+
+pub(crate) fn check_community_deleted_or_removed(community: &Community) -> Result<(), LemmyError> {
+ if community.deleted || community.removed {
+ Err(LemmyErrorType::CannotCreatePostOrCommentInDeletedOrRemovedCommunity)?
+ } else {
+ Ok(())
+ }
+}
+
+/// Generate a unique ID for an activity, in the format:
+/// `http(s)://example.com/receive/create/202daf0a-1489-45df-8d2e-c8a3173fed36`
+fn generate_activity_id<T>(kind: T, protocol_and_hostname: &str) -> Result<Url, ParseError>
+where
+ T: ToString,
+{
+ let id = format!(
+ "{}/activities/{}/{}",
+ protocol_and_hostname,
+ kind.to_string().to_lowercase(),
+ Uuid::new_v4()
+ );
+ Url::parse(&id)
+}
+
+#[tracing::instrument(skip_all)]
+async fn send_lemmy_activity<Activity, ActorT>(
+ data: &Data<LemmyContext>,
+ activity: Activity,
+ actor: &ActorT,
+ mut inbox: Vec<Url>,
+ sensitive: bool,
+) -> Result<(), LemmyError>
+where
+ Activity: ActivityHandler + Serialize + Send + Sync + Clone,
+ ActorT: Actor,
+ Activity: ActivityHandler<Error = LemmyError>,
+{
+ static CACHE: Lazy<Cache<(), Arc<Vec<String>>>> = Lazy::new(|| {
+ Cache::builder()
+ .max_capacity(1)
+ .time_to_live(DEAD_INSTANCE_LIST_CACHE_DURATION)
+ .build()
+ });
+ let dead_instances = CACHE
+ .try_get_with((), async {
+ Ok::<_, diesel::result::Error>(Arc::new(Instance::dead_instances(&mut data.pool()).await?))
+ })
+ .await?;
+
+ inbox.retain(|i| {
+ let domain = i.domain().expect("has domain").to_string();
+ !dead_instances.contains(&domain)
+ });
+ info!("Sending activity {}", activity.id().to_string());
+ let activity = WithContext::new(activity, CONTEXT.deref().clone());
+
+ let form = SentActivityForm {
+ ap_id: activity.id().clone().into(),
+ data: serde_json::to_value(activity.clone())?,
+ sensitive,
+ };
+ SentActivity::create(&mut data.pool(), form).await?;
+ send_activity(activity, actor, inbox, data).await?;
+
+ Ok(())
+}