lemmy_apub/src/inbox/community_inbox.rs

   1 use crate::{
   2   activities::receive::verify_activity_domains_valid,
   3   inbox::{
   4     assert_activity_not_local,
   5     get_activity_id,
   6     get_activity_to_and_cc,
   7     inbox_verify_http_signature,
   8     is_activity_already_known,
   9     is_addressed_to_public,
  10     receive_for_community::{
  11       receive_create_for_community,
  12       receive_delete_for_community,
  13       receive_dislike_for_community,
  14       receive_like_for_community,
  15       receive_undo_for_community,
  16       receive_update_for_community,
  17     },
  18   },
  19   insert_activity,
  20   ActorType,
  21 };
  22 use activitystreams::{
  23   activity::{kind::FollowType, ActorAndObject, Follow, Undo},
  24   base::AnyBase,
  25   prelude::*,
  26 };
  27 use actix_web::{web, HttpRequest, HttpResponse};
  28 use anyhow::{anyhow, Context};
  29 use lemmy_db::{
  30   community::{Community, CommunityFollower, CommunityFollowerForm},
  31   user::User_,
  32   views::community_user_ban_view::CommunityUserBanView,
  33   DbPool,
  34   Followable,
  35 };
  36 use lemmy_structs::blocking;
  37 use lemmy_utils::{location_info, LemmyError};
  38 use lemmy_websocket::LemmyContext;
  39 use log::info;
  40 use serde::{Deserialize, Serialize};
  41 use std::fmt::Debug;
  42 use url::Url;
  43
  44 /// Allowed activities for community inbox.
  45 #[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd, Deserialize, Serialize)]
  46 #[serde(rename_all = "PascalCase")]
  47 pub enum CommunityValidTypes {
  48   Follow,  // follow request from a user
  49   Undo,    // unfollow from a user
  50   Create,  // create post or comment
  51   Update,  // update post or comment
  52   Like,    // upvote post or comment
  53   Dislike, // downvote post or comment
  54   Delete,  // post or comment deleted by creator
  55   Remove,  // post or comment removed by mod or admin
  56 }
  57
  58 pub type CommunityAcceptedActivities = ActorAndObject<CommunityValidTypes>;
  59
  60 /// Handler for all incoming receive to community inboxes.
  61 pub async fn community_inbox(
  62   request: HttpRequest,
  63   input: web::Json<CommunityAcceptedActivities>,
  64   path: web::Path<String>,
  65   context: web::Data<LemmyContext>,
  66 ) -> Result<HttpResponse, LemmyError> {
  67   let activity = input.into_inner();
  68   // First of all check the http signature
  69   let request_counter = &mut 0;
  70   let actor = inbox_verify_http_signature(&activity, &context, request, request_counter).await?;
  71
  72   // Do nothing if we received the same activity before
  73   let activity_id = get_activity_id(&activity, &actor.actor_id()?)?;
  74   if is_activity_already_known(context.pool(), &activity_id).await? {
  75     return Ok(HttpResponse::Ok().finish());
  76   }
  77
  78   // Check if the activity is actually meant for us
  79   let path = path.into_inner();
  80   let community = blocking(&context.pool(), move |conn| {
  81     Community::read_from_name(&conn, &path)
  82   })
  83   .await??;
  84   let to_and_cc = get_activity_to_and_cc(&activity);
  85   if !to_and_cc.contains(&&community.actor_id()?) {
  86     return Err(anyhow!("Activity delivered to wrong community").into());
  87   }
  88
  89   assert_activity_not_local(&activity)?;
  90   insert_activity(&activity_id, activity.clone(), false, true, context.pool()).await?;
  91
  92   info!(
  93     "Community {} received activity {:?} from {}",
  94     community.name,
  95     &activity.id_unchecked(),
  96     &actor.actor_id_str()
  97   );
  98
  99   community_receive_message(
 100     activity.clone(),
 101     community.clone(),
 102     actor.as_ref(),
 103     &context,
 104     request_counter,
 105   )
 106   .await
 107 }
 108
 109 /// Receives Follow, Undo/Follow, post actions, comment actions (including votes)
 110 pub(crate) async fn community_receive_message(
 111   activity: CommunityAcceptedActivities,
 112   to_community: Community,
 113   actor: &dyn ActorType,
 114   context: &LemmyContext,
 115   request_counter: &mut i32,
 116 ) -> Result<HttpResponse, LemmyError> {
 117   // Only users can send activities to the community, so we can get the actor as user
 118   // unconditionally.
 119   let actor_id = actor.actor_id_str();
 120   let user = blocking(&context.pool(), move |conn| {
 121     User_::read_from_actor_id(&conn, &actor_id)
 122   })
 123   .await??;
 124   check_community_or_site_ban(&user, &to_community, context.pool()).await?;
 125
 126   let any_base = activity.clone().into_any_base()?;
 127   let actor_url = actor.actor_id()?;
 128   let activity_kind = activity.kind().context(location_info!())?;
 129   let do_announce = match activity_kind {
 130     CommunityValidTypes::Follow => {
 131       handle_follow(any_base.clone(), user, &to_community, &context).await?;
 132       false
 133     }
 134     CommunityValidTypes::Undo => {
 135       handle_undo(
 136         context,
 137         activity.clone(),
 138         actor_url,
 139         &to_community,
 140         request_counter,
 141       )
 142       .await?
 143     }
 144     CommunityValidTypes::Create => {
 145       receive_create_for_community(context, any_base.clone(), &actor_url, request_counter).await?;
 146       true
 147     }
 148     CommunityValidTypes::Update => {
 149       receive_update_for_community(context, any_base.clone(), &actor_url, request_counter).await?;
 150       true
 151     }
 152     CommunityValidTypes::Like => {
 153       receive_like_for_community(context, any_base.clone(), &actor_url, request_counter).await?;
 154       true
 155     }
 156     CommunityValidTypes::Dislike => {
 157       receive_dislike_for_community(context, any_base.clone(), &actor_url, request_counter).await?;
 158       true
 159     }
 160     CommunityValidTypes::Delete => {
 161       receive_delete_for_community(context, any_base.clone(), &actor_url).await?;
 162       true
 163     }
 164     CommunityValidTypes::Remove => {
 165       // TODO: we dont support remote mods, so this is ignored for now
 166       //receive_remove_for_community(context, any_base.clone(), &user_url).await?
 167       false
 168     }
 169   };
 170
 171   if do_announce {
 172     // Check again that the activity is public, just to be sure
 173     is_addressed_to_public(&activity)?;
 174     to_community
 175       .send_announce(activity.into_any_base()?, context)
 176       .await?;
 177   }
 178
 179   return Ok(HttpResponse::Ok().finish());
 180 }
 181
 182 /// Handle a follow request from a remote user, adding the user as follower and returning an
 183 /// Accept activity.
 184 async fn handle_follow(
 185   activity: AnyBase,
 186   user: User_,
 187   community: &Community,
 188   context: &LemmyContext,
 189 ) -> Result<HttpResponse, LemmyError> {
 190   let follow = Follow::from_any_base(activity)?.context(location_info!())?;
 191   verify_activity_domains_valid(&follow, &user.actor_id()?, false)?;
 192
 193   let community_follower_form = CommunityFollowerForm {
 194     community_id: community.id,
 195     user_id: user.id,
 196     pending: false,
 197   };
 198
 199   // This will fail if they're already a follower, but ignore the error.
 200   blocking(&context.pool(), move |conn| {
 201     CommunityFollower::follow(&conn, &community_follower_form).ok()
 202   })
 203   .await?;
 204
 205   community.send_accept_follow(follow, context).await?;
 206
 207   Ok(HttpResponse::Ok().finish())
 208 }
 209
 210 async fn handle_undo(
 211   context: &LemmyContext,
 212   activity: CommunityAcceptedActivities,
 213   actor_url: Url,
 214   to_community: &Community,
 215   request_counter: &mut i32,
 216 ) -> Result<bool, LemmyError> {
 217   let inner_kind = activity
 218     .object()
 219     .is_single_kind(&FollowType::Follow.to_string());
 220   let any_base = activity.into_any_base()?;
 221   if inner_kind {
 222     handle_undo_follow(any_base, actor_url, to_community, &context).await?;
 223     Ok(false)
 224   } else {
 225     receive_undo_for_community(context, any_base, &actor_url, request_counter).await?;
 226     Ok(true)
 227   }
 228 }
 229
 230 /// Handle `Undo/Follow` from a user, removing the user from followers list.
 231 async fn handle_undo_follow(
 232   activity: AnyBase,
 233   user_url: Url,
 234   community: &Community,
 235   context: &LemmyContext,
 236 ) -> Result<(), LemmyError> {
 237   let undo = Undo::from_any_base(activity)?.context(location_info!())?;
 238   verify_activity_domains_valid(&undo, &user_url, true)?;
 239
 240   let object = undo.object().to_owned().one().context(location_info!())?;
 241   let follow = Follow::from_any_base(object)?.context(location_info!())?;
 242   verify_activity_domains_valid(&follow, &user_url, false)?;
 243
 244   let user = blocking(&context.pool(), move |conn| {
 245     User_::read_from_actor_id(&conn, user_url.as_str())
 246   })
 247   .await??;
 248   let community_follower_form = CommunityFollowerForm {
 249     community_id: community.id,
 250     user_id: user.id,
 251     pending: false,
 252   };
 253
 254   // This will fail if they aren't a follower, but ignore the error.
 255   blocking(&context.pool(), move |conn| {
 256     CommunityFollower::unfollow(&conn, &community_follower_form).ok()
 257   })
 258   .await?;
 259
 260   Ok(())
 261 }
 262
 263 async fn check_community_or_site_ban(
 264   user: &User_,
 265   community: &Community,
 266   pool: &DbPool,
 267 ) -> Result<(), LemmyError> {
 268   if user.banned {
 269     return Err(anyhow!("User is banned from site").into());
 270   }
 271   let user_id = user.id;
 272   let community_id = community.id;
 273   let is_banned = move |conn: &'_ _| CommunityUserBanView::get(conn, user_id, community_id).is_ok();
 274   if blocking(pool, is_banned).await? {
 275     return Err(anyhow!("User is banned from community").into());
 276   }
 277
 278   Ok(())
 279 }