From 95ac570a24b891de67fbffe9a3cea9b1d2662faa Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Tue, 28 Sep 2021 18:06:33 +0200
Subject: [PATCH] Implement instance actor

---
 crates/api/src/community.rs                   |   1 +
 crates/api/src/local_user.rs                  |   4 +-
 crates/api/src/site.rs                        |   4 +-
 crates/api_common/src/community.rs            |  11 +-
 crates/api_common/src/lib.rs                  |   6 +-
 crates/api_crud/src/community/create.rs       |   2 +-
 crates/api_crud/src/community/read.rs         |  14 +-
 crates/api_crud/src/site/create.rs            |  14 +-
 crates/api_crud/src/site/update.rs            |   4 +-
 crates/api_crud/src/user/create.rs            |   2 +-
 .../apub/assets/lemmy/objects/instance.json   |  39 ++++
 .../src/collections/community_moderators.rs   |   4 +
 .../apub/src/fetcher/deletable_apub_object.rs |  99 +++++++++
 crates/apub/src/http/mod.rs                   |   1 +
 crates/apub/src/http/person.rs                |   6 +-
 crates/apub/src/http/routes.rs                |   3 +
 crates/apub/src/http/site.rs                  |  33 +++
 crates/apub/src/objects/comment.rs            |  17 +-
 crates/apub/src/objects/community.rs          |  37 ++--
 crates/apub/src/objects/instance.rs           | 205 ++++++++++++++++++
 crates/apub/src/objects/mod.rs                |   1 +
 crates/apub/src/objects/person.rs             |  13 +-
 crates/apub/src/objects/post.rs               |   4 +
 crates/apub/src/objects/private_message.rs    |   7 +-
 .../{person_outbox.rs => empty_outbox.rs}     |  13 +-
 crates/apub/src/protocol/collections/mod.rs   |   6 +-
 crates/apub/src/protocol/mod.rs               |   9 +
 crates/apub/src/protocol/objects/instance.rs  |  39 ++++
 crates/apub/src/protocol/objects/mod.rs       |  15 +-
 .../src/aggregates/site_aggregates.rs         |  17 +-
 crates/db_schema/src/impls/site.rs            |  29 ++-
 crates/db_schema/src/schema.rs                |   5 +
 crates/db_schema/src/source/site.rs           |  10 +
 .../2022-01-28-104106_instance-actor/down.sql |   6 +
 .../2022-01-28-104106_instance-actor/up.sql   |   6 +
 src/code_migrations.rs                        |  29 +++
 36 files changed, 629 insertions(+), 86 deletions(-)
 create mode 100644 crates/apub/assets/lemmy/objects/instance.json
 create mode 100644 crates/apub/src/fetcher/deletable_apub_object.rs
 create mode 100644 crates/apub/src/http/site.rs
 create mode 100644 crates/apub/src/objects/instance.rs
 rename crates/apub/src/protocol/collections/{person_outbox.rs => empty_outbox.rs} (60%)
 create mode 100644 crates/apub/src/protocol/objects/instance.rs
 create mode 100644 migrations/2022-01-28-104106_instance-actor/down.sql
 create mode 100644 migrations/2022-01-28-104106_instance-actor/up.sql

diff --git a/crates/api/src/community.rs b/crates/api/src/community.rs
index a1a44f094..5f4fe3c71 100644
--- a/crates/api/src/community.rs
+++ b/crates/api/src/community.rs
@@ -540,6 +540,7 @@ impl Perform for TransferCommunity {
       community_view,
       moderators,
       online: 0,
+      site: None,
     })
   }
 }
diff --git a/crates/api/src/local_user.rs b/crates/api/src/local_user.rs
index 974beb6ea..bd32280e7 100644
--- a/crates/api/src/local_user.rs
+++ b/crates/api/src/local_user.rs
@@ -91,7 +91,7 @@ impl Perform for Login {
       return Err(LemmyError::from_message("password_incorrect"));
     }
 
-    let site = blocking(context.pool(), Site::read_simple).await??;
+    let site = blocking(context.pool(), Site::read_local_site).await??;
     if site.require_email_verification && !local_user_view.local_user.email_verified {
       return Err(LemmyError::from_message("email_not_verified"));
     }
@@ -200,7 +200,7 @@ impl Perform for SaveUserSettings {
 
     // When the site requires email, make sure email is not Some(None). IE, an overwrite to a None value
     if let Some(email) = &email {
-      let site_fut = blocking(context.pool(), Site::read_simple);
+      let site_fut = blocking(context.pool(), Site::read_local_site);
       if email.is_none() && site_fut.await??.require_email_verification {
         return Err(LemmyError::from_message("email_required"));
       }
diff --git a/crates/api/src/site.rs b/crates/api/src/site.rs
index 20ceffe57..92dbdd64d 100644
--- a/crates/api/src/site.rs
+++ b/crates/api/src/site.rs
@@ -583,7 +583,7 @@ impl Perform for ListRegistrationApplications {
     is_admin(&local_user_view)?;
 
     let unread_only = data.unread_only;
-    let verified_email_only = blocking(context.pool(), Site::read_simple)
+    let verified_email_only = blocking(context.pool(), Site::read_local_site)
       .await??
       .require_email_verification;
 
@@ -689,7 +689,7 @@ impl Perform for GetUnreadRegistrationApplicationCount {
     // Only let admins do this
     is_admin(&local_user_view)?;
 
-    let verified_email_only = blocking(context.pool(), Site::read_simple)
+    let verified_email_only = blocking(context.pool(), Site::read_local_site)
       .await??
       .require_email_verification;
 
diff --git a/crates/api_common/src/community.rs b/crates/api_common/src/community.rs
index 9686172ac..03b224e00 100644
--- a/crates/api_common/src/community.rs
+++ b/crates/api_common/src/community.rs
@@ -1,4 +1,7 @@
-use lemmy_db_schema::newtypes::{CommunityId, PersonId};
+use lemmy_db_schema::{
+  newtypes::{CommunityId, PersonId},
+  source::site::Site,
+};
 use lemmy_db_views_actor::{
   community_moderator_view::CommunityModeratorView,
   community_view::CommunityView,
@@ -20,6 +23,12 @@ pub struct GetCommunityResponse {
   pub community_view: CommunityView,
   pub moderators: Vec<CommunityModeratorView>,
   pub online: usize,
+  /// Metadata of the instance where the community is located. Only fields name, sidebar,
+  /// description, icon, banner, actor_id, last_refreshed_at get federated, everything else uses
+  /// default values. May be null if the community is hosted on an older Lemmy version, or on
+  /// another software.
+  /// TODO: this should probably be SiteView
+  pub site: Option<Site>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
diff --git a/crates/api_common/src/lib.rs b/crates/api_common/src/lib.rs
index 2d1f1bf50..a49e8e4f3 100644
--- a/crates/api_common/src/lib.rs
+++ b/crates/api_common/src/lib.rs
@@ -267,7 +267,7 @@ pub async fn check_person_block(
 #[tracing::instrument(skip_all)]
 pub async fn check_downvotes_enabled(score: i16, pool: &DbPool) -> Result<(), LemmyError> {
   if score == -1 {
-    let site = blocking(pool, Site::read_simple).await??;
+    let site = blocking(pool, Site::read_local_site).await??;
     if !site.enable_downvotes {
       return Err(LemmyError::from_message("downvotes_disabled"));
     }
@@ -281,7 +281,7 @@ pub async fn check_private_instance(
   pool: &DbPool,
 ) -> Result<(), LemmyError> {
   if local_user_view.is_none() {
-    let site = blocking(pool, Site::read_simple).await?;
+    let site = blocking(pool, Site::read_local_site).await?;
 
     // The site might not be set up yet
     if let Ok(site) = site {
@@ -511,7 +511,7 @@ pub async fn check_private_instance_and_federation_enabled(
   pool: &DbPool,
   settings: &Settings,
 ) -> Result<(), LemmyError> {
-  let site_opt = blocking(pool, Site::read_simple).await?;
+  let site_opt = blocking(pool, Site::read_local_site).await?;
 
   if let Ok(site) = site_opt {
     if site.private_instance && settings.federation.enabled {
diff --git a/crates/api_crud/src/community/create.rs b/crates/api_crud/src/community/create.rs
index fb090b864..d78c8ad7a 100644
--- a/crates/api_crud/src/community/create.rs
+++ b/crates/api_crud/src/community/create.rs
@@ -53,7 +53,7 @@ impl PerformCrud for CreateCommunity {
     let local_user_view =
       get_local_user_view_from_jwt(&data.auth, context.pool(), context.secret()).await?;
 
-    let site = blocking(context.pool(), move |conn| Site::read(conn, 0)).await??;
+    let site = blocking(context.pool(), Site::read_local_site).await??;
     if site.community_creation_admin_only && is_admin(&local_user_view).is_err() {
       return Err(LemmyError::from_message(
         "only_admins_can_create_communities",
diff --git a/crates/api_crud/src/community/read.rs b/crates/api_crud/src/community/read.rs
index 7e61bfa71..caeffcadc 100644
--- a/crates/api_crud/src/community/read.rs
+++ b/crates/api_crud/src/community/read.rs
@@ -7,9 +7,10 @@ use lemmy_api_common::{
   get_local_user_view_from_jwt_opt,
   resolve_actor_identifier,
 };
+use lemmy_apub::objects::instance::instance_actor_id_from_url;
 use lemmy_db_schema::{
   from_opt_str_to_opt_enum,
-  source::community::Community,
+  source::{community::Community, site::Site},
   traits::DeleteableOrRemoveable,
   ListingType,
   SortType,
@@ -78,10 +79,21 @@ impl PerformCrud for GetCommunity {
       .await
       .unwrap_or(1);
 
+    let site_id = instance_actor_id_from_url(community_view.community.actor_id.clone().into());
+    let site = blocking(context.pool(), move |conn| {
+      Site::read_from_apub_id(conn, site_id)
+    })
+    .await
+    .map(|s| s.ok())
+    .ok()
+    .flatten()
+    .flatten();
+
     let res = GetCommunityResponse {
       community_view,
       moderators,
       online,
+      site,
     };
 
     // Return the jwt
diff --git a/crates/api_crud/src/site/create.rs b/crates/api_crud/src/site/create.rs
index 3de2c3ab8..9b4266e2a 100644
--- a/crates/api_crud/src/site/create.rs
+++ b/crates/api_crud/src/site/create.rs
@@ -7,19 +7,25 @@ use lemmy_api_common::{
   site::*,
   site_description_length_check,
 };
+use lemmy_apub::generate_inbox_url;
 use lemmy_db_schema::{
   diesel_option_overwrite,
   diesel_option_overwrite_to_url,
+  naive_now,
+  newtypes::DbUrl,
   source::site::{Site, SiteForm},
   traits::Crud,
 };
 use lemmy_db_views::site_view::SiteView;
 use lemmy_utils::{
+  apub::generate_actor_keypair,
+  settings::structs::Settings,
   utils::{check_slurs, check_slurs_opt},
   ConnectionId,
   LemmyError,
 };
 use lemmy_websocket::LemmyContext;
+use url::Url;
 
 #[async_trait::async_trait(?Send)]
 impl PerformCrud for CreateSite {
@@ -33,7 +39,7 @@ impl PerformCrud for CreateSite {
   ) -> Result<SiteResponse, LemmyError> {
     let data: &CreateSite = self;
 
-    let read_site = Site::read_simple;
+    let read_site = Site::read_local_site;
     if blocking(context.pool(), read_site).await?.is_ok() {
       return Err(LemmyError::from_message("site_already_exists"));
     };
@@ -56,6 +62,8 @@ impl PerformCrud for CreateSite {
       site_description_length_check(desc)?;
     }
 
+    let actor_id: DbUrl = Url::parse(&Settings::get().get_protocol_and_hostname())?.into();
+    let keypair = generate_actor_keypair()?;
     let site_form = SiteForm {
       name: data.name.to_owned(),
       sidebar,
@@ -66,6 +74,10 @@ impl PerformCrud for CreateSite {
       open_registration: data.open_registration,
       enable_nsfw: data.enable_nsfw,
       community_creation_admin_only: data.community_creation_admin_only,
+      last_refreshed_at: Some(naive_now()),
+      inbox_url: Some(generate_inbox_url(&actor_id)?),
+      private_key: Some(Some(keypair.private_key)),
+      public_key: Some(keypair.public_key),
       ..SiteForm::default()
     };
 
diff --git a/crates/api_crud/src/site/update.rs b/crates/api_crud/src/site/update.rs
index 0a94062a7..c6f595230 100644
--- a/crates/api_crud/src/site/update.rs
+++ b/crates/api_crud/src/site/update.rs
@@ -20,6 +20,7 @@ use lemmy_db_schema::{
 use lemmy_db_views::site_view::SiteView;
 use lemmy_utils::{utils::check_slurs_opt, ConnectionId, LemmyError};
 use lemmy_websocket::{messages::SendAllMessage, LemmyContext, UserOperationCrud};
+use std::default::Default;
 
 #[async_trait::async_trait(?Send)]
 impl PerformCrud for EditSite {
@@ -41,7 +42,7 @@ impl PerformCrud for EditSite {
     // Make sure user is an admin
     is_admin(&local_user_view)?;
 
-    let found_site = blocking(context.pool(), Site::read_simple).await??;
+    let found_site = blocking(context.pool(), Site::read_local_site).await??;
 
     let sidebar = diesel_option_overwrite(&data.sidebar);
     let description = diesel_option_overwrite(&data.description);
@@ -68,6 +69,7 @@ impl PerformCrud for EditSite {
       require_application: data.require_application,
       application_question,
       private_instance: data.private_instance,
+      ..SiteForm::default()
     };
 
     let update_site = blocking(context.pool(), move |conn| {
diff --git a/crates/api_crud/src/user/create.rs b/crates/api_crud/src/user/create.rs
index 6f8a5fa0e..06b576e51 100644
--- a/crates/api_crud/src/user/create.rs
+++ b/crates/api_crud/src/user/create.rs
@@ -58,7 +58,7 @@ impl PerformCrud for Register {
     let (mut email_verification, mut require_application) = (false, false);
 
     // Make sure site has open registration
-    if let Ok(site) = blocking(context.pool(), Site::read_simple).await? {
+    if let Ok(site) = blocking(context.pool(), Site::read_local_site).await? {
       if !site.open_registration {
         return Err(LemmyError::from_message("registration_closed"));
       }
diff --git a/crates/apub/assets/lemmy/objects/instance.json b/crates/apub/assets/lemmy/objects/instance.json
new file mode 100644
index 000000000..73df87759
--- /dev/null
+++ b/crates/apub/assets/lemmy/objects/instance.json
@@ -0,0 +1,39 @@
+{
+  "@context": [
+    "https://www.w3.org/ns/activitystreams",
+    {
+      "stickied": "as:stickied",
+      "pt": "https://join-lemmy.org#",
+      "sc": "http://schema.org#",
+      "matrixUserId": {
+        "type": "sc:Text",
+        "id": "as:alsoKnownAs"
+      },
+      "sensitive": "as:sensitive",
+      "comments_enabled": {
+        "type": "sc:Boolean",
+        "id": "pt:commentsEnabled"
+      },
+      "moderators": "as:moderators"
+    },
+    "https://w3id.org/security/v1"
+  ],
+  "type": "Service",
+  "id": "https://enterprise.lemmy.ml/",
+  "name": "Enterprise",
+  "summary": "A test instance",
+  "content": "<p>Enterprise sidebar</p>\\n",
+  "mediaType": "text/html",
+  "source": {
+    "content": "Enterprise sidebar",
+    "mediaType": "text/markdown"
+  },
+  "inbox": "https://enterprise.lemmy.ml/inbox",
+  "outbox": "https://enterprise.lemmy.ml/outbox",
+  "publicKey": {
+    "id": "https://enterprise.lemmy.ml/#main-key",
+    "owner": "https://enterprise.lemmy.ml/",
+    "publicKeyPem": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAupcK0xTw5yQb/fnztAmb\n9LfPbhJJP1+1GwUaOXGYiDJD6uYJhl9CLmgztLl3RyV9ltOYoN8/NLNDfOMmgOjd\nrsNWEjDI9IcVPmiZnhU7hsi6KgQvJzzv8O5/xYjAGhDfrGmtdpL+lyG0B5fQod8J\n/V5VWvTQ0B0qFrLSBBuhOrp8/fTtDskdtElDPtnNfH2jn6FgtLOijidWwf9ekFo4\n0I1JeuEw6LuD/CzKVJTPoztzabUV1DQF/DnFJm+8y7SCJa9jEO56Uf9eVfa1jF6f\ndH6ZvNJMiafstVuLMAw7C/eNJy3ufXgtZ4403oOKA0aRSYf1cc9pHSZ9gDE/mevH\nLwIDAQAB\n-----END PUBLIC KEY-----\n"
+  },
+  "published": "2022-01-19T21:52:11.110741+00:00"
+}
\ No newline at end of file
diff --git a/crates/apub/src/collections/community_moderators.rs b/crates/apub/src/collections/community_moderators.rs
index 338ed0f5a..56b9bca97 100644
--- a/crates/apub/src/collections/community_moderators.rs
+++ b/crates/apub/src/collections/community_moderators.rs
@@ -140,6 +140,7 @@ mod tests {
   use super::*;
   use crate::objects::{
     community::tests::parse_lemmy_community,
+    instance::tests::parse_lemmy_instance,
     person::tests::parse_lemmy_person,
     tests::{file_to_json_object, init_context},
   };
@@ -148,6 +149,7 @@ mod tests {
     source::{
       community::Community,
       person::{Person, PersonForm},
+      site::Site,
     },
     traits::Crud,
   };
@@ -159,6 +161,7 @@ mod tests {
     let client = reqwest::Client::new().into();
     let manager = create_activity_queue(client);
     let context = init_context(manager.queue_handle().clone());
+    let site = parse_lemmy_instance(&context).await;
     let community = parse_lemmy_community(&context).await;
     let community_id = community.id;
 
@@ -209,5 +212,6 @@ mod tests {
       community_context.0.id,
     )
     .unwrap();
+    Site::delete(&*community_context.1.pool().get().unwrap(), site.id).unwrap();
   }
 }
diff --git a/crates/apub/src/fetcher/deletable_apub_object.rs b/crates/apub/src/fetcher/deletable_apub_object.rs
new file mode 100644
index 000000000..ccb409e8d
--- /dev/null
+++ b/crates/apub/src/fetcher/deletable_apub_object.rs
@@ -0,0 +1,99 @@
+use crate::fetcher::post_or_comment::PostOrComment;
+use lemmy_api_common::blocking;
+use lemmy_db_queries::source::{
+  comment::Comment_,
+  community::Community_,
+  person::Person_,
+  post::Post_,
+};
+use lemmy_db_schema::source::{
+  comment::Comment,
+  community::Community,
+  person::Person,
+  post::Post,
+  site::Site,
+};
+use lemmy_utils::LemmyError;
+use lemmy_websocket::LemmyContext;
+
+// TODO: merge this trait with ApubObject (means that db_schema needs to depend on apub_lib)
+#[async_trait::async_trait(?Send)]
+pub trait DeletableApubObject {
+  // TODO: pass in tombstone with summary field, to decide between remove/delete
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError>;
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for Community {
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let id = self.id;
+    blocking(context.pool(), move |conn| {
+      Community::update_deleted(conn, id, true)
+    })
+    .await??;
+    Ok(())
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for Person {
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let id = self.id;
+    blocking(context.pool(), move |conn| Person::delete_account(conn, id)).await??;
+    Ok(())
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for Post {
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let id = self.id;
+    blocking(context.pool(), move |conn| {
+      Post::update_deleted(conn, id, true)
+    })
+    .await??;
+    Ok(())
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for Comment {
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError> {
+    let id = self.id;
+    blocking(context.pool(), move |conn| {
+      Comment::update_deleted(conn, id, true)
+    })
+    .await??;
+    Ok(())
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for PostOrComment {
+  async fn delete(self, context: &LemmyContext) -> Result<(), LemmyError> {
+    match self {
+      PostOrComment::Comment(c) => {
+        blocking(context.pool(), move |conn| {
+          Comment::update_deleted(conn, c.id, true)
+        })
+        .await??;
+      }
+      PostOrComment::Post(p) => {
+        blocking(context.pool(), move |conn| {
+          Post::update_deleted(conn, p.id, true)
+        })
+        .await??;
+      }
+    }
+
+    Ok(())
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl DeletableApubObject for Site {
+  async fn delete(self, _context: &LemmyContext) -> Result<(), LemmyError> {
+    // not implemented, ignore
+    Ok(())
+  }
+}
diff --git a/crates/apub/src/http/mod.rs b/crates/apub/src/http/mod.rs
index 399793e14..1cf705ae2 100644
--- a/crates/apub/src/http/mod.rs
+++ b/crates/apub/src/http/mod.rs
@@ -36,6 +36,7 @@ mod community;
 mod person;
 mod post;
 pub mod routes;
+pub mod site;
 
 #[tracing::instrument(skip_all)]
 pub async fn shared_inbox(
diff --git a/crates/apub/src/http/person.rs b/crates/apub/src/http/person.rs
index bc0633d8d..9081d5a55 100644
--- a/crates/apub/src/http/person.rs
+++ b/crates/apub/src/http/person.rs
@@ -1,6 +1,7 @@
 use crate::{
   activity_lists::PersonInboxActivities,
   context::WithContext,
+  generate_outbox_url,
   http::{
     create_apub_response,
     create_apub_tombstone_response,
@@ -9,7 +10,7 @@ use crate::{
     ActivityCommonFields,
   },
   objects::person::ApubPerson,
-  protocol::collections::person_outbox::PersonOutbox,
+  protocol::collections::empty_outbox::EmptyOutbox,
 };
 use actix_web::{web, web::Payload, HttpRequest, HttpResponse};
 use lemmy_api_common::blocking;
@@ -80,6 +81,7 @@ pub(crate) async fn get_apub_person_outbox(
     Person::read_from_name(conn, &info.user_name)
   })
   .await??;
-  let outbox = PersonOutbox::new(person).await?;
+  let outbox_id = generate_outbox_url(&person.actor_id)?.into();
+  let outbox = EmptyOutbox::new(outbox_id).await?;
   Ok(create_apub_response(&outbox))
 }
diff --git a/crates/apub/src/http/routes.rs b/crates/apub/src/http/routes.rs
index a57290e4b..271c1b14e 100644
--- a/crates/apub/src/http/routes.rs
+++ b/crates/apub/src/http/routes.rs
@@ -11,6 +11,7 @@ use crate::http::{
   person::{get_apub_person_http, get_apub_person_outbox, person_inbox},
   post::get_apub_post,
   shared_inbox,
+  site::get_apub_site_http,
 };
 use actix_web::{
   guard::{Guard, GuardContext},
@@ -26,6 +27,8 @@ pub fn config(cfg: &mut web::ServiceConfig, settings: &Settings) {
     println!("federation enabled, host is {}", settings.hostname);
 
     cfg
+      .route("/", web::get().to(get_apub_site_http))
+      .route("/site_outbox", web::get().to(get_apub_site_http))
       .route(
         "/c/{community_name}",
         web::get().to(get_apub_community_http),
diff --git a/crates/apub/src/http/site.rs b/crates/apub/src/http/site.rs
new file mode 100644
index 000000000..3439ef1d9
--- /dev/null
+++ b/crates/apub/src/http/site.rs
@@ -0,0 +1,33 @@
+use crate::{
+  http::create_apub_response,
+  objects::instance::ApubSite,
+  protocol::collections::empty_outbox::EmptyOutbox,
+};
+use actix_web::{web, HttpResponse};
+use lemmy_api_common::blocking;
+use lemmy_apub_lib::traits::ApubObject;
+use lemmy_db_schema::source::site::Site;
+use lemmy_utils::{settings::structs::Settings, LemmyError};
+use lemmy_websocket::LemmyContext;
+use url::Url;
+
+pub(crate) async fn get_apub_site_http(
+  context: web::Data<LemmyContext>,
+) -> Result<HttpResponse, LemmyError> {
+  let site: ApubSite = blocking(context.pool(), Site::read_local_site)
+    .await??
+    .into();
+
+  let apub = site.into_apub(&context).await?;
+  Ok(create_apub_response(&apub))
+}
+
+#[tracing::instrument(skip_all)]
+pub(crate) async fn get_apub_site_outbox() -> Result<HttpResponse, LemmyError> {
+  let outbox_id = format!(
+    "{}/site_outbox",
+    Settings::get().get_protocol_and_hostname()
+  );
+  let outbox = EmptyOutbox::new(Url::parse(&outbox_id)?).await?;
+  Ok(create_apub_response(&outbox))
+}
diff --git a/crates/apub/src/objects/comment.rs b/crates/apub/src/objects/comment.rs
index ee131adf7..f8e7045d2 100644
--- a/crates/apub/src/objects/comment.rs
+++ b/crates/apub/src/objects/comment.rs
@@ -18,7 +18,7 @@ use lemmy_api_common::blocking;
 use lemmy_apub_lib::{
   object_id::ObjectId,
   traits::ApubObject,
-  values::{MediaTypeHtml, MediaTypeMarkdown},
+  values::MediaTypeHtml,
   verify::verify_domains_match,
 };
 use lemmy_db_schema::{
@@ -120,10 +120,7 @@ impl ApubObject for ApubComment {
       cc: maa.ccs,
       content: markdown_to_html(&self.content),
       media_type: Some(MediaTypeHtml::Html),
-      source: SourceCompat::Lemmy(Source {
-        content: self.content.clone(),
-        media_type: MediaTypeMarkdown::Markdown,
-      }),
+      source: SourceCompat::Lemmy(Source::new(self.content.clone())),
       in_reply_to,
       published: Some(convert_datetime(self.published)),
       updated: self.updated.map(convert_datetime),
@@ -213,19 +210,22 @@ pub(crate) mod tests {
   use super::*;
   use crate::objects::{
     community::{tests::parse_lemmy_community, ApubCommunity},
+    instance::{tests::parse_lemmy_instance, ApubSite},
     person::{tests::parse_lemmy_person, ApubPerson},
     post::ApubPost,
     tests::{file_to_json_object, init_context},
   };
   use assert_json_diff::assert_json_include;
   use lemmy_apub_lib::activity_queue::create_activity_queue;
+  use lemmy_db_schema::source::site::Site;
   use serial_test::serial;
 
   async fn prepare_comment_test(
     url: &Url,
     context: &LemmyContext,
-  ) -> (ApubPerson, ApubCommunity, ApubPost) {
+  ) -> (ApubPerson, ApubCommunity, ApubPost, ApubSite) {
     let person = parse_lemmy_person(context).await;
+    let site = parse_lemmy_instance(context).await;
     let community = parse_lemmy_community(context).await;
     let post_json = file_to_json_object("assets/lemmy/objects/page.json").unwrap();
     ApubPost::verify(&post_json, url, context, &mut 0)
@@ -234,13 +234,14 @@ pub(crate) mod tests {
     let post = ApubPost::from_apub(post_json, context, &mut 0)
       .await
       .unwrap();
-    (person, community, post)
+    (person, community, post, site)
   }
 
-  fn cleanup(data: (ApubPerson, ApubCommunity, ApubPost), context: &LemmyContext) {
+  fn cleanup(data: (ApubPerson, ApubCommunity, ApubPost, ApubSite), context: &LemmyContext) {
     Post::delete(&*context.pool().get().unwrap(), data.2.id).unwrap();
     Community::delete(&*context.pool().get().unwrap(), data.1.id).unwrap();
     Person::delete(&*context.pool().get().unwrap(), data.0.id).unwrap();
+    Site::delete(&*context.pool().get().unwrap(), data.3.id).unwrap();
   }
 
   #[actix_rt::test]
diff --git a/crates/apub/src/objects/community.rs b/crates/apub/src/objects/community.rs
index cce61b57f..8070c131a 100644
--- a/crates/apub/src/objects/community.rs
+++ b/crates/apub/src/objects/community.rs
@@ -3,6 +3,7 @@ use crate::{
   collections::{community_moderators::ApubCommunityModerators, CommunityContext},
   generate_moderators_url,
   generate_outbox_url,
+  objects::instance::{instance_actor_id_from_url, ApubSite},
   protocol::{
     objects::{group::Group, tombstone::Tombstone, Endpoints},
     ImageObject,
@@ -16,7 +17,6 @@ use lemmy_api_common::blocking;
 use lemmy_apub_lib::{
   object_id::ObjectId,
   traits::{ActorType, ApubObject},
-  values::MediaTypeMarkdown,
 };
 use lemmy_db_schema::{source::community::Community, traits::ApubActor};
 use lemmy_db_views_actor::community_follower_view::CommunityFollowerView;
@@ -26,7 +26,7 @@ use lemmy_utils::{
 };
 use lemmy_websocket::LemmyContext;
 use std::ops::Deref;
-use tracing::debug;
+use tracing::{debug, info};
 use url::Url;
 
 #[derive(Clone, Debug)]
@@ -80,22 +80,15 @@ impl ApubObject for ApubCommunity {
 
   #[tracing::instrument(skip_all)]
   async fn into_apub(self, _context: &LemmyContext) -> Result<Group, LemmyError> {
-    let source = self.description.clone().map(|bio| Source {
-      content: bio,
-      media_type: MediaTypeMarkdown::Markdown,
-    });
-    let icon = self.icon.clone().map(ImageObject::new);
-    let image = self.banner.clone().map(ImageObject::new);
-
     let group = Group {
       kind: GroupType::Group,
       id: ObjectId::new(self.actor_id()),
       preferred_username: self.name.clone(),
       name: self.title.clone(),
       summary: self.description.as_ref().map(|b| markdown_to_html(b)),
-      source,
-      icon,
-      image,
+      source: self.description.clone().map(Source::new),
+      icon: self.icon.clone().map(ImageObject::new),
+      image: self.banner.clone().map(ImageObject::new),
       sensitive: Some(self.nsfw),
       moderators: Some(ObjectId::<ApubCommunityModerators>::new(
         generate_moderators_url(&self.actor_id)?,
@@ -160,6 +153,15 @@ impl ApubObject for ApubCommunity {
         .ok();
     }
 
+    // try to fetch the instance actor (to make things like instance rules available)
+    let instance_id = instance_actor_id_from_url(community.actor_id.clone().into());
+    let site = ObjectId::<ApubSite>::new(instance_id.clone())
+      .dereference(context, context.client(), request_counter)
+      .await;
+    if let Err(e) = site {
+      info!("Failed to dereference site for {}: {}", instance_id, e);
+    }
+
     Ok(community)
   }
 }
@@ -219,9 +221,12 @@ impl ApubCommunity {
 #[cfg(test)]
 pub(crate) mod tests {
   use super::*;
-  use crate::objects::tests::{file_to_json_object, init_context};
+  use crate::objects::{
+    instance::tests::parse_lemmy_instance,
+    tests::{file_to_json_object, init_context},
+  };
   use lemmy_apub_lib::activity_queue::create_activity_queue;
-  use lemmy_db_schema::traits::Crud;
+  use lemmy_db_schema::{source::site::Site, traits::Crud};
   use serial_test::serial;
 
   pub(crate) async fn parse_lemmy_community(context: &LemmyContext) -> ApubCommunity {
@@ -239,7 +244,7 @@ pub(crate) mod tests {
     let community = ApubCommunity::from_apub(json, context, &mut request_counter)
       .await
       .unwrap();
-    // this makes two requests to the (intentionally) broken outbox/moderators collections
+    // this makes one requests to the (intentionally broken) outbox collection
     assert_eq!(request_counter, 1);
     community
   }
@@ -250,6 +255,7 @@ pub(crate) mod tests {
     let client = reqwest::Client::new().into();
     let manager = create_activity_queue(client);
     let context = init_context(manager.queue_handle().clone());
+    let site = parse_lemmy_instance(&context).await;
     let community = parse_lemmy_community(&context).await;
 
     assert_eq!(community.title, "Ten Forward");
@@ -257,5 +263,6 @@ pub(crate) mod tests {
     assert_eq!(community.description.as_ref().unwrap().len(), 132);
 
     Community::delete(&*context.pool().get().unwrap(), community.id).unwrap();
+    Site::delete(&*context.pool().get().unwrap(), site.id).unwrap();
   }
 }
diff --git a/crates/apub/src/objects/instance.rs b/crates/apub/src/objects/instance.rs
new file mode 100644
index 000000000..333092b1f
--- /dev/null
+++ b/crates/apub/src/objects/instance.rs
@@ -0,0 +1,205 @@
+use crate::{
+  check_is_apub_id_valid,
+  generate_outbox_url,
+  objects::get_summary_from_string_or_source,
+  protocol::{objects::instance::Instance, ImageObject, Source, Unparsed},
+};
+use activitystreams_kinds::actor::ServiceType;
+use chrono::NaiveDateTime;
+use lemmy_api_common::blocking;
+use lemmy_apub_lib::{
+  object_id::ObjectId,
+  traits::{ActorType, ApubObject},
+  values::MediaTypeHtml,
+  verify::verify_domains_match,
+};
+use lemmy_db_schema::{
+  naive_now,
+  source::site::{Site, SiteForm},
+};
+use lemmy_utils::{
+  utils::{check_slurs, check_slurs_opt, convert_datetime, markdown_to_html},
+  LemmyError,
+};
+use lemmy_websocket::LemmyContext;
+use std::ops::Deref;
+use url::Url;
+
+#[derive(Clone, Debug)]
+pub struct ApubSite(Site);
+
+impl Deref for ApubSite {
+  type Target = Site;
+  fn deref(&self) -> &Self::Target {
+    &self.0
+  }
+}
+
+impl From<Site> for ApubSite {
+  fn from(s: Site) -> Self {
+    ApubSite { 0: s }
+  }
+}
+
+#[async_trait::async_trait(?Send)]
+impl ApubObject for ApubSite {
+  type DataType = LemmyContext;
+  type ApubType = Instance;
+  type TombstoneType = ();
+
+  fn last_refreshed_at(&self) -> Option<NaiveDateTime> {
+    Some(self.last_refreshed_at)
+  }
+
+  #[tracing::instrument(skip_all)]
+  async fn read_from_apub_id(
+    object_id: Url,
+    data: &Self::DataType,
+  ) -> Result<Option<Self>, LemmyError> {
+    Ok(
+      blocking(data.pool(), move |conn| {
+        Site::read_from_apub_id(conn, object_id)
+      })
+      .await??
+      .map(Into::into),
+    )
+  }
+
+  async fn delete(self, _data: &Self::DataType) -> Result<(), LemmyError> {
+    unimplemented!()
+  }
+
+  #[tracing::instrument(skip_all)]
+  async fn into_apub(self, _data: &Self::DataType) -> Result<Self::ApubType, LemmyError> {
+    let instance = Instance {
+      kind: ServiceType::Service,
+      id: ObjectId::new(self.actor_id()),
+      name: self.name.clone(),
+      content: self.sidebar.as_ref().map(|d| markdown_to_html(d)),
+      source: self.sidebar.clone().map(Source::new),
+      summary: self.description.clone(),
+      media_type: self.sidebar.as_ref().map(|_| MediaTypeHtml::Html),
+      icon: self.icon.clone().map(ImageObject::new),
+      image: self.banner.clone().map(ImageObject::new),
+      inbox: self.inbox_url.clone().into(),
+      outbox: generate_outbox_url(&self.actor_id)?.into(),
+      public_key: self.get_public_key()?,
+      published: convert_datetime(self.published),
+      updated: self.updated.map(convert_datetime),
+      unparsed: Unparsed::default(),
+    };
+    Ok(instance)
+  }
+
+  fn to_tombstone(&self) -> Result<Self::TombstoneType, LemmyError> {
+    unimplemented!()
+  }
+
+  #[tracing::instrument(skip_all)]
+  async fn verify(
+    apub: &Self::ApubType,
+    expected_domain: &Url,
+    data: &Self::DataType,
+    _request_counter: &mut i32,
+  ) -> Result<(), LemmyError> {
+    check_is_apub_id_valid(apub.id.inner(), true, &data.settings())?;
+    verify_domains_match(expected_domain, apub.id.inner())?;
+
+    let slur_regex = &data.settings().slur_regex();
+    check_slurs(&apub.name, slur_regex)?;
+    check_slurs_opt(&apub.summary, slur_regex)?;
+    Ok(())
+  }
+
+  #[tracing::instrument(skip_all)]
+  async fn from_apub(
+    apub: Self::ApubType,
+    data: &Self::DataType,
+    _request_counter: &mut i32,
+  ) -> Result<Self, LemmyError> {
+    let site_form = SiteForm {
+      name: apub.name.clone(),
+      sidebar: Some(get_summary_from_string_or_source(
+        &apub.content,
+        &apub.source,
+      )),
+      updated: apub.updated.map(|u| u.clone().naive_local()),
+      icon: Some(apub.icon.clone().map(|i| i.url.into())),
+      banner: Some(apub.image.clone().map(|i| i.url.into())),
+      description: Some(apub.summary.clone()),
+      actor_id: Some(apub.id.clone().into()),
+      last_refreshed_at: Some(naive_now()),
+      inbox_url: Some(apub.inbox.clone().into()),
+      public_key: Some(apub.public_key.public_key_pem.clone()),
+      ..SiteForm::default()
+    };
+    let site = blocking(data.pool(), move |conn| Site::upsert(conn, &site_form)).await??;
+    Ok(site.into())
+  }
+}
+
+impl ActorType for ApubSite {
+  fn actor_id(&self) -> Url {
+    self.actor_id.to_owned().into()
+  }
+  fn public_key(&self) -> String {
+    self.public_key.to_owned()
+  }
+  fn private_key(&self) -> Option<String> {
+    self.private_key.to_owned()
+  }
+
+  fn inbox_url(&self) -> Url {
+    self.inbox_url.clone().into()
+  }
+
+  fn shared_inbox_url(&self) -> Option<Url> {
+    None
+  }
+}
+
+/// Instance actor is at the root path, so we simply need to clear the path and other unnecessary
+/// parts of the url.
+pub fn instance_actor_id_from_url(mut url: Url) -> Url {
+  url.set_fragment(None);
+  url.set_path("");
+  url.set_query(None);
+  url
+}
+
+#[cfg(test)]
+pub(crate) mod tests {
+  use super::*;
+  use crate::objects::tests::{file_to_json_object, init_context};
+  use lemmy_apub_lib::activity_queue::create_activity_queue;
+  use lemmy_db_schema::traits::Crud;
+  use serial_test::serial;
+
+  pub(crate) async fn parse_lemmy_instance(context: &LemmyContext) -> ApubSite {
+    let json: Instance = file_to_json_object("assets/lemmy/objects/instance.json").unwrap();
+    let id = Url::parse("https://enterprise.lemmy.ml/").unwrap();
+    let mut request_counter = 0;
+    ApubSite::verify(&json, &id, context, &mut request_counter)
+      .await
+      .unwrap();
+    let site = ApubSite::from_apub(json, context, &mut request_counter)
+      .await
+      .unwrap();
+    assert_eq!(request_counter, 0);
+    site
+  }
+
+  #[actix_rt::test]
+  #[serial]
+  async fn test_parse_lemmy_instance() {
+    let client = reqwest::Client::new().into();
+    let manager = create_activity_queue(client);
+    let context = init_context(manager.queue_handle().clone());
+    let site = parse_lemmy_instance(&context).await;
+
+    assert_eq!(site.name, "Enterprise");
+    assert_eq!(site.description.as_ref().unwrap().len(), 15);
+
+    Site::delete(&*context.pool().get().unwrap(), site.id).unwrap();
+  }
+}
diff --git a/crates/apub/src/objects/mod.rs b/crates/apub/src/objects/mod.rs
index b5a4760d6..d7e386b10 100644
--- a/crates/apub/src/objects/mod.rs
+++ b/crates/apub/src/objects/mod.rs
@@ -3,6 +3,7 @@ use html2md::parse_html;
 
 pub mod comment;
 pub mod community;
+pub mod instance;
 pub mod person;
 pub mod post;
 pub mod private_message;
diff --git a/crates/apub/src/objects/person.rs b/crates/apub/src/objects/person.rs
index 21f0f248c..14245acf7 100644
--- a/crates/apub/src/objects/person.rs
+++ b/crates/apub/src/objects/person.rs
@@ -16,7 +16,6 @@ use lemmy_api_common::blocking;
 use lemmy_apub_lib::{
   object_id::ObjectId,
   traits::{ActorType, ApubObject},
-  values::MediaTypeMarkdown,
   verify::verify_domains_match,
 };
 use lemmy_db_schema::{
@@ -88,12 +87,6 @@ impl ApubObject for ApubPerson {
     } else {
       UserTypes::Person
     };
-    let source = self.bio.clone().map(|bio| Source {
-      content: bio,
-      media_type: MediaTypeMarkdown::Markdown,
-    });
-    let icon = self.avatar.clone().map(ImageObject::new);
-    let image = self.banner.clone().map(ImageObject::new);
 
     let person = Person {
       kind,
@@ -101,9 +94,9 @@ impl ApubObject for ApubPerson {
       preferred_username: self.name.clone(),
       name: self.display_name.clone(),
       summary: self.bio.as_ref().map(|b| markdown_to_html(b)),
-      source,
-      icon,
-      image,
+      source: self.bio.clone().map(Source::new),
+      icon: self.avatar.clone().map(ImageObject::new),
+      image: self.banner.clone().map(ImageObject::new),
       matrix_user_id: self.matrix_user_id.clone(),
       published: Some(convert_datetime(self.published)),
       outbox: generate_outbox_url(&self.actor_id)?.into(),
diff --git a/crates/apub/src/objects/post.rs b/crates/apub/src/objects/post.rs
index e4206080a..233d43951 100644
--- a/crates/apub/src/objects/post.rs
+++ b/crates/apub/src/objects/post.rs
@@ -209,11 +209,13 @@ mod tests {
   use super::*;
   use crate::objects::{
     community::tests::parse_lemmy_community,
+    instance::tests::parse_lemmy_instance,
     person::tests::parse_lemmy_person,
     post::ApubPost,
     tests::{file_to_json_object, init_context},
   };
   use lemmy_apub_lib::activity_queue::create_activity_queue;
+  use lemmy_db_schema::source::site::Site;
   use serial_test::serial;
 
   #[actix_rt::test]
@@ -222,6 +224,7 @@ mod tests {
     let client = reqwest::Client::new().into();
     let manager = create_activity_queue(client);
     let context = init_context(manager.queue_handle().clone());
+    let site = parse_lemmy_instance(&context).await;
     let community = parse_lemmy_community(&context).await;
     let person = parse_lemmy_person(&context).await;
 
@@ -246,5 +249,6 @@ mod tests {
     Post::delete(&*context.pool().get().unwrap(), post.id).unwrap();
     Person::delete(&*context.pool().get().unwrap(), person.id).unwrap();
     Community::delete(&*context.pool().get().unwrap(), community.id).unwrap();
+    Site::delete(&*context.pool().get().unwrap(), site.id).unwrap();
   }
 }
diff --git a/crates/apub/src/objects/private_message.rs b/crates/apub/src/objects/private_message.rs
index 176ee009e..62af38553 100644
--- a/crates/apub/src/objects/private_message.rs
+++ b/crates/apub/src/objects/private_message.rs
@@ -8,7 +8,7 @@ use lemmy_api_common::blocking;
 use lemmy_apub_lib::{
   object_id::ObjectId,
   traits::ApubObject,
-  values::{MediaTypeHtml, MediaTypeMarkdown},
+  values::MediaTypeHtml,
   verify::verify_domains_match,
 };
 use lemmy_db_schema::{
@@ -87,10 +87,7 @@ impl ApubObject for ApubPrivateMessage {
       to: [ObjectId::new(recipient.actor_id)],
       content: markdown_to_html(&self.content),
       media_type: Some(MediaTypeHtml::Html),
-      source: Some(Source {
-        content: self.content.clone(),
-        media_type: MediaTypeMarkdown::Markdown,
-      }),
+      source: Some(Source::new(self.content.clone())),
       published: Some(convert_datetime(self.published)),
       updated: self.updated.map(convert_datetime),
       unparsed: Default::default(),
diff --git a/crates/apub/src/protocol/collections/person_outbox.rs b/crates/apub/src/protocol/collections/empty_outbox.rs
similarity index 60%
rename from crates/apub/src/protocol/collections/person_outbox.rs
rename to crates/apub/src/protocol/collections/empty_outbox.rs
index e616794c6..265575af4 100644
--- a/crates/apub/src/protocol/collections/person_outbox.rs
+++ b/crates/apub/src/protocol/collections/empty_outbox.rs
@@ -1,24 +1,23 @@
-use crate::generate_outbox_url;
 use activitystreams_kinds::collection::OrderedCollectionType;
-use lemmy_db_schema::source::person::Person;
 use lemmy_utils::LemmyError;
 use serde::{Deserialize, Serialize};
 use url::Url;
 
+/// Empty placeholder outbox used for Person, Instance, which dont implement a proper outbox yet.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
-pub(crate) struct PersonOutbox {
+pub(crate) struct EmptyOutbox {
   r#type: OrderedCollectionType,
   id: Url,
   ordered_items: Vec<()>,
   total_items: i32,
 }
 
-impl PersonOutbox {
-  pub(crate) async fn new(user: Person) -> Result<PersonOutbox, LemmyError> {
-    Ok(PersonOutbox {
+impl EmptyOutbox {
+  pub(crate) async fn new(outbox_id: Url) -> Result<EmptyOutbox, LemmyError> {
+    Ok(EmptyOutbox {
       r#type: OrderedCollectionType::OrderedCollection,
-      id: generate_outbox_url(&user.actor_id)?.into(),
+      id: outbox_id,
       ordered_items: vec![],
       total_items: 0,
     })
diff --git a/crates/apub/src/protocol/collections/mod.rs b/crates/apub/src/protocol/collections/mod.rs
index 183052be6..f34dd1d10 100644
--- a/crates/apub/src/protocol/collections/mod.rs
+++ b/crates/apub/src/protocol/collections/mod.rs
@@ -1,16 +1,16 @@
+pub(crate) mod empty_outbox;
 pub(crate) mod group_followers;
 pub(crate) mod group_moderators;
 pub(crate) mod group_outbox;
-pub(crate) mod person_outbox;
 
 #[cfg(test)]
 mod tests {
   use crate::protocol::{
     collections::{
+      empty_outbox::EmptyOutbox,
       group_followers::GroupFollowers,
       group_moderators::GroupModerators,
       group_outbox::GroupOutbox,
-      person_outbox::PersonOutbox,
     },
     tests::test_parse_lemmy_item,
   };
@@ -24,6 +24,6 @@ mod tests {
     assert_eq!(outbox.ordered_items.len() as i32, outbox.total_items);
     test_parse_lemmy_item::<GroupModerators>("assets/lemmy/collections/group_moderators.json")
       .unwrap();
-    test_parse_lemmy_item::<PersonOutbox>("assets/lemmy/collections/person_outbox.json").unwrap();
+    test_parse_lemmy_item::<EmptyOutbox>("assets/lemmy/collections/person_outbox.json").unwrap();
   }
 }
diff --git a/crates/apub/src/protocol/mod.rs b/crates/apub/src/protocol/mod.rs
index 4b3992fdd..d1532a952 100644
--- a/crates/apub/src/protocol/mod.rs
+++ b/crates/apub/src/protocol/mod.rs
@@ -17,6 +17,15 @@ pub struct Source {
   pub(crate) media_type: MediaTypeMarkdown,
 }
 
+impl Source {
+  pub(crate) fn new(content: String) -> Self {
+    Source {
+      content,
+      media_type: MediaTypeMarkdown::Markdown,
+    }
+  }
+}
+
 #[derive(Clone, Debug, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct ImageObject {
diff --git a/crates/apub/src/protocol/objects/instance.rs b/crates/apub/src/protocol/objects/instance.rs
new file mode 100644
index 000000000..2a967ac52
--- /dev/null
+++ b/crates/apub/src/protocol/objects/instance.rs
@@ -0,0 +1,39 @@
+use crate::{
+  objects::instance::ApubSite,
+  protocol::{ImageObject, Source, Unparsed},
+};
+use activitystreams_kinds::actor::ServiceType;
+use chrono::{DateTime, FixedOffset};
+use lemmy_apub_lib::{object_id::ObjectId, signatures::PublicKey, values::MediaTypeHtml};
+use serde::{Deserialize, Serialize};
+use serde_with::skip_serializing_none;
+use url::Url;
+
+#[skip_serializing_none]
+#[derive(Clone, Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Instance {
+  #[serde(rename = "type")]
+  pub(crate) kind: ServiceType,
+  pub(crate) id: ObjectId<ApubSite>,
+  // site name
+  pub(crate) name: String,
+  // sidebar
+  pub(crate) content: Option<String>,
+  pub(crate) source: Option<Source>,
+  // short instance description
+  pub(crate) summary: Option<String>,
+  pub(crate) media_type: Option<MediaTypeHtml>,
+  /// instance icon
+  pub(crate) icon: Option<ImageObject>,
+  /// instance banner
+  pub(crate) image: Option<ImageObject>,
+  pub(crate) inbox: Url,
+  /// mandatory field in activitypub, currently empty in lemmy
+  pub(crate) outbox: Url,
+  pub(crate) public_key: PublicKey,
+  pub(crate) published: DateTime<FixedOffset>,
+  pub(crate) updated: Option<DateTime<FixedOffset>>,
+  #[serde(flatten)]
+  pub(crate) unparsed: Unparsed,
+}
diff --git a/crates/apub/src/protocol/objects/mod.rs b/crates/apub/src/protocol/objects/mod.rs
index 2367b6863..20aaca181 100644
--- a/crates/apub/src/protocol/objects/mod.rs
+++ b/crates/apub/src/protocol/objects/mod.rs
@@ -3,6 +3,7 @@ use url::Url;
 
 pub(crate) mod chat_message;
 pub(crate) mod group;
+pub(crate) mod instance;
 pub(crate) mod note;
 pub(crate) mod page;
 pub(crate) mod person;
@@ -23,6 +24,7 @@ mod tests {
       objects::{
         chat_message::ChatMessage,
         group::Group,
+        instance::Instance,
         note::Note,
         page::Page,
         person::Person,
@@ -33,9 +35,10 @@ mod tests {
   };
 
   #[actix_rt::test]
-  async fn test_parse_object_lemmy() {
-    test_parse_lemmy_item::<Person>("assets/lemmy/objects/person.json").unwrap();
+  async fn test_parse_objects_lemmy() {
+    test_parse_lemmy_item::<Instance>("assets/lemmy/objects/instance.json").unwrap();
     test_parse_lemmy_item::<Group>("assets/lemmy/objects/group.json").unwrap();
+    test_parse_lemmy_item::<Person>("assets/lemmy/objects/person.json").unwrap();
     test_parse_lemmy_item::<Page>("assets/lemmy/objects/page.json").unwrap();
     test_parse_lemmy_item::<Note>("assets/lemmy/objects/note.json").unwrap();
     test_parse_lemmy_item::<ChatMessage>("assets/lemmy/objects/chat_message.json").unwrap();
@@ -43,7 +46,7 @@ mod tests {
   }
 
   #[actix_rt::test]
-  async fn test_parse_object_pleroma() {
+  async fn test_parse_objects_pleroma() {
     file_to_json_object::<WithContext<Person>>("assets/pleroma/objects/person.json").unwrap();
     file_to_json_object::<WithContext<Note>>("assets/pleroma/objects/note.json").unwrap();
     file_to_json_object::<WithContext<ChatMessage>>("assets/pleroma/objects/chat_message.json")
@@ -51,19 +54,19 @@ mod tests {
   }
 
   #[actix_rt::test]
-  async fn test_parse_object_smithereen() {
+  async fn test_parse_objects_smithereen() {
     file_to_json_object::<WithContext<Person>>("assets/smithereen/objects/person.json").unwrap();
     file_to_json_object::<Note>("assets/smithereen/objects/note.json").unwrap();
   }
 
   #[actix_rt::test]
-  async fn test_parse_object_mastodon() {
+  async fn test_parse_objects_mastodon() {
     file_to_json_object::<WithContext<Person>>("assets/mastodon/objects/person.json").unwrap();
     file_to_json_object::<WithContext<Note>>("assets/mastodon/objects/note.json").unwrap();
   }
 
   #[actix_rt::test]
-  async fn test_parse_object_lotide() {
+  async fn test_parse_objects_lotide() {
     file_to_json_object::<WithContext<Group>>("assets/lotide/objects/group.json").unwrap();
     file_to_json_object::<WithContext<Person>>("assets/lotide/objects/person.json").unwrap();
     file_to_json_object::<WithContext<Note>>("assets/lotide/objects/note.json").unwrap();
diff --git a/crates/db_schema/src/aggregates/site_aggregates.rs b/crates/db_schema/src/aggregates/site_aggregates.rs
index b94899247..58dfe0b01 100644
--- a/crates/db_schema/src/aggregates/site_aggregates.rs
+++ b/crates/db_schema/src/aggregates/site_aggregates.rs
@@ -55,19 +55,7 @@ mod tests {
 
     let site_form = SiteForm {
       name: "test_site".into(),
-      sidebar: None,
-      description: None,
-      icon: None,
-      banner: None,
-      enable_downvotes: None,
-      open_registration: None,
-      enable_nsfw: None,
-      updated: None,
-      community_creation_admin_only: Some(false),
-      require_email_verification: None,
-      require_application: None,
-      application_question: None,
-      private_instance: None,
+      ..Default::default()
     };
 
     Site::create(&conn, &site_form).unwrap();
@@ -136,7 +124,8 @@ mod tests {
     let after_delete_creator = SiteAggregates::read(&conn);
     assert!(after_delete_creator.is_ok());
 
-    Site::delete(&conn, 1).unwrap();
+    let site_id = after_delete_creator.unwrap().id;
+    Site::delete(&conn, site_id).unwrap();
     let after_delete_site = SiteAggregates::read(&conn);
     assert!(after_delete_site.is_err());
   }
diff --git a/crates/db_schema/src/impls/site.rs b/crates/db_schema/src/impls/site.rs
index 8a84bdfbb..d38ef9715 100644
--- a/crates/db_schema/src/impls/site.rs
+++ b/crates/db_schema/src/impls/site.rs
@@ -1,5 +1,6 @@
-use crate::{source::site::*, traits::Crud};
+use crate::{source::site::*, traits::Crud, DbUrl};
 use diesel::{dsl::*, result::Error, *};
+use url::Url;
 
 impl Crud for Site {
   type Form = SiteForm;
@@ -27,8 +28,30 @@ impl Crud for Site {
 }
 
 impl Site {
-  pub fn read_simple(conn: &PgConnection) -> Result<Self, Error> {
+  pub fn read_local_site(conn: &PgConnection) -> Result<Self, Error> {
     use crate::schema::site::dsl::*;
-    site.first::<Self>(conn)
+    site.order_by(id).first::<Self>(conn)
+  }
+
+  pub fn upsert(conn: &PgConnection, site_form: &SiteForm) -> Result<Site, Error> {
+    use crate::schema::site::dsl::*;
+    insert_into(site)
+      .values(site_form)
+      .on_conflict(actor_id)
+      .do_update()
+      .set(site_form)
+      .get_result::<Self>(conn)
+  }
+
+  pub fn read_from_apub_id(conn: &PgConnection, object_id: Url) -> Result<Option<Self>, Error> {
+    use crate::schema::site::dsl::*;
+    let object_id: DbUrl = object_id.into();
+    Ok(
+      site
+        .filter(actor_id.eq(object_id))
+        .first::<Site>(conn)
+        .ok()
+        .map(Into::into),
+    )
   }
 }
diff --git a/crates/db_schema/src/schema.rs b/crates/db_schema/src/schema.rs
index 681452d9f..b93cd4e72 100644
--- a/crates/db_schema/src/schema.rs
+++ b/crates/db_schema/src/schema.rs
@@ -454,6 +454,11 @@ table! {
         require_application -> Bool,
         application_question -> Nullable<Text>,
         private_instance -> Bool,
+        actor_id -> Text,
+        last_refreshed_at -> Timestamp,
+        inbox_url -> Text,
+        private_key -> Nullable<Text>,
+        public_key -> Text,
     }
 }
 
diff --git a/crates/db_schema/src/source/site.rs b/crates/db_schema/src/source/site.rs
index 01c5bc16e..25bed1c24 100644
--- a/crates/db_schema/src/source/site.rs
+++ b/crates/db_schema/src/source/site.rs
@@ -20,6 +20,11 @@ pub struct Site {
   pub require_application: bool,
   pub application_question: Option<String>,
   pub private_instance: bool,
+  pub actor_id: DbUrl,
+  pub last_refreshed_at: chrono::NaiveDateTime,
+  pub inbox_url: DbUrl,
+  pub private_key: Option<String>,
+  pub public_key: String,
 }
 
 #[derive(Insertable, AsChangeset, Default)]
@@ -40,4 +45,9 @@ pub struct SiteForm {
   pub require_application: Option<bool>,
   pub application_question: Option<Option<String>>,
   pub private_instance: Option<bool>,
+  pub actor_id: Option<DbUrl>,
+  pub last_refreshed_at: Option<chrono::NaiveDateTime>,
+  pub inbox_url: Option<DbUrl>,
+  pub private_key: Option<Option<String>>,
+  pub public_key: Option<String>,
 }
diff --git a/migrations/2022-01-28-104106_instance-actor/down.sql b/migrations/2022-01-28-104106_instance-actor/down.sql
new file mode 100644
index 000000000..a258c27a4
--- /dev/null
+++ b/migrations/2022-01-28-104106_instance-actor/down.sql
@@ -0,0 +1,6 @@
+alter table site
+    drop column actor_id,
+    drop column last_refreshed_at,
+    drop column inbox_url,
+    drop column private_key,
+    drop column public_key;
diff --git a/migrations/2022-01-28-104106_instance-actor/up.sql b/migrations/2022-01-28-104106_instance-actor/up.sql
new file mode 100644
index 000000000..914ab757e
--- /dev/null
+++ b/migrations/2022-01-28-104106_instance-actor/up.sql
@@ -0,0 +1,6 @@
+alter table site
+    add column actor_id varchar(255) not null unique default generate_unique_changeme(),
+    add column last_refreshed_at Timestamp not null default now(),
+    add column inbox_url varchar(255) not null default generate_unique_changeme(),
+    add column private_key text,
+    add column public_key text not null default generate_unique_changeme();
diff --git a/src/code_migrations.rs b/src/code_migrations.rs
index 4737066bb..07a969ec5 100644
--- a/src/code_migrations.rs
+++ b/src/code_migrations.rs
@@ -18,11 +18,13 @@ use lemmy_db_schema::{
     person::{Person, PersonForm},
     post::Post,
     private_message::PrivateMessage,
+    site::{Site, SiteForm},
   },
   traits::Crud,
 };
 use lemmy_utils::{apub::generate_actor_keypair, LemmyError};
 use tracing::info;
+use url::Url;
 
 pub fn run_advanced_migrations(
   conn: &PgConnection,
@@ -35,6 +37,7 @@ pub fn run_advanced_migrations(
   private_message_updates_2020_05_05(conn, protocol_and_hostname)?;
   post_thumbnail_url_updates_2020_07_27(conn, protocol_and_hostname)?;
   apub_columns_2021_02_02(conn)?;
+  instance_actor_2022_01_28(conn, protocol_and_hostname)?;
 
   Ok(())
 }
@@ -284,3 +287,29 @@ fn apub_columns_2021_02_02(conn: &PgConnection) -> Result<(), LemmyError> {
 
   Ok(())
 }
+
+/// Site object turns into an actor, so that things like instance description can be federated. This
+/// means we need to add actor columns to the site table, and initialize them with correct values.
+/// Before this point, there is only a single value in the site table which refers to the local
+/// Lemmy instance, so thats all we need to update.
+fn instance_actor_2022_01_28(
+  conn: &PgConnection,
+  protocol_and_hostname: &str,
+) -> Result<(), LemmyError> {
+  info!("Running instance_actor_2021_09_29");
+  if let Ok(site) = Site::read_local_site(conn) {
+    let key_pair = generate_actor_keypair()?;
+    let actor_id = Url::parse(protocol_and_hostname)?;
+    let site_form = SiteForm {
+      name: site.name,
+      actor_id: Some(actor_id.clone().into()),
+      last_refreshed_at: Some(naive_now()),
+      inbox_url: Some(generate_inbox_url(&actor_id.into())?),
+      private_key: Some(Some(key_pair.private_key)),
+      public_key: Some(key_pair.public_key),
+      ..Default::default()
+    };
+    Site::update(conn, site.id, &site_form)?;
+  }
+  Ok(())
+}