feat: Refactor migration and follow code

migration/src/m20240505_002524_user_follow_relation.rs

@@ -8,7 +8,6 @@ pub struct Migration;
 #[async_trait::async_trait]
 impl MigrationTrait for Migration {
     async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
-
         manager
             .create_table(
                 Table::create()
@@ -21,8 +20,16 @@ impl MigrationTrait for Migration {
                             .auto_increment()
                             .primary_key(),
                     )
-                    .col(ColumnDef::new(FollowRelation::FolloweeId).string().not_null())
+                    .col(
-                    .col(ColumnDef::new(FollowRelation::FollowerId).string().not_null())
+                        ColumnDef::new(FollowRelation::FolloweeId)
+                            .string()
+                            .not_null(),
+                    )
+                    .col(
+                        ColumnDef::new(FollowRelation::FollowerId)
+                            .string()
+                            .not_null(),
+                    )
                     .col(ColumnDef::new(FollowRelation::FolloweeHost).string())
                     .col(ColumnDef::new(FollowRelation::FollowerHost).string())
                     .col(ColumnDef::new(FollowRelation::FolloweeInbox).string())
@@ -62,5 +69,5 @@ enum FollowRelation {
     FolloweeHost,
     FollowerHost,
     FolloweeInbox,
-    FollowerInbox
+    FollowerInbox,
 }

src/activities/follow.rs

@@ -0,0 +1,63 @@
+use activitypub_federation::{config::Data, fetch::object_id::ObjectId, traits::ActivityHandler};
+use activitystreams_kinds::activity::FollowType;
+use sea_orm::{ActiveModelTrait, Set};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+use crate::{
+    database::StateHandle,
+    entities::{follow_relation, prelude::FollowRelation, user},
+    DB,
+};
+
+#[derive(Deserialize, Serialize, Debug)]
+pub struct Follow {
+    actor: ObjectId<user::Model>,
+    object: ObjectId<user::Model>,
+    #[serde(rename = "type")]
+    kind: FollowType,
+    id: Url,
+}
+
+#[async_trait::async_trait]
+impl ActivityHandler for Follow {
+    type DataType = StateHandle;
+    type Error = crate::error::Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn verify(&self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    async fn receive(self, data: &Data<Self::DataType>) -> Result<(), Self::Error> {
+        let local_user = self.object.dereference(data).await?;
+        let follower = self.actor.dereference(data).await?;
+        save_follow(local_user, follower).await?;
+        Ok(())
+    }
+}
+
+async fn save_follow(
+    local_user: user::Model,
+    follower: user::Model,
+) -> Result<(), crate::error::Error> {
+    let url = Url::parse(&follower.url)?;
+    let follow_relation = follow_relation::ActiveModel {
+        followee_id: Set(local_user.id.clone()),
+        follower_id: Set(follower.id.clone()),
+        followee_host: Set(None),
+        follower_host: Set(Some(url.host_str().unwrap().to_string())),
+        followee_inbox: Set(Some(local_user.inbox.clone())),
+        follower_inbox: Set(Some(follower.inbox.clone())),
+        ..Default::default()
+    };
+    follow_relation.insert(DB.get().unwrap()).await?;
+    Ok(())
+}

src/activities/mod.rs

@@ -1 +1,2 @@
 pub mod create_post;
+pub mod follow;

src/entities/mod.rs

@@ -2,6 +2,6 @@
 
 pub mod prelude;
 
+pub mod follow_relation;
 pub mod post;
 pub mod user;
-pub mod follow_relation;

src/objects/person.rs

@@ -1,5 +1,5 @@
 use crate::{
-    activities::create_post::CreatePost,
+    activities::{create_post::CreatePost, follow::Follow},
     database::{State, StateHandle},
     entities::{self, user},
     error::Error,
@@ -40,6 +40,7 @@ pub struct DbUser {
 #[enum_delegate::implement(ActivityHandler)]
 pub enum PersonAcceptedActivities {
     CreateNote(CreatePost),
+    Follow(Follow),
 }
 
 impl DbUser {