diff --git a/src/federation/activities/accept.rs b/src/federation/activities/accept.rs
index 7b8aa6b..9dc6b11 100644
--- a/src/federation/activities/accept.rs
+++ b/src/federation/activities/accept.rs
@@ -20,7 +20,7 @@ pub struct Accept {
 
 impl Accept {
     pub fn new(actor: ObjectId<DbInstance>, object: Follow) -> MyResult<Accept> {
-        let id = generate_object_id(actor.inner().domain().unwrap())?;
+        let id = generate_object_id(actor.inner())?;
         Ok(Accept {
             actor,
             object,
diff --git a/src/federation/activities/follow.rs b/src/federation/activities/follow.rs
index 90d5089..07fc85f 100644
--- a/src/federation/activities/follow.rs
+++ b/src/federation/activities/follow.rs
@@ -22,7 +22,7 @@ pub struct Follow {
 
 impl Follow {
     pub fn new(actor: ObjectId<DbInstance>, object: ObjectId<DbInstance>) -> MyResult<Follow> {
-        let id = generate_object_id(actor.inner().domain().unwrap())?;
+        let id = generate_object_id(actor.inner())?;
         Ok(Follow {
             actor,
             object,
diff --git a/src/federation/activities/update.rs b/src/federation/activities/update.rs
index ebba508..29ae0fa 100644
--- a/src/federation/activities/update.rs
+++ b/src/federation/activities/update.rs
@@ -25,7 +25,7 @@ pub struct Update {
 
 impl Update {
     pub fn new(actor: ObjectId<DbUser>, object: ObjectId<DbArticle>) -> MyResult<Update> {
-        let id = generate_object_id(actor.inner().domain().unwrap())?;
+        let id = generate_object_id(actor.inner())?;
         Ok(Update {
             actor,
             object,
diff --git a/src/federation/objects/article.rs b/src/federation/objects/article.rs
index 0598327..83fb7b8 100644
--- a/src/federation/objects/article.rs
+++ b/src/federation/objects/article.rs
@@ -21,7 +21,7 @@ pub struct DbArticle {
 
 impl DbArticle {
     pub fn new(text: String, attributed_to: ObjectId<DbInstance>) -> Result<DbArticle, Error> {
-        let ap_id = generate_object_id(attributed_to.inner().domain().unwrap())?.into();
+        let ap_id = generate_object_id(attributed_to.inner())?.into();
         Ok(DbArticle {
             text,
             ap_id,
diff --git a/src/utils.rs b/src/utils.rs
index 6b5f9d0..dc21bf5 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -3,7 +3,8 @@ use url::{ParseError, Url};
 
 /// Just generate random url as object id. In a real project, you probably want to use
 /// an url which contains the database id for easy retrieval (or store the random id in db).
-pub fn generate_object_id(domain: &str) -> Result<Url, ParseError> {
+pub fn generate_object_id(domain: &Url) -> Result<Url, ParseError> {
+    let domain = domain.domain().unwrap();
     let id: String = thread_rng()
         .sample_iter(&Alphanumeric)
         .take(7)