From a2ac97db98c82b9bdfddcec73fcc84451ffea8aa Mon Sep 17 00:00:00 2001
From: Nutomic <me@nutomic.com>
Date: Tue, 9 Apr 2024 11:28:22 +0200
Subject: [PATCH] Allow fetching from local domain in case it redirects to
 remote (#104)

* Allow fetching from local domain in case it redirects to remote

* clippy

* fix lemmy tests
---
 examples/local_federation/instance.rs |  1 +
 src/fetch/mod.rs                      | 11 ++++++++---
 src/fetch/object_id.rs                | 12 +++---------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/examples/local_federation/instance.rs b/examples/local_federation/instance.rs
index f377f31..ad1fd12 100644
--- a/examples/local_federation/instance.rs
+++ b/examples/local_federation/instance.rs
@@ -28,6 +28,7 @@ pub async fn new_instance(
         .domain(hostname)
         .signed_fetch_actor(&system_user)
         .app_data(database)
+        .url_verifier(Box::new(MyUrlVerifier()))
         .debug(true)
         .build()
         .await?;
diff --git a/src/fetch/mod.rs b/src/fetch/mod.rs
index 13ea16c..4d563b6 100644
--- a/src/fetch/mod.rs
+++ b/src/fetch/mod.rs
@@ -69,10 +69,17 @@ pub async fn fetch_object_http<T: Clone, Kind: DeserializeOwned>(
         return Err(Error::FetchInvalidContentType(res.url));
     }
 
-    // Ensure id field matches final url
+    // Ensure id field matches final url after redirect
     if res.object_id.as_ref() != Some(&res.url) {
         return Err(Error::FetchWrongId(res.url));
     }
+
+    // Dont allow fetching local object. Only check this after the request as a local url
+    // may redirect to a remote object.
+    if data.config.is_local_url(&res.url) {
+        return Err(Error::NotFound);
+    }
+
     Ok(res)
 }
 
@@ -84,8 +91,6 @@ async fn fetch_object_http_with_accept<T: Clone, Kind: DeserializeOwned>(
     content_type: &HeaderValue,
 ) -> Result<FetchObjectResponse<Kind>, Error> {
     let config = &data.config;
-    // dont fetch local objects this way
-    debug_assert!(url.domain() != Some(&config.domain));
     config.verify_url_valid(url).await?;
     info!("Fetching remote object {}", url.to_string());
 
diff --git a/src/fetch/object_id.rs b/src/fetch/object_id.rs
index 061a9f5..50e75bc 100644
--- a/src/fetch/object_id.rs
+++ b/src/fetch/object_id.rs
@@ -88,19 +88,13 @@ where
         <Kind as Object>::Error: From<Error>,
     {
         let db_object = self.dereference_from_db(data).await?;
-        // if its a local object, only fetch it from the database and not over http
-        if data.config.is_local_url(&self.0) {
-            return match db_object {
-                None => Err(Error::NotFound.into()),
-                Some(o) => Ok(o),
-            };
-        }
 
         // object found in database
         if let Some(object) = db_object {
-            // object is old and should be refetched
             if let Some(last_refreshed_at) = object.last_refreshed_at() {
-                if should_refetch_object(last_refreshed_at) {
+                let is_local = data.config.is_local_url(&self.0);
+                if !is_local && should_refetch_object(last_refreshed_at) {
+                    // object is outdated and should be refetched
                     return self.dereference_from_http(data, Some(object)).await;
                 }
             }