more robust 3xx handling

Signed-off-by: eternal-flame-AD <yume@yumechi.jp>

src/fetch/mod.rs

@@ -350,6 +350,7 @@ pub mod reqwest {
                     ))
                     .await;
                 }
+                return Err(ErrorResponse::missing_location());
             }
 
             if !resp.status().is_success() {
@@ -593,7 +594,7 @@ pub mod cf_worker {
                 .map_err(ErrorResponse::worker_fetch_error))
             .await?;
 
-            if resp.status_code() == 301 || resp.status_code() == 302 {
+            if resp.status_code() >= 300 && resp.status_code() < 400 {
                 if let Ok(Some(location)) = resp.headers().get("location") {
                     return Box::pin(self.request_upstream(
                         info,
@@ -604,6 +605,7 @@ pub mod cf_worker {
                     ))
                     .await;
                 }
+                return Err(ErrorResponse::missing_location());
             }
 
             if resp.status_code() < 200 || resp.status_code() >= 300 {

src/lib.rs

@@ -596,6 +596,14 @@ impl Display for ErrorResponse {
 impl std::error::Error for ErrorResponse {}
 
 impl ErrorResponse {
+    /// Received a redirect without a location
+    #[must_use]
+    pub const fn missing_location() -> Self {
+        Self {
+            status: StatusCode::BAD_GATEWAY,
+            message: Cow::Borrowed("Redirect location missing"),
+        }
+    }
     #[cfg(not(feature = "cf-worker"))]
     /// URL must be a DNS name
     #[must_use]