fix!: ignore unparseable Range headers instead of returning 400

Per RFC 9110 Section 14.2, a server that receives a Range header it
cannot parse or does not support (unknown range unit, multiple ranges,
malformed values) must ignore the header and serve the full
representation. The axum extractor was previously propagating all parse
errors as rejections, which mapped to 400 Bad Request responses.

Change the extractor to return Ok(None) for any unparseable Range
header, so the server falls back to serving the complete resource.

Author: paolobarbolini

src/headers/range.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "axum")]
+use std::convert::Infallible;
 use std::{
     fmt::{self, Display},
     str::FromStr,
@@ -84,19 +86,26 @@ impl<S> axum_core::extract::OptionalFromRequestParts<S> for HttpRange
 where
     S: Send + Sync,
 {
-    type Rejection = ParseHttpRangeOrContentRangeError;
-
+    type Rejection = Infallible;
+
+    /// Extracts an optional [`HttpRange`] from the request's `Range` header.
+    ///
+    /// Per [RFC 9110 Section 14.2], a server that receives a `Range` header it
+    /// cannot parse or does not support (unknown range unit, multiple ranges,
+    /// malformed values) **must** ignore the header and serve the full
+    /// representation. This extractor returns `Ok(None)` in all such cases
+    /// instead of rejecting the request.
+    ///
+    /// [RFC 9110 Section 14.2]: https://www.rfc-editor.org/rfc/rfc9110#section-14.2
     async fn from_request_parts(
         parts: &mut http::request::Parts,
         _state: &S,
     ) -> Result<Option<Self>, Self::Rejection> {
-        match parts.headers.get(http::header::RANGE) {
-            Some(range) => {
-                let range = HttpRange::try_from(range)?;
-                Ok(Some(range))
-            }
-            None => Ok(None),
-        }
+        let range = parts
+            .headers
+            .get(http::header::RANGE)
+            .and_then(|range| HttpRange::try_from(range).ok());
+        Ok(range)
     }
 }