message: Check for .json extension in a non-allocating way
diff: @@ -43,7 +43,7 @@ pub fn build_list_handler(req: &mut Request) -> IronResult<Response> {
  let mut conn = extension!(req, Pool).get()?;
  let limits = ctry!(req, Limits::for_crate(&mut conn, name));
  - let is_json = req.url.path().join("/").ends_with(".json");
  + let is_json = req.url.path().last().map_or(false, |segment| segment.ends_with(".json"));
  let version =
  match match_version(&mut conn, name, req_version).and_then(|m| m.assume_exact())? {
  