+ case get_pagination_fields(conn, activities, extra_params) do
+ %{"next" => next_url, "prev" => prev_url} ->
+ put_resp_header(conn, "link", "<#{next_url}>; rel=\"next\", <#{prev_url}>; rel=\"prev\"")
+
+ _ ->
+ conn
+ end
+ end
+
+ @id_keys Pagination.page_keys() -- ["limit", "order"]
+ defp build_pagination_fields(conn, min_id, max_id, extra_params) do
+ params =
+ conn.params
+ |> Map.drop(Map.keys(conn.path_params))
+ |> Map.merge(extra_params)
+ |> Map.drop(Pagination.page_keys() -- ["limit", "order"])
+
+ fields = %{
+ "next" => current_url(conn, Map.put(params, :max_id, max_id)),
+ "prev" => current_url(conn, Map.put(params, :min_id, min_id))
+ }
+
+ # Generating an `id` without already present pagination keys would
+ # need a query-restriction with an `q.id >= ^id` or `q.id <= ^id`
+ # instead of the `q.id > ^min_id` and `q.id < ^max_id`.
+ # This is because we only have ids present inside of the page, while
+ # `min_id`, `since_id` and `max_id` requires to know one outside of it.
+ if Map.take(conn.params, Pagination.page_keys() -- ["limit", "order"]) != [] do
+ Map.put(fields, "id", current_url(conn, conn.params))
+ else
+ fields
+ end
+ end
+
+ def get_pagination_fields(conn, activities, extra_params \\ %{}) do