Add support for GraalVM ResourceURLConnection

ring-core/src/ring/util/response.clj

@@ -289,6 +289,19 @@
  (if-not (zero? last-mod)
  (Date. last-mod))))
 
+(defmethod resource-data :resource
+ [^java.net.URL url]
+ ;; GraalVM creates a resource substitution for regular resources on SubstrateVM
+ ;; @see https://github.com/oracle/graal/blob/db22885e2deb21ff0c1a72314f7b9bb86b7d334c/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/resources/ResourceURLConnection.java#L38
+ ;;
+ ;; Differences between regular URLConnection & ResourceURLConnection:
+ ;; - `resource:` - protocol instead of `jar:` or `file:`
+ ;; - no way of checking if the resource is a directory
+ (let [resource (.openConnection url)]
+ {:content (.getInputStream resource)
+ :content-length (connection-content-length resource)
+ :last-modified (connection-last-modified resource)}))
+
 (defmethod resource-data :jar
  [^java.net.URL url]
  (let [conn (.openConnection url)]