Return status 400 on invalid file names

The multipart middleware would throw an exception when it encountered an
invalid filename.

For most apps that exception would be caught by the default exception
handler and result in a status code of 500 instead of 400.

This commit catches this specific exception and returns a 400 response
from the server instead.

Author: expez

ring-core/src/ring/middleware/multipart_params.clj

@@ -14,6 +14,7 @@
                                           FileItemIterator
                                           FileItemStream
                                           FileUpload
+                                          InvalidFileNameException
                                           ProgressListener]
            [org.apache.commons.io IOUtils]))
 (defn- progress-listener
@@ -170,6 +171,12 @@
   ([handler options]
    (fn
      ([request]
-      (handler (multipart-params-request request options)))
+      (try
+        (handler (multipart-params-request request options))
+        (catch InvalidFileNameException e
+            {:status 400 :body (.getMessage e)})))
      ([request respond raise]
-      (handler (multipart-params-request request options) respond raise)))))
+      (try
+        (handler (multipart-params-request request options) respond raise)
+        (catch InvalidFileNameException e
+            {:status 400 :body (.getMessage e)}))))))