Tweaks after review 6

- Only catch InvalidFileNameException.
- Test for InvalidFileNameException instead of Throwable.
- Add CPS style arities to default-invalid-filename-handler
- Add the exception to the request, so it's available for the
  invalid-filename-handler.
- Update docstring.
- Update tests.

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

@@ -137,8 +137,11 @@
                  {:multipart-params params}
                  {:params params}))))
 
-(defn default-invalid-filename-handler [request e]
-  (response/bad-request (.getMessage e)))
+(defn default-invalid-filename-handler
+  ([request]
+   (-> request ::invalid-filename-exception .getMessage response/bad-request))
+  ([request respond raise]
+   (respond (default-invalid-filename-handler request))))
 
 (defn wrap-multipart-params
   "Middleware to parse multipart parameters from a request. Adds the following
@@ -172,9 +175,9 @@
     parameters: request, bytes-read, content-length, and item-count.
 
   :invalid-filename-handler
-  - A function that gets called when the file being uploaded has an invalid name.
-    The function should expect two parameters: request and an exception of type
-    InvalidFileNameException. It should return a ring response."
+  - A handler that gets called when the file being uploaded has an invalid name.
+    When this handler receives the request it can expect one additional key,
+    ::invalid-filename-exception, which contains an InvalidFileNameException."
   ([handler]
    (wrap-multipart-params handler {}))
   ([handler options]
@@ -183,14 +186,16 @@
      (fn ([request]
           (let [req-or-ex (try
                             (multipart-params-request request options)
-                            (catch Exception ex ex))]
-            (if (instance? Throwable req-or-ex)
-              (invalid-filename-handler request req-or-ex)
+                            (catch InvalidFileNameException ex ex))]
+            (if (instance? InvalidFileNameException req-or-ex)
+              (invalid-filename-handler
+               (assoc request ::invalid-filename-exception req-or-ex))
               (handler req-or-ex))))
        ([request respond raise]
         (let [req-or-ex (try
                           (multipart-params-request request options)
-                          (catch Exception ex ex))]
-          (if (instance? Throwable req-or-ex)
-            (respond (invalid-filename-handler request req-or-ex))
+                          (catch InvalidFileNameException ex ex))]
+          (if (instance? InvalidFileNameException req-or-ex)
+            (invalid-filename-handler
+             (assoc request ::invalid-filename-exception req-or-ex) respond raise)
             (handler req-or-ex respond raise))))))))

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

@@ -1,6 +1,6 @@
 (ns ring.middleware.test.multipart-params
   (:require [clojure.test :refer :all]
-            [ring.middleware.multipart-params :refer :all]
+            [ring.middleware.multipart-params :refer :all :as multipart-params]
             [ring.middleware.multipart-params.byte-array :refer :all]
             [ring.util.io :refer [string-input-stream]])
   (:import org.apache.commons.fileupload.InvalidFileNameException))
@@ -191,10 +191,10 @@
         invalid-filename-exception
         (try
           (org.apache.commons.fileupload.util.Streams/checkFileName invalid-filename)
-          (catch Exception e
-            e))
+          (catch Exception e e))
         err-response (default-invalid-filename-handler
-                       :unused-arg invalid-filename-exception)]
+                      {::multipart-params/invalid-filename-exception
+                       invalid-filename-exception})]
     (testing "Synchronous error response"
       (let [handler (wrap-multipart-params identity)]
         (is (= err-response (handler request)))))