Add :field to :store option in ring.middleware.multipart-params

It would be nice to also have the field name passed to the :store function, like so:

(defn- parse-file-item
  "Parse a FileItemStream into a key-value pair. If the request is a file the
  supplied store function is used to save it."
  [^FileItemStream item store encoding]
  [(.getFieldName item)
   (if (.isFormField item)
     (Streams/asString (.openStream item) encoding)
     (store {:filename     (.getName item)
             :field        (.getFieldName item)
             :content-type (.getContentType item)
             :stream       (.openStream item)}))])

This way different logic can be applied depending on the field.

Thanks

Locate the parse-file-item function in ring.middleware.multipart-params and read how its store callback is currently invoked. Update the behavior so the callback receives the field name as shown in the issue, then verify that field-specific storage logic works without changing ordinary form-field parsing.