(defun matching-files (dir regex)
  (when dir
   (let ((files (print (uiop:directory-files dir))))
     (mapcar (lambda (filename)
               (ppcre:scan-to-strings regex (namestring filename)))
             files))))

(defun get-user-photo-by-etri (etri)
  (let* ((photo-dir (rel-path (format nil "static/img/user/~A/" (gethash :etri *session*))))
         (photo (first (matching-files photo-dir  ".*\.([Jj][Pp][Ee]?[Gg]|[Pp][Nn][Gg]|[Ww][Ee][Bb][Pp])"))))
    (and photo (format nil "/img/user/~A/photo-~A.~A" etri etri (pathname-type photo)))))