the exceptions were raising exceptions...

client.rkt

@@ -195,7 +195,9 @@
           (struct-copy
            url
            destination
-           [query `((,(string->symbol (read-line)) . #f))]))]
+           [query `((,(string->symbol
+                       (read-line (current-input-port)
+                                  'any)) . #f))]))]
 
         ;;
         ;; 20-29 SUCCESS
@@ -230,7 +232,7 @@
               'get-document
               (string-append "maximum redirect depth exceeded. "
                              "bailing"))
-             (get-document (string->url meta)
+             (get-document (url->string meta)
                            (add1 redirect-depth)))]
 
         ;;
@@ -243,7 +245,7 @@
                          "  url: ~a~n"
                          "  explanation: ~a~n")
           status
-          (string->url destination)
+          (url->string destination)
           (dict-ref temporary-failures
                     status
                     "temporary failure"))]
@@ -258,7 +260,7 @@
                          "  url: ~a~n"
                          "  explanation: ~a~n")
           status
-          (string->url destination)
+          (url->string destination)
           (dict-ref permanent-failures
                     status
                     "temporary failure"))]
@@ -273,4 +275,4 @@
                          "which this client does not yet support~a~n"
                          "  url: ~a~n"))])
 
-      (next-cmd)))
+      (next-cmd))))