From 6789074d4fb6f46abdb77f5957620745337e7e2c Mon Sep 17 00:00:00 2001
From: w6vvn <vivienne@w6vvn.net>
Date: Fri, 5 Sep 2025 17:24:02 -0700
Subject: [PATCH] complete response handling

---
 gem300.rkt | 85 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 23 deletions(-)

diff --git a/gem300.rkt b/gem300.rkt
index ca9be90..3bc571b 100644
--- a/gem300.rkt
+++ b/gem300.rkt
@@ -15,6 +15,20 @@
 ;; global state for the url of the currently visited document
 (define current-url null)
 
+(define temporary-failures
+  '((40 . "temporary failure")
+    (41 . "server unavailable")
+    (42 . "CGI error")
+    (43 . "proxy error")
+    (44 . "slow down")))
+
+(define permanent-failures
+  '((50 . "permanent failure")
+    (51 . "not found")
+    (52 . "gone")
+    (53 . "proxy request refused")
+    (59 . "bad request")))
+
 (define (get url-str)
   (define (iter url-str depth)
     (let-values ([(status header c-in) (net:request url-str)])
@@ -24,19 +38,59 @@
         ;; clients MUST reject status codes outside of the 10-69 range
         [(or (< status 10)
              (> status 69))
-         (error "server returned invalid status code")]
+         (displayln "WARNING: server returned invalid status code")]
 
-        ;; 30-39 redirection
+        ;; 10-19 INPUT REQUIRED
+        [(and (>= status 10)
+              (<= status 19))
+         (display "input requested > ")
+         (get (string-append url-str "?" (read-line)))]
+
+        ;; 20-29 SUCCESS
+        [(and (>= status 20)
+              (<= status 29))
+
+         (let-values ([(doc) (gmi:parse (port->lines c-in))]
+                      [(db-in db-out) (make-pipe #f)])
+
+           (set! document doc)
+
+           (set! document-buffer db-in)
+           (parameterize ([current-output-port db-out])
+             (gmi:render doc))
+
+           (set! current-url url-str)
+
+           (let ([remaining (pipe-content-length db-in)])
+             (printf "document retrieved. ~a bytes\n" remaining))
+
+           (next-cmd))]
+
+        ;; 30-39 REDIRECT
         [(and (>= status 30)
               (<= status 39))
          (if (> depth 5)
-             (error "maximum redirection depth exceeded")
+             (displayln "WARNING: maximum redirection depth exceeded")
              (iter header (sub1 depth)))]
 
-        [else
-         (values status header c-in)])))
+        ;; 40-49 TEMPORARY FAILURE
+        [(and (>= status 40)
+              (<= status 49))
+         (printf "status ~a: ~a\n" status
+                 (dict-ref temporary-failures status "temporary failure"))]
 
-     (iter url-str 5))
+        ;; 50-59 PERMANENT FAILURE
+        [(and (>= status 50)
+              (<= status 59))
+         (printf "status ~a: ~a\n" status
+                 (dict-ref permanent-failures status "permanent failure"))]
+
+        ;; 60-69 CERTIFICATE REQUIRED
+        [(and (>= status 60)
+              (<= status 69))
+         (displayln "certificate handling not yet implemented")])))
+
+    (iter url-str 5))
 
 (define (go-cmd url)
   (if (non-empty-string? url)
@@ -44,22 +98,7 @@
         (when (not (string-contains? url "://"))
           (set! url (string-append "gemini://" url)))
 
-        (let-values ([(status meta c-in) (get url)])
-          (let-values ([(doc) (gmi:parse (port->lines c-in))]
-                       [(db-in db-out) (make-pipe #f)])
-
-            (set! document doc)
-
-            (set! document-buffer db-in)
-            (parameterize ([current-output-port db-out])
-              (gmi:render doc))
-
-            (set! current-url url)
-
-            (let ([remaining (pipe-content-length db-in)])
-              (printf "document retrieved. ~a bytes\n" remaining))
-
-            (next-cmd))))
+        (get url))
 
       (displayln "go where?")))
 
@@ -81,7 +120,7 @@
   (set! url
         (url->string (combine-url/relative (string->url current-url)
                                            url)))
-  (go-cmd url))
+  (get url))
 
 (define (repl)
   (display "G-300 > ")