implement a procedure to visit documents. NOT compliant, but enough to move on.

gem300.rkt

@@ -17,7 +17,6 @@
                   (car split))
               link-#))))
 
-
 (define (gemtext-parse lines)
   (define (iter document lines state link-#)
     ;; when there are no more lines, we have finished parsing.
@@ -85,6 +84,11 @@
 
   (iter (list) lines 'normal 1))
 
+
+;; sends a request to a gemini server, and returns the status, header,
+;; and the input port for the rest of the body.
+;; this procedure will fail if the response is malformed, however, it
+;; is not up to it to validate the contents of the response.
 (define (request url-str)
   (define url (string->url url-str))
   (define-values (c-in c-out)
@@ -97,10 +101,31 @@
   (define-values (status header)
     (read-response c-in))
 
-  (println status)
+  (values status header c-in))
-  (println header)
 
-  c-in)
+(define (go-cmd url-str)
+  (define (iter url-str depth)
+    (let-values ([(status header c-in) (request url-str)])
+      ;; TODO there are bunch of other status codes to deal with for
+      ;; compliance
+      (cond
+        ;; clients MUST reject status codes outside of the 10-69 range
+        [(or (< status 10)
+             (> status 69))
+         (error "server returned invalid status code")]
+
+        ;; 30-39 redirection
+        [(and (>= status 30)
+              (<= status 39))
+         (if (> depth 5)
+             (error "maximum redirection depth exceeded")
+             (iter header (sub1 depth)))]
+
+        [else
+         (values status header c-in)])))
+
+  (let-values ([(status header c-in) (iter url-str 5)])
+    (render-gemtext (gemtext-parse (port->lines c-in)))))
 
 (define (read-response (c-in (current-input-port)))
   (define maxlen 1027)