Convert the mod-lisp headers to lowercase

HTTP headers are expected to be treated case-insensitively.

tekuti/mod-lisp.scm

@@ -45,7 +45,8 @@
     (let ((k (read-line*)))
       (if (string=? k "end")
           (reverse (map cons keys values))
-          (lp (cons k keys) (cons (read-line*) values))))))
+          (lp (cons (string-downcase k) keys)
+              (cons (read-line*) values))))))
 
 (define (read-chars nchars port)
   (let ((buf (make-string nchars)))

tekuti/page.scm

@@ -308,7 +308,7 @@
         (server-name (request-server-name request)))
     (cond
      ((let ((since (assoc-ref (rref request 'headers '())
-                              "If-Modified-Since")))
+                              "if-modified-since")))
         (and since (>= (rfc822-date->timestamp since) last-modified)))
       (rcons* request
               'status 304

tekuti/request.scm

@@ -118,7 +118,7 @@
 ;; danger here, regarding the optional alternate clauses...
 (define (request-authenticated? request)
   (let ((headers (rref request 'headers '())))
-    (let ((auth (assoc-ref headers "Authorization")))
+    (let ((auth (assoc-ref headers "authorization")))
       (and auth
            (match-bind "^Basic ([A-Za-z0-9+/=]*)$" auth (_ b64)
                        (match-bind "^([^:]*):(.*)$"
@@ -193,7 +193,7 @@
 
 (define (request-server-name request)
   (let ((headers (rref request 'headers)))
-    (or (assoc-ref headers "Host")
+    (or (assoc-ref headers "host")
         (assoc-ref headers "server-ip-addr"))))