change URL-Parser's interface: parser now preserves info whether

Request-URI's path ends with a slash.
(See http://httpd.apache.org/docs-2.0/misc/rewriteguide.html ->
"Trailing slash problem" for reasons).

doc/latex/url.tex

@@ -26,26 +26,35 @@ The \ex{url} module contains procedures to parse and unparse HTTP 1.1 Request-UR
 
   The \var{port} slot is an integer or \sharpf.
  
-  The \var{path} slot is a list containing the Request-URI's  path
-  split at slashes and \emph{unescaped}.
+  The \var{path} slot is a list of strings containing the
+  Request-URI's path split at slashes and \emph{unescaped}.If the
+  Request-URI's path ends with a slash, an empty string is inserted as
+  the last element of the list.
 
   The \var{query} slot is an non-empty-string, still in its
   \emph{escaped} representation, or \sharpf.
 \end{desc}
 %
-Examples for Request-URI strings and the slots of the corresponding http-url record:
+Examples for Request-URI strings and the slots of the corresponding
+http-url record: \nopagebreak
 \begin{alltt}
 "http://foo.bar.org:7777///foo%20foo//bar.htm?bulb%20bulb"
 \(\Rightarrow\) "foo.bar.org" 7777 '("foo foo" "bar.htm") "bulb%20bulb"
 
-"http://foo.bar.org/"
+"http://foo.bar.org"
 \(\Rightarrow\) "foo.bar.org" #f '() #f
 
+"http://foo.bar.org//"
+\(\Rightarrow\) "foo.bar.org" #f '("") #f
+
 "/foo%20foo//bar.htm?bulb%20bulb"
 \(\Rightarrow\)  #f #f '("foo foo" "bar.htm") "bulb%20bulb"
 
+"/foo%20foo//?bulb%20bulb"
+\(\Rightarrow\)  #f #f '("foo foo" "") "bulb%20bulb"
+
 "/" 
-\(\Rightarrow\) #f #f '() #f
+\(\Rightarrow\) #f #f '("") #f
 \end{alltt}
 
 

scheme/lib/url.scm

@@ -194,23 +194,34 @@
 ;;; SPLIT-PATH assumes abs-path if either #f or matches the RegExp abs_path, 
 ;;; no checks are done.
 ;;;
-;;; remark: abs_path allows for strings containing several consecutive slashes;
+;;; Remark: abs_path allows for strings containing several consecutive slashes;
 ;;; SPLIT-ABS-PATH treats them as one slash.
-;;; (e.g., "/foo///bar//baz/" => ("foo" "bar" "baz")) 
+;;; (e.g., "/foo///bar//baz" => ("foo" "bar" "baz")) 
+;;; 
+;;; Note: we have to differentiate between paths with trailing
+;;; slash(es) and paths without and hand that information over
+;;; to the request handler. (See
+;;; http://httpd.apache.org/docs-2.0/misc/rewriteguide.html -> 
+;;;"Trailing Slash problem" for the reasons.) 
+;;; If there is one or more trailing slash(es) the last element of the
+;;; returned list will be an empty string.  
+;;; (e.g., "/foo///bar//baz//" => ("foo" "bar" "baz" ""))
 
 
 (define (split-abs-path abs-path)
 
   (if abs-path 
 
-      (regexp-fold-right 
-       (rx (+ (~ ("/"))))
-       (lambda (match i res)
-	 (cons (match:substring match 0) res))
-       '()
-       abs-path)
+      (let* ((trailing-slash (char=? #\/ (string-ref abs-path (- (string-length abs-path) 1))))
+	    (last-element (if trailing-slash '("") '())))
+	(regexp-fold-right 
+	 (rx (+ (~ ("/"))))
+	 (lambda (match i res)
+	   (cons (match:substring match 0) res))
+	 last-element
+	 abs-path))
 
-      '()))
+	'()))
 
 
 ;;; record type HTTP-URL for Request_URIs
@@ -219,9 +230,12 @@
 ;;;
 ;;; The PORT slot is an integer or #f.
 ;;;
-;;; The PATH slot is the Request_URI's path split at slashes
-;;; (e.g., "/foo///bar//baz/" => ("foo" "bar" "baz")) 
-;;; and unescaped. 
+;;; The PATH slot is a list of strings containing the Request_URI's
+;;; path split at slashes and unescaped. If the Request_URI's path
+;;; ends with a slash, an empty string is inserted as the last element
+;;; of the list.
+;;; (e.g., "/foo///bar//baz" => ("foo" "bar" "baz")) 
+;;; (e.g., "/foo///bar//baz//" => ("foo" "bar" "baz" "")) 
 ;;;
 ;;; The QUERY slot is an non-empty-string, still in its escaped
 ;;; representation, or #f.