Fix uri-decode behavior for "+"

* module/web/uri.scm (uri-decode): Add #:decode-plus-to-space? keyword
  argument.
  (split-and-decode-uri-path): Don't decode plus to space.
* doc/ref/web.texi (URIs): Update documentation.
* test-suite/tests/web-uri.test ("decode"): Add tests.
* NEWS: Add entry.

Based on a patch by Brent <brent@tomski.co.za>.

NEWS

@@ -6,6 +6,13 @@ Please send Guile bug reports to bug-guile@gnu.org.
 
 
 
+Changes in 2.1.4 (changes since the 2.1.3 alpha release):
+
+* Bug fixes
+** Don't replace + with space when splitting and decoding URI paths
+
+
+[TODO: Fold into generic 2.2 release notes.]
 Changes in 2.1.3 (changes since the 2.1.2 alpha release):
 
 * Notable changes

doc/ref/web.texi

@@ -269,7 +269,7 @@ serialization.
 Declare a default port for the given URI scheme.
 @end deffn
 
-@deffn {Scheme Procedure} uri-decode str [#:encoding=@code{"utf-8"}]
+@deffn {Scheme Procedure} uri-decode str [#:encoding=@code{"utf-8"}] [#:decode-plus-to-space? #t]
 Percent-decode the given @var{str}, according to @var{encoding}, which
 should be the name of a character encoding.
 
@@ -286,6 +286,11 @@ decoded bytes are not valid for the given encoding. Pass @code{#f} for
 @xref{Ports, @code{set-port-encoding!}}, for more information on
 character encodings.
 
+If @var{decode-plus-to-space?} is true, which is the default, also
+replace instances of the plus character @samp{+} with a space character.
+This is needed when parsing @code{application/x-www-form-urlencoded}
+data.
+
 Returns a string of the decoded characters, or a bytevector if
 @var{encoding} was @code{#f}.
 @end deffn

module/web/uri.scm

@@ -322,7 +322,7 @@ serialization."
 (define hex-chars
   (string->char-set "0123456789abcdefABCDEF"))
 
-(define* (uri-decode str #:key (encoding "utf-8"))
+(define* (uri-decode str #:key (encoding "utf-8") (decode-plus-to-space? #t))
   "Percent-decode the given STR, according to ENCODING,
 which should be the name of a character encoding.
 
@@ -338,6 +338,10 @@ bytes are not valid for the given encoding. Pass ‘#f’ for ENCODING if
 you want decoded bytes as a bytevector directly.  ‘set-port-encoding!’,
 for more information on character encodings.
 
+If DECODE-PLUS-TO-SPACE? is true, which is the default, also replace
+instances of the plus character (+) with a space character.  This is
+needed when parsing application/x-www-form-urlencoded data.
+
 Returns a string of the decoded characters, or a bytevector if
 ENCODING was ‘#f’."
   (let* ((len (string-length str))
@@ -348,7 +352,7 @@ ENCODING was ‘#f’."
                (if (< i len)
                    (let ((ch (string-ref str i)))
                      (cond
-                      ((eqv? ch #\+)
+                      ((and (eqv? ch #\+) decode-plus-to-space?)
                        (put-u8 port (char->integer #\space))
                        (lp (1+ i)))
                       ((and (< (+ i 2) len) (eqv? ch #\%)
@@ -431,7 +435,8 @@ removing empty components.
 For example, ‘\"/foo/bar%20baz/\"’ decodes to the two-element list,
 ‘(\"foo\" \"bar baz\")’."
   (filter (lambda (x) (not (string-null? x)))
-          (map uri-decode (string-split path #\/))))
+          (map (lambda (s) (uri-decode s #:decode-plus-to-space? #f))
+               (string-split path #\/))))
 
 (define (encode-and-join-uri-path parts)
   "URI-encode each element of PARTS, which should be a list of

test-suite/tests/web-uri.test

@@ -594,7 +594,10 @@
     (equal? "foo bar" (uri-decode "foo%20bar")))
 
   (pass-if "foo+bar"
-    (equal? "foo bar" (uri-decode "foo+bar"))))
+    (equal? "foo bar" (uri-decode "foo+bar")))
+
+  (pass-if "foo+bar"
+    (equal? '("foo+bar") (split-and-decode-uri-path "foo+bar"))))
 
 (with-test-prefix "encode"
   (pass-if (equal? "foo%20bar" (uri-encode "foo bar")))