From e73f183699f8ab7d54609771e1fa0ab7ffddc21b Mon Sep 17 00:00:00 2001
From: Kamil Kisiel <kamil@kamilkisiel.net>
Date: Thu, 6 Aug 2015 20:31:19 -0700
Subject: [PATCH] fix use of capturing subexpressions in pattern matches.

The router now associates a regexp named group with each mux variable.
It only fills variables when capturing group name match instead of
relying on indices, which doesn't work if a variable regexp has interior
capturing groups.

Fixes #62
---
 mux_test.go | 27 +++++++++++++++++++++++++++
 regexp.go   | 29 ++++++++++++++++++++++-------
 2 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/mux_test.go b/mux_test.go
index ba47727..455d68e 100644
--- a/mux_test.go
+++ b/mux_test.go
@@ -108,6 +108,15 @@ func TestHost(t *testing.T) {
 			path:        "",
 			shouldMatch: true,
 		},
+		{
+			title:       "Host route with pattern, additional capturing group, match",
+			route:       new(Route).Host("aaa.{v1:[a-z]{2}(b|c)}.ccc"),
+			request:     newRequest("GET", "http://aaa.bbb.ccc/111/222/333"),
+			vars:        map[string]string{"v1": "bbb"},
+			host:        "aaa.bbb.ccc",
+			path:        "",
+			shouldMatch: true,
+		},
 		{
 			title:       "Host route with pattern, wrong host in request URL",
 			route:       new(Route).Host("aaa.{v1:[a-z]{3}}.ccc"),
@@ -260,6 +269,15 @@ func TestPath(t *testing.T) {
 			path:        "/111/222/333",
 			shouldMatch: false,
 		},
+		{
+			title:       "Path route with multiple patterns with pipe, match",
+			route:       new(Route).Path("/{category:a|(b/c)}/{product}/{id:[0-9]+}"),
+			request:     newRequest("GET", "http://localhost/a/product_name/1"),
+			vars:        map[string]string{"category": "a", "product": "product_name", "id": "1"},
+			host:        "",
+			path:        "/a/product_name/1",
+			shouldMatch: true,
+		},
 	}
 
 	for _, test := range tests {
@@ -597,6 +615,15 @@ func TestQueries(t *testing.T) {
 			path:        "",
 			shouldMatch: false,
 		},
+		{
+			title:       "Queries route with regexp pattern with quantifier, additional capturing group",
+			route:       new(Route).Queries("foo", "{v1:[0-9]{1}(a|b)}"),
+			request:     newRequest("GET", "http://localhost?foo=1a"),
+			vars:        map[string]string{"v1": "1a"},
+			host:        "",
+			path:        "",
+			shouldMatch: true,
+		},
 		{
 			title:       "Queries route with regexp pattern with quantifier, additional variable in query string, regexp does not match",
 			route:       new(Route).Queries("foo", "{v1:[0-9]{1}}"),
diff --git a/regexp.go b/regexp.go
index 7c636d0..6b34fec 100644
--- a/regexp.go
+++ b/regexp.go
@@ -72,7 +72,7 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash
 				tpl[idxs[i]:end])
 		}
 		// Build the regexp pattern.
-		fmt.Fprintf(pattern, "%s(%s)", regexp.QuoteMeta(raw), patt)
+		fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), name, patt)
 		// Build the reverse template.
 		fmt.Fprintf(reverse, "%s%%s", raw)
 
@@ -241,8 +241,13 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 	if v.host != nil {
 		hostVars := v.host.regexp.FindStringSubmatch(getHost(req))
 		if hostVars != nil {
-			for k, v := range v.host.varsN {
-				m.Vars[v] = hostVars[k+1]
+			subexpNames := v.host.regexp.SubexpNames()
+			varName := 0
+			for i, name := range subexpNames[1:] {
+				if name != "" && v.host.varsN[varName] == name {
+					m.Vars[name] = hostVars[i+1]
+					varName++
+				}
 			}
 		}
 	}
@@ -250,8 +255,13 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 	if v.path != nil {
 		pathVars := v.path.regexp.FindStringSubmatch(req.URL.Path)
 		if pathVars != nil {
-			for k, v := range v.path.varsN {
-				m.Vars[v] = pathVars[k+1]
+			subexpNames := v.path.regexp.SubexpNames()
+			varName := 0
+			for i, name := range subexpNames[1:] {
+				if name != "" && v.path.varsN[varName] == name {
+					m.Vars[name] = pathVars[i+1]
+					varName++
+				}
 			}
 			// Check if we should redirect.
 			if v.path.strictSlash {
@@ -273,8 +283,13 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 	for _, q := range v.queries {
 		queryVars := q.regexp.FindStringSubmatch(q.getUrlQuery(req))
 		if queryVars != nil {
-			for k, v := range q.varsN {
-				m.Vars[v] = queryVars[k+1]
+			subexpNames := q.regexp.SubexpNames()
+			varName := 0
+			for i, name := range subexpNames[1:] {
+				if name != "" && q.varsN[varName] == name {
+					m.Vars[name] = queryVars[i+1]
+					varName++
+				}
 			}
 		}
 	}