Regex capturing group.

vendor/github.com/containous/mux/regexp.go

@@ -109,13 +109,6 @@ func newRouteRegexp(tpl string, matchHost, matchPrefix, matchQuery, strictSlash,
 	if errCompile != nil {
 		return nil, errCompile
 	}
-
-	// Check for capturing groups which used to work in older versions
-	if reg.NumSubexp() != len(idxs)/2 {
-		panic(fmt.Sprintf("route %s contains capture groups in its regexp. ", template) +
-			"Only non-capturing groups are accepted: e.g. (?:pattern) instead of (pattern)")
-	}
-
 	// Done!
 	return &routeRegexp{
 		template:       template,
@@ -141,7 +134,7 @@ type routeRegexp struct {
 	matchQuery bool
 	// The strictSlash value defined on the route, but disabled if PathPrefix was used.
 	strictSlash bool
-	// Determines whether to use encoded path from getPath function or unencoded
+	// Determines whether to use encoded req.URL.EnscapedPath() or unencoded
 	// req.URL.Path for path matching
 	useEncodedPath bool
 	// Expanded regexp.
@@ -162,7 +155,7 @@ func (r *routeRegexp) Match(req *http.Request, match *RouteMatch) bool {
 		}
 		path := req.URL.Path
 		if r.useEncodedPath {
-			path = getPath(req)
+			path = req.URL.EscapedPath()
 		}
 		return r.regexp.MatchString(path)
 	}
@@ -272,7 +265,7 @@ func (v *routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route)
 	}
 	path := req.URL.Path
 	if r.useEncodedPath {
-		path = getPath(req)
+		path = req.URL.EscapedPath()
 	}
 	// Store path variables.
 	if v.path != nil {
@@ -320,7 +313,14 @@ func getHost(r *http.Request) string {
 }
 
 func extractVars(input string, matches []int, names []string, output map[string]string) {
-	for i, name := range names {
-		output[name] = input[matches[2*i+2]:matches[2*i+3]]
+	matchesCount := 0
+	prevEnd := -1
+	for i := 2; i < len(matches) && matchesCount < len(names); i += 2 {
+		if prevEnd < matches[i+1] {
+			value := input[matches[i]:matches[i+1]]
+			output[names[matchesCount]] = value
+			prevEnd = matches[i+1]
+			matchesCount++
+		}
 	}
 }