Dynamic Configuration Refactoring

old/middlewares/replace_path_regex.go

@@ -0,0 +1,40 @@
+package middlewares
+
+import (
+	"context"
+	"net/http"
+	"regexp"
+	"strings"
+
+	"github.com/containous/traefik/old/log"
+)
+
+// ReplacePathRegex is a middleware used to replace the path of a URL request with a regular expression
+type ReplacePathRegex struct {
+	Handler     http.Handler
+	Regexp      *regexp.Regexp
+	Replacement string
+}
+
+// NewReplacePathRegexHandler returns a new ReplacePathRegex
+func NewReplacePathRegexHandler(regex string, replacement string, handler http.Handler) http.Handler {
+	exp, err := regexp.Compile(strings.TrimSpace(regex))
+	if err != nil {
+		log.Errorf("Error compiling regular expression %s: %s", regex, err)
+	}
+	return &ReplacePathRegex{
+		Regexp:      exp,
+		Replacement: strings.TrimSpace(replacement),
+		Handler:     handler,
+	}
+}
+
+func (s *ReplacePathRegex) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if s.Regexp != nil && len(s.Replacement) > 0 && s.Regexp.MatchString(r.URL.Path) {
+		r = r.WithContext(context.WithValue(r.Context(), ReplacePathKey, r.URL.Path))
+		r.Header.Add(ReplacedPathHeader, r.URL.Path)
+		r.URL.Path = s.Regexp.ReplaceAllString(r.URL.Path, s.Replacement)
+		r.RequestURI = r.URL.RequestURI()
+	}
+	s.Handler.ServeHTTP(w, r)
+}