fix: stripPrefix and stripPrefixRegex.

docs/content/middlewares/stripprefixregex.md

@@ -3,20 +3,16 @@
 Removing Prefixes From the Path Before Forwarding the Request (Using a Regex)
 {: .subtitle }
 
-`TODO: add schema`
-
 Remove the matching prefixes from the URL path.
 
 ## Configuration Examples
 
 ```yaml tab="Docker"
-# Replace the path by /foo
 labels:
-- "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=^/foo/(.*)",
+- "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/",
 ```
 
 ```yaml tab="Kubernetes"
-# Replace the path by /foo
 apiVersion: traefik.containo.us/v1alpha1
 kind: Middleware
 metadata:
@@ -24,36 +20,33 @@ metadata:
 spec:
   stripPrefixRegex:
     regex:
-    - "^/foo/(.*)"
+    - "/foo/[a-z0-9]+/[0-9]+/"
 ```
 
 ```json tab="Marathon"
 "labels": {
-  "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex": "^/foo/(.*)"
+  "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex": "/foo/[a-z0-9]+/[0-9]+/"
 }
 ```
 
 ```yaml tab="Rancher"
-# Replace the path by /foo
 labels:
-- "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=^/foo/(.*)",
+- "traefik.http.middlewares.test-stripprefixregex.stripprefixregex.regex=/foo/[a-z0-9]+/[0-9]+/",
 ```
 
 ```toml tab="File (TOML)"
-# Replace the path by /foo
 [http.middlewares]
   [http.middlewares.test-stripprefixregex.stripPrefixRegex]
-    regex = ["^/foo/(.*)"]
+    regex = ["/foo/[a-z0-9]+/[0-9]+/"]
 ```
 
 ```yaml tab="File (YAML)"
-# Replace the path by /foo
 http:
   middlewares:
     test-stripprefixregex:
       stripPrefixRegex:
         regex:
-        - "^/foo/(.*)"
+        - "/foo/[a-z0-9]+/[0-9]+/"
 ```
 
 ## Configuration Options

integration/fixtures/https/https_redirect.toml

@@ -150,9 +150,9 @@
   [http.middlewares.foo-slash-add-prefix.addPrefix]
     prefix = "/foo/"
   [http.middlewares.id-strip-regex-prefix.stripPrefixRegex]
-    regex = ["/{id:[a-z]+}"]
+    regex = ["/[a-z]+"]
   [http.middlewares.id-slash-strip-regex-prefix.stripPrefixRegex]
-    regex = ["/{id:[a-z]+}/"]
+    regex = ["/[a-z]+/"]
   [http.middlewares.api-regex-replace.replacePathRegex]
     regex = "/api"
     replacement = "/"

pkg/middlewares/stripprefix/strip_prefix.go

@@ -49,7 +49,7 @@ func (s *stripPrefix) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 			return
 		}
 	}
-	http.NotFound(rw, req)
+	s.next.ServeHTTP(rw, req)
 }
 
 func (s *stripPrefix) serveRequest(rw http.ResponseWriter, req *http.Request, prefix string) {

pkg/middlewares/stripprefix/strip_prefix_test.go

@@ -28,7 +28,8 @@ func TestStripPrefix(t *testing.T) {
 				Prefixes: []string{},
 			},
 			path:               "/noprefixes",
-			expectedStatusCode: http.StatusNotFound,
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/noprefixes",
 		},
 		{
 			desc: "wildcard (.*) requests",
@@ -76,7 +77,8 @@ func TestStripPrefix(t *testing.T) {
 				Prefixes: []string{"/stat/"},
 			},
 			path:               "/status",
-			expectedStatusCode: http.StatusNotFound,
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/status",
 		},
 		{
 			desc: "general prefix on matching path",
@@ -149,6 +151,8 @@ func TestStripPrefix(t *testing.T) {
 			require.NoError(t, err)
 
 			req := testhelpers.MustNewRequest(http.MethodGet, "http://localhost"+test.path, nil)
+			req.RequestURI = req.URL.RequestURI()
+
 			resp := &httptest.ResponseRecorder{Code: http.StatusOK}
 
 			handler.ServeHTTP(resp, req)

pkg/middlewares/stripprefixregex/strip_prefix_regex.go

@@ -3,13 +3,13 @@ package stripprefixregex
 import (
 	"context"
 	"net/http"
+	"regexp"
 	"strings"
 
 	"github.com/containous/traefik/v2/pkg/config/dynamic"
 	"github.com/containous/traefik/v2/pkg/middlewares"
 	"github.com/containous/traefik/v2/pkg/middlewares/stripprefix"
 	"github.com/containous/traefik/v2/pkg/tracing"
-	"github.com/gorilla/mux"
 	"github.com/opentracing/opentracing-go/ext"
 )
 
@@ -20,7 +20,7 @@ const (
 // StripPrefixRegex is a middleware used to strip prefix from an URL request.
 type stripPrefixRegex struct {
 	next        http.Handler
-	router *mux.Router
+	expressions []*regexp.Regexp
 	name        string
 }
 
@@ -30,12 +30,15 @@ func New(ctx context.Context, next http.Handler, config dynamic.StripPrefixRegex
 
 	stripPrefix := stripPrefixRegex{
 		next: next,
-		router: mux.NewRouter(),
 		name: name,
 	}
 
-	for _, prefix := range config.Regex {
+	for _, exp := range config.Regex {
-		stripPrefix.router.PathPrefix(prefix)
+		reg, err := regexp.Compile(strings.TrimSpace(exp))
+		if err != nil {
+			return nil, err
+		}
+		stripPrefix.expressions = append(stripPrefix.expressions, reg)
 	}
 
 	return &stripPrefix, nil
@@ -46,32 +49,28 @@ func (s *stripPrefixRegex) GetTracingInformation() (string, ext.SpanKindEnum) {
 }
 
 func (s *stripPrefixRegex) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
-	var match mux.RouteMatch
+	for _, exp := range s.expressions {
-	if s.router.Match(req, &match) {
+		parts := exp.FindStringSubmatch(req.URL.Path)
-		params := make([]string, 0, len(match.Vars)*2)
+		if len(parts) > 0 && len(parts[0]) > 0 {
-		for key, val := range match.Vars {
+			prefix := parts[0]
-			params = append(params, key)
+			if !strings.HasPrefix(req.URL.Path, prefix) {
-			params = append(params, val)
+				continue
 			}
 
-		prefix, err := match.Route.URL(params...)
+			req.Header.Add(stripprefix.ForwardedPrefixHeader, prefix)
-		if err != nil || len(prefix.Path) > len(req.URL.Path) {
-			logger := middlewares.GetLogger(req.Context(), s.name, typeName)
-			logger.Error("Error in stripPrefix middleware", err)
-			return
-		}
 
-		req.URL.Path = req.URL.Path[len(prefix.Path):]
+			req.URL.Path = strings.Replace(req.URL.Path, prefix, "", 1)
 			if req.URL.RawPath != "" {
-			req.URL.RawPath = req.URL.RawPath[len(prefix.Path):]
+				req.URL.RawPath = req.URL.RawPath[len(prefix):]
 			}
-		req.Header.Add(stripprefix.ForwardedPrefixHeader, prefix.Path)
-		req.RequestURI = ensureLeadingSlash(req.URL.RequestURI())
 
+			req.RequestURI = ensureLeadingSlash(req.URL.RequestURI())
 			s.next.ServeHTTP(rw, req)
 			return
 		}
-	http.NotFound(rw, req)
+	}
+
+	s.next.ServeHTTP(rw, req)
 }
 
 func ensureLeadingSlash(str string) string {

pkg/middlewares/stripprefixregex/strip_prefix_regex_test.go

@@ -15,7 +15,7 @@ import (
 
 func TestStripPrefixRegex(t *testing.T) {
 	testPrefixRegex := dynamic.StripPrefixRegex{
-		Regex: []string{"/a/api/", "/b/{regex}/", "/c/{category}/{id:[0-9]+}/"},
+		Regex: []string{"/a/api/", "/b/([a-z0-9]+)/", "/c/[a-z0-9]+/[0-9]+/"},
 	}
 
 	testCases := []struct {
@@ -27,7 +27,13 @@ func TestStripPrefixRegex(t *testing.T) {
 	}{
 		{
 			path:               "/a/test",
-			expectedStatusCode: http.StatusNotFound,
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/a/test",
+		},
+		{
+			path:               "/a/test",
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/a/test",
 		},
 		{
 			path:               "/a/api/test",
@@ -65,7 +71,8 @@ func TestStripPrefixRegex(t *testing.T) {
 		},
 		{
 			path:               "/c/api/abc/test4",
-			expectedStatusCode: http.StatusNotFound,
+			expectedStatusCode: http.StatusOK,
+			expectedPath:       "/c/api/abc/test4",
 		},
 		{
 			path:               "/a/api/a%2Fb",