Fix regex with PathStrip

docs/basics.md

@@ -104,9 +104,11 @@ Following is the list of existing matcher rules along with examples:
 - `HostRegexp: traefik.io, {subdomain:[a-z]+}.traefik.io`: Match request host. It accepts a sequence of literal and regular expression hosts.
 - `Method: GET, POST, PUT`: Match request HTTP method. It accepts a sequence of HTTP methods.
 - `Path: /products/, /articles/{category}/{id:[0-9]+}`: Match exact request path. It accepts a sequence of literal and regular expression paths.
-- `PathStrip: /products/, /articles/{category}/{id:[0-9]+}`: Match exact path and strip off the path prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression paths.
+- `PathStrip: /products/`: Match exact path and strip off the path prior to forwarding the request to the backend. It accepts a sequence of literal paths.
+- `PathStripRegex: /articles/{category}/{id:[0-9]+}`: Match exact path and strip off the path prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression paths.
 - `PathPrefix: /products/, /articles/{category}/{id:[0-9]+}`: Match request prefix path. It accepts a sequence of literal and regular expression prefix paths.
-- `PathPrefixStrip: /products/, /articles/{category}/{id:[0-9]+}`: Match request prefix path and strip off the path prefix prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression prefix paths. Starting with Traefik 1.3, the stripped prefix path will be available in the `X-Forwarded-Prefix` header.
+- `PathPrefixStrip: /products/`: Match request prefix path and strip off the path prefix prior to forwarding the request to the backend. It accepts a sequence of literal prefix paths. Starting with Traefik 1.3, the stripped prefix path will be available in the `X-Forwarded-Prefix` header.
+- `PathPrefixStripRegex: /articles/{category}/{id:[0-9]+}`: Match request prefix path and strip off the path prefix prior to forwarding the request to the backend. It accepts a sequence of literal and regular expression prefix paths. Starting with Traefik 1.3, the stripped prefix path will be available in the `X-Forwarded-Prefix` header.
 
 In order to use regular expressions with Host and Path matchers, you must declare an arbitrarily named variable followed by the colon-separated regular expression, all enclosed in curly braces. Any pattern supported by [Go's regexp package](https://golang.org/pkg/regexp/) may be used. Example: `/posts/{id:[0-9]+}`.
 

middlewares/stripPrefixRegex.go

@@ -0,0 +1,54 @@
+package middlewares
+
+import (
+	"net/http"
+
+	"github.com/containous/mux"
+	"github.com/containous/traefik/log"
+)
+
+// StripPrefixRegex is a middleware used to strip prefix from an URL request
+type StripPrefixRegex struct {
+	Handler http.Handler
+	router  *mux.Router
+}
+
+// NewStripPrefixRegex builds a new StripPrefixRegex given a handler and prefixes
+func NewStripPrefixRegex(handler http.Handler, prefixes []string) *StripPrefixRegex {
+	stripPrefix := StripPrefixRegex{Handler: handler, router: mux.NewRouter()}
+
+	for _, prefix := range prefixes {
+		stripPrefix.router.PathPrefix(prefix)
+	}
+
+	return &stripPrefix
+}
+
+func (s *StripPrefixRegex) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var match mux.RouteMatch
+	if s.router.Match(r, &match) {
+		params := make([]string, 0, len(match.Vars)*2)
+		for key, val := range match.Vars {
+			params = append(params, key)
+			params = append(params, val)
+		}
+
+		prefix, err := match.Route.URL(params...)
+		if err != nil || len(prefix.Path) > len(r.URL.Path) {
+			log.Error("Error in stripPrefix middleware", err)
+			return
+		}
+
+		r.URL.Path = r.URL.Path[len(prefix.Path):]
+		r.Header[forwardedPrefixHeader] = []string{prefix.Path}
+		r.RequestURI = r.URL.RequestURI()
+		s.Handler.ServeHTTP(w, r)
+		return
+	}
+	http.NotFound(w, r)
+}
+
+// SetHandler sets handler
+func (s *StripPrefixRegex) SetHandler(Handler http.Handler) {
+	s.Handler = Handler
+}

middlewares/stripPrefixRegex_test.go

@@ -0,0 +1,55 @@
+package middlewares
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestStripPrefixRegex(t *testing.T) {
+
+	handlerPath := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, r.URL.Path)
+	})
+
+	handler := NewStripPrefixRegex(handlerPath, []string{"/a/api/", "/b/{regex}/", "/c/{category}/{id:[0-9]+}/"})
+	server := httptest.NewServer(handler)
+	defer server.Close()
+
+	tests := []struct {
+		expectedCode     int
+		expectedResponse string
+		url              string
+	}{
+		{url: "/a/test", expectedCode: 404, expectedResponse: "404 page not found\n"},
+		{url: "/a/api/test", expectedCode: 200, expectedResponse: "test"},
+
+		{url: "/b/api/", expectedCode: 200, expectedResponse: ""},
+		{url: "/b/api/test1", expectedCode: 200, expectedResponse: "test1"},
+		{url: "/b/api2/test2", expectedCode: 200, expectedResponse: "test2"},
+
+		{url: "/c/api/123/", expectedCode: 200, expectedResponse: ""},
+		{url: "/c/api/123/test3", expectedCode: 200, expectedResponse: "test3"},
+		{url: "/c/api/abc/test4", expectedCode: 404, expectedResponse: "404 page not found\n"},
+	}
+
+	for _, test := range tests {
+		resp, err := http.Get(server.URL + test.url)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if resp.StatusCode != test.expectedCode {
+			t.Fatalf("Received non-%d response: %d\n", test.expectedCode, resp.StatusCode)
+		}
+		response, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if test.expectedResponse != string(response) {
+			t.Errorf("Expected '%s' :  '%s'\n", test.expectedResponse, response)
+		}
+	}
+
+}

server/rules.go

@@ -75,6 +75,16 @@ func (r *Rules) pathStrip(paths ...string) *mux.Route {
 	return r.route.route
 }
 
+func (r *Rules) pathStripRegex(paths ...string) *mux.Route {
+	sort.Sort(bySize(paths))
+	r.route.stripPrefixesRegex = paths
+	router := r.route.route.Subrouter()
+	for _, path := range paths {
+		router.Path(strings.TrimSpace(path))
+	}
+	return r.route.route
+}
+
 func (r *Rules) replacePath(paths ...string) *mux.Route {
 	for _, path := range paths {
 		r.route.replacePath = path
@@ -99,6 +109,16 @@ func (r *Rules) pathPrefixStrip(paths ...string) *mux.Route {
 	return r.route.route
 }
 
+func (r *Rules) pathPrefixStripRegex(paths ...string) *mux.Route {
+	sort.Sort(bySize(paths))
+	r.route.stripPrefixesRegex = paths
+	router := r.route.route.Subrouter()
+	for _, path := range paths {
+		router.PathPrefix(strings.TrimSpace(path))
+	}
+	return r.route.route
+}
+
 func (r *Rules) methods(methods ...string) *mux.Route {
 	return r.route.route.Methods(methods...)
 }
@@ -113,17 +133,19 @@ func (r *Rules) headersRegexp(headers ...string) *mux.Route {
 
 func (r *Rules) parseRules(expression string, onRule func(functionName string, function interface{}, arguments []string) error) error {
 	functions := map[string]interface{}{
-		"Host":            r.host,
-		"HostRegexp":      r.hostRegexp,
-		"Path":            r.path,
-		"PathStrip":       r.pathStrip,
-		"PathPrefix":      r.pathPrefix,
-		"PathPrefixStrip": r.pathPrefixStrip,
-		"Method":          r.methods,
-		"Headers":         r.headers,
-		"HeadersRegexp":   r.headersRegexp,
-		"AddPrefix":       r.addPrefix,
-		"ReplacePath":     r.replacePath,
+		"Host":                 r.host,
+		"HostRegexp":           r.hostRegexp,
+		"Path":                 r.path,
+		"PathStrip":            r.pathStrip,
+		"PathStripRegex":       r.pathStripRegex,
+		"PathPrefix":           r.pathPrefix,
+		"PathPrefixStrip":      r.pathPrefixStrip,
+		"PathPrefixStripRegex": r.pathPrefixStripRegex,
+		"Method":               r.methods,
+		"Headers":              r.headers,
+		"HeadersRegexp":        r.headersRegexp,
+		"AddPrefix":            r.addPrefix,
+		"ReplacePath":          r.replacePath,
 	}
 
 	if len(expression) == 0 {

server/server.go

@@ -62,10 +62,11 @@ type serverEntryPoint struct {
 }
 
 type serverRoute struct {
-	route         *mux.Route
-	stripPrefixes []string
-	addPrefix     string
-	replacePath   string
+	route              *mux.Route
+	stripPrefixes      []string
+	stripPrefixesRegex []string
+	addPrefix          string
+	replacePath        string
 }
 
 // NewServer returns an initialized Server.
@@ -807,6 +808,11 @@ func (server *Server) wireFrontendBackend(serverRoute *serverRoute, handler http
 		}
 	}
 
+	// strip prefix with regex
+	if len(serverRoute.stripPrefixesRegex) > 0 {
+		handler = middlewares.NewStripPrefixRegex(handler, serverRoute.stripPrefixesRegex)
+	}
+
 	// path replace
 	if len(serverRoute.replacePath) > 0 {
 		handler = &middlewares.ReplacePath{