Add PathPrefixStrip and PathStrip rules

Signed-off-by: Emile Vauge <emile@vauge.com>

docs/index.md

@@ -37,7 +37,9 @@ Frontends can be defined using the following rules:
 - `Host`: Host adds a matcher for the URL host. It accepts a template with zero or more URL variables enclosed by `{}`. Variables can define an optional regexp pattern to be matched: `www.traefik.io`, `{subdomain:[a-z]+}.traefik.io`
 - `Methods`: Methods adds a matcher for HTTP methods. It accepts a sequence of one or more methods to be matched, e.g.: `GET`, `POST`, `PUT`
 - `Path`: Path adds a matcher for the URL path. It accepts a template with zero or more URL variables enclosed by `{}`. The template must start with a `/`. For exemple `/products/` `/articles/{category}/{id:[0-9]+}`
+- `PathStrip`: Same as `Path` but strip the given prefix from the request URL's Path.
 - `PathPrefix`: PathPrefix adds a matcher for the URL path prefix. This matches if the given template is a prefix of the full URL path.
+- `PathPrefixStrip`: Same as `PathPrefix` but strip the given prefix from the request URL's Path.
 
 
  A frontend is a set of rules that forwards the incoming http traffic to a backend.

middlewares/StripPrefix.go

@@ -0,0 +1,22 @@
+package middlewares
+
+import (
+	"net/http"
+	"strings"
+)
+
+// StripPrefix is a middleware used to strip prefix from an URL request
+type StripPrefix struct {
+	Handler http.Handler
+	Prefix  string
+}
+
+func (s *StripPrefix) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if p := strings.TrimPrefix(r.URL.Path, s.Prefix); len(p) < len(r.URL.Path) {
+		r.URL.Path = p
+		r.RequestURI = r.URL.RequestURI()
+		s.Handler.ServeHTTP(w, r)
+	} else {
+		http.NotFound(w, r)
+	}
+}

server.go

@@ -7,6 +7,16 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"errors"
+	"net/http"
+	"net/url"
+	"os"
+	"os/signal"
+	"reflect"
+	"regexp"
+	"sort"
+	"sync"
+	"syscall"
+	"time"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/codegangsta/negroni"
@@ -18,16 +28,6 @@ import (
 	"github.com/mailgun/oxy/cbreaker"
 	"github.com/mailgun/oxy/forward"
 	"github.com/mailgun/oxy/roundrobin"
-	"net/http"
-	"net/url"
-	"os"
-	"os/signal"
-	"reflect"
-	"regexp"
-	"sort"
-	"sync"
-	"syscall"
-	"time"
 )
 
 var oxyLogger = &OxyLogger{}
@@ -335,11 +335,11 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 				newRoute := serverEntryPoints[entryPointName].httpRouter.NewRoute().Name(frontendName)
 				for routeName, route := range frontend.Routes {
 					log.Debugf("Creating route %s %s:%s", routeName, route.Rule, route.Value)
-					newRouteReflect, err := invoke(newRoute, route.Rule, route.Value)
+					route, err := getRoute(newRoute, route.Rule, route.Value)
 					if err != nil {
 						return nil, err
 					}
-					newRoute = newRouteReflect[0].Interface().(*mux.Route)
+					newRoute = route
 				}
 				entryPoint := globalConfiguration.EntryPoints[entryPointName]
 				if entryPoint.Redirect != nil {
@@ -399,7 +399,7 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 					} else {
 						log.Debugf("Reusing backend %s", frontend.Backend)
 					}
-					newRoute.Handler(backends[frontend.Backend])
+					server.wireFrontendBackend(frontend.Routes, newRoute, backends[frontend.Backend])
 				}
 				err := newRoute.GetError()
 				if err != nil {
@@ -411,6 +411,32 @@ func (server *Server) loadConfig(configurations configs, globalConfiguration Glo
 	return serverEntryPoints, nil
 }
 
+func (server *Server) wireFrontendBackend(routes map[string]types.Route, newRoute *mux.Route, handler http.Handler) {
+	// strip prefix
+	var strip bool
+	for _, route := range routes {
+		switch route.Rule {
+		case "PathStrip":
+			newRoute.Handler(&middlewares.StripPrefix{
+				Prefix:  route.Value,
+				Handler: handler,
+			})
+			strip = true
+			break
+		case "PathPrefixStrip":
+			newRoute.Handler(&middlewares.StripPrefix{
+				Prefix:  route.Value,
+				Handler: handler,
+			})
+			strip = true
+			break
+		}
+	}
+	if !strip {
+		newRoute.Handler(handler)
+	}
+}
+
 func (server *Server) loadEntryPointConfig(entryPointName string, entryPoint *EntryPoint) (http.Handler, error) {
 	regex := entryPoint.Redirect.Regex
 	replacement := entryPoint.Redirect.Replacement
@@ -443,9 +469,28 @@ func (server *Server) loadEntryPointConfig(entryPointName string, entryPoint *En
 func (server *Server) buildDefaultHTTPRouter() *mux.Router {
 	router := mux.NewRouter()
 	router.NotFoundHandler = http.HandlerFunc(notFoundHandler)
+	router.StrictSlash(true)
 	return router
 }
 
+func getRoute(any interface{}, rule string, value ...interface{}) (*mux.Route, error) {
+	switch rule {
+	case "PathStrip":
+		rule = "Path"
+	case "PathPrefixStrip":
+		rule = "PathPrefix"
+	}
+	inputs := make([]reflect.Value, len(value))
+	for i := range value {
+		inputs[i] = reflect.ValueOf(value[i])
+	}
+	method := reflect.ValueOf(any).MethodByName(rule)
+	if method.IsValid() {
+		return method.Call(inputs)[0].Interface().(*mux.Route), nil
+	}
+	return nil, errors.New("Method not found: " + rule)
+}
+
 func sortedFrontendNamesForConfig(configuration *types.Configuration) []string {
 	keys := []string{}
 

utils.go

@@ -1,23 +0,0 @@
-/*
-Copyright
-*/
-package main
-
-import (
-	"errors"
-	"reflect"
-)
-
-// Invoke calls the specified method with the specified arguments on the specified interface.
-// It uses the go(lang) reflect package.
-func invoke(any interface{}, name string, args ...interface{}) ([]reflect.Value, error) {
-	inputs := make([]reflect.Value, len(args))
-	for i := range args {
-		inputs[i] = reflect.ValueOf(args[i])
-	}
-	method := reflect.ValueOf(any).MethodByName(name)
-	if method.IsValid() {
-		return method.Call(inputs), nil
-	}
-	return nil, errors.New("Method not found: " + name)
-}