Backward compatibility ensured.

caddy/setup/rewrite.go

@@ -78,8 +78,8 @@ func rewriteParse(c *Controller) ([]rewrite.Rule, error) {
 					return nil, c.ArgErr()
 				}
 			}
-			// ensure pattern and to are specified
-			if pattern == "" || to == "" {
+			// ensure to is specified
+			if to == "" {
 				return nil, c.ArgErr()
 			}
 			if rule, err = rewrite.NewComplexRule(base, pattern, to, ext, ifs); err != nil {

caddy/setup/rewrite_test.go

@@ -119,11 +119,6 @@ func TestRewriteParse(t *testing.T) {
 			&rewrite.ComplexRule{Base: "/path", To: "/dest", Regexp: regexp.MustCompile("rr")},
 			&rewrite.ComplexRule{Base: "/", To: "/to", Regexp: regexp.MustCompile("[a-z]+")},
 		}},
-		{`rewrite {
-			to	/to
-		 }`, true, []rewrite.Rule{
-			&rewrite.ComplexRule{},
-		}},
 		{`rewrite {
 			r	.*
 		 }`, true, []rewrite.Rule{

middleware/rewrite/rewrite.go

@@ -128,9 +128,18 @@ func (r *ComplexRule) Rewrite(fs http.FileSystem, req *http.Request) bool {
 		start--
 	}
 
-	// validate regexp
-	if !r.MatchString(rPath[start:]) {
-		return false
+	// validate regexp if present
+	if r.Regexp != nil {
+		if !r.MatchString(rPath[start:]) {
+			return false
+		}
+	}
+
+	// validate rewrite conditions
+	for _, i := range r.Ifs {
+		if !i.True(req) {
+			return false
+		}
 	}
 
 	// attempt rewrite

middleware/rewrite/rewrite_test.go

@@ -18,6 +18,7 @@ func TestRewrite(t *testing.T) {
 			NewSimpleRule("/a", "/b"),
 			NewSimpleRule("/b", "/b{uri}"),
 		},
+		FileSys: http.Dir("."),
 	}
 
 	regexpRules := [][]string{
@@ -37,7 +38,7 @@ func TestRewrite(t *testing.T) {
 		if s := strings.Split(regexpRule[3], "|"); len(s) > 1 {
 			ext = s[:len(s)-1]
 		}
-		rule, err := NewComplexRule(regexpRule[0], regexpRule[1], regexpRule[2], ext)
+		rule, err := NewComplexRule(regexpRule[0], regexpRule[1], regexpRule[2], ext, nil)
 		if err != nil {
 			t.Fatal(err)
 		}

middleware/rewrite/to.go

@@ -4,6 +4,7 @@ import (
 	"log"
 	"net/http"
 	"net/url"
+	"path"
 	"strings"
 )
 
@@ -17,7 +18,7 @@ func To(fs http.FileSystem, r *http.Request, to string) bool {
 	// try each rewrite paths
 	t := ""
 	for _, v := range tos {
-		t = replacer.Replace(v)
+		t = path.Clean(replacer.Replace(v))
 		if isValidFile(fs, t) {
 			break
 		}