Refactored rewrite middleware

main.go

@@ -16,7 +16,7 @@ var (
 
 func init() {
 	flag.StringVar(&conf, "conf", server.DefaultConfigFile, "the configuration file to use")
-	flag.BoolVar(&http2, "http2", true, "enable HTTP/2 support") // flag temporary until http2 merged into std lib
+	flag.BoolVar(&http2, "http2", true, "enable HTTP/2 support") // temporary flag until http2 merged into std lib
 }
 
 func main() {
@@ -38,7 +38,7 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		s.HTTP2 = http2
+		s.HTTP2 = http2 // TODO: This setting is temporary
 		wg.Add(1)
 		go func(s *server.Server) {
 			defer wg.Done()

middleware/rewrite/rewrite.go

@@ -8,42 +8,58 @@ import (
 	"github.com/mholt/caddy/middleware"
 )
 
-// New instantiates a new rewrite middleware.
+// New instantiates a new Rewrites middleware.
 func New(c middleware.Controller) (middleware.Middleware, error) {
-	var rewrites []rewrite
+	rewrites, err := parse(c)
+	if err != nil {
+		return nil, err
+	}
+
+	return func(next middleware.Handler) middleware.Handler {
+		return Rewrite{Next: next, Rules: rewrites}
+	}, nil
+}
+
+// Rewrite is middleware to rewrite request locations internally before being handled.
+type Rewrite struct {
+	Next  middleware.Handler
+	Rules []RewriteRule
+}
+
+// ServeHTTP implements the middleware.Handler interface.
+func (rw Rewrite) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
+	for _, rule := range rw.Rules {
+		if r.URL.Path == rule.From {
+			r.URL.Path = rule.To
+			break
+		}
+	}
+	return rw.Next.ServeHTTP(w, r)
+}
+
+func parse(c middleware.Controller) ([]RewriteRule, error) {
+	var rewrites []RewriteRule
 
 	for c.Next() {
-		var rule rewrite
+		var rule RewriteRule
 
 		if !c.NextArg() {
-			return nil, c.ArgErr()
+			return rewrites, c.ArgErr()
 		}
 		rule.From = c.Val()
 
 		if !c.NextArg() {
-			return nil, c.ArgErr()
+			return rewrites, c.ArgErr()
 		}
 		rule.To = c.Val()
 
 		rewrites = append(rewrites, rule)
 	}
 
-	// TODO: Why can't we just return an http.Handler here instead?
-	return func(next middleware.Handler) middleware.Handler {
-		return middleware.HandlerFunc(func(w http.ResponseWriter, r *http.Request) (int, error) {
-			for _, rule := range rewrites {
-				if r.URL.Path == rule.From {
-					r.URL.Path = rule.To
-					break
-				}
-			}
-			return next.ServeHTTP(w, r)
-		})
-	}, nil
+	return rewrites, nil
 }
 
-// rewrite describes an internal location rewrite rule.
-type rewrite struct {
-	From string
-	To   string
+// RewriteRule describes an internal location rewrite rule.
+type RewriteRule struct {
+	From, To string
 }