diff --git a/common.go b/common.go
new file mode 100644
index 0000000..fca9607
--- /dev/null
+++ b/common.go
@@ -0,0 +1,41 @@
+package router
+
+import (
+	"fmt"
+	"reflect"
+)
+
+type GenericValues map[string][]string
+
+func (gv GenericValues) Parse(data any, tag string) {
+	if gv == nil {
+		gv = make(GenericValues)
+	}
+	d := reflect.ValueOf(data)
+	if d.Kind() != reflect.Struct {
+		panic(fmt.Errorf("expected struct input for data"))
+	}
+	for i := 0; i < d.NumField(); i++ {
+		key, ok := d.Type().Field(i).Tag.Lookup(tag)
+		if !ok || key == "" {
+			continue
+		}
+		v := make([]string, 0)
+		val := d.Field(i)
+		if val.Kind() == reflect.Pointer || val.Kind() == reflect.Interface {
+			val = val.Elem()
+		}
+		if val.Kind() == reflect.Slice || val.Kind() == reflect.Array {
+			for j := 0; j < val.Len(); j++ {
+				item := val.Index(j)
+				if item.Kind() == reflect.Pointer || item.Kind() == reflect.Interface {
+					item = item.Elem()
+				}
+				v = append(v, fmt.Sprintf("%s", item.Interface()))
+			}
+		} else {
+			v = append(v, fmt.Sprintf("%s", val.Interface()))
+		}
+		gv[key] = v
+	}
+}
diff --git a/header.go b/header.go
index 0bc5bc0..f175110 100644
--- a/header.go
+++ b/header.go
@@ -1,44 +1,13 @@
 package router
 
 import (
-	"fmt"
-	"reflect"
 	"strings"
 )
 
 type Header map[string][]string
 
 func (h Header) Parse(data any) {
-	if h == nil {
-		h = make(Header)
-	}
-	d := reflect.ValueOf(data)
-	if d.Kind() != reflect.Struct {
-		panic(fmt.Errorf("expected struct input for data"))
-	}
-	for i := 0; i < d.NumField(); i++ {
-		key, ok := d.Type().Field(i).Tag.Lookup("header")
-		if !ok || key == "" {
-			continue
-		}
-		v := make([]string, 0)
-		val := d.Field(i)
-		if val.Kind() == reflect.Pointer || val.Kind() == reflect.Interface {
-			val = val.Elem()
-		}
-		if val.Kind() == reflect.Slice || val.Kind() == reflect.Array {
-			for j := 0; j < val.Len(); j++ {
-				item := val.Index(j)
-				if item.Kind() == reflect.Pointer || item.Kind() == reflect.Interface {
-					item = item.Elem()
-				}
-				v = append(v, fmt.Sprintf("%s", item.Interface()))
-			}
-		} else {
-			v = append(v, fmt.Sprintf("%s", val.Interface()))
-		}
-		h[key] = v
-	}
+	GenericValues(h).Parse(data, "header")
 }
 
 func (h Header) Get(key string) (value string) {
diff --git a/prototype.go b/prototype.go
index 1e7f9d7..cb0a15a 100644
--- a/prototype.go
+++ b/prototype.go
@@ -2,15 +2,18 @@ package router
 
 import "io"
 
-type Request interface {
+type RequestBuilder interface {
 	Allowed(method string) ErrorResponse
-	Header() Header
-	ReadBody(body io.ReadCloser) ErrorResponse
-	ParseForm(values map[string][]string) ErrorResponse
+	Header(Header) ErrorResponse
+	Body(body io.ReadCloser) ErrorResponse
+	Values(values Values) ErrorResponse
+	AllowedError() ErrorResponse
+	ReadError() ErrorResponse
+	ParseError() ErrorResponse
 }
 
-type PrototypeRequest interface {
-	Request() Request
+type PrototypeRequestBuilder interface {
+	RequestBuilder() RequestBuilder
 }
 
 type Response interface {
@@ -32,13 +35,10 @@ type ErrorResponse interface {
 
 type PrototypeErrorResponse interface {
 	ErrorResponse() ErrorResponse
-	AllowedError() ErrorResponse
-	ReadError() ErrorResponse
-	ParseError() ErrorResponse
 }
 
 type Prototype struct {
-	PrototypeRequest
+	PrototypeRequestBuilder
 	PrototypeResponse
 	PrototypeErrorResponse
 }
diff --git a/server.go b/server.go
index 9bf955c..2892c61 100644
--- a/server.go
+++ b/server.go
@@ -15,7 +15,7 @@ const (
 	numStages
 )
 
-type ServeFunc func(req Request, res Response) (errRes ErrorResponse)
+type ServeFunc func(req RequestBuilder, res Response) (errRes ErrorResponse)
 
 type server struct {
 	prototype Prototype
@@ -65,16 +65,18 @@ func (srv *server) handleError(errRes ErrorResponse, w http.ResponseWriter) (ok
 
 func (srv *server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	pro := srv.prototype
-	req := pro.Request()
+	req := pro.RequestBuilder()
 	if ok := srv.handleError(req.Allowed(r.Method), w); !ok {
 		return
 	}
-	req.Header().MergeOverwrite(Header(r.Header))
-	if ok := srv.handleError(req.ReadBody(r.Body), w); !ok {
+	if ok := srv.handleError(req.Header(Header(r.Header)), w); !ok {
+		return
+	}
+	if ok := srv.handleError(req.Body(r.Body), w); !ok {
 		return
 	}
 	r.ParseForm()
-	if ok := srv.handleError(req.ParseForm(r.Form), w); !ok {
+	if ok := srv.handleError(req.Values(Values(r.Form)), w); !ok {
 		return
 	}
 	res := pro.Response()
diff --git a/values.go b/values.go
new file mode 100644
index 0000000..050efa5
--- /dev/null
+++ b/values.go
@@ -0,0 +1,7 @@
+package router
+
+type Values map[string][]string
+
+func (v Values) Parse(data any) {
+	GenericValues(v).Parse(data, "form")
+}