encode/decode: adds SetElementNamePrefix which allows a prefix to be specified for all element names

decode.go

@@ -18,6 +18,7 @@ type HTTPDecoder struct {
 	validationStore           ValidationStore
 	setValueOnValidationError bool
 	numValidationErrors       int
+	elementNamePrefix         string
 }
 
 // NewDecoder creates a new HTTPDecoder.
@@ -40,6 +41,10 @@ func (h *HTTPDecoder) SetValidationStore(v ValidationStore) {
 	h.validationStore = v
 }
 
+func (h *HTTPDecoder) SetElementNamePrefix(prefix string) {
+	h.elementNamePrefix = prefix
+}
+
 // SetValueOnValidationError indicates whether a form value should be set in the form if there was a validation error on that value.
 func (h *HTTPDecoder) SetValueOnValidationError(b bool) {
 	h.setValueOnValidationError = b
@@ -122,7 +127,7 @@ func (h *HTTPDecoder) Decode(data interface{}) error {
 }
 
 func (h *HTTPDecoder) getFormValues(key string) []string {
-	key = FormElementName(key)
+	key = FormElementName(h.elementNamePrefix, key)
 
 	var vals []string
 
@@ -137,7 +142,7 @@ func (h *HTTPDecoder) decode(val reflect.Value, key string, validators []Validat
 	if val.CanInterface() {
 		switch a := val.Interface().(type) {
 		case CustomDecoder:
-			decodedFormVal, err := a.DecodeFormValue(h.form, key, h.getFormValues(key))
+			decodedFormVal, err := a.DecodeFormValue(h.form, FormElementName(h.elementNamePrefix, key), h.getFormValues(key))
 
 			if err != nil {
 				return err
@@ -162,7 +167,7 @@ func (h *HTTPDecoder) decode(val reflect.Value, key string, validators []Validat
 
 			return nil
 		case time.Time:
-			formValue, ok := PopFormValue(h.form, FormElementName(key))
+			formValue, ok := PopFormValue(h.form, FormElementName(h.elementNamePrefix, key))
 
 			var t time.Time
 
@@ -230,7 +235,7 @@ func (h *HTTPDecoder) decode(val reflect.Value, key string, validators []Validat
 		return nil
 	}
 
-	formValue, ok := PopFormValue(h.form, FormElementName(key))
+	formValue, ok := PopFormValue(h.form, FormElementName(h.elementNamePrefix, key))
 
 	if !ok {
 		// below we are dealing with concrete types that do not call decode recursively.
@@ -358,7 +363,7 @@ func (h *HTTPDecoder) passedValidation(key string, value interface{}, validators
 		if !valid {
 			h.numValidationErrors++
 
-			err := h.validationStore.AddValidationError(FormElementName(key), ValidationError{
+			err := h.validationStore.AddValidationError(FormElementName(h.elementNamePrefix, key), ValidationError{
 				Value: value,
 				Error: message,
 			})

encode.go

@@ -25,9 +25,10 @@ type HTMLEncoder struct {
 	w io.Writer
 	r *http.Request
 
-	decorator       Decorator
-	format          bool
-	validationStore ValidationStore
+	decorator         Decorator
+	format            bool
+	validationStore   ValidationStore
+	elementNamePrefix string
 
 	csrfProtection bool
 }
@@ -69,6 +70,11 @@ func (h *HTMLEncoder) SetCSRFProtection(enabled bool) {
 	h.csrfProtection = enabled
 }
 
+// SetElementNamePrefix allows a prefix to be specified for all element names.
+func (h *HTMLEncoder) SetElementNamePrefix(prefix string) {
+	h.elementNamePrefix = prefix
+}
+
 // SetValidationStore can be used to tell the HTMLEncoder about previous validation errors.
 func (h *HTMLEncoder) SetValidationStore(v ValidationStore) {
 	if v == nil {
@@ -78,6 +84,11 @@ func (h *HTMLEncoder) SetValidationStore(v ValidationStore) {
 	h.validationStore = v
 }
 
+// GetValidationStore returns the current validation store.
+func (h *HTMLEncoder) GetValidationStore() ValidationStore {
+	return h.validationStore
+}
+
 func errorIncorrectValue(t reflect.Type) error {
 	return fmt.Errorf("formulate: encode expects a struct value, got: %s", t.String())
 }
@@ -146,7 +157,7 @@ func (h *HTMLEncoder) recurse(v reflect.Value, key string, field StructField, pa
 	if v.CanInterface() {
 		switch v.Interface().(type) {
 		case time.Time, Select, RadioList, CustomEncoder:
-			return BuildField(v, FormElementName(key), field, parent, h.decorator, h.ShowConditions)
+			return BuildField(v, FormElementName(h.elementNamePrefix, key), field, parent, h.decorator, h.ShowConditions)
 		}
 	}
 
@@ -171,7 +182,7 @@ func (h *HTMLEncoder) recurse(v reflect.Value, key string, field StructField, pa
 
 			nextKey := key + fieldSeparator + v.Type().Field(i).Name
 
-			validationErrors, err := h.validationStore.GetValidationErrors(FormElementName(nextKey))
+			validationErrors, err := h.validationStore.GetValidationErrors(FormElementName(h.elementNamePrefix, nextKey))
 
 			if err != nil {
 				return err
@@ -217,7 +228,7 @@ func (h *HTMLEncoder) recurse(v reflect.Value, key string, field StructField, pa
 
 		return h.recurse(reflect.ValueOf(Raw(buf.Bytes())), key, field, parent)
 	default:
-		return BuildField(v, FormElementName(key), field, parent, h.decorator, h.ShowConditions)
+		return BuildField(v, FormElementName(h.elementNamePrefix, key), field, parent, h.decorator, h.ShowConditions)
 	}
 }
 
@@ -787,14 +798,14 @@ func BuildRadioButtons(r RadioList, key string, field StructField, decorator Dec
 const fieldSeparator = "."
 
 // FormElementName returns the name of the form element within the form, removing the package path and base struct name.
-func FormElementName(key string) string {
+func FormElementName(prefix string, key string) string {
 	keySplit := strings.Split(key, fieldSeparator)
 
 	if len(keySplit) > 2 {
-		return strings.Join(keySplit[2:], fieldSeparator)
+		return prefix + strings.Join(keySplit[2:], fieldSeparator)
 	}
 
-	return key
+	return prefix + key
 }
 
 func BuildLabel(label string, parent *html.Node, field StructField, decorator Decorator) {

encode_test.go

@@ -156,6 +156,7 @@ func TestHtmlEncoder_Encode(t *testing.T) {
 	buf := new(bytes.Buffer)
 	m := NewEncoder(buf, nil, nil)
 	m.SetFormat(true)
+	m.SetElementNamePrefix("EncoderPrefix")
 
 	if err := m.Encode(&YourDetails{
 		Name:           "Jane Doe",

types.go

@@ -93,7 +93,7 @@ type BoolNumber int
 
 // DecodeFormValue implements the CustomDecoder interface.
 func (bn BoolNumber) DecodeFormValue(form url.Values, name string, _ []string) (reflect.Value, error) {
-	val, _ := PopFormValue(form, FormElementName(name))
+	val, _ := PopFormValue(form, name)
 
 	if val == "on" || val == "1" {
 		return reflect.ValueOf(BoolNumber(1)), nil