Add support for form files

Author: mjarkk

create_error.go

@@ -10,6 +10,10 @@ func CreateJsonError(errors map[string]string) error {
 	return createCustomError(JsonMode, errors)
 }
 
+func CreateFormError(errors map[string]string) error {
+	return createCustomError(FormMode, errors)
+}
+
 func createCustomError(mode Mode, errors map[string]string) error {
 	fieldErrors := []FieldErrors{}
 	for key, message := range errors {

laravalidate.go

@@ -35,11 +35,13 @@ func newValidator(ctx context.Context, languages []language.Tag, value reflect.V
 type Mode uint8
 
 const (
-	GoMode Mode = iota
-	JsonMode
+	GoMode   Mode = iota
+	JsonMode      // Tries to use json struct tags
+	FormMode      // Tries to use form struct tags
 )
 
 // JsonValidate should be used to validate a json parsed message, errors returned will have a json paths.
+// These look at the `json="xx"` struct tag for hints how to name the error keys.
 //
 // If an error is returned the type should be of *ValidationError.
 //
@@ -49,6 +51,17 @@ func JsonValidate(ctx context.Context, languages []language.Tag, input any) erro
 	return validate(ctx, languages, input, JsonMode)
 }
 
+// FormValidate should be used to validate a form parsed message, errors returned will have a form paths.
+// These look at the `form="xx"` struct tag for hints how to name the error keys.
+//
+// If an error is returned the type should be of *ValidationError.
+//
+// Ctx can be set to nil, default value will be context.Background().
+// Languages can be set to nil, default value will be []language.Tag{language.English}.
+func FormValidate(ctx context.Context, languages []language.Tag, input any) error {
+	return validate(ctx, languages, input, FormMode)
+}
+
 // GoValidate should be used to validate something within a go codebase with validation errors that apply to the go codebase.
 //
 // If an error is returned the type should be of *ValidationError.
@@ -259,10 +272,12 @@ func (v *Validator) Validate(stack Stack, value *reflect.Value, valueType reflec
 		return
 	}
 
-	goPath, jsonPath := stack.ToPaths()
+	goPath, jsonPath, formPath := stack.ToPaths()
 	path := goPath
 	if v.mode == JsonMode {
 		path = jsonPath
+	} else if v.mode == FormMode {
+		path = formPath
 	}
 
 	v.errors = append(v.errors, FieldErrors{
@@ -295,6 +310,8 @@ outer:
 			stackElement := stack[len(stack)-1]
 			if v.mode == JsonMode {
 				replaceVariable(variable, stackElement.JsonName)
+			} else if v.mode == FormMode {
+				replaceVariable(variable, stackElement.FormName)
 			} else {
 				replaceVariable(variable, stackElement.GoName)
 			}

stack.go

@@ -16,6 +16,7 @@ const (
 type StackElement struct {
 	GoName     string
 	JsonName   string
+	FormName   string
 	Index      int // Only for kind == StackKindList
 	Kind       StackKind
 	Parent     *reflect.Value
@@ -24,20 +25,18 @@ type StackElement struct {
 
 type Stack []StackElement
 
-func (s Stack) ToPaths() (golang, json string) {
-	golang = ""
-	json = ""
-
+func (s Stack) ToPaths() (golang, json, form string) {
 	for idx, e := range s {
 		if idx == 0 {
 			golang = e.GoName
 			json = e.JsonName
+			form = e.FormName
 			continue
 		}
 		golang += "." + e.GoName
 		json += "." + e.JsonName
+		form += "." + e.FormName
 	}
-
 	return
 }
 
@@ -46,6 +45,7 @@ func (s Stack) AppendIndex(index int, parent *reflect.Value, parentType reflect.
 	return append(s, StackElement{
 		GoName:     indexStr,
 		JsonName:   indexStr,
+		FormName:   indexStr,
 		Index:      index,
 		Kind:       StackKindList,
 		Parent:     parent,
@@ -54,17 +54,30 @@ func (s Stack) AppendIndex(index int, parent *reflect.Value, parentType reflect.
 }
 
 func (s Stack) AppendField(field reflect.StructField, parent *reflect.Value, parentType reflect.Type) Stack {
-	jsonTag := field.Tag.Get("json")
-	jsonTag = strings.Split(jsonTag, ",")[0]
-
+	jsonTag, ok := field.Tag.Lookup("json")
 	jsonName := field.Name
-	if jsonTag != "" && jsonTag != "-" {
-		jsonName = jsonTag
+	if ok {
+		jsonTag = strings.Split(jsonTag, ",")[0]
+
+		if jsonTag != "" && jsonTag != "-" {
+			jsonName = jsonTag
+		}
+	}
+
+	formTag, ok := field.Tag.Lookup("form")
+	formName := field.Name
+	if ok {
+		formTag = strings.Split(formTag, ",")[0]
+
+		if formTag != "" && formTag != "-" {
+			formName = formTag
+		}
 	}
 
 	return append(s, StackElement{
 		GoName:     field.Name,
 		JsonName:   jsonName,
+		FormName:   formName,
 		Index:      -1,
 		Kind:       StackKindObject,
 		Parent:     parent,