Initial commit of form submission struct.

controller/form.go

@@ -0,0 +1,91 @@
+package controller
+
+import (
+	"reflect"
+
+	"github.com/go-playground/validator/v10"
+
+	"github.com/labstack/echo/v4"
+)
+
+type FormSubmission struct {
+	IsSubmitted bool
+
+	Errors map[string][]string
+}
+
+func (f *FormSubmission) Process(ctx echo.Context, form interface{}) error {
+	f.Errors = make(map[string][]string)
+	f.IsSubmitted = true
+
+	// Validate the form
+	if err := ctx.Validate(form); err != nil {
+		f.setErrorMessages(form, err)
+	}
+
+	return nil
+}
+
+func (f FormSubmission) HasErrors() bool {
+	if f.Errors == nil {
+		return false
+	}
+	return len(f.Errors) > 0
+}
+
+func (f FormSubmission) FieldHasError(fieldName string) bool {
+	return len(f.GetFieldErrors(fieldName)) > 0
+}
+
+func (f FormSubmission) GetFieldErrors(fieldName string) []string {
+	if f.Errors == nil {
+		return []string{}
+	}
+
+	errors, has := f.Errors[fieldName]
+	if !has {
+		return []string{}
+	}
+
+	return errors
+}
+
+func (f *FormSubmission) setErrorMessages(form interface{}, err error) {
+	// Only this is supported right now
+	ves, ok := err.(validator.ValidationErrors)
+	if !ok {
+		return
+	}
+
+	formType := reflect.TypeOf(form)
+
+	for _, ve := range ves {
+		var message string
+
+		// Default the field form name to the name of the struct field
+		fieldName := ve.StructField()
+
+		// Attempt to get the form field name from the field's struct tag
+		if field, ok := formType.FieldByName(ve.Field()); ok {
+			if fieldNameTag := field.Tag.Get("form"); fieldNameTag != "" {
+				fieldName = fieldNameTag
+			}
+		}
+
+		// Provide better error messages depending on the failed validation tag
+		// This should be expanded as you use additional tags in your validation
+		switch ve.Tag() {
+		case "required":
+			message = "This field is required."
+		case "email":
+			message = "Enter a valid email address."
+		case "eqfield":
+			message = "Does not match."
+		default:
+			message = "Invalid value."
+		}
+
+		// Add the error
+		f.Errors[fieldName] = append(f.Errors[fieldName], message)
+	}
+}