Function FormValue

binder_generic.go:213–234

FormValue extracts and parses a single form value from the request by key. It returns the typed value and an error if binding fails. Returns ErrNonExistentKey if parameter not found. Empty String Handling: If the form field exists but has an empty value, the zero value of type T is returned with

(c *Context, key string, opts ...any)

//
// See ParseValue for supported types and options
func FormValue[T any](c *Context, key string, opts ...any) (T, error) {
	formValues, err := c.FormValues()
	if err != nil {
		var zero T
		return zero, fmt.Errorf("failed to parse form value, key: %s, err: %w", key, err)
	}
	values, ok := formValues[key]
	if !ok {
		var zero T
		return zero, ErrNonExistentKey
	}
	if len(values) == 0 {
		var zero T
		return zero, nil
	}
	value := values[0]
	v, err := ParseValue[T](value, opts...)
	if err != nil {
		return v, NewBindingError(key, []string{value}, "form value", err)
	}
	return v, nil
}

// FormValueOr extracts and parses a single form value from the request by key.
// Returns defaultValue if the parameter is not found or has an empty value.