wtforms.py 文件源码

def render(self, context):
        try:
            if '.' in self.field_var:
                base, field_name = self.field_var.rsplit('.', 1)
                field = getattr(Variable(base).resolve(context), field_name)
            else:
                field = context[self.field_var]
        except (template.VariableDoesNotExist, KeyError, AttributeError):
            return settings.TEMPLATE_STRING_IF_INVALID

        h_attrs = {}
        for k, v in iteritems(self.html_attrs):
            try:
                h_attrs[k] = v.resolve(context)
            except template.VariableDoesNotExist:
                h_attrs[k] = settings.TEMPLATE_STRING_IF_INVALID

        return field(**h_attrs)