wtforms.py 文件源码

def do_form_field(parser, token):
    """
    Render a WTForms form field allowing optional HTML attributes.
    Invocation looks like this:
      {% form_field form.username class="big_text" onclick="alert('hello')" %}
    where form.username is the path to the field value we want.  Any number
    of key="value" arguments are supported. Unquoted values are resolved as
    template variables.
    """
    parts = token.contents.split(' ', 2)
    if len(parts) < 2:
        error_text = '%r tag must have the form field name as the first value, followed by optional key="value" attributes.'
        raise template.TemplateSyntaxError(error_text % parts[0])

    html_attrs = {}
    if len(parts) == 3:
        raw_args = list(args_split(parts[2]))
        if (len(raw_args) % 2) != 0:
            raise template.TemplateSyntaxError('%r tag received the incorrect number of key=value arguments.' % parts[0])
        for x in range(0, len(raw_args), 2):
            html_attrs[str(raw_args[x])] = Variable(raw_args[x + 1])

    return FormFieldNode(parts[1], html_attrs)