django-widget-tweaks / widget_tweaks / templatetags /

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import re
from django.template import Library, Node, Variable, TemplateSyntaxError
register = Library()

def silence_without_field(fn):
    def wrapped(field, attr):
        if not field:
            return ""
            return fn(field, attr)
    return wrapped

def _process_field_attributes(field, attr, process):

    # split attribute name and value from 'attr:value' string
    params = attr.split(':', 1)
    attribute = params[0]
    value = params[1] if len(params) == 2 else ''

    # decorate field.as_widget method with updated attributes
    old_as_widget = field.as_widget

    def as_widget(self, widget=None, attrs=None, only_initial=False):
        attrs = attrs or {}
        process(widget or self.field.widget, attrs, attribute, value)
        return old_as_widget(widget, attrs, only_initial)

    bound_method = type(old_as_widget)
        field.as_widget = bound_method(as_widget, field, field.__class__)
    except TypeError: # python 3
        field.as_widget = bound_method(as_widget, field)
    return field

def set_attr(field, attr):

    def process(widget, attrs, attribute, value):
        attrs[attribute] = value

    return _process_field_attributes(field, attr, process)

def append_attr(field, attr):
    def process(widget, attrs, attribute, value):
        if attrs.get(attribute):
            attrs[attribute] += ' ' + value
        elif widget.attrs.get(attribute):
            attrs[attribute] = widget.attrs[attribute] + ' ' + value
            attrs[attribute] = value
    return _process_field_attributes(field, attr, process)

def add_class(field, css_class):
    return append_attr(field, 'class:' + css_class)

def add_error_class(field, css_class):
    if hasattr(field, 'errors') and field.errors:
        return add_class(field, css_class)
    return field

def set_data(field, data):
    return set_attr(field, 'data-' + data)

# render_field tag

ATTRIBUTE_RE = re.compile(r"""
    ['"]? # start quote
    ['"]? # end quote
""", re.VERBOSE | re.UNICODE)

def render_field(parser, token):
    Render a form field using given attribute-value pairs

    Takes form field as first argument and list of attribute-value pairs for
    all other arguments.  Attribute-value pairs should be in the form of
    attribute=value or attribute="a value" for assignment and attribute+=value
    or attribute+="value" for appending.
    error_msg = '%r tag requires a form field followed by a list of attributes and values in the form attr="value"' % token.split_contents()[0]
        bits = token.split_contents()
        tag_name = bits[0]
        form_field = bits[1]
        attr_list = bits[2:]
    except ValueError:
        raise TemplateSyntaxError(error_msg)

    form_field = parser.compile_filter(form_field)

    set_attrs = []
    append_attrs = []
    for pair in attr_list:
        match = ATTRIBUTE_RE.match(pair)
        if not match:
            raise TemplateSyntaxError(error_msg + ": %s" % pair)
        dct = match.groupdict()
        attr, sign, value = dct['attr'], dct['sign'], parser.compile_filter(dct['value'])
        if sign == "=":
            set_attrs.append((attr, value))
            append_attrs.append((attr, value))

    return FieldAttributeNode(form_field, set_attrs, append_attrs)

class FieldAttributeNode(Node):
    def __init__(self, field, set_attrs, append_attrs):
        self.field = field
        self.set_attrs = set_attrs
        self.append_attrs = append_attrs

    def render(self, context):
        bounded_field = self.field.resolve(context)
        for k, v in self.set_attrs:
            bounded_field = set_attr(bounded_field, '%s:%s' % (k,v.resolve(context)))
        for k, v in self.append_attrs:
            bounded_field = append_attr(bounded_field, '%s:%s' % (k,v.resolve(context)))
        return bounded_field

def field_type(value):
    return value.field.__class__.__name__.lower()

def widget_type(value):
    return value.field.widget.__class__.__name__.lower()