django-tag-parser 1.0.2

Arguments and keyword arguments

To parse a syntax like:

{% my_tag "arg1" keyword1="bar" keyword2="foo" %}

use:

@template_tag(register, 'my_tag')
class MyTagNode(BaseNode):
    max_args = 1
    allowed_kwargs = ('keyword1', 'keyword2',)

    def render_tag(self, context, *tag_args, **tag_kwargs):
        return "Tag Output"

Inclusion tags

To create an inclusion tag with overwritable template_name:

{% my_include_tag "foo" template="custom/example.html" %}

use:

@template_tag(register, "my_include_tag")
class MyIncludeTag(BaseInclusionNode):
    template_name = "mytags/default.html"
    max_args = 1

    def get_context_data(self, parent_context, *tag_args, **tag_kwargs):
        (foo,) = *tag_args
        return {
            'foo': foo
        }

The get_template_name() method can be overwritten too to support dynamic resolving of template names. Note the template nodes are cached afterwards, it’s not possible to return random templates at each call.

Custom parsing

With a standard Node class, it’s easier to implement custom syntax. For example, to parse:

{% getfirstof val1 val2 as val3 %}

use:

@template_tag(register, 'getfirstof')
class GetFirstOfNode(Node):
    def __init__(self, options, as_var):
        self.options = options    # list of FilterExpression nodes.
        self.as_var = as_var

    @classmethod
    def parse(cls, parser, token):
        bits, as_var = parse_as_var(parser, token)
        tag_name, options, _ = parse_token_kwargs(parser, bits, allowed_kwargs=())

        if as_var is None or not choices:
            raise TemplateSyntaxError("Expected syntax: {{% {0} val1 val2 as val %}}".format(tag_name))

        return cls(options, as_var)

    def render(self, context):
        value = None
        for filterexpr in self.options:
            # The ignore_failures argument prevents that the value becomes TEMPLATE_STRING_IF_INVALID.
            value = filterexpr.resolve(context, ignore_failures=True)
            if value is not None:
                break

        context[self.as_var] = value
        return ''

Contributing

This module is designed to be generic. In case there is anything you didn’t like about it, or think it’s not flexible enough, please let us know. We’d love to improve it!

If you have any other valuable contribution, suggestion or idea, please let us know as well because we will look into it. Pull requests are welcome too. :-)