Helpers

AsTag

class ttag.helpers.AsTag

Assists with the common case of tags which want to add something to the context.

For example, if you wanted a tag which would add a QuerySet containing a user’s friends to the context ({% get_friends user as friends %}):

class GetName(ttag.helpers.AsTag)
    user = ttag.Arg()

    def output(self, data, context):
        return data['user'].friends_set.all()

Some additional customization attributes to those which are provided in the standard Tag‘s Meta class are available:

class Meta

as_name

Use some other argument name rather than the default of as.

as_required

Set whether or not as varname argument is required (defaults to True).

Two additional methods of interest are as_value, which allows you to more completely customise output.

ttag.helpers.as_value(self, data, context)

Returns the value you want to put into the context variable. By default, returns the value of output().

ttag.helpers.as_output(self, data, context)

Returns the data you want to render when as varname is used. Defaults to ''.

TemplateTag

class ttag.helpers.TemplateTag

Allows creating a template tag whose output is rendered with a template.

For example, if you wanted a tag which would render a QuerySet containing a user’s friends with a specific template ({% render_friends user using "friend_list.html" %}):

class RenderFriends(ttag.helpers.TemplateTag)
    user = ttag.Arg()

    def output(self, data):
        return data['user'].friends_set.all()

the template friend_list.html would automatically be passed the data and output variables as well as the rest of the context in which the template tag was called in:

<h3>Friends of {{ data.user }} for {{ user }}</h3>
<ul>
{% for friend in output %}
    <li>{{ friend.username }}</li>
{% endfor %}
</ul>

One additional method of interest is using, which allows you to provide the template(s) to render the template tag with if no template was given via the using tag argument.

using(self, context)

Returns the template path or a list of template paths to be used when rendering the template tag with the render_to_string(). This method will only be considered if the template tag wasn’t passed a template path with the using argument.

Following the example above you could extend it to use a user specific template if available and fall back to a general template otherwise:

class RenderFriends(ttag.helpers.TemplateTag)
    user = ttag.Arg()

    def output(self, data):
        return data['user'].friends_set.all()

    def using(self, data):
        return [
            'friend_list_%s.html' % data['user'].username,
            'friend_list.html',
        ]

An additional customization attribute to those which are provided in the standard Tag‘s Meta class is available:

class Meta

template_name

Use some other argument name rather than the default of using.