custom django templatetags libraries

[amitu]

Once # 30 is merged, the following diff implements this feature.

diff --git a/cactus/models.py b/cactus/models.py
new file mode 100644
index 0000000..e69de29
diff --git a/cactus/site.py b/cactus/site.py
index 0650d8f..f6e1f35 100644
--- a/cactus/site.py
+++ b/cactus/site.py
@@ -61,7 +61,9 @@ class Site(object):
                        logging.exception("Caught exception while opening config file")
                        config = {}

-               config.setdefault("INSTALLED_APPS", []).append("django.contrib.markup")
+               config.setdefault("INSTALLED_APPS", []).extends(
+                       ["django.contrib.markup", "cactus"]
+               )
                config.setdefault("TEMPLATE_DIRS", []).extend(
                        [self.paths['templates'], self.paths['pages']],
                )
@@ -358,6 +360,7 @@ class Site(object):
                        # Set an id based on the file name
                        plugin.id = pluginHandle

+                       sys.modules["cactus.templatetags.%s" % pluginHandle] = plugin
                        plugins.append(plugin)

                # Sort the plugins by their defined order (optional)
diff --git a/cactus/templatetags/__init__.py b/cactus/templatetags/__init__.py
new file mode 100644
index 0000000..e69de29

It is a bit hacky, I am making cactus project itself a valid django app by adding cactus.models module and cactus.templatetags package. Then I am putting all plugins available as cactus.templatestags.PLUGIN_NAME, Sample plugin, plugins/t.py:

from django import template
import random

register = template.Library()

@register.filter
def randomize(value):
    return "".join(random.sample(value, len(value)))

To use it in template:

{% extends "base.html" %}
{% load t %}
{% block content %}
    {{ "Welcome to Cactus!"|randomize }}
{% endblock %}

I thought of some naming convention for plugins, so only some plugins are added to cactus.templatetags.PLUGIN_NAME, but rejected it as now I can ship a blog plugin that contains both plugin hooks and custom templatetag libraries all related to blogging, list of posts etc.

[rukeba]

+1

[stepmr]

+1

[moskrc]

+1

[WillsB3]

Can anyone tell me what the status is here? I'd like to know if (and how) to create and use custom Django template tags with Cactus?

Thanks.

[krallin]

You can actually do this today (at least in v3, which is now the master version) using a plugin.

Here's an example:

from django import template
from django.template.loader import get_template

def signup_button(context, location):
    """
    Display the signup button
    """
    ctx = copy.copy(context)
    ctx.update({"loc": location})
    return ctx

def preBuild(_):
    register = template.Library()
    register.inclusion_tag(get_template('includes/buttons/signup-button.html'), takes_context=True)(signup_button)
    template.base.builtins.append(register)

Note that it's probably possible to clean this up a bit (and not hack into builtins). Looking at how Django loads new templatetags files is probably the best way to find out.

I seem to recall I had injected into builtins to not have to re-load this tag which was going to be used on every single page of my website, but I'm sure there's a cleaner way.

[WillsB3]

Thanks @krallin - I'll give that a go :+1:

[krallin]

Let me know if you run into any trouble. It's been a while since I used that plugin, but I'm pretty sure that site used to build so there has to be a way to make it work! : )

[pmdarrow]

@krallin the snippet you posted doesn't seem to work. I tried it with a really simple filter:

from django import template

def mymarkdown(value):
    return 'test'

def preBuild(site):
    register = template.Library()
    register.filter('mymarkdown', mymarkdown)

Which gives me:

django.template.base.TemplateSyntaxError: Invalid filter: 'mymarkdown'

[pmdarrow]

Update: the following works

from cactus.template_tags import register

def mymarkdown(value):
    return 'test'

def preBuild(site):
    register.filter('mymarkdown', mymarkdown)

[krallin]

@pmdarrow ,

You might have missed that line from the snippet:

template.base.builtins.append(register)

If you don't add that line, then you'd have to {% load ... %} the library.

Cheers,

[pmdarrow]

@krallin I'm writing a custom filter, and I registered it with Cactus' library using

from cactus.template_tags import register
register.filter('mymarkdown', mymarkdown)

so no builtins hacking was required.

[krallin]

@pmdarrow ,

I understand that. I was simply explaining why the snippet I provided did not work for you.

Basically, there are two ways to add a filter:

• Add the filter to a new library, and add that library to the built-ins (what I had originally suggested).
• Add the filter to a library that is already present in the built-ins (this is what you did).

Note that the cactus.template_tags library is added to the Django built-ins for you by Cactus:

https://github.com/koenbok/Cactus/blob/2dd7159280363f0b762d43e3bfa1ec1a2a6effea/cactus/site.py#L156

So, there's still builtins hacking, only it's not your plugin doing it ;)

Now, obviously, both ways work equally well! : )

Cheers,

[pmdarrow]

@krallin ah, that makes sense :smiley:. It would be awesome if there was some docs for this, but I see that's on the roadmap in #117. Might be worth closing this issue now that there's a solution.