Limit the number of nested plugins

I know that django-cms allows to limit the number of plugins inside a placeholder, but I need to limit the number of the nested plugins. I spent some time on how to do and then I found a possible solution, that I call inception plugin, see below.

from cms.plugin_base import CMSPluginBase
from cms.plugin_pool import plugin_pool
from django.template.response import SimpleTemplateResponse
import models

class CMSPluginMaxPluginAllowed(CMSPluginBase):
    max_plugins = None

    def add_view(self, request, form_url='', extra_context=None):
        num_children = len([v for v in self.parent.get_children() if v.get_plugin_instance()[0] is not None])
        if self.max_plugins and num_children >= self.max_plugins:
                return SimpleTemplateResponse('djangocms_inception/max_reached.html', {
                    'num_allowed': self.max_plugins,
                })
        return super(CMSPluginMaxPluginAllowed, self).add_view(request, form_url, extra_context)

class ParentPlugin(CMSPluginBase):
    admin_preview = False
    model = models.ParentModel
    render_template = "djangocms_inception/parent.html"
    allow_children = True
    child_classes = ['ChildPlugin']

plugin_pool.register_plugin(ParentPlugin)

class ChildPlugin(CMSPluginMaxPluginAllowed):
    admin_preview = False
    model = models.ChildModel
    render_template = "djangocms_inception/child.html"
    require_parent = True
    parent_classes = ['ParentPlugin']
    allow_children = True
    child_classes = ['SweetChildPlugin']
    max_plugins = 3

plugin_pool.register_plugin(ChildPlugin)

class SweetChildPlugin(CMSPluginMaxPluginAllowed):
    admin_preview = False
    model = models.SweetChild
    name = "SweetChild"
    render_template = "djangocms_inception/sweetchild.html"
    require_parent = True
    parent_classes = ['ChildPlugin']
    max_plugins = 1

plugin_pool.register_plugin(SweetChildPlugin)

My thoughts are:

• Is it a good choice using the add_view method?
• Are there any other solutions?
• It could be interesting to have this kind of feature in django-cms, what do you think about it?

Thanks!

[joshyu]

What is the progress about this issue? Is there a solution now?

[joeribekker]

I needed something similar and made a quick workaround by overriding the template. Simply add max_children = <number> to your Plugin class and create a new dragitem.html template in your templates folder templates/cms/toolbar/ to override the existing Django CMS template. See the diff below:

This nicely disabled the + icon when the maximum number of children has been reached.

--- env/lib/python3.5/site-packages/cms/templates/cms/toolbar/dragitem.html       2016-09-15 12:06:26.132803200 +0200
+++ templates/cms/toolbar/dragitem.html    2017-02-08 12:26:59.343312100 +0100
@@ -9,6 +9,17 @@
         {% if plugin.child_plugin_instances %} cms-dragitem-collapsable{% endif %}">
         {% language request.toolbar.toolbar_language %}
         {% if not disabled_child %}
+            {% with max_children=plugin.get_plugin_instance.1.max_children child_count=plugin.child_plugin_instances|length %}
+                {% if max_children %}
+                    <div class="cms-submenu-btn cms-submenu-add cms-btn
+                        {% if child_count >= max_children %} cms-btn-disabled{% endif %}">
+                        {% if child_count >= max_children %}
+                            <span class="cms-hover-tooltip" data-cms-tooltip="{% trans "You cannot add plugins to this plugin." %}"></span>
+                        {% else %}
+                            <span class="cms-hover-tooltip cms-hover-tooltip-left cms-hover-tooltip-delay" data-cms-tooltip="{% trans "Add plugin" %}"></span>
+                        {% endif %}
+                    </div>
+                {% else %}
             <div class="cms-submenu-btn cms-submenu-add cms-btn
                 {% if not allow_children %} cms-btn-disabled{% endif %}">
                 {% if not allow_children %}
@@ -17,6 +28,8 @@
                 <span class="cms-hover-tooltip cms-hover-tooltip-left cms-hover-tooltip-delay" data-cms-tooltip="{% trans "Add plugin" %}"></span>
                 {% endif %}
             </div>
+                {% endif %}
+            {% endwith %}
             <div class="cms-submenu-btn cms-submenu-edit cms-btn" data-rel="edit">
                 <span class="cms-hover-tooltip cms-hover-tooltip-left cms-hover-tooltip-delay" data-cms-tooltip="{% trans "Edit" %}"></span>
             </div>

I’ll wrap this as PR when I added a test.