Django: set default behavior in include template - python

I'm looking to set a default behavior in a template to be included.
I have a problem with Django template system not allowing to set variables in template (I've read about the Django Philosophy, and I understand it).
Here is my example problem:
I want to include a template to render a newsfeed:
template.html:
...
{% include "_newsfeed.html" with slicing=":20" %}
...
I would like to not be forced to enter the slicing argument, and set a default behavior, let's say ":20"
In my _newsfeed.html , I would like to do (pseudo-code, it doesn't work):
_newsfeed.html:
...
{% if not slicing %}{% with slicing=":20" %}{% endif %}
{% for content in newsfeed_content|slice:slicing %}
{# Display content #}
{% endfor %}
{% if not slicing %}{% endwith %}{% endif %}
Instead, I end up doing this below, that doesn't follow the DRY rule (and doesn't satisfy me!):
_newsfeed.html:
...
{% if not slicing %}{% with slicing=":20" %}
{% for content in newsfeed_content|slice:slicing %}
{# Display content #}
{% endfor %}
{% endwith %}{% else %}
{% for content in newsfeed_content|slice:slicing %}
{# Display content #}
{% endfor %}
{% endif %}
How should I do ?

If you want to do this via your template not your views file, you could create your own filter based on slice e.g.
from django.template.defaultfilters import slice_filter
#register.filter("slice_default", is_safe=True)
def slice_filter_20(value, arg=":20"):
return slice_filter(value, arg)

Related

Nest {% block %} in {% for %} Django template inheritance

I am developing a dictionary application using Django. One of the main themes of the app is displaying feeds of definitions.
Specifically, I have:
an "index" feed where new definitions are listed,
a "headword" feed where definitions of a particular headword are listed,
and a "tag" feed where definitions tagged with a particular tag are listed.
index.html:
{% block body %}
<h1>Definitions</h1>
<ul>
{% for definition in definitions %}
// definition HTML
{% endfor %}
</ul>
{% endblock %}
headword.html:
{% block body %}
<h1>{{ headword }}</h1>
<ul>
{% for definition in headword.definitions_headword.all %}
// definition HTML
{% endfor %}
</ul>
tag.html:
{% block body %}
<h1>{{ tag }}</h1>
<ul>
{% for definition in tag.definitions_tag.all %}
// definition HTML
{% endfor %}
</ul>
Clearly, I need a base feed.html template that these three files can share. For the h1 tag no problem. However, I am having problems with the for loop iterable variables.
I tried nesting a {% block iterable %}{% endblock %} in the for loop of feed.html as in {% for definition in {% block iterable %}{% endblock %} %} and then plugging definitions, headword.definitions_headword.all, and tag.definitions_tag.all in {% block iterable %}, but Django does not seem to support that.
I could probably pass to all three templates a "definitions" context variable and use that as the iterable in all three for loops, but is there a way to do it without touching Python code?
Your explanation was a bit fuzzy to me at the end there, but going just based off your first sentence of "Clearly, I need a base feed.html template that these three files can share."
I think {% include %} may be what you are looking for.
https://docs.djangoproject.com/en/3.0/ref/templates/builtins/#include
Create your base template of "feed.html" which includes generic variables. Generic variables below are "header_name" and "definitions".
<h1>{{ header_name }}</h1>
<ul>
{% for definition in definitions %}
// definition HTML
{% endfor %}
</ul>
In your parent templates (index, headword, tag), use the "include" tag. Pass in your parent template variables into the child template. Examples below:
headword.html
{% block body %}
{% include 'pathname/feed.html' with header_name=headword definitions=headword.definitions_headword.all %}
{% endblock %}
tag.html
{% block body %}
{% include 'pathname/feed.html' with header_name=tag definitions=tag.definitions_tag.all %}
{% endblock %}

Django assignment_tag conditional

I'm trying to show partials based on a simple condition. My condition is whether an assignment_tag is True or False.
Templatetag:
from django import template
register = template.Library()
#register.assignment_tag
def partner():
return False
Template:
{% load partner_check %}
{% if partner %}
{% block header %}
{% include 'includes/partner_header.djhtml' %}
{% endblock header %}
{% block footer %}
{% include 'includes/partner_footer.djhtml' %}
{% endblock footer %}
{% endif %}
No matter what I set partner to, the blocks still appear. What am I missing?
Firstly, that's not how assignment tags work. You have never actually called the tag; if partner refers to a (non-existent) template variable named "partner". You call an assignment tag by using it on its own along with a variable to assign it to:
{% partner as partner_value %}
{% if partner_value %}...{% endif %}
Secondly, that's not how blocks work either. You can't dynamically define blocks; they are part of the basic structure of a template, not something that is assigned during evaluation.
I accomplished this by using a context_processor (https://docs.djangoproject.com/en/1.7/ref/settings/#std:setting-TEMPLATE_CONTEXT_PROCESSORS)
Context Processor:
def partners(context):
return {
'partner': False
}
Template:
{% block header %}
{% if partner %}
{% include 'includes/partner_header.djhtml' %}
{% else %}
{{ block.super }}
{% endif %}
{% endblock header %}
{% block footer %}
{% if partner %}
{% include 'includes/partner_footer.djhtml' %}
{% else %}
{{ block.super }}
{% endif %}
{% endblock footer %}

Conditionally extending a template in Django

I have a download page on a Django site that I want to serve for both users who are logged in and who aren't. Instead of having a user_download.html and login_download.html, I want to have a single download.html that conditionally extends the correct base.
However, I get an error when I use the following code.
{% if user.is_authenticated %}
{% extends 'user_base.html' %}
{% else %}
{% extends 'login_base.html' %}
{% endif %}
{% block content %}
<h2>Downloadable content</h2>
...
{% endblock %}
The error I receive is
TemplateSyntaxError at /download/
Invalid block tag: 'else'
What's wrong with the else? I tried
{% if user.is_authenticated %}
{% extends 'user_base.html' %}
{% else %}{% if AnonymousUser.is_authenticated %}
{% extends 'login_base.html' %}
{% endif %}{% endif %}
{% block content %}
<h2>Downloadable content</h2>
...
{% endblock %}
but this didn't work, either.
Thanks,
erip
The {% extends %} tag supports variables. See the doc for reference.
def my_view(request):
if request.user.is_authenicated
base_template_name = 'user_base.html'
else:
base_template_name = 'login_base.html'
# Pass base template name to the renderer
return render_to_response('your_template.html', {'base_template_name':base_template_name})
Template (please note that the value is not quoted):
{% extends base_template_name %}
...
You're getting an error because extends needs to be defined at the top of the template. extends controls template inheritance: you are basically creating a subclass from some parent class, which is why extends needs to be the first thing in the template.
Imagine writing a class, and in the __init__() you said something like
class DoesntKnowWhereToInheritFrom(object):
def __init__():
if something:
self.inherits_from(x)
else
self.inherits_from(y)
The compiler/interpreter would freak out.
The common way to do what you are trying to do here is to check for is_authenticated in the view, and then render the appropriate template.

Is there a way to use django-inplaceedit to do in-place editing of a column in django-tables2 TemplateColumn?

I tried to make a state_template.html with
{% load inplace_edit %}
{% block extra_header %}
{% inplace_static %}
{% endblock %}
{% inplace_edit "action.action_state" %}
And tables.py has:
action_state = tables.TemplateColumn(template_name='django_tables2/state_template.html', verbose_name="State")
But since action is never being passed to the template, it is giving an error.
Does anyone have any ideas on how to make this work?
This is a very nice question :-)
I think if you update your template (state_template.html), with this should works:
{% load inplace_edit %}
{% block extra_header %}
{% inplace_static %}
{% endblock %}
{% inplace_edit "record.action_state" %}
And this is a recomendation, You should move to the template of the view that renderthe table, but this is only to efficiency:
{% block extra_header %}
{% inplace_static %}
{% endblock %}

How to override block of included template in Django?

Let's say I have this structure:
{# base.html #}
{% block content %}{% endblock %}
{# page.html #}
{% extends "base.html" %}
{% block content %}
{% include "snippet.html" %}
{# and I also want somehow to redefine {% block snippet_content %} of snippet here #}
{% endblock %}
{# snippet.html #}
<bells_and_whistles>
{% block snippet_content %}{% endblock %}
</bells_and_whistles>
I hope that the code is self-explaining.
Is there an elegant way to achieve this?
I'm afraid it is not possible in the way you want to do it.
Your options are:
Create a modified_snippet.html inheriting from snippet.html and overriding the block and include it instead
Change your snippet_content block to a {{ snippet_content }} variable and pass its contents using {% include "snippet.html" with snippet_content="My content" %}. Of course this method is quite limited.

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