I want to make all of my asterisks (*) in a template in red color in a Django Template. (E.g. in form labels that * symbol points the field is required. But when putting * in label of a form field it is rendered as black color as usual.
How can I accomplish this by for example registering a filter or tag?
Note that I use some libraries (e.g. bootstrap4 form) and the page is full of {{ }} tags. BUT I want to find&replace all ;black *' with 'red *' in final rendered html page.
EDIT: I use django-bootstrap4 and so I simply use
{% bootstrap_form form %} in my templates. (So not have explicit access to label texts) How can I perform my goal?
This is what works for me
# templatetags/custom_tags.py
from django import template
register = template.Library()
#register.filter
def mark_as_required(text):
return '<span style="color:red">{text}</span>'.format(text=text)
# templates/xxx.html
...
{% load custom_tags %}
...
{{ '*'|mark_as_required|safe }}
...
I am new to Django and I am trying to make my data accessible to templates in different apps by creating custom tags in Django.
my model.py
from django.db import models
class my_Model(models.Model):
name = models.CharField(max_length=20)
age = models.CharField(max_length=20)
my custom tag file templatetag/custom_tag.py(why I did this is to make my data accessible to templates in different apps)
from django import template
from model_file.models import my_Model
register = template.Library()
#register.simple_tag
def get_custom_tag_fn():
return my_Model.objects.order_by('-pk')[0]
my html file
{% load custom_tag %}
{% get_custom_tag_fn as ct %}
{% for item in ct %}
<p> {{ item }} </p>
{% endfor %}
I am getting the error 'My_Model' object is not iterable. Any thought about how to solve this.
The problem is here:
return my_Model.objects.order_by('-pk')[0]
Model objects.order_by(...) returns queryset, alike to the list it`s a collection, so with [0] index you take the first object of that collection which of course is not iterable (it's just a single object). So, after that, when you trying to iterate:
{% for item in ct %}
...
you`re catching this error.
I'm using Django 1.8.
I want to use a CharField with an internal context variable.
For example,
in models.py
...
content = models.CharField(max_length=200)
...
in template:
...
{{ model_instance.content }}
...
The output in html:
...
The content of a context variable is {{ request.variable }}
...
But I want to get:
...
The content of a context variable is test-test-test
...
How can I accomlpish it? I used {{ model_instance.content|safe }}, but it had no effect.
A simple template tag will do it:
yourapp/templatetags/yourapp_tags.py
from django.template import Template
#register.simple_tag(takes_context=True)
def render(context, content):
return Template(content).render(context)
yourapp/templates/template.html
{% load yourapp_tags %}
{% render model_instance.content %}
Just make sure your content fields are not writable for plain site users, as it imposes a security risk.
I have this data that comes from a field in the database:
item_list = Links.objects.filter(visible=True)
In an iteration of item_list there is item.name and item.link. In item.link there could potentially be a string value of
'/app/user/{{user.id}}/'.
When rendering this particular item.link in a Django template, it comes out literally in html output as:
/app/user/{{user.id}}/
when literally I am hoping for it to render as:
/app/user/1/
Is there any way to force the template to recognize this as a compiled value for output?
You have to create a custom template tag:
from django import template
register = template.Library()
#register.simple_tag(takes_context=True)
def render(context, tpl_string):
t = template.Template(tpl_string)
return t.render(context)
And the in your template:
{% load my_tags %}
{% render item.link %}
I'm implementing a custom permissions application in my Django project, and I'm lost as to how to implement a custom template tag that checks a logged in user's permissions for a specific object instance and shows a piece of HTML based on the outcome of the check.
What I have now is (pseudocode):
{% check_permission request.user "can_edit" on article %}
<form>...</form>
{% endcheck %}
('check_permission' is my custom template tag).
The templatetag takes in the user, the permission and the object instance and returns the enclosed HTML (the form). This currently works fine.
What I would like to do however, is something like:
{% if check_permission request.user "can_edit" on article %}
<form>...</form>
{% else %}
{{ article }}
{% endif %}
I've read about the assignment tag, but my fear is that I would pollute the context variable space with this (meaning I might overwrite previous permission context variables). In other words, as the context variables are being defined on different levels (the view, middleware in my case, and now this assignment template tag), I'm worried about maintainability.
You can use template filters inside if statements. So you could rewrite your tag as a filter:
{% if request.user|check_can_edit:article %}
Note that it's tricky to pass multiple arguments of different types to a filter, so you'll probably want to use one filter per permission, above I've used check_can_edit.
You can definitely do that if you're willing to write some more lines of python code to improve your template readability! :)
You need to parse the tag content yourself, even the parameters it takes and then resolve them, if you want to use variables on them.
The tag implemented below can be used like this:
{% load mytag %}
{% mytag True %}Hi{% else %}Hey{% endmytag %} Bro
Or with a variable:
{% mytag myobject.myflag %}Hi{% else %}Hey{% endmytag %} Bro
So, here's the way I did it:
from django.template import Library, Node, TemplateSyntaxError
register = Library()
#register.tag
def mytag(parser, token):
# Separating the tag name from the "test" parameter.
try:
tag, test = token.contents.split()
except (ValueError, TypeError):
raise TemplateSyntaxError(
"'%s' tag takes two parameters" % tag)
default_states = ['mytag', 'else']
end_tag = 'endmytag'
# Place to store the states and their values
states = {}
# Let's iterate over our context and find our tokens
while token.contents != end_tag:
current = token.contents
states[current.split()[0]] = parser.parse(default_states + [end_tag])
token = parser.next_token()
test_var = parser.compile_filter(test)
return MyNode(states, test_var)
class MyNode(Node):
def __init__(self, states, test_var):
self.states = states
self.test_var = test_var
def render(self, context):
# Resolving variables passed by the user
test_var = self.test_name.resolve(context, True)
# Rendering the right state. You can add a function call, use a
# library or whatever here to decide if the value is true or false.
is_true = bool(test_var)
return self.states[is_true and 'myvar' or 'else'].render(context)
And that's it. HTH.
In Django 2 the assignment tag was replaced by simple_tag() but you could store the custom tag result as a template variable:
# I'm assuming that check_permission receives user and article,
# checks if the user can edit the article and return True or False
{% check_permission user article as permission_cleared %}
{% if permission_cleared %}
<form>...</form>
{% else %}
{{ article }}
{% endif %}
Check the current doc about custom template tags: https://docs.djangoproject.com/en/2.1/howto/custom-template-tags/#simple-tags
inside my_tags.py
from django import template
register = template.Library()
#register.simple_tag(takes_context=True)
def make_my_variable_true(context):
context['my_variable'] = True
return '' # without this you'll get a "None" in your html
inside my_template.html
{% load my_tags %}
{% make_my_variable_true %}
{% if my_variable %}foo{% endif %}
In this case best solution is to use custom filter. If you don't want write long code for custom tag. Also if you don't want to copy/paste others code.
Here is an example
Inside templatetag
register = template.Library()
def exam_available(user, skill):
skill = get_object_or_404(Skill, id=skill)
return skill.exam_available(user)
register.filter('exam_available', exam_available)
Inside template
{{ request.user|exam:skill.id }}
or
{% if request.user|exam:skill.id %}
Since one of the main common of it is to use request.user or any specific object(id) inside model's custom method, so filtering that individual object or user is the easiest way to make it done. :)