Using variables in Django model content - python

i like to use the url template tag in my model's content.
example:
models content:
Car.description = 'this is a link to our main page: home'
in template.html:
<div>{{ Car.description }}</div>
result
<div>this is a link to our main page: home
is it possible, or do i have to write my own template tag?
thanks in advance
Roman

Assuming you have this:
car.description = 'this is a link to our main page: home'
You can do:
from django.template import Context, Template
from django.core.urlresolvers import reverse
class Car(models.Model):
def description_with_url(self):
return Template(self.description).render({'url': reverse('home')})
or use the same logic in custom template tag instead of method..

I can't figure out why you would need to do that. Assuming that I fully-understood your question, you are attempting to store something within a model's field that then behaves "dynamically" when rendered.
A model field's content that stores a URL should contain a URL and only a URL by utilizing the URLField.
Else, if you're dynamically building the URL from somewhere else, simply use template markup, i.e. the url template tag as it is meant to be used; it can also take parameters depending on the specific URL pattern. I.e. the url tag is meant to be used in the template's context.
Let me know if you update the question to describe what you are trying to achieve. But storing "behaviour" at data level is something to simply stay away from.

Related

Can Django's URL tag show the URL of the RedirectView

Let's say that in my urls.py I have a url like this:
path("support/", RedirectView.as_view(url="http://www.example.com"), name="support"),
And in one of my templates I use the url tag:
{% url "support" %}
This of course outputs /support/ as expected. But what if I want it to output http://www.example.com instead? Is that at all possible? Skip the redirect basically.
So Link would output Link.
But what if I want it to render http://www.example.com instead? Is that at all possible? Skip the redirect basically.
No, in short it is not possible with django views, since the url is of another website and you can't render it in your own.
You can see what exactly render() does.
If you'd like to directly redirect, then simply use anchor tag as:
Visit website.
You can also do this dynamically, by creating a URLField in one of the models and simply iterating it with href attribute of anchor tag.

How to access to get URL address by name in Django at model file (like {{ url 'urlname' }} at template)

Need to access URL by name at model, can't just hardcode it. Need it for error message for a new object creating. Any suggestions?
Update: Just need to put url to error message, not reverse
Your question is not totally clear, but I think you are asking about the reverse function.
You can define get_absolute_url method in your model and than access it in other model's methods. Check https://docs.djangoproject.com/en/2.1/ref/models/instances/#get-absolute-url
I suggest you use a template tag. You can build one for your model and avoid polluting the model about stuff not related to the domain level and keep the presentation level to the template.
Check the docs here on how add a templatetags your app.: https://docs.djangoproject.com/en/2.1/howto/custom-template-tags/
Here a snippet of code to use as starting point for your url generation
from django import template
register = template.Library()
#register.simple_tag(takes_context=True)
def url_for_object(context, object):
# you have both the context and the object available to
# generate your url here
url = ....
return url
In your template use
{% url_for_object my_object %}

Changing css styles from view in Django

Sorry in advance if there is an obvious answer to this, I'm still learning the ropes with Django.
I'm creating a website which has 6 pre determined subjects (not stored in DB)
english, civics, literature, language, history, bible
each subject is going to be associated with a unique color.
I've got a template for a subject.html page and a view that loads from the url appname/subject/subjectname
what I need to do is apply particular css to style the page according to the subject accessed. for example if the user goes to appname/subject/english I want the page to be "themed" to english.
I hope I've made myself clear, also I would like to know if there is a way I can add actual css code to the stylesheet and not have to change attributes one by one from the back-end.
thanks very much!
In templates you can use conditionals for add css, like this:
<div class="{% if subject=='civics' %}civic-class{% endif %}"></div>
For this, subject value should come from view.
Now, for themed page, you could use the extends tag. Let's supose:
def your_view(request):
subject # Here you get the url subject, 'how' is up to you
if subject == 'english'
template_base = '/some/html/tenplate.html'
elif subject == 'civis':
template_base = '/some/other/template.html'
... # then you return 'template_base' variable to template
Then in template:
{% extends template_base %} # at the top
Hope this helps, is the same logic if you use Class-Based views.
Django's views are not responsible for the presentation, it's the template (and css etc of course)'s reponsability. Now assuming you have the same view serving different subjects, the view obviously need to know which is the current subject (I assume from a captured part of the url passed as argument to the view), so it can easily pass this information to the template, which in turn can use it to add a subject-specific class to the body tag. Then you only have to write your css accordingly.
As an example:
# urls.py
patterns = urlpatterns('',
#...
url(r'whatever/(P?<subject>[a-z-]+>)/$', 'myviews.index', ...),
)
# myviews.py
def index(request, subject):
# do whatever
context = {
# whatever else
'subject':subject
}
return render(request, "whatever/index.html", context)
# whatever/index.html
<html>
# headers etc
<body class="something {{ subject }} etc">
# whatever here
</body>
</html>
You can do this is many ways.
In general you need to return some variable from your view to the html and depending on this variable select a style sheet, if your variable name will match you style sheet's name you can do "{{variable}}.css", if not you can use JQuery.

How to get the current URL of a page in a Django template?

I know there is another question with virtually the same title as mine but the solution in that one didn't work for me. My url is like this:
http://domain.com/videos/dvd/1/
If I use either {{baseurl}} or {{ request.get_full_path }} I get just this part:
http://domain.com/videos/
How can I get the entire url? I need to be able to do this from the template level.
EDIT
P.S. it should disregard any parameters that may be in the url.
You could get it in your view and pass it along into your template context so that it is available to you there.
https://docs.djangoproject.com/en/1.3/ref/request-response/#django.http.HttpRequest.build_absolute_uri
full_url = request.build_absolute_uri(None)
# pass full_url into the template context.

confusion in url and template in django

My url is :
1. http://localhost:8000/docs/[slug]
2. http://localhost:8000/docs/[slug]/login
1. url calls before number 2. url I want to send
the slug value to the function mapped by the url 2. In template
what should i wrote for form action event.
I agree, this is nearly incomprehensible, but I'm going to give it a go in terms of an answer.
In terms of calling sequence, there is none. A user might first visit url 2 or url 1. You have no way of guaranteeing which they will try to access first because they might directly input the url into their browser. The only thing you can do is set a variable in request.session's dict and test for it with your login url.
In terms of passing slug to another url, if you're having a url with this in it:
urls = ('',
url(r'docs/(?P<slug>\w+)', 'app.views.slug', name='slug-view'),
url(r'docs/(?P<slug>\w+)/login', 'app.views.slug_login', name='slug-login'),
#..
)
Then in your template you can do this:
<form action="{% url slug-login slugname %}" method="POST">
Your views.py would look something like this.
def slug(request, slug):
#
#
return render_to_response('templatename.html', {'slugname':slug}, context_instance=RequestContext(request))
def slug_login(request, slug):
# do something with slug.
This way, when you access the slug view, you pass into the template a variable called slugname, which the template uses with django's url library to resolve a specifically named url in urls.py with one named parameter, slug, which it will assign the value of slugname.
I suggest you try it.
I might also reccoment you read up on the django url dispatcher. Your use of regex without named parameters is acceptable but really not best practice. I'd also suggest django shortcuts (render_to_response) as a quick way to pass variables into templates and the django template language itself.

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