Django : filter Datefield in template - django

I'm using Django 1.5.8
I'd like to filter Datefield type data in template like following code.
express with timesince format for recent articles
express with date format for old articles
some_template.html
{% for article in articles %}
{# recent articles #}
{% if article.created >= (now - 7 days) %}
{{ article.created|timesince }}
{# old articles more than one week past #}
{% else %}
{{ article.created|date:"m d" }}
{% endif %}
{% endfor %}
Is there a solution to handle {% if article.created >= (now - 7 days) %} by django's own template tags?
Or do I have to make new custom filter?

Although I'm sure it's possible to do this with a custom template tag, I think you'll find it is a lot easier to implement this test in your model code. For example:
from datetime import date, timedelta
class Article(models.Model):
[...]
def is_recent(self):
return self.created >= date.today() - timedelta(days=7)
Then your template can be:
{% for article in articles %}
{% if article.is_recent %}
{{ article.created|timesince }}
{% else %}
{{ article.created|date:"m d" }}
{% endif %}
{% endfor %}

Related

Test date value in django views

In order to make sure my database values don't create null value exceptions I created a dummy date of 01-01-0001 in Postgresql.
However I want my views to return none if it's the dummy date in the view.
I tried the following but it's not working:
{% if myDate == "0001-01-01" %}
None
{% else %}
{{ myDate }}
{% endif %}
You can use Django date filter template tag
{% if myDate|date:"Y-m-d" == "0001-01-01" %}
None
{% else %}
{{ myDate }}
{% endif %}

how to query for the full name in django

I have a template which will display all the likes and the person liked for a particular forum. In the template it can display numbers of likes and all the person's username that liked that forum. But I want the full name and not the username (here it is the email). How do I get the full name in the template or if possible from the view itself. Thank you.
forums.html:
{% extends "base.html" %}
{% load forum_tags %}
{% block content %}
<h2>Logged in as -- {{request.user}}</h2>
<h1>Forums:</h1>
{% if forums.count > 0 %}
{% for forum in forums %}
<h2>{{forum.question}}</h2>
<p>{{forum.body | truncatewords:"30"}}</p>
{% if user in forum.likes.all and forum.likes.count > 1 %}
<p>Unlike You and {{forum.likes.count | substract:1}} others liked</p>
{% elif user in forum.likes.all %}
<p>You liked it</p>
{% else %}
<p>Like</p>
{% endif %}
{% for likes in forum.likes.all %}
<li>{{likes}}</li>
{% endfor %}
{% endfor %}
{% else %}
<p>Sorry! No forum to display.</p>
{% endif %}
{% endblock %}
snippet of views.py:
def forums(request):
forums = Forum.objects.all()
c = {'forums': forums}
return render(request, 'forums.html', c)
If you're using the default User model from django.contrib.auth.models, it has a get_full_name method that you can use in your template:
{{ user.get_full_name }}
Otherwise, you can implement that method in your own User model too. Any method that accepts no arguments can be called from templates (unless they have a alters_data attribute set to True).

Detect row difference (view or model)?

I would like to display a list of publications on my website; however, I would also like to diaplay a header stating the year for each set of publications published on that particular year.
So I would like for my end result to be like this (my reputation is 1 :( I could not upload the image):
https://dl.dropboxusercontent.com/u/10752936/Screen%20Shot%202013-06-21%20at%206.00.15%20PM.png
I have a table with three columns; id (primary key), title (the title of the article), and date (the date of publications)
In my template file; doing the following will print the header before every article:
{% for curr_pub in all_publications %}
<h1>{{ curr_pub.date.year }}</h1>
<li>{{ curr_pub.title }}</li>
{% endfor %}
I am passing all_publications ordered by '-date' which means that I can compare the year of the current row curr_pub with the previous one and check if it differs or not; and print (or not print) the header accordingly. It seems however, that I cannot do that in the template.
Since I am new to Django and Python, I wasn't sure what to do and this is where I need help; my thoughts were the following:
1) Add a function in the model (def is_it_first_publication(self):) that returns true or false - but I really wasn't able to do that :| - ...and I'm not sure if that is what I needed to do or not!
2) Second one is to do in in the view, and pass extra variable(s) to the template; here's an example (which works just fine for this case):
In the view:
def publications(request):
all_publications = Publications.objects.order_by('-date')
after_first_row_flag = False
f_year = 'Null'
list_of_ids_of_first_publications = []
for curr_pub in all_publications:
if after_first_row_flag:
if curr_pub.date.year != f_year:
list_of_ids_of_first_publications.append(curr_pub.id)
f_year = curr_pub.date.year
else:
# The year of first (or earliest) publication has to be added
#
list_of_ids_of_first_publications.append(curr_pub.id)
f_year = curr_pub.date.year
after_first_row_flag = True
template = loader.get_template('counters/publications.html')
context = RequestContext(request, {
'all_publications': all_publications,
'list_of_first_publications': list_of_ids_of_first_publications,
})
return HttpResponse(template.render(context))
In the template:
{% for curr_pub in all_publications %}
{% if curr_pub.id in list_of_first_publications %}
<h1> {{ curr_pub.date.year }} </h1>
{% endif %}
<li> Placeholder for [curr_pub.title] </li>
{% endfor %}
The regroup built in filter can do this for you without annotating your objects in the view. As the documentation says, it's kind of complicated.
https://docs.djangoproject.com/en/dev/ref/templates/builtins/#regroup
{% regroup all_publications by date.year as year_list %}
{% for year in year_list %}
<h1>{{ year.grouper }}</h1>
{% for publication in year.list %}
<li>{{ publication.title }}</li>
{% endfor %}
{% endfor %}
I think you want the regroup template tag;
{% regroup all_publications by date as publication_groups %}
<ul>
{% for publication_group in publication_groups %}
<li>{{ publication_group.grouper }}
<ul>
{% for publication in publication_group.list %}
<li>{{ publication.title }}</li>
{% endfor %}
</ul>
</li>
{% endfor %}
</ul>
Maybe the template tag regroup could help.
Alternatively, you could do this grouping by year in the view function (will try to provide code later).

reduce django db calls

I noticed that my django code calls my database very often with the exact same queries.
I understand that a db hit is made when I actually need the data to display on a page or to evaluate. However, my template code looks like this:
template:
{% if item.listing %}
{{ item.name }} text <strong>{{ item.listing|lowestprice }}</strong> more text
{% else %}
{{ item.name }} even more text
{% endif %}
....
{% for listed_item in item.listing %}
....
{% endfor %}
custom filter:
def lowestprice(value):
try:
val = unicode(value[0].price) + unicode(value[0].symbol)
return val
except:
return "not available"
This code hits my db three times. First on template {% if .. %} second on my custom filter, third on the {% for %} loop.
listing is a method of my models class which is returning a raw SQL queryset with some very expensive joins.
def listing(self):
return Universe.objects.raw("ONE HELL OF A QUERY")
How can I reduce my code to hit the db only once?
Edit: Using with works, but is it possible to avoid db hits on custom filters?
You should use with to do the expensive query once and store it the context.
{% with item.listing as item_listing %}
{% if item_listing %} ... {% endif %} ... etc ...
{% endwith %}

How to limit a collection of objects related on a foreign key in Django Templates?

Given is a model called "comment" with a foreign key relationship to a model called "task".
{% for task in tasks %}
{% for comment in task.comment_set.all %}
{{ comment }}
{% endfor %}
...
What is the best way to limit this to 5 comments like:
Entry.objects.all()[:5]
{% for task in tasks %}
{% for comment in task.comment_set.all|slice:"5" %}
{{ comment }}
{% endfor %}
{% endfor %}
You don't. You should not do "real work" in a template, this breaks the MVC pattern.
Do the real work in the view, and pass the data to the template (using the context dictionary).
def handle_comments(request):
tasks = Task.objects.all()
comments = {}
for task in tasks:
comments[task] = task.comment_set.all()[:5]
return render_to_response('commenting.html', {'comments': comments})
You can then iterate over the comments in your template:
{% for task, task_comments in comments.items %}{{ task }}{% endfor %}