django sorting table with pagination - django

Question

I want to sort my table columns both ways (ascending and descending, switch upon pressing a button). The problem I have is my tables go out of order when I switch a page.
views.py
def company_index(request):
order_by = request.GET.get('order_by')
companies = Company.objects.all().order_by(Lower(order_by))
paginator = Paginator(companies, 10)
page = request.GET.get('page')
try:
all_companies = paginator.page(page)
except PageNotAnInteger:
all_companies = paginator.page(1)
except EmptyPage:
all_companies = paginator.page(paginator.num_pages)
return render(request, 'companies/company_index.html',
{'all_companies': all_companies})
Here is how I display data in my templates (I shortened class names for better post visibility):
<thead>
<tr>
<th>Company name <a class="glyphicon" href="?order_by=company_name"></a></th>
<th>Company address <a class="glyphicon" href="?order_by=company_address"></a></th>
<th>Tax ID <a class="glyphicon" href="?order_by=tax_id"></a></th>
<th>Company ID <a class="glyphicon" href="?order_by=company_id"></a></th>
<th>KRS Number <a class="glyphicon" href="?order_by=KRS_number"></a></th>
</tr>
</thead>
My pagination code:
<ul class="pagination">
{% if all_companies.has_previous %}
<li>previous</li>
{% endif %}
<li class="disabled"><a>Page {{ all_companies.number }} of {{ all_companies.paginator.num_pages }}</a></li>
{% if all_companies.has_next %}
<li>next</li>
{% endif %}
</ul>
When I switch to other page {{order_by}} passes None. Also, how can I make it sort descending or ascending, after pressing a button?
I want to do it without outside apps or libraries, to have a better understanding of django.

Answer 1

You forgot to add order_by in the context:
return render(request, 'companies/company_index.html',
{'all_companies': all_companies, 'order_by': order_by})
Ascending/descending in template:
company name ascending
company name descending
...
previous
...
next
In the view:
def company_index(request):
order_by = request.GET.get('order_by')
direction = request.GET.get('direction')
ordering = Lower(order_by)
if direction == 'desc':
ordering = '-{}'.format(ordering)
companies = Company.objects.all().order_by(ordering)
paginator = Paginator(companies, 10)
page = request.GET.get('page')
try:
all_companies = paginator.page(page)
except PageNotAnInteger:
all_companies = paginator.page(1)
except EmptyPage:
all_companies = paginator.page(paginator.num_pages)
return render(request, 'companies/company_index.html',
{'all_companies': all_companies,
'order_by': order_by, 'direction': direction})