I'm using Django Forms to do a filtered/faceted search via POST, and I would like to Django's paginator class to organize the results. How do I preserve the original request when passing the client between the various pages? In other words, it seems that I lose the POST data as soon as I pass the GET request for another page back to my views. I've seen some recommendations to use AJAX t开发者_高级运维o refresh only the results block of the page, but I'm wondering if there is a Django-native mechanism for doing this.
Thanks.
If you want to access the store data in later request, you would have to store it somewhere. Django provides several ways to archive this:
1) You can use sessions to store the query: Every visitor who visits your site will get an empty session object and you can store whatever you want inside this object, which acts like a dict. Drawback: A single visitor can't do multiple searches with pagination concurrently.
2) Use cookies: If you set a cookie which is stored on the client side, the browser will append the data of the cookie to each request where you can access it. Cookies are more server friendly, because you don't need a session manager for them on the server, but the data stored in cookies is visible (and editable) to the client. Drawback: same as before.
3) Use hidden fields: You can add a form with some hidden fields on your search-result page and store the query inside them. Then, the client will resend the query whenever you submit the form. Drawback: You must use a form with submit buttons for the pagination on your page (simple links wont work).
4) Create Links which contain the query: Instead of using POST, you can also use GET. For example, you could have a link like "/search/hello+world/?order=votes" and "paginated links" like "/search/hello+world/2/?order-votes". Then the query can be easily retrieved from the URL. Drawback: The maximum amount of data you can send via GET is limited (But that shouldn't be a problem for a simple search).
5) Use a combination: You might want to store all the data in a session or a database and access them via a generated key which you can put in the URL. URLs might then look like "/search/029af239ccd23/2" (for the 2nd page) and you can use the key to access a huge amount of data which you have stored before. This eliminates the drawback of solution 1 as well as that of solution 4. New drawback: much work :)
6) Use AJAX: With ajax you can store the data inside some js-variables on the client side, which can then passed to the other requests. And since ajax will only update your result list, the variables aren't getting lost.
Reading the very nice answer from tux21b I decided to implement the first option, i.e., to use the session to store the query. This is an application that searches real estate databases. Here is the view code (using django 1.5):
def main_search(request):
search_form = UserSearchForm()
return render(request, 'search/busca_inicial.html', {'search_form': search_form})
def result(request):
if request.method == 'POST':
search_form = UserSearchForm(request.POST)
if search_form.is_valid():
# Loads the values entered by the user on the form. The first and the second
# are MultiChoiceFields. The third and fourth are Integer fields
location_query_list = search_form.cleaned_data['location']
realty_type_query_list = search_form.cleaned_data['realty_type']
price_min = search_form.cleaned_data['price_min']
price_max = search_form.cleaned_data['price_max']
# Those ifs here populate the fields with convenient values if the user
# left them blank. Basically the idea is to populate them with values
# that correspond to the broadest search possible.
if location_query_list == []:
location_query_list = [l for l in range(483)]
if realty_type_query_list == []:
realty_type_query_list = [r for r in range(20)]
if price_min == None:
price_min = 0
if price_max == None:
price_max = 100000000
# Saving the search parameters on the session
request.session['location_query_list'] = location_query_list
request.session['price_min'] = price_min
request.session['price_max'] = price_max
request.session['realty_type_query_lyst'] = realty_type_query_list
# making a query outside the if method == POST. This logic makes the pagination possible.
# If the user has made a new search, the session values would be updated. If not,
# the session values will be from the former search. Of course, that is what we want because
# we want the 'next' and 'previous' pages correspond to the original search
realty_list_result = FctRealtyOffer.objects.filter(location__in=request.session['location_query_list']
).filter(price__range=(request.session['price_min'], request.session['price_max'])
).filter(realty_type__in=request.session['realty_type_query_lyst'])
# Here we pass the list to a table created using django-tables2 that handles sorting
# and pagination for us
table = FctRealtyOfferTable(realty_list_result)
# django-tables2 pagination configuration
RequestConfig(request, paginate={'per_page': 10}).configure(table)
return render(request, 'search/search_result.html', {'realty_list_size': len(realty_list_result),
'table': table})
Hope it helps!If anyone has any improvement to suggest, be welcome.
As @rvnovaes, a way to use session to solve the matter.
The drawback of his solution is that if there are many search fields you have to write many lines of code, and also if you show the search form in the result page, all the fields will be blank, while they should keep their values.
So I'd rather save all the post data in session, and at the beginning of the view force the value of request.POST and request.method if a session is defined:
""" ... """
if not request.method == 'POST':
if 'search-persons-post' in request.session:
request.POST = request.session['search-persons-post']
request.method = 'POST'
if request.method == 'POST':
form = PersonForm(request.POST)
request.session['search-persons-post'] = request.POST
if form.is_valid():
id = form.cleaned_data['id']
""" ... """
More info here
I did this in my web application with get parameters Maybe i can help you :
Views.py
class HomeView(ListView):
model = Hotel
template_name = 'index.html'
paginate_by = 10 # if pagination is desired
def get_queryset(self):
qs = super().get_queryset()
kwargs = {}
if 'title' in self.request.GET:
title = self.request.GET.get('title')
if title != '':
kwargs['title__icontains'] = title
if 'category' in self.request.GET:
category = self.request.GET.get('category')
if category:
kwargs['category_id'] = category
if 'size' in self.request.GET:
size = self.request.GET.get('size')
if size:
kwargs['size_id'] = size
if 'service' in self.request.GET:
service = self.request.GET.get('service')
if service:
kwargs['service_id'] = service
if 'ownership' in self.request.GET:
ownership = self.request.GET.get('ownership')
if ownership:
kwargs['ownership_id'] = ownership
qs = qs.filter(**kwargs)
return qs
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
form_init = {}
form = SearchForm()
if self.request.GET.items():
try:
parameters = self.request.GET.items()
except KeyError:
parameters = {}
for key, value in parameters:
for field in form.fields:
if key == field:
form_init[key] = value
form.initial = form_init
if 'title' in self.request.GET:
title = self.request.GET.get('title')
if title != '':
context.update({
'title': title
})
if 'category' in self.request.GET:
category = self.request.GET.get('category')
context.update({
'category': category
})
if 'size' in self.request.GET:
size = self.request.GET.get('size')
context.update({
'size': size
})
if 'service' in self.request.GET:
service = self.request.GET.get('service')
context.update({
'service': service
})
if 'ownership' in self.request.GET:
ownership = self.request.GET.get('ownership')
context.update({
'ownership': ownership
})
context.update({
'search_form': form
})
return context
Pagination file html
<div class="row">
{% if is_paginated %}
<nav aria-label="...">
<ul class="pagination">
{% if page_obj.has_previous %}
<li class="page-item"><a class="page-link" href="?category={{category}}&size={{size}}&service={{service}}&ownership={{ownership}}&page={{ page_obj.previous_page_number }}">Previous</a></li>
{% else %}
<li class="page-item disabled"><span class="page-link">Previous</span></li>
{% endif %}
<span class="page-current">
Page {{ page_obj.number }} of {{ page_obj.paginator.num_pages }}.
</span>
{% if page_obj.has_next %}
<li class="page-item"><a class="page-link" href="?category={{category}}&size={{size}}&service={{service}}&ownership={{ownership}}&page={{ page_obj.next_page_number }}">Next</a></li>
{% else %}
<li class="page-item disabled"><span class="page-link">Next</span></li>
{% endif %}
</ul>
</nav>
{% endif %}
</div>
You can ask request object if it's ajax, simply request.is_ajax. This way you can detect, whether it's first post request or further questions about the next pages.
Have the search form and the results display on one single django template. Initially, use css to hide the results display area. On POSTing the form, you could check to see if the search returned any results and hide the search form with css if results exist. If results do not exist, use css to hide the results display area like before. In your pagination links, use javascript to submit the form, this could be as simple as document.forms[0].submit(); return false;
You will need to handle how to pass the page number to django's paging engine.
My suggestion would be to store the post request using a session or a cookie. In case the post data is sensitive, you should use session to store it. The code below contains my logic to implement it using session.
def index(request):
is_cookie_set = 0
# Check if the session has already been created. If created, get their values and store it.
if 'age' in request.session and 'sex' in request.session:
age = request.session['age']
sex = request.session['sex']
is_cookie_set = 1
else:
# Store the data in the session object which can be used later
request.session['age'] = age
request.session['sex'] = sex
if(request.method == 'POST'):
if(is_cookie_set == 0): # form submission by the user
form = EmployeeForm(request.POST)
sex = form.cleaned_data['sex']
age = form.cleaned_data['age']
if form.is_valid():
result = Employee.objects.all(sex=sex,age_gte=age) # filter all employees based on sex and age
else: # When the session has been created
result = Employee.objects.all(sex=sex,age_gte=age)
paginator = Paginator(result, 20) # Show 20 results per page
page = request.GET.get('page')
r = paginator.get_page(page)
response = render(request, 'app/result.html',{'result':result})
return response
else:
form = EmployeeForm()
return render(request,'app/home.html',{'form':form})
You should also check if the post fields are empty or not and change the logic according to it. You can also store the whole post request in the session as suggested by @abidibo.
You can also use cookies for the same. I have explained it here
The Below code is working, the first request is a GET request, which accesses the form, will go directly to the else block. Once the user puts up a search query, results will be shown, which will be a post request, and 2nd if block will be activated, this request we will store in a session. When the user accesses 2nd search page, it will be a GET request, but we are checking whether there is an active pagination session, and also checking whether it's not a page request of GET. At this point 1st if block will be trigerred.
def search(request):
if not request.method == "POST" and 'page' in request.GET:
if 'search-query' in request.session:
request.POST = request.session['search-query']
request.method = 'POST'
if request.method == 'POST':
form = Search_form(request.POST)
request.session['search-query'] = request.POST
if form.is_valid():
search_query = form.cleaned_data.get('search_query')
search_parameter = form.cleaned_data.get('search_parameter')
print(search_query, search_parameter)
queryset_list = CompanyRecords.objects.filter(**{f'{search_parameter}__icontains': search_query}).exclude(
company_name__isnull=True).exclude(description__isnull=True).exclude(phones__isnull=True).exclude(
emails__isnull=True)[:5]
page = request.GET.get('page', 1)
paginator = Paginator(queryset_list, 2)
try:
queryset = paginator.page(page)
except PageNotAnInteger:
queryset = paginator.page(1)
except EmptyPage:
queryset = paginator.page(paginator.num_pages)
return render(request, 'search/search_results.html', {'queryset': queryset})
else:
context = {
'form': Search_form()
}
return render(request, 'search/search.html', context)
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