I'm trying to build a search page that will allow a user to find any instances of a model which meet certain threshold criteria and am having trouble avoiding seriously redundant code. I'm hoping there's a better way to do it. Here's a slightly contrived example that should illustrate what I'm trying to do, with the relevant code adjusted at the end. The user will interact with the search with checkboxes.
models.py:
class Icecream(models.Model()):
name = models.CharField()
bad_threshold = models.IntegerField()
okay_threshold = models.IntegerField()
tasty_threshold = models.IntegerField()
delicious_threshold = models.IntegerField()
views.py:
def search_icecreams(request):
user = request.user
q_search = None
if 'taste_search' in request.GET:
q_search = taste_threshold_set(request, user, q_search)
if q_search == None:
icecream_list = Icecream.objects.order_by('name')
else:
icecream_list = College.objects.filter(q_search)
context = { 'icecream_list' : icecream_list }
return render(request, '/icecream/icecreamsearch.html', context)
The relevant code that I want to cut down is as follows, this is pretty much straight from my project, with the names changed.
def taste_threshold_set(request, user, q_search):
threshold = request.GET.getlist('taste_search')
user_type_tolerance = user.profile.get_tolerance_of(icea
# 1-5 are the various thresholds. They are abbreviated to cut down on the
# length of the url.
if '1' in threshold:
new_q = Q(bad_threshold__gt = user.profile.taste_tolerance)
if q_search == None:
q_search = new_q
else:
q_search = (q_search) | (new_q)
if '2' in threshold:
new_q = Q(bad_threshold__lte=user.profile.taste_tolerance) & \
~Q(okay_threshold__lte=user.profile.taste_tolerance)
if q_search == None:
q_search = new_q
else:
q_search = (q_search) | (new_q)
if '3' in threshold:
new_q = Q(okay_threshold_3__lte=user.profile.taste_tolerance) & \
~Q(tasty_threshold__lte=user.profile.taste_tolerance)
if q_search == None:
q_search = new_q
else:
q_search = (q_search) | (new_q)
if '4' in threshold:
new_q = Q(tasty_threshold__lte=user.profile.taste_tolerance) & \
~Q(delicious_threshold__lte=user.profile.taste_tolerance)
if q_search == None:
q_search = new_q
else:
q_search = (q_search) | (new_q)
if '5' in threshold:
new_q = Q(delicious_threshold__lte = user.profile.taste_tolerance)
if q_search == None:
q_search = new_q
else:
q_search = (q_search) | (new_q)
return q_search
Basically I want the user to be able to find all instances of a certain object which meet a given threshold level. So, for example, all icecreams that they would find bad and all icecreams that they would find delicious.
There are a number of things I'm not happy with about this code. I don't like checking to see if the Q object hasn't been instantiated yet for each possible threshold, but don't see a way around it. Further, if this were a non-django problem I'd use a loop to check each of the given thresholds, instead of writing each one out. But again, I'm not sure how to do that.
Finally, the biggest problem is, I need to check thresholds for probably 20 different attributes of the model. As it stands, I'd have to write a new threshold checker for each one, each only slightly different than the other (the name of the attribute they're checking). I'd love to be able to write a generic checker, then pass it the specific attribute. Is there any way to solve this, or my other two problems?
Thanks!
How about this approach?
query_arg = ['bad_threshold__lte', 'bad_threshold__lte', 'okay_threshold_3__lte', 'tasty_threshold__lte', 'delicious_threshold__lte']
Q(**{query_arg[int(threshold) - 1]: user.profile.taste_tolerance})