Basically I have this url dispatcher that capture a search term with each word separated by + to be search in the query. I have done this this is works but I think this will hit the performance due to repeated search to the database. Is there a better way to do this?
def search(request, **kwargs):
context = RequestContext(request)
test = {}
result = BlogPage.objects.select_related('ImageMedia')
if 'search_content' in kwargs:
test['search_content'] = kwargs['search_content']
if kwargs['search_content'] != '0':
search_words = kwargs['search_content'].split('+')
for words in search_words:
result = result.filter(content__icontains=words)
context_dict = {'blog_list': result}
return render_to_response('blog/blog_search.html', context_dict, context)
You could pre-build your filter, like (untested):
from django.db import Q
search_content = kwargs.get('search_content', '')
myfilter = Q()
for term in search_content.split('+'):
myfilter |= Q(content__icontains=term)
result = BlogPage.objects.filter(myfilter).select_related('ImageMedia')
I think Python list to bitwise operations is simpler when you are using python 2.7
PS: reduce() function has been removed in Python 3, so you can't use it and it is no compatibility.reduce() has been move into module functools
Related
i want to search field of a multiple model in a single search view here is what i tried i know this is not a clean and better way to do that's why i am looking for a clean and better way to do it i read it is possible with (from itertools import chain) but i did not completely understand how to use it in my function based views without passing so many context here is my view
def search_item(request):
search_item = request.GET.get('search')
if search_item:
story = Story.objects.filter(Q(title__icontains=search_item)|Q(written_by__icontains=search_item))
news = News.objects.filter(Q(title__icontains=search_item)|Q(written_by__icontains=search_item))
Stock = stock.objects.filter(Q(title__icontains=search_item)|Q(written_by__icontains=search_item))
return render(request, 'search_result.html', {'ttts':ttt,'story':story,'news':news,'stock':Stock,})
thank you
You don't need itertools.chain.
def search_item(request):
results = []
search_item = request.GET.get("search")
if search_item:
q = Q(title__icontains=search_item) | Q(written_by__icontains=search_item)
for model in (Story, News, Stock):
results.extend(model.objects.filter(q))
return render(request, "search_result.html", {"results": results})
would be a simple, DRY way to write what you have.
so on the way of learning process, I am making my first side-project on django.
I want to make my search more accurate, for example: when post body contains text with 3 words "I love stackoverflow" and someone searches for "I stackoverflow" (without word LOVE), result is not shown on the search page.
What could be the best approach in this case to get the result, even if the post body does not contain words in that order as a search query?
views.py
def search(request):
posts = Post.objects.all().order_by('title')
query = request.GET.get('q')
print(query)
if query:
posts = Post.objects.filter(
Q(title__icontains=query)|
Q(body__icontains=query)
)
context = {
"posts": posts,
}
return render(request, "search.html", context)
I'd recommend using full text search with django haystack with any search engine. But, to respond to your case, something like following would do the trick, though is not very optimised:
from django.db.models import Q
# consider only words which are having a length greater than 2
# also, words should be sanitised and cleaned before using for db queries.
# use a form for that.
parts = [i for i in request.GET.get('q').split(' ') if len(i) >= 3]
qs = Q()
query = [qs | Q(title__icontains=query) | Q(body__icontains=query) for q in parts]
result = Post.objects.filter(query).order_by().distinct()
Django provides multiple efficient ways to search on a postgreSQL database that you can find on the official docs.
Try to split your query
from itertools import chain
def search(request):
posts = Post.objects.all().order_by('title')
query = request.GET.get('q')
if query:
words = query.split(" ")
results = []
for word in words:
match = posts.filter(
Q(title__icontains=word)|
Q(body__icontains=word)
)
if match:
results.append(match)
posts = set(chain(*results))
context = {
"posts": posts,
}
return render(request, "search.html", context)
I have a template view in Django2.2, where I added two models & queries to look up metrics on user data (how many articles they read each month).
I ran into a strange issue where if I place multiple context variables on the page, every variable on the page but the First Variable will return '0'. If I simply change the order of the variables in the markup, each date function appears to be calculating correctly (as long as it is the first to appear). I couldn't find anything about this in the docs...and I'm guessing that this isn't a great approach to display this information either and I should instead use a DjangoTemplateTag and perform the operations there.
*Define the Object & Query
def get_context_data(self, **kwargs):
context = super(userDashBoardView, self).get_context_data(**kwargs)
context['readArticleList'] = Articles.objects.filter(Unread = False,userId = self.request.user.SFPK )
*To avoid making further queries, I mutated the query into a set to perform further functions
article_list = set(context['readArticleList'])
article_read_date = (article_list.read_date for article_list in article_list)
context['articles_last30'] = len(set(x for x in article_read_date if x > timezone.now() - timedelta(days=30)))
context['articles_last60'] = len(set(x for x in article_read_date if x > timezone.now() - timedelta(days=60)))
context['articles_last90'] = len(set(x for x in article_read_date if x > timezone.now() - timedelta(days=90)))
return context
{% block content %}
{{articles_last30}}
{{articles_last60}}
{{articles_last90}}
{% endblock %}
<br/>
For context,context,context in the example above *using sample data
the output on the page is (4,0,0)
If the order is reversed, I get
(20,0,0)
NOTE: I am NOT receiving any errors in the console, and the page(s) are loading fine. Can anyone point me in the right direction?
-Thank you for your time =)
You use a generator for article_read_date, indeed:
article_read_date = (article_list.read_date for article_list in article_list)
This means that after you have iterated over it, the generator is "exhausted". Another loop over the iterator will not yield any values anymore. An illustrative example is the following:
>>> l = [1,4,2,5]
>>> g = (x for x in l)
>>> list(g)
[1, 4, 2, 5]
>>> list(g)
[]
as you can see, the second list(g) does not produces any values anymore.
You can create a set with:
article_read_date = [a.read_date for a in context['readArticleList']]
def count_since(iterable, _timed):
timestamp = timezone.now() - timed
return sum(x > timestamp for x in iterable)
context['articles_last30'] = count_since(article_read_date, timedelta(days=30))
context['articles_last60'] = count_since(article_read_date, timedelta(days=60))
context['articles_last90'] = count_since(article_read_date, timedelta(days=90))
That being said, since django-2.0, Count [Django-doc] has a filter= attribute, so you can count the articles with one extra query like:
from django.db.models import Count, Q
nw = timezone.now()
context.update(
context['readArticleList'].aggregate(
articles_last30=Count('pk', filter=Q(read_date__gt=nw-timedelta(days=30))),
articles_last60=Count('pk', filter=Q(read_date__gt=nw-timedelta(days=60))),
articles_last90=Count('pk', filter=Q(read_date__gt=nw-timedelta(days=90)))
)
)
You can do what you are doing in a much more efficient way and cleaner way.
First though you should Note that the convention is models are not named in plural. So it is not Articles.objects.. but Article.objects... You should rename your model to Article instead of Articles.
If we assume that as should be the case that Article(s) is a model which has field read date.
class Article(models.Model):
read_date = models.DateTimeField()
... other_fields ..
Since you very much want efficiency. You can count the results straight from the DB.
def get_context_data(self, **kwargs):
thirty_days_ago = datetime.now() - timedelta(days=30)
sixty_days_ago = datetime.now() - timedelta(day=60)
ninty_days_ago = datetime.now() - timedelta(day=90)
ctx = super().get_context_data(**kwargs)
ctx['articles_last90'] = \
Article.objects.filter(read_date__gt=ninty_days_ago).count()
ctx['articles_last60'] = \
Article.objects.filter(read_date__gt=sixty_days_ago).count()
ctx['last_last30'] = \
Article.objects.filter(read_date__gt=thirty_days_ago).count()
return ctx
This way you never ever load anything into python memory except the number of articles. It is much better than iterating or even using len(list_of_items).
You just have to be conscious of that read_time__gt=ninty_days_ago means articles that were last read more than ninty days ago.
See more from Django Docs.
I've created this simple search function:
def search(request):
if "q" in request.GET:
querystring = request.GET.get("q")
print(querystring)
if len(querystring) == 0:
return redirect("/search/")
posts = Blog.objects.filter(title__icontains=querystring | tagline__icontains=querystring | contents__icontains=querystring)
context= {"posts": posts}
return render(request, "kernel/search.html", context)
else:
return render(request, "kernel/search.html")
When I use only one condition, for example:
posts = Blog.objects.filter(title__icontains=querystring)
it's shown me the correct results. But when I use multiple parameters I have SyntaxError: invalid syntax.
I was sure the query corresponded to:
SELECT * FROM Post WHERE "title" is "key_search" or "tagline" is
"key_search" or "contents" is "key_search"
How I can resolve?
The above is incorrect Python syntax, you can not put operators between named parameters.
Django however has Q objects [Django-doc] to express "conditions", so you can wrap the conditions in Q objects, and use the | operator to express a logical or, like:
from django.db.models import Q
posts = Blog.objects.filter(
Q(title__icontains=querystring) |
Q(tagline__icontains=querystring) |
Q(contents__icontains=querystring)
)
This will result in a query that looks, more or less, like:
SELECT *
FROM Post
WHERE "title" LIKE "%key_search%"
OR "tagline" LIKE "%key_search%"
OR "contents" LIKE "%key_search%"
I would like to retrieve a bunch of rows from my database using a set of filters.
I was wondering if conditional filter is applicable in django. That is, "filter if variable is not None, or not apply filtering otherwise".
Something like this:
user = User.objects.get(pk=1)
category = Category.objects.get(pk=1)
todays_items = Item.objects.filter(user=user, date=now()).conditional_filter(category=category))
What I would like to do is apply category filter only if category is not None.
If category is None (means it is not given in the request object) then this filter would not be applied at all. This would save me a bunch of 'if-elif-else' situations.
Is there a way to do this?
You can chain queries:
user = User.objects.get(pk=1)
category = Category.objects.get(pk=1)
qs = Item.objects.filter(user=user, date=now())
if category:
qs = qs.filter(category=category)
As queryset are executed lazily, DB hit will occur only when you display items.
They are several approach to your issue. One approach is to play with Complex lookups with Q objects
from django.db.models import Q
user = User.objects.get(pk=1)
category = Category.objects.get(pk=1)
f1 = Q( user=user, date=now() )
f_cat_is_none = Q( category__isnull = True )
f_cat_is_not_none = Q( category=category )
todays_items = Item.objects.filter( f1 & ( f_cat_is_none | f_cat_is_not_none ) )
I don't right understand in your answer if this is the query you are looking for, but, with this example you can compose easily your own query.
Edited due OP comment
category__isnull == True means that, in database, the item has not an associated category.
Perhaps the query you are looking for is:
from django.db.models import Q
user_pk = 1
category_pk = 1 #some times None
f = Q( user__pk = user_pk, date=now() )
if category_pk is not None:
f &= Q( category__pk = category_pk )
todays_items = Item.objects.filter( f )
This is only a code sample, fit it to your requirements. Be careful with single _ and double __.
Well, this is rather old question but for those who would like to do the conditional filtering on one line, here is my approach (Btw, the following code can probably be written in a more generic way):
from django.db.models import Q
def conditional_category_filter(category):
if category != None:
return Q(category=category)
else:
return Q() #Dummy filter
user = User.objects.get(pk=1)
category = Category.objects.get(pk=1)
todays_items = Item.objects.filter(conditional_category_filter(category), user=user, date=now())
The only thing you need to watch is to use the conditional_category_filter(category) call before the keyword arguments like user=user. For example the following code would throw an error:
todays_items = Item.objects.filter(user=user, date=now(), conditional_category_filter(category))
To continue on #iuysal answer:
To make it generic you need to pass the key too as parameter, to do that you need to pass a dictionary, here's how I did it:
Create your dictionary like this:
filters = {'filter1': 'value1', 'filter2__startswith': 'valu', ...}
Then pass it to your Item filters like this:
Item.objects.filter(*[Q(**{k: v}) for k, v in filters.items() if v], filter3='value3')
The first version less cryptic version I had:
def _filter(filters):
filters = []
for k, v in n.items():
if v:
filters.append(Q(**{k: v}))
return filters
filters = _filter({'name': name})
return Item.objects.filter(*filters)
Unpacking explanation: We want to give Q (queries) as args to objects.filter as args while we want to give kwargs to Q()
I have this on production now (I will just modify the filters names because it's sensitive):
def get_queryset(self):
filter1 = self.request.GET.get('filter1 ', '')
filter2__startswith = self.request.GET.get('filter2_prefix ', '')
def filters_to_Qs(filters):
return [Q(**{k: v}) for k, v in filters.items() if v]
filters = {'filter1': filter1 ,
'filter2__startswith': filter2__startswith }
return Order.objects.filter(*filters_to_Qs(filters))
from django.db.models import Q
qs = Users.objects.filter(
p_id=parent_id,
status=True
).all()
if user_id>0:
qs = qs.filter( ~Q(id=user_id) )
in qs we will get the filtered results