Need help to fetch required data from model in django - django

Question

I have below two models,
class user_files(models.Model):
Filename = models.CharField(max_length=50)
Browse = models.FileField(upload_to='img/')
user_uploaded = models.CharField(max_length=50, blank=True)
class share_files(models.Model):
select_file = models.CharField(max_length=300)
from_user = models.CharField(max_length=50)
select_user = models.CharField(max_length=50,default=None)
user_files stores file uploaded by respective user.
and share_files stores shared file name yo user xx by user bb.
I want to show shared files with logged in user in template,
my function for it in view.py is,
def user_files_all(request):
if not request.user.is_authenticated:
return render(request, 'accounts/logout.html')
else:
data = user_files.objects.filter(user_uploaded=request.user)
data1 = share_files.objects.filter(select_user=request.user)
data2 = user_files.objects.filter(Filename=data1.select_file,user_uploaded=data1.from_user)
args = {'data': data,'data1':data1}
return render(request, 'accounts/files.html', args)
but i am getting error for line,
data2 = user_files.objects.filter(Filename=data1.select_file,user_uploaded=data1.from_user)
as attribute select_file is not present for data1. I want data from user_files model for all users and filename selected in data1. And then want to render that in template.
How to achieve that? Need help.
Thanks in advance.

Answer 1

filter(...) is a model manager method, it returns a queryset instead of an object. So you can do:
Use first() or last() method after using filter. Because these methods return a object from the queryset:
data_list = user_files.objects.filter(user_uploaded=request.user)
data1_list = share_files.objects.filter(select_user=request.user)
if data_list.exists():
data= data_list.first()
else:
data = None
if data1_list.exists():
data1 = data1_list.first()
data2 = user_files.objects.filter(Filename=data1.select_file,user_uploaded=data1.from_user) # its a queryset btw
else:
data1 = None
data2 = None # or user_files.objects.none()

Answer 2

.filter() returns a list of objects. So your data1 variable is a list. You cannot just get value of any attribute.
To achieve what you want you could try something like -
data2 = []
for d in data1:
ufs = user_files.objects.filter(Filename=d.select_file,user_uploaded=d.from_user)
for uf in ufs:
include = True
for d2 in data2:
if d2.pk == uf.pk:
include = False
break
if include:
data2.append(uf)
On a side note - your model design does not look good. Consider using ForeignKey. For more refer this.
Hope it helps.
EDIT
If you are using version 1.11 you can use union()
data2 = []
for d in data1:
ufs = user_files.objects.filter(Filename=d.select_file,user_uploaded=d.from_user)
data2 = data2.union(ufs)
I haven't tested the above codes but you get the idea. For more info on union(), look into this.