Develop Reference

Django : Best way to Query a M2M Field , and count occurences

class Edge(BaseInfo):
source = models.ForeignKey('Node', on_delete=models.CASCADE,related_name="is_source")
target = models.ForeignKey('Node', on_delete=models.CASCADE,related_name="is_target")
def __str__(self):
return '%s' % (self.label)
class Meta:
unique_together = ('source','target','label','notes')
class Node(BaseInfo):
item_type_list = [('profile','Profile'),
('page','Page'),
('group','Group'),
('post','Post'),
('phone','Phone'),
('website','Website'),
('email','Email'),
('varia','Varia')
]
item_type = models.CharField(max_length=200,choices=item_type_list,blank = True,null=True)
firstname = models.CharField(max_length=200,blank = True, null=True)
lastname = models.CharField(max_length=200,blank = True,null=True)
identified = models.BooleanField(blank=True,null=True,default=False)
username = models.CharField(max_length=200, blank=True, null=True)
uid = models.CharField(max_length=200,blank=True,null=True)
url = models.CharField(max_length=2000,blank=True,null=True)
edges = models.ManyToManyField('self', through='Edge',blank = True)
I have a Model Node (in this case a soc media profile - item_type) that has relations with other nodes (in this case a post). A profile can be the author of a post. An other profile can like or comment that post.
Question : what is the most efficient way to get all the distinct profiles that liked or commented on anothes profile's post + the count of these likes /comments.
print(Edge.objects.filter(Q(label="Liked")|Q(label="Commented"),q).values("source").annotate(c=Count('source')))
Gets me somewhere but i have the values then (id) and i want to pass the objects to my template rather then .get() all the profiles again...
Result :
Thanks in advance

I ended up with iterating over the queryset and adding the objects that i wanted in a dictionary , if the object was already in dictionary , i would count +1 and add the relation in a nested list.
This doesnt feel right but works for now.
posts = Edge.objects.filter(source = self,target__item_type='post',label='Author')
if posts:
q = Q()
for post in posts:
q = q | Q(target=post.target)
contributors = Edge.objects.filter(Q(label="Liked")|Q(label="Commented"),q)
if contributors:
for i in contributors:
if i.source.uid in results:
if i.label in results[i.source.uid]['relation']:
pass
else:
results[i.source.uid]["relation"].append(i.label)
if 'post' in results[i.source.uid]:
results[i.source.uid]['post'].append(i.target)
else:
results[i.source.uid]['post']=[i.target]
else:
results[i.source.uid] = {'profile' : i.source , 'relation':[i.label],'post':[i.target]}

How can I override a DjangoModelFormMutation field type in graphene?

I'm building a simple recipe storage application that uses the Graphene package for GraphQL. I've been able to use Django Forms so far very easily in my mutations, however one of my models fields is really an Enum and I'd like to expose it in Graphene/GraphQL as such.
My enum:
class Unit(Enum):
# Volume
TEASPOON = "teaspoon"
TABLESPOON = "tablespoon"
FLUID_OUNCE = "fl oz"
CUP = "cup"
US_PINT = "us pint"
IMPERIAL_PINT = "imperial pint"
US_QUART = "us quart"
IMPERIAL_QUART = "imperial quart"
US_GALLON = "us gallon"
IMPERIAL_GALLON = "imperial gallon"
MILLILITER = "milliliter"
LITER = "liter"
# Mass and Weight
POUND = "pound"
OUNCE = "ounce"
MILLIGRAM = "milligram"
GRAM = "gram"
KILOGRAM = "kilogram"
My Model:
class RecipeIngredient(TimeStampedModel):
recipe = models.ForeignKey(Recipe, on_delete=models.CASCADE, related_name='ingredients')
direction = models.ForeignKey(RecipeDirection, on_delete=models.CASCADE, null=True, related_name='ingredients')
quantity = models.DecimalField(decimal_places=2, max_digits=10)
unit = models.TextField(choices=Unit.as_tuple_list())
My form:
class RecipeIngredientForm(forms.ModelForm):
class Meta:
model = RecipeIngredient
fields = (
'recipe',
'direction',
'quantity',
'unit',
)
My Mutation:
class CreateRecipeIngredientMutation(DjangoModelFormMutation):
class Meta:
form_class = RecipeIngredientForm
exclude_fields = ('id',)
I've created this graphene enum UnitEnum = Enum.from_enum(Unit) however I haven't been able to get graphene to pick it up. I've tried adding it to the CreateRecipeIngredientMutation as a regular field like unit = UnitEnum() as well as an Input class on that mutation. So far, the closest I've gotten is this Github issue from awhile ago. After playing around with the class in an iPython shell, I think I could just do CreateRecipeIngredientMutation.Input.unit.type.of_type = UnitEnum() but this feels awful.

I came up with a solution that works but is not pretty. I used the https://github.com/hzdg/django-enumfields package to help with this.
I created my own form field:
class EnumChoiceField(enumfields.forms.EnumChoiceField):
def __init__(self, enum, *, coerce=lambda val: val, empty_value='', **kwargs):
if isinstance(enum, six.string_types):
self.enum = import_string(enum)
else:
self.enum = enum
super().__init__(coerce=coerce, empty_value=empty_value, **kwargs)
And used it in my Django form. Then in my custom AppConfig I did this:
class CoreAppConfig(AppConfig):
name = 'myapp.core'
def ready(self):
registry = get_global_registry()
#convert_form_field.register(EnumChoiceField)
def convert_form_field_to_enum(field: EnumChoiceField):
converted = registry.get_converted_field(field.enum)
if converted is None:
raise ImproperlyConfigured("Enum %r is not registered." % field.enum)
return converted(description=field.help_text, required=field.required)
And finally in my schema:
UnitEnum = Enum.from_enum(Unit)
get_global_registry().register_converted_field(Unit, UnitEnum)
I really don't like this, but couldn't think of a better way to handle this. I came across this idea when searching down another graphene django issue here https://github.com/graphql-python/graphene-django/issues/481#issuecomment-412227036.
I feel like there has to be a better way to do this.

NameError in Django simple search

I have a simple search in my Django project. I want to search through documents using their type and part of factory info in addition to search by name.
Here is my models.py:
class Docs(models.Model):
Date = models.DateField(default=date.today)
Name = models.CharField(max_length=50)
Type = models.ForeignKey(DocTypes)
Part = models.ForeignKey(Parts)
Link = models.FileField(upload_to='Docs/%Y/%m/%d')
class Parts(models.Model):
Name = models.CharField(max_length=50)
def __str__(self):
return str(self.Name)
class DocTypes(models.Model):
Type = models.CharField(max_length=50)
def __str__(self):
return str(self.Type)
My forms.py:
class DocsSearchForm(ModelForm):
class Meta:
model = Docs
fields = [ 'Name', 'Type', 'Part']
And this is part of my views.py, if no search was done then all documents are given
def showdocs(request):
if request.method == 'POST':
form = DocsSearchForm(request.POST)
documents = Docs.objects.filter(Name__contains=request.POST['Name']|
Type==request.POST['Type']|
Part==request.POST['Part'])
else:
form = DocsSearchForm()
documents = Docs.objects.all()
return render(
request,
'showdocs.html',
{'documents': documents, 'form':form}
So, the problem is the following: if I try to use a search then I have
NameError at /showdocs
name 'Type' is not defined.
POST values are:Part '1', Name 'Example', Type '1'.
If I delete
Type==request.POST['Type']|
Part==request.POST['Part']
then search by name works well. So I have a guess that problem is about searching by foreign key values, but have no ideas more. Will appreciate any help.

Try replacing the line with this
Docs.objects.filter(Name__contains=request.POST['Name'],
Type=request.POST['Type'],
Part=request.POST['Part']
)
It seems you have misunderstood the syntax. I don't know why you are trying to use | operator here.

That's not how Django filters work. You can't | them because they are not actually expressions, just keyword arguments. In this case, correct syntax would be:
Docs.objects.filter(
Name__contains=request.POST['Name'],
Type_Type=request.POST['Type'],
Part_Name=request.POST['Part'],
)`

Django ManyToManyField Error when saving in admin?

What is wrong with my code?
class Group(ImageModel):
title = models.CharField(verbose_name = "Title", max_length=7)
photos = models.ManyToManyField('Photo', related_name='+',
verbose_name=_('Photo'),
null=True, blank=True)
.....
pid = Photo.objects.get(image = str_path)
gid= Group.objects.get(id = self.id)
self.save_photos(gid, pid)
....
def save_photos(self, gid, pid):
group_photo = GroupPhotos(groupupload=gid.id,
photo=pid.id
)
group_photo.save()
and my GroupPhotos models is:
class GroupPhotos(models.Model):
groupupload = models.ForeignKey('Group')
photo = models.ForeignKey('Photo')
class Meta:
db_table = u'group_photos'
when i want to save it from admin panel i am getting value error sth like this:
Cannot assign "38": "GroupPhotos.groupupload" must be a "Group" instance.
with group_photo = GroupPhotos(groupupload=gid, photo=pid) defination it is working but there is no any changes in GroupPhotos table(group_photos). printing this print pid.id,' >>> ',gid.id i am getting true relation...
UPDATE:
I have been working since morning, but no progress... i have also tried this but nothing changed:
pid = Photo.objects.get(image = str_path)
ger = Group.objects.get(id = self.id)
ger.title = self.title
ger.save()
ger.photos.add(pid)

The error is here:
group_photo = GroupPhotos(groupupload=gid.id, photo=pid.id)
The arguments to groupupload and photo should be instances of Group and Photo respectively. Try the following:
group_photo = GroupPhotos(groupupload=gid, photo=pid)
In other words, when creating an object you need to pass arguments of the expected type and not an integer (which may be the primary key key of the desired object but it also might not, which is why you need to pass an object of the correct type).

i have solved my problem with adding through option to my manytomanyfield:
photos = models.ManyToManyField('Photo', related_name='+',
verbose_name=_('Photo'),
null=True, blank=True, through=GroupPhotos)
some info about ManyToManyField.through here:
Django will automatically generate a table to manage many-to-many
relationships. However, if you want to manually specify the
intermediary table, you can use the through option to specify the
Django model that represents the intermediate table that you want to
use.
The most common use for this option is when you want to associate extra data with a many-to-many relationship.

How to group the choices in a Django Select widget?

Is it possible to created named choice groups in a Django select (dropdown) widget, when that widget is on a form that is auto-generated from a data Model? Can I create the widget on the left-side picture below?
My first experiment in creating a form with named groups, was done manually, like this:
class GroupMenuOrderForm(forms.Form):
food_list = [(1, 'burger'), (2, 'pizza'), (3, 'taco'),]
drink_list = [(4, 'coke'), (5, 'pepsi'), (6, 'root beer'),]
item_list = ( ('food', tuple(food_list)), ('drinks', tuple(drink_list)),)
itemsField = forms.ChoiceField(choices = tuple(item_list))
def GroupMenuOrder(request):
theForm = GroupMenuOrderForm()
return render_to_response(menu_template, {'form': theForm,})
# generates the widget in left-side picture
And it worked nicely, creating the dropdown widget on the left, with named groups.
I then created a data Model that had basically the same structure, and used Django's ability to auto-generate forms from Models. It worked - in the sense that it showed all of the options. But the options were not in named groups, and so far, I haven't figured out how to do so - if it's even possible.
I have found several questions, where the answer was, “create a form constructor and do any special processing there”. But It seems like the forms.ChoiceField requires a tuple for named groups, and I’m not sure how to convert a tuple to a QuerySet (which is probably impossible anyway, if I understand QuerySets correctly as being pointer to the data, not the actual data).
The code I used for the data Model is:
class ItemDesc(models.Model):
''' one of "food", "drink", where ID of “food” = 1, “drink” = 2 '''
desc = models.CharField(max_length=10, unique=True)
def __unicode__(self):
return self.desc
class MenuItem(models.Model):
''' one of ("burger", 1), ("pizza", 1), ("taco", 1),
("coke", 2), ("pepsi", 2), ("root beer", 2) '''
name = models.CharField(max_length=50, unique=True)
itemDesc = models.ForeignKey(ItemDesc)
def __unicode__(self):
return self.name
class PatronOrder(models.Model):
itemWanted = models.ForeignKey(MenuItem)
class ListMenuOrderForm(forms.ModelForm):
class Meta:
model = PatronOrder
def ListMenuOrder(request):
theForm = ListMenuOrderForm()
return render_to_response(menu_template, {'form': theForm,})
# generates the widget in right-side picture
I'll change the data model, if need be, but this seemed like a straightforward structure. Maybe too many ForeignKeys? Collapse the data and accept denormalization? :) Or is there some way to convert a tuple to a QuerySet, or something acceptable to a ModelChoiceField?
Update: final code, based on meshantz' answer:
class FooIterator(forms.models.ModelChoiceIterator):
def __init__(self, *args, **kwargs):
super(forms.models.ModelChoiceIterator, self).__init__(*args, **kwargs)
def __iter__(self):
yield ('food', [(1L, u'burger'), (2L, u'pizza')])
yield ('drinks', [(3L, u'coke'), (4L, u'pepsi')])
class ListMenuOrderForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(ListMenuOrderForm, self).__init__(*args, **kwargs)
self.fields['itemWanted'].choices = FooIterator()
class Meta:
model = PatronOrder
(Of course the actual code, I'll have something pull the item data from the database.)
The biggest change from the djangosnippet he linked, appears to be that Django has incorporated some of the code, making it possible to directly assign an Iterator to choices, rather than having to override the entire class. Which is very nice.

After a quick look at the ModelChoiceField code in django.forms.models, I'd say try extending that class and override its choice property.
Set up the property to return a custom iterator, based on the orignial ModelChoiceIterator in the same module (which returns the tuple you're having trouble with) - a new GroupedModelChoiceIterator or some such.
I'm going to have to leave the figuring out of exactly how to write that iterator to you, but my guess is you just need to get it returning a tuple of tuples in a custom manner, instead of the default setup.
Happy to reply to comments, as I'm pretty sure this answer needs a little fine tuning :)
EDIT BELOW
Just had a thought and checked djangosnippets, turns out someone's done just this:
ModelChoiceField with optiongroups. It's a year old, so it might need some tweaks to work with the latest django, but it's exactly what I was thinking.

Here's what worked for me, not extending any of the current django classes:
I have a list of types of organism, given the different Kingdoms as the optgroup. In a form OrganismForm, you can select the organism from a drop-down select box, and they are ordered by the optgroup of the Kingdom, and then all of the organisms from that kingdom. Like so:
[----------------|V]
|Plantae |
| Angiosperm |
| Conifer |
|Animalia |
| Mammal |
| Amphibian |
| Marsupial |
|Fungi |
| Zygomycota |
| Ascomycota |
| Basidiomycota |
| Deuteromycota |
|... |
|________________|
models.py
from django.models import Model
class Kingdom(Model):
name = models.CharField(max_length=16)
class Organism(Model):
kingdom = models.ForeignKeyField(Kingdom)
name = models.CharField(max_length=64)
forms.py:
from models import Kingdom, Organism
class OrganismForm(forms.ModelForm):
organism = forms.ModelChoiceField(
queryset=Organism.objects.all().order_by('kingdom__name', 'name')
)
class Meta:
model = Organism
views.py:
from models import Organism, Kingdom
from forms import OrganismForm
form = OrganismForm()
form.fields['organism'].choices = list()
# Now loop the kingdoms, to get all organisms in each.
for k in Kingdom.objects.all():
# Append the tuple of OptGroup Name, Organism.
form.fields['organism'].choices = form.fields['organism'].choices.append(
(
k.name, # First tuple part is the optgroup name/label
list( # Second tuple part is a list of tuples for each option.
(o.id, o.name) for o in Organism.objects.filter(kingdom=k).order_by('name')
# Each option itself is a tuple of id and name for the label.
)
)
)

You don't need custom iterators. You're gonna need to support that code. Just pass the right choices:
from django import forms
from django.db.models import Prefetch
class ProductForm(forms.ModelForm):
class Meta:
model = Product
fields = [...]
def __init__(self, *args, **kwargs):
super(ProductForm, self).__init__(*args, **kwargs)
cats = Category.objects \
.filter(category__isnull=True) \
.order_by('order') \
.prefetch_related(Prefetch('subcategories',
queryset=Category.objects.order_by('order')))
self.fields['subcategory'].choices = \
[("", self.fields['subcategory'].empty_label)] \
+ [(c.name, [
(self.fields['subcategory'].prepare_value(sc),
self.fields['subcategory'].label_from_instance(sc))
for sc in c.subcategories.all()
]) for c in cats]
Here,
class Category(models.Model):
category = models.ForeignKey('self', null=True, on_delete=models.CASCADE,
related_name='subcategories', related_query_name='subcategory')
class Product(models.Model):
subcategory = models.ForeignKey(Category, on_delete=models.CASCADE,
related_name='products', related_query_name='product')
This same technique can be used to customize a Django admin form. Although, Meta class is not needed in this case.