Is it possible to use create_object view to create a new object and automatically assign request.user as foreign key?
P.E:
class Post(models.Model):
text = models.TextField()
author = models.ForeignKey(User)
What I want is to use create_object and fill author with request.user.
In many ways, all the solutions to this will be more trouble than they are worth. This one qualifies as a hack. It is possible for a django update to leave you high and dry if they change the way create_update is implemented. For simplicity sake, I'll assume that you are trying to set a default user, not silently force the user to be the logged in user.
Write a context processor:
from django.views.generic.create_update import get_model_and_form_class
def form_user_default(request):
if request.method == 'GET':
model, custom_form = get_model_and_form_class(Post,None)
custom_form.author = request.user
return {'form':custom_form}
else: return {}
What this will do is override the form object that create_update passes to the template. What it's technically doing is re-creating the form after the default view has done it.
Then in your url conf:
url(r'pattern_to_match', 'django.views.generic.create_update.create_object', kwargs={'context_processors':form_user_default})
Again, I had to delve into the source code to figure out how to do this. It might really be best to try writing your own view (but incorporate as many Django custom objects as possible). There's no "simple default" way to do this, because in the django paradigm forms are more closely tied to the model layer than to views, and only views have knowledge of the request object.
You may want to consider a closure.
from django.forms import ModelForm
from django.views.generic.create_update import create_object, update_object
def make_foo_form(request):
class FooForm(ModelForm):
class Meta:
model = Foo
fields = ['foo', 'bar']
def save(self, commit=True):
f = super(FooForm, self).save(commit=False)
if not f.pk: f.user = request.user
if commit: f.save()
return f
return FooForm
def create_foo(request):
FooForm = make_foo_form(request)
return create_object(form_class=FooForm)
There is some inefficiency here, since you need to create the ModelForm object on each request, but it does allow you to inject functionality into the generic view.
You need to decide whether the added complexity for the form creation is worth maintaining simplicity on the view side.
A benefit here, though, is that this also works with the update case with practically no extra effort:
def update_foo(request, object_id):
FooForm = make_foo_form(request)
return update_object(form_class=FooForm, object_id=object_id)
Obviously, you can use this approach for more complex cases as well.
If a user is authenticated, their user object is the request.user object.
I'm not familiar with create_object... I'm still a beginner to django and have only just started my first real project with it.
Note that you should check to make sure a user is logged in before using this. This can be done with request.user.is_authenticated().
There is no good way to hook into the saving of an object when using the current Django generic views. Once they are rewritten as classes, you'll be able to subclass the view and hook in at the proper place without having to rewrite the whole view.
I already use my own class-based generic views for this reason.
I would suggest to make a wrapper for the create_object, as this author suggest
http://www.b-list.org/weblog/2006/nov/16/django-tips-get-most-out-generic-views/
in the view you'll have access to the user info.
Afterwards, you will need to use the extra_context to pass the user to the template. Finally at the template you can add a hidden field with the user info. I haven't tried it, but I have been thinking of it for quite some time. Hope this solution suits you!
;) cheers!
Related
Background: I would like to enhance a page instance during an admin page view with some admin request related information (some pre-population in general). Basically I would need some function like "get_queryset", but not for list view, just for edit view.
In my older question related to a similar problem: Wagtail - how to preopulate fields in admin form? I was provided with instructions to use something called
CreatePageView
However, I cannot import it. Furthermore, I cannot even found any mention about that in google if I search:
Wagtail +CreatePageView
The closest thing I found is https://docs.wagtail.io/en/v2.1.1/reference/contrib/modeladmin/create_edit_delete_views.html but the page also states:
NOTE: modeladmin only provides ‘create’, ‘edit’ and ‘delete’
functionality for non page type models (i.e. models that do not extend
wagtailcore.models.Page). If your model is a ‘page type’ model,
customising any of the following will not have any effect
I am quite confused. What should I do if I need to customize the admin view for Page model extension?
I studied the wagtail source codes for Model.admin and Page and I have not found any way. Any ideas?
The related code simplified:
wagtail hooks:
class ItemAdmin(ModelAdmin):
pass
# some function override here maybe?
models:
class ItemPage(Page):
pass
# override for a function that gives data to the admin view maybe here?
Edit
As suggested in comments, it is possible to modify the admin page form during creation:
from wagtail.admin.forms import WagtailAdminPageForm
class ItemPageForm(WagtailAdminPageForm):
def __init__(self, data=None, files=None, parent_page=None, *args, **kwargs):
super().__init__(data, files, *args, **kwargs)
class ItemPage(Page):
base_form_class = ItemPageForm
however, acquiring the "request" in the WagtailAdminPageForm constructor does not seem possible.
This question is a bit ambiguous, so it is not super clear exactly what you need.
Interpreted question: When crediting (or editing) a page, I need access to the request to modify the initial values of some fields in the page form.
Potential Approach
Note: This may not be best practice and could be fragile depending on future changes to Wagtail.
First, we need a custom EditHandler, these are the way Wagtail builds up forms and even Panels within the editing interface. An EditHandler's job is to manage the form to return based on the model and even the current request.
As a first step, it would be good to get your page create form showing correctly by following the instructions on using a custom tabbed interface. From here, you can replace the TabbedInterface with your custom class (e.g. CustomTabbedInterface) and add some functionality to this which will allow for a dynamic form_class to be returned.
get_form_class should return the form_class, however, we can modify it to return a function that, when called, will instantiate the class with custom information based on the request.
There may be some issues with this approach below in edit views or scenarios not considered by this example so validate this fully before using.
Example Code
from wagtail.admin.edit_handlers import TabbedInterface, ObjectList
from wagtail.core.models import Page
class CustomTabbedInterface(TabbedInterface):
def get_form_class(self):
form_class = super().get_form_class()
request = self.request
if request and request.method != 'POST':
# check request is available to ensure this instance has been bound to it
user = self.request.user
def initiate_class(**kwargs):
# instead of returning the class, return a function that returns the instantiated class
# here we can inject a kwarg `initial` into the generated form
# important: this gets called for edit view also and initial will override the instance data
# kwarg['instance'] will be the `Page` instance and can be inspected as needed
kwargs['initial'] = {'introduction': user.first_name}
return form_class(**kwargs)
return initiate_class
return form_class
class StandardPage(Page):
# ... field etc
edit_handler = CustomTabbedInterface([
ObjectList(content_panels, heading='Content'),
ObjectList(Page.promote_panels, heading='Promote'),
ObjectList(Page.settings_panels, heading='Settings', classname="settings"),
])
Explanation
wagtail/admin/views/pages.py contains the create view, which will use the edit_handler, bind it to the model and the request and then call its get_form_class.
The form_class is used for the response here form = form_class(instance=page, parent_page=parent_page)
It gets called with the instance and the parent_page kwargs
Our custom get_form_class response takes those kwargs and injects an additional initial kwarg.
initial is used by Django forms to add any initial data - https://docs.djangoproject.com/en/3.0/ref/forms/api/#dynamic-initial-values
Finally, the Django form will merge the instance field values with the intial kwarg to generate the final pre-filled data for the form. You can see how this works in Django's BaseModelForm.
Be careful to consider what will happen on an update view, you likely do not want to override existing values with your initial values when a user has already entered something in the field.
I'm creating UserSerializer and want to allow users to create new accounts but forbid them to change their usernames. There is a read_only attribute that I can apply but then users won't be able to set a username when creating a new one. But without that It allows me to change it. There is also a required attribute which unfortunately cannot be used with read_only. There is no other relevant attribute.
One solution is to create 2 different Serializers one for creating User and another from changing him, but that seems the ugly and wrong thing to do. Do you have any suggestions on how to accomplish that without writing 2 serializers?
Thanks for any advice.
PS: I'm using python3.6 and django2.1
EDIT: I'm using generics.{ListCreateAPIView|RetrieveUpdateDestroyAPIView} classes for views. Like this:
class UserList(generics.ListCreateAPIView):
queryset = User.objects.all()
serializer_class = UserSerializer
class UserDetails(generics.RetrieveUpdateAPIView):
# this magic means (read only request OR accessing user is the same user being edited OR user is admin)
permission_classes = (perm_or(ReadOnly, perm_or(IsUserOwner, IsAdmin)),)
queryset = User.objects.all()
serializer_class = UserSerializer
EDIT2: There is a duplicate question (probably mine is duplicate) here
Assuming you are using a viewset class for your view, then you could override the init method of serializer as,
class UserSerializer(serializers.ModelSerializer):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if 'view' in self.context and self.context['view'].action in ['update', 'partial_update']:
self.fields.pop('username', None)
class Meta:
....
If you are trying to update the username field while update (HTTP PUT) or partial update (HTTP PATCH), the serializer will remove the username field from the list of fields and hence it wont affect the data/model
UPDATE
Why the above answer not woking with documentaion API?
From the doc
Note: By default include_docs_urls configures the underlying SchemaView to generate public schemas. This means that views will not be instantiated with a request instance. i.e. Inside the view self.request will be None.
In the answer, the fields are pops out dynamically with the help of a request object.
So, If you wish to handle API documentaion also, define multiple serializer and use get_serializer_class() method efficently. That's the DRF way.
Perhaps, one of the possible approaches would be to create a RegistrationSerializer which you use only in registration process/endpoint.
And then, you create another serializer UserSerializer where you make username read_only field and you use this serializer everywhere else ( eg. when updating user).
Anwser from #JPG is pretty accurate, but it has one limitation. You can use the serializer only in DRF views, because in other views or anywhere else the context will not have view.actions. To fix it self.instance can be used. It will make the code shorter and more versatile. Also instead of popping the field its better to make it read only, so that it can still be viewed but cannot be changed.
class UserSerializer(serializers.ModelSerializer):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
if self.instance is not None: # if object is being created the instance doesn't exist yet, otherwise it exists.
# self.fields.pop('username', None)
self.fields.get('username').read_only = True # An even better solution is to make the field read only instead of popping it.
class Meta:
....
Another possible solution is to use CreateOnlyDefault() which is a builtin feature in DRF now. You can read more about it here in the docs
I have a form (WTForms via Flask-WTF) that includes a QuerySelectMultipleField, something like this:
class EditDocumentForm(Form):
# other fields omitted for brevity
users = QuerySelectMultipleField('Select Users',
query_factory=User.query.all,
get_label=lambda u: u.username)
This works great—I just instantiate the form and pass it to my template for rendering, and all the right choices are there.
However, when I POST the form back and try to suck up the data with Form.populate_obj(), I get an angry message from SQLAlchemy:
InvalidRequestError: Object '<User at 0x10a4d33d0>' is already attached to session '1' (this is '3')
The view function:
#app.route("/document/edit/<doc_id>", methods=['GET', 'POST'])
#login_required
def edit_document(doc_id):
doc = Document.query.filter_by(id=doc_id).first()
if (doc is not None) and (doc.user_id == current_user.id):
form = EditDocumentForm(obj=doc)
if request.method == "POST":
if form.validate():
form.populate_obj(doc)
db.session.commit()
return redirect('/')
else:
_flash_validation_errors(form)
return render_template("edit.html", form=form)
flash("The document you requested doesn't exist, or you don't have permission to access it.", "error")
return(redirect('/'))
So it looks like there's one session used when the form is created, and another when I'm trying to populate my model object. This is all happening under the hood, as I'm relying on Flask-SQLAlchemy to do all the session stuff for me.
In the Document model, the user field is declared this way:
users = db.relationship('User',
secondary=shares,
backref=db.backref('shared_docs', lazy='dynamic'))
(where of course shares is an instance of SQLAlchemy.table for a many-to-many relationship).
So: am I doing something wrong, or is Form.populate_obj() the problem, or perhaps I can blame aliens? Let me rephrase: What am I doing wrong?
Edit
The workaround this answer seems to fix the problem, namely changing my query_factory by importing my SQLAlchemy object and explicitly using its session:
query_factory=lambda: db.session.query(User)
I have to say, though, this has a weird smell to me. Is this really the best way to handle it?
It all depends on how your models classes are bound to a session. My guess is: you're not using the base class provided by Flask-SQLAlchemy: db.Model for your Document and User models ?
As stated in your ''edit'', by not using User's query method, and using db.session.query instead, you are forcing populate_obj to use the same session that you will commit later with your db.session.commit call. That said, you are still probably using another session when doing Document.query.filter_by which most likely means you are still using 2 DB connections and could reduce it to one.
Overall, I would advise you to stay away from using the query method on your models (but that's because I don't like magic stuff ;) ), make sure to use Flask-SQLAlchemy's db.Model if you can and read in-depth how the framework / libraries you use work, as it's a very good habit to take, does not take a lot of time, and can significantly improve the quality and maintainability of your code.
I'm trying to set up a django form consisting solely of a formset. In forms.py I have:
class StudentEnrolmentForm(forms.ModelForm):
school_class = forms.ModelChoiceField(SchoolClass.objects.currently_enrolling())
class Meta:
model = StudentApplication
fields = []
StudentEnrolmentFormSet = modelformset_factory(StudentApplication, StudentEnrolmentForm, extra=0)
but I'm unclear how to incorporate the FormSet into a CBV (In this case I've chosen a FormView). In this case I'm basically displaying a table of students, and allowing the operator to assign each student to a class. I only want a single 'submit' button at the end of the page.
If you will take a look on sources of Django views and check how FormView is working, you find that it just overrides default get and post methods of base View class and adds some additional methods for the form handling.
So you can:
try to assign your formset to the form_class field of your view and
play around. Probably you will have to override some additional
methods;
take a look on https://github.com/AndrewIngram/django-extra-views;
if options #1 and #2 causes too much pain - use default View
What I would like to achive is:
I go to admin site, apply some filters to the list of objects
I click and object edit, edit, edit, hit 'Save'
Site takes me to the list of objects... unfiltered. I'd like to have the filter from step 1 remembered and applied.
Is there an easy way to do it?
Unfortunately there's no easy way to do this. The filtering does not seem to be saved in any session variable.
Clicking back twice is the normal method, but it can be unweildy and annoying if you've just changed an object so that it should no longer be shown using your filter.
If it's just a one-off, click back twice or go through the filtering again, it's the easiest way.
If you're going to be filtering more often, or you just want to learn about hacking the admin (which is pretty open and easy), you'll want to write a FilterSpec.
Have a look here and here for examples of people writing their own.
A really, really terrible way to do this would be to edit the admin interface so that after you click "Save", you are redirected to you filtered URL. I wouldn't recommend this at all, but it's an option.
Another fairly simple way to do this would be to write a generic view to show your filtered objects, then use Django forms to edit the items from there. I'd have a look at this, you'll be stunned just how little code you have to write to get a simple view/edit page going.
Click 2 times "Back"?
There's a simple hack to do this, but it's not a general solution and requires modifying every ModelAdmin which you want to support this. Maybe there is a general way to do this, but I've not spent the time to solve it on a general level.
The first step is to write a custom FilterSpec for the filter (see Harley's post for links that will help) which saves the chosen filter value in the session (and deletes it when no longer wanted).
# in cust_admin/filterspecs.py
from django.contrib.admin.filterspecs import FilterSpec, ChoicesFilterSpec
class MyFilterSpec(ChoicesFilterSpec):
def __init__(self, f, request, params, model, model_admin):
super(MyFilterSpec, self).__init__(f, request, params, model,
model_admin)
if self.lookup_val is not None:
request.session[self.lookup_kwarg] = self.lookup_val
elif self.lookup_kwarg in request.session:
del(request.session[self.lookup_kwarg])
# Register the filter with a test function which will apply it to any field
# with a my_filter attribute equal to True
FilterSpec.filter_specs.insert(0, (lambda f: getattr(f, 'my_filter', False),
MyFilterSpec))
You must import the module this is in somewhere, for example your urls.py:
# in urls.py
from cust_admin import filterspecs
Set a property on the field you want to apply the filter to:
# in models.py
class MyModel(models.Model):
my_field = Models.IntegerField(choices=MY_CHOICES)
my_field.my_filter = True
In a custom ModelAdmin class, override the change_view method, so that after the user clicks save, they are returned to the list view with their filter field value added to the URL.
class MyModelAdmin(admin.ModelAdmin):
def change_view(self, request, object_id, extra_context=None):
result = super(MyModelAdmin, self).change_view(request, object_id,
extra_context)
if '_save' in request.POST:
if 'my_field__exact' in request.session:
result['Location'] = '/admin/myapp/mymodel/?my_field__exact=%s' \
% request.session['my_field__exact']
return result
Another way to do this is to embed the filter in the queryset.
You can dynamically create a proxy model with a manager that filters the way you want, then call admin.site.register() to create a new model admin. All the links would then be relative to this view.
In my opinion its better to override methods from ModelAdmin changelist_view and change_view:
Like so:
class FakturaAdmin(admin.ModelAdmin):
[...]
def changelist_view(self, request, extra_context=None):
result = super(FakturaAdmin, self).changelist_view(request, extra_context=None)
request.session['qdict'] = request.GET
return result
def change_view(self, request, object_id, extra_context=None):
result = super(FakturaAdmin, self).change_view(request, object_id, extra_context)
try:
result['location'] = result['location']+"?"+request.session['qdict'].urlencode()
except:
pass
return result
As you wish, after save object you go back to list of objects with active filters.
There is a change request at the Django project asking for exactly this functionality.
All it's waiting for to be checked in is some tests and documentation. You could write those, and help the whole project, or you could just take the proposed patch (near the bottom of the page) and try it out.
https://code.djangoproject.com/ticket/6903
This feature has been added to Django as part of the 1.6 release and is enabled now by default. It is described in the release notes:
ModelAdmin now preserves filters on the list view after creating,
editing or deleting an object. It’s possible to restore the previous
behavior of clearing filters by setting the preserve_filters attribute
to False.