Develop Reference

Django: Pass a variable/parameter to form from view? [duplicate]

I have a Model as follows:
class TankJournal(models.Model):
user = models.ForeignKey(User)
tank = models.ForeignKey(TankProfile)
ts = models.IntegerField(max_length=15)
title = models.CharField(max_length=50)
body = models.TextField()
I also have a model form for the above model as follows:
class JournalForm(ModelForm):
tank = forms.IntegerField(widget=forms.HiddenInput())
class Meta:
model = TankJournal
exclude = ('user','ts')
I want to know how to set the default value for that tank hidden field. Here is my function to show/save the form so far:
def addJournal(request, id=0):
if not request.user.is_authenticated():
return HttpResponseRedirect('/')
# checking if they own the tank
from django.contrib.auth.models import User
user = User.objects.get(pk=request.session['id'])
if request.method == 'POST':
form = JournalForm(request.POST)
if form.is_valid():
obj = form.save(commit=False)
# setting the user and ts
from time import time
obj.ts = int(time())
obj.user = user
obj.tank = TankProfile.objects.get(pk=form.cleaned_data['tank_id'])
# saving the test
obj.save()
else:
form = JournalForm()
try:
tank = TankProfile.objects.get(user=user, id=id)
except TankProfile.DoesNotExist:
return HttpResponseRedirect('/error/')

You can use Form.initial, which is explained here.
You have two options either populate the value when calling form constructor:
form = JournalForm(initial={'tank': 123})
or set the value in the form definition:
tank = forms.IntegerField(widget=forms.HiddenInput(), initial=123)

Other solution: Set initial after creating the form:
form.fields['tank'].initial = 123

If you are creating modelform from POST values initial can be assigned this way:
form = SomeModelForm(request.POST, initial={"option": "10"})
https://docs.djangoproject.com/en/1.10/topics/forms/modelforms/#providing-initial-values

I had this other solution (I'm posting it in case someone else as me is using the following method from the model):
class onlyUserIsActiveField(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(onlyUserIsActiveField, self).__init__(*args, **kwargs)
self.fields['is_active'].initial = False
class Meta:
model = User
fields = ['is_active']
labels = {'is_active': 'Is Active'}
widgets = {
'is_active': forms.CheckboxInput( attrs={
'class': 'form-control bootstrap-switch',
'data-size': 'mini',
'data-on-color': 'success',
'data-on-text': 'Active',
'data-off-color': 'danger',
'data-off-text': 'Inactive',
'name': 'is_active',
})
}
The initial is definded on the __init__ function as self.fields['is_active'].initial = False

As explained in Django docs, initial is not default.
The initial value of a field is intended to be displayed in an HTML . But if the user delete this value, and finally send back a blank value for this field, the initial value is lost. So you do not obtain what is expected by a default behaviour.
The default behaviour is : the value that validation process will take if data argument do not contain any value for the field.
To implement that, a straightforward way is to combine initial and clean_<field>():
class JournalForm(ModelForm):
tank = forms.IntegerField(widget=forms.HiddenInput(), initial=123)
(...)
def clean_tank(self):
if not self['tank'].html_name in self.data:
return self.fields['tank'].initial
return self.cleaned_data['tank']

If you want to add initial value and post other value you have to add the following :
or None after request.POST
form = JournalForm(request.POST or None,initial={'tank': 123})
If you want to add files or images also
form = JournalForm(request.POST or None,request.FILES or None,initial={'tank': 123})

I hope this can help you:
form.instance.updatedby = form.cleaned_data['updatedby'] = request.user.id

I also encountered the need to set default values in the form during development. My solution is
initial={"":""}
form=ArticleModel(request.POST)
if form.has_changed():
data = {i: form.cleaned_data[i] for i in form.changed_data}
data.update({key: val for key, val in init_praram.items() if key not in form.changed_data})
use form.has_changed ,if form.fields is required you can use this method

How I added the initial to the form:
I read #Sergey Golovchenko answer.
So I just added it to the form in if request.method == 'POST':.
But that's not where you place it, if you want to see what value it got before posting the form.
You need to put it in the form where the else is.
Example here from views.py
def myForm(request):
kontext = {}
if request.method == 'POST':
# You might want to use clean_data instead of initial here. I found something on a stack overflow question, and you add clean data to the Forms.py, if you want to change the post data. https://stackoverflow.com/questions/36711229/django-forms-clean-data
form = myModelForm(request.POST, initial={'user': request.user})
if form.is_valid():
form.save()
return redirect('/')
else:
# you need to put initial here, if you want to see the value before you post it
form = myModelForm(initial={'user': request.user})
kontext['form'] = form
return render(request, 'app1/my_form.html', kontext)

Assigning the correct ID to a form?

So I'm expanding on the official tutorial, and I'm trying to let a user create their own poll. I'm having trouble assigning the correct question_id to the choice, so the choice aligns in the database with the question and both can be read off. Here is my view:
def poll_create(request):
if request.method == "POST":
Qform = QuestionForm(request.POST)
Cform = ChoiceForm(request.POST)
if Qform.is_valid():
poll = Qform.save(commit=False)
poll.author = request.user
poll.pub_date = timezone.now()
poll.save()
if Cform.is_valid():
poll = Cform.save(commit=False)
poll.author = request.user
findid = Question.objects.all().order_by("-id")[0] ##Finds the id of the last question in database
poll.question_id = findid.id + 1
poll.save()
return redirect('polls:detail', pk=poll.pk)
else:
Qform = QuestionForm()
Cform = ChoiceForm()
return render(request, 'polls/create.html', {'Qform': Qform, 'Cform': Cform})
So the idea is to have a question form (Qform) which writes the question to the database, and then below on the webpage a choice form (Cform), which writes the answer to the database. I'm really confused about applying a question_id to the Cform. At the moment, I have this line:
findid = Question.objects.all().order_by("-id")[0] ##Finds the id of the last question in database
poll.question_id = findid.id + 1
Which seems like a very hacky attempt to find the last id and assign it to the next one. It doesnt line up because the poll.pk has a different value. I'm at a loss here and don't really understand what's going on. Any help would be appreciated.

Your code is a bit confusing because you are using the variable poll for questions and choices. It would be better to use question and choice instead.
You should check that both forms are valid before you start saving, otherwise you can end up with a question without a choice if the question form is valid but the choice form is invalid.
After you have saved the question, you can get the id with question.id, and you can assign the question to the choice object. There is no need to do a query to find the latest question id.
Putting that together, you have something like:
if Qform.is_valid() and Cform.is_valid():
question = Qform.save(commit=False)
question.author = request.user
question.pub_date = timezone.now()
question.save()
choice = Cform.save(commit=False)
choice.author = request.user
choice.question = question
choice.save()
return redirect('polls:detail', pk=question.pk)
Note also that it's recommended to use lowercase question_form and choice_form, for the form instances, and uppercase QuestionForm and ChoiceForm for the classes.

Django - Get previous form filled data when I come back to form [duplicate]

i'm new to django so i'm sorry for my newbie question
i have a model and i need to let user edit data inside it using django forms or any other way.
look at the image above , i want to show this form ready populated with the data and let user update it.
what is the best way to do this ?
EDIT : here is my views.py code
def exam_Edit(request,examName,number=0):
numner = int(number)
number = int(number)
questionNo = int(numner)
Myexam = models.Exam.objects.get(name = examName)
QuestionsAll = models.Question.objects.filter(exam = Myexam)
myQeustion = Question.objects.filter(exam = Myexam)[nextQuestion]
answer1 = models.Asnwers.objects.filter(question=myQeustion)[0]
answer2 = models.Asnwers.objects.filter(question=myQeustion)[1]
answer3 = models.Asnwers.objects.filter(question=myQeustion)[2]
answer4 = models.Asnwers.objects.filter(question=myQeustion)[3]
# HERE IS MY PROBLEM : the line below creates a form with a data but it doesn't save it to the save object
form = QuestionsEditForm(initial = {'questionText':myQeustion.__unicode__() , 'firstChoiceText':answer1.__unicode__(),'secondChoiceText':answer2.__unicode__(),'thirdChoiceText':answer3.__unicode__(),'forthChoiceText':answer4.__unicode__()})
if request.method =='POST':
#if post
if form.is_valid():
questionText = form.cleaned_data['questionText']
Myexam = Exam.objects.get(name = examName)
myQeustion.questionText = form.cleaned_data['questionText']
answer1.answerText = form.cleaned_data['firstChoiceText']
answer1.save()
answer2.answerText = form.cleaned_data['secondChoiceText']
answer2.save()
answer3.answerText = form.cleaned_data['thirdChoiceText']
answer3.save()
answer4.answerText = form.cleaned_data['forthChoiceText']
answer4.save()
variables = RequestContext(request, {'form':form,'examName':examName,'questionNo':str(nextQuestion)})
return render_to_response('exam_edit.html',variables)
please help

Assuming you are using a ModelForm, use the instance keyword argument, and pass the model you are updating.
So, if you have MyModel and MyModelForm (the latter of which must extend django.forms.ModelForm), then your code snippet might look like:
my_record = MyModel.objects.get(id=XXX)
form = MyModelForm(instance=my_record)
And then, when the user sends back data by POST:
form = MyModelForm(request.POST, instance=my_record)
Incidentally, the documentation for ModelForm is here: http://docs.djangoproject.com/en/1.8/topics/forms/modelforms/

django get_or_create method always results in a new record

Model
class projects(models.Model):
"""Table that holds the details of the projects."""
toiName = models.CharField(max_length=100)
toiOwner = models.CharField(max_length=50)
receiver = models.CharField(max_length=50)
manager = models.CharField(max_length=50)
toiOwnerEmail = models.EmailField(max_length=70)
receiverEmail = models.EmailField(max_length=70)
managerEmail = models.EmailField(max_length=70)
dateUpdated= models.DateTimeField(default=datetime.today())
dateCreated = models.DateTimeField(default=datetime.today())
class Meta:
db_table="projects"
View, the original code to save the model works fine, when I go ahead and edit the form in the view, I always end up with a new record.
data = model_to_dict(projects.objects.filter(toiName=pid, managerEmail=request.user)[0])
if request.method == 'POST':
form = projectsForm(request.POST)
if form.is_valid():
#form = projectsForm(request.POST, instance=projects.objects.get(toiName=pid))
#obj = projects\
obj, created = projects.objects.get_or_create\
(toiName=request.POST['toiName'],
toiOwnerEmail=request.POST['toiOwnerEmail'],
toiOwner=request.POST['toiOwner'],
manager=request.POST['manager'],
receiver=request.POST['receiver'],
receiverEmail=request.POST['receiverEmail'],
dateUpdated=datetime.now(),
dateCreated=data['dateCreated'],
managerEmail=request.user,)
Here created always results in True.

At least this dateUpdated=datetime.now() causes get_or_create to always create new record, because each time datetime.now() is different.

I believe I was using the get_or_create incorrectly, since I was only trying to update the entry.
I fixed the code in the view with:
data = model_to_dict(projects.objects.filter(toiName=pid, managerEmail=request.user)[0])
proj = projects.objects.get(toiName=pid, managerEmail=request.user)
if request.method == 'POST':
form = projectsForm(request.POST)
if form.is_valid():
proj.toiName=form.cleaned_data['toiName']
proj.toiOwnerEmail=form.cleaned_data['toiOwnerEmail']
proj.toiOwner=form.cleaned_data['toiOwner']
proj.manager=form.cleaned_data['manager']
proj.receiver=form.cleaned_data['receiver']
proj.receiverEmail=form.cleaned_data['receiverEmail']
proj.dateUpdated=datetime.now()
#proj.dateCreated=data['dateCreated']
proj.save()

additional to #user1865366 answer, projects.objects.get should be enclose it with try ... except ... like so
try:
proj = Projects.objects.get(toiName=pid,manageEmail=request.user)
except Projects.DoesNotExist :
# do something create new proj and do something with the form
...
otherwise there will be big error screen when django cannot get the object

change a form value before validation in Django form

I have a django form and on my view function I do this :
search_packages_form = SearchPackagesForm( data = request.POST )
I would like to overwrite a form field called price which is decleared as such :
price = forms.ChoiceField( choices = PRICE_CHOICES, required = False,widget = forms.RadioSelect )
I would like to overwrite the form field before calling search_packages_form.is_valid()
I thought of doing :
search_packages_form.data['price'] = NEW_PRICE
But it does not work. Any ideas ?

Probably not the Django way but based on https://stackoverflow.com/a/17304350/2730032 I'm guessing the easiest way to change your form value before validation is to do something like the following:
def search_packages_view(request):
if request.method == 'POST'
updated_request = request.POST.copy()
updated_request.update({'price': NEW_PRICE})
search_packages_form = SearchPackagesForm(updated_request)
if search_packages_form.is_valid():
# You're all good
This works but I'd be interested if anyone has another way that seems more in line with Django, or if there isn't: then an explanation about why.

one trick for what you want is to do it like this:
changed_data = dict(request.POST)
changed_data['price'] = NEW_PRICE
search_packages_form = SearchPackagesForm(data = changed_data)

My solution is build on an earlier proposal. It is a working solution, which can be used in several cases.
#Milad Khodabandehloo
had a tricky solution to solve the problem.
changed_data = dict(request.POST)
changed_data['price'] = NEW_PRICE
search_packages_form = SearchPackagesForm(data = changed_data)
as #The EasyLearn Academy commented: it does not allow you to access actual data submitted in form.
This is because the request.POST is immutable.
But there is a solution to the problem - just have to be more tricky.
This solution is only good if a reference to the object is enough for the certain cause. It leaves the object itself the same.
# write object to variable (data)
data = request.POST
# set to mutable
data._mutable = True
# modify the values in data
data[modified_field] = new_value
# set mutable flag back (optional)
data._mutable = False
Hope it's useful!

form.is_valid() runs through your form's (and model's in case of a ModelForm) clean method's, returning True or False
If you plan on changing form data you can do it within the general clean method or at field level, e.g.
class YourForm(DerivingClass):
# regular stuff
def clean_<ATTR>(self):
# here
return self.cleaned_data
def clean(self):
# or here
return super(YourForm, self).clean()