Deleting an object field before saving using django forms - django

The following code uses a form to save a new user avatar picture, however I cannot get this to delete the delete the old avatar and update with the new on. I've tried many different code variations.
Could someone point me in the correct direction. An explanation on why this is happening and brief example would be very helpful. All help is greatly appreciated.
model
class Profile(models.Model):
user = models.ForeignKey('auth.User')
avatar = Image..................
view
#login_required
def profile(request, pk):
profile = Profile.objects.get(user=pk)
pf = ProfileForm(request.POST, request.FILES, instance=profile)
if request.method =="POST":
if pf.is_valid():
profile.avatar.delete() #doesn't work
pf.save()
return render_to_response('template.html', {
'profile': profile,
'pf':pf
}, context_instance=RequestContext(request))
template
<form enctype="multipart/form-data" action="" method="POST"> {% csrf_token %}
{{ pf }}
<input type="submit" value="Submit" id="submit" />
</form>

Relationships act like the objects attribute. MyModel.objects.delete() wouldn't work either. You need to do something like profile.avatar.all().delete()
UPDATE: The above applies to many-to-many relationships. delete() can be accessed directly off a foreign key.
When deleting a foreign key, though, Django removes the associated database row and nullifies the foreign key's pk/id attribute, but it does not clear out the data for the foreign key immediately. You could technically, do something like:
profile.avatar.delete()
profile.avatar.save()
And, you would end up with the same object, only with a different primary key.

Related

Django - how to go back to previous view with parameters

I am relatively new with Django, this must be a common problem.
I have created a view to show a form to input date (using widget that returns separate fields):
when date is inserted, I call a function userPage(request, my_date)
that filters, processes and renders a page (user.html) showing a list of items.
def datePage(request):
user=request.user
context = {}
context['form'] = UserDateForm()
if request.GET:
date_yr = request.GET['food_date_year']
date_mo = request.GET['food_date_month']
date_day = request.GET['food_date_day']
my_date_string = date_yr+'-'+date_mo+'-'+date_day
my_date = datetime.strptime(my_date_string, "%Y-%m-%d").date()
return userPage(request,my_date)
return render(request, "date.html", context)
def userPage(request, my_date):
user=request.user
# process context using user, my_date
context={...:..., 'my_date': my_date}
return render(request,'user.html',context)
In user.html I include a URL to add an item:
</div>
<form action="{% url 'My_ItemCreate' %}" method="POST">
{%csrf_token%}
<button type="submit" class="btn btn-success">
<span class="glyphicon glyphicon-plus"></span>
</button>
</form>
</div>
'My_ItemCreate' points to a django.views.generic CreateView that creates an item.:
path('MyItemCreate/',views.My_ItemCreate.as_view(),name='My_ItemCreate'),
class My_ItemCreate(CreateView):
model = MyItem
fields = ...
After creating the item in the CreateView, how do I go back to the user page
after I inserted the date? I have lost the date in the new URL.
If I use URL resolver to go to userPage, how do I pass a date in the format?
It would be nice that I am able to pass initial values in the CreateView, and
make some fields read-only, how do I modify/override CreateView ?
Many Thanks for your help!
I have found an answer to my problem: using request.session
to store a value and retrieving in other views, it works fine.
I am still curious to know if there are experts who
would provide a more elegant solution, and if someone
could be so kind to answer point 2) regarding CreateView read_only fields
Thanks
D

Forms, Model, and updating with current user

I think this works, but I came across a couple of things before getting it to work that I want to understand better, so the question. It also looks like other people do this a variety of ways looking at other answers on stack overflow. What I am trying to avoid is having the user to have to select his username from the pulldown when creating a new search-profile. The search profile model is:
class Search_Profile(models.Model):
author_of_profile = models.ForeignKey(settings.AUTH_USER_MODEL,on_delete=models.CASCADE,blank=True)
keyword_string = models.CharField(max_length=200)
other_stuff = models.CharField(max_length=200)
The form I ended up with was:
class Search_Profile_Form(ModelForm):
class Meta:
model = Search_Profile
fields = [ 'keyword_string', 'other_stuff']
Where I deliberately left out 'author_of_profile' so that it wouldn't be shown or need to be validated. I tried hiding it, but then the form would not save to the model because a field hadn't been entered. If I was o.k. with a pulldown I guess I could have left it in.
I didn't have any issues with the HTML while testing for completeness:
<form action="" method="POST">
{% csrf_token %}
{{ form.author_of_profile}}
{{ form.keyword_string }}
{{ form.other_stuff }}
<input type="submit" value="Save and Return to Home Page">
</form>
And the View is where I ended up treating the form and the model separated, saving the form first, then updating the model, which is where I think there might be some other way people do it.
def New_Profile(request):
if request.method=='POST':
form = Search_Profile_Form(request.POST)
if form.is_valid():
post=form.save(commit=False)
# here is where I thought I could update the author of profile field somehow with USER
# but If I include the author_of_profile field in the form it seems I can't.
post.save()
#So instead I tried to update the author_of profile directly in the model
current_profile=Search_Profile.objects.last()
current_profile.author_of_profile=request.user
current_profile.save()
return(redirect('home'))
else:
form=Search_Profile_Form()
return render(request, 'mainapp/New_Profile.html', {'form': form})
So a few questions:
For the Foreign Key in author_of_profile field, is it better to use blank=True, or null=True
I ended up using request.user rather than importing from django.contrib.auth.models import User is there any difference?
My real question though, is the above a reasonable way to get form data and update the database with that data and the user? Or am I missing some other way that is more build in?
post=form.save()
current_profile.author_of_profile=request.user
post.save()
return(redirect('home'))
try something like this. save the form to db then change the author again. save(commit=False) will not save the date to db immediately.

How edit data from form django admin

I'm learning Django Framework, and I have a question. To help you understand I will try and explain using the example below:
Suppose that we have some table in db as is:
CREATE TABLE names (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, name VARCHAR(100));
And I have the form in Django Admin as is:
<form>
<textarea name="names"></textarea>
<input type="submit" name="sbt" value="Submit">
</form>
User entered something in the input names in the form and submitted it. Then a script catches this data and splits it into an array (str.split("\n")) and in cycle adding to table names!
And I many quetion:
How i can add form to Django Admin?
How i can catch form data and add this data to somethink table in database?
Thanks.
First of all you must create a django model.
Put this code in models.py.
class Names(models.Model):
name = models.CharField(max_length = 100)
Then you must create the admin model.
Put this code in admin.py.
class NamesAdmin(admin.ModelAdmin):
list_display = ['name']
# whatever you want in your admin panel like filter, search and ...
admin.site.register(Names, NamesAdmin)
I think it meet your request. And for split the names you can override save model method and split the names in there. But if you want to have an extra form, you can easily create a django model form.
Put the code somewhere like admin.py, views.py or forms.py
class NamesForm(forms.ModelForm)
class Meta:
model = Names
That's your model and form. So, if your want to add the form to django admin panel you must create a view for it in django admin. For do this create a view as common.
Put the code in your admin.py or views.py.
def spliter(req):
if req.method == 'POST':
form = NamesForm(req.POST)
if form.is_valid():
for name in form.cleaned_data['names'].split(' '):
Names(name = name).save()
return HttpResponseRedirect('') # wherever you want to redirect
return render(req, 'names.html', {'form': form})
return render(req, 'names.html', {'form': NamesForm()})
Be aware you must create the names.html and put the below code in you html page.
{% extends 'admin/base_site.html' %}
{% block content %}
<!-- /admin/names/spliter/ is your url in admin panel (you can change it whatever you want) -->
<form action="/admin/names/spliter/" method="post" >{% csrf_token %}
{{ form }}
<input type="submit" value="'Send'" >
</form>
{% endblock %}
This is your view and your can use it everywhere. But if you want only the admin have permission to see this page you must add this method too your NamesAdmin class.
def get_urls(self):
return patterns(
'',
(r'^spliter/$', self.admin_site.admin_view(spliter)) # spliter is your view
) + super(NamesAdmin, self).get_urls()
That's It. I hope this can help you.

Cannot get selection from one page to another - need to know what choice user chose

I'm trying to let the user select one 'thing' from a list (from the database), then go find other stuff in the database using that record. But I cannot get the selection info from the selection page.
I'll try to make this a pretty complete snapshot of the relevant code, but I may remove too much or leave too much in, sorry.
my models.py:
urlpatterns = patterns('',
url(r'^$', 'dblook.views.index', name='home'),
url(r'^dblook3/', 'dblook.views.try3', name='home2'),
url(r'^dblook4/', 'dblook.views.try4', name='home3'),
)
my dblook/models.py:
from django.db import models
class serial_number(models.Model):
def __unicode__(self):
return self.serialno
#return self.question
class Meta:
managed=False
db_table='serial_number'
sn_id = models.AutoField(primary_key=True)
serialno = models.CharField(max_length=128)
comment = models.ForeignKey(comment,null=True,db_column='comment')
my views.py (I will skip all the imports other than the database model import. If anyone really wants them I'll update with them)
from dblook.models import *
class SerialnoSelectForm(forms.Form):
serialno = forms.CharField(max_length=16)
selected = forms.BooleanField()
class serialform(ModelForm):
class Meta:
model = serial_number
exclude=('comment','sn_id')
selected = forms.BooleanField()
class snselect(forms.Form):
sno = forms.ChoiceField()
def try3(request):
if ( request.POST ):
output = "HEllo world, thanks for posting"
return HttpResponse(output)
else:
sslst = snselect(serial_number.objects.filter(serialno__startswith="A128").order_by('-serialno'))
t = loader.get_template('select_serialno.html')
c = Context({
'sslst': sslst,
})
c.update(csrf(request))
return HttpResponse(t.render(c))
def try4(request,dsn):
if ( request.POST ):
output = "HEllo world, thanks for posting to 4"
return HttpResponse(output)
else:
return HttpResponse("Error")
And my template (select_serialno.html) is:
<h1>Select a serial number</h1>
<ul>
<form method='post' action'='/dbtest4/{{serial_number.sn_id}}/showme'>
{% csrf_token %}
{% for sn in sslst %}
<input type="submit" name="sn.serialno" id="choice{{ forloop.counter }}" value="{{choice.id}}"/>
<label for="choice{{ forloop.counter }}">{{ sn.serialno }}</label><br/>
{% endfor %}
<input type="submit" value="data" />
</form>
When I go to dblook3, I get a nice list from the database of serial numbers, along with a button that, if I hit goes immediately to the dblook4 URL (in this case, its ALWAYS '/dbtest4//showme/' instead of something like '/dbtest4/3/showme/). Unfortunately, I cannot seem to have any way to tell what button they hit.
No matter WHAT I put in for the 'stuff' in <form method='post' action'='/dbtest/{{stuff}}/showme'>, it is always empty.
I also tried things like if( 'choice' in request.POST ): in try4 in veiws.py, but that didn't work either.
So, how do I get ANY information about what was selected from 'look3' over to 'look4'? I'll take just about anything... However, if you can explain why I'm doing that hopefully your answer will not only solve my problem, but help others understand...
(if the above looks pretty 'evolutionary' that's because I've been hacking on this for 3 days now...)
Thanks!
You need to POST the information to the look4 dblook form:
<form method='post' action'='{% url dblook.views.try4 %}'>
At the moment you have /dbtest/{{serial_number.sn_id}}/showme which doesn't make any sense. You don't have a serial_number variable in your context so I don't know where that comes from. You have def try4(request,dsn): as your view definition which suggests that you are trying to load information on the try4 view depending on what was selected fromt he try3 view (although I am guessing this as you haven't explained what you are trying to do). If that is the case, you need to do that based on the data passed via POST instead of url parameters. Something very vaguely like the following:
def try4(request):
if request.method == "POST":
form = snselect(request.POST)
if form.is_valid():
data = form.cleaned_data
# Get the selected item from your choice field and retrieve the
# corresonding model object with that id
...

Update non-request user information in a Django template and view

So I have a ManageUserForm in forms.py-- it renders correctly but it doesn't pull the right data from the user i'm trying to edit.
In the template, I have a for loop that works correctly
{% for tenants in tenants %}
{{ tenants.user }} {{ tenants.type }}
{% endfor %}
This template renders the list of objects in the UserProfile. And it does it correctly. The challenge I face is updating the "tenants.type" attribute. Again, the type shows up correctly but I don't know how to update it from this template page.
#views.py
def manage_users(request):
tenants = UserProfile.objects.all()
form = ManageUserForm(request.POST or None)
if form.is_valid():
update = form.save(commit=False)
update.save()
return render_to_response('manage_users.html', locals(), context_instance=RequestContext(request))
#forms.py
class ManageUserForm(forms.ModelForm):
class Meta:
model = UserProfile
exclude = ('full_name', 'user',)
`I think I need to call an instance but I have no idea how to do so for the non-request users AND still follow the pattern for the template. The template basically is a list of users where the request user (staff user) will be able to change the data in the list.
Thank you for your help!
You have one form for one user. You need a FormSet if you want to use that form to edit multiple tenants. Editing objects and displaying them are entirely different beasts; dont' confuse them.
formset = modelformset_factory(form=ManageUserForm, queryset=tenants)
Update:
You should have one {{ form.management_form }} and the rest of the {% for form in formset %}{{ form }}{% endfor %} in one <form> tag. All of your forms are the first form in the formset.
You should rewrite your template loop to iterate through formset forms instead of tenant objects. The tenant object can be accessed through {{ form.instance }}
Update 2:
You have an extra form because you probably haven't passed in the extra=0 parameter to the modelformset_factory function. These forms are typically used to add/edit data; thus it has support for adding N blank forms for creating.