here is based-class views code:
# views.py
class ObjectCreate(CreateView):
model = ObjectModel
fields = "__all__"
its simple to create an object and save it use this class.
I wonder how?
what if I want to use based-function views to achieve it?
Using a function view you would need to implement everything, including creating a form for your model:
def create_object(request):
if request.method == 'GET':
form = ObjectForm()
if request.method == 'POST':
form = ObjectForm(request.POST)
if form.is_valid():
instance = form.save() # instance created
# now redirect user or render a success template
return redirect(...)
# if request method is GET or form is invalid return the form
return render(request, 'path/template_name.html', {'form': form})
If you want to learn how the CreateView works, look at its source code. Or for easier overview of the structure, look at this site which lists all the Django CBVs.
You'll find that CreateView inherits from 9 other classes, has about 20 attributes (of which model and fields) and 24 methods that you can override to customise its behaviour.
Related
I am trying to create A Project where I Have A model Form Which Takes A set of data as Input.
However that is not an issue, How Do I Have Multiple Forms of that One single Model Form .
I tried Using something like this
from .forms import BookForm
# Create your views here.
def home_page(request):
context = {}
form = BookForm(request.POST or None)
form1 = BookForm(request.POST or None)
if form.is_valid():
form.save()
if form1.is_valid():
form1.save()
context['form']= form
context['form1']= form1
return render(request, "home.html", context)
But What Happens is the Data passed in the last form is passed in all of the forms.
How Do I Implement this in Django Handling multiple forms in single view, which gets submitted on click of a button
You can use formsets in django.
Since you are using a model form, you can use something known as model formsets using something known as modelformset_factory.
Basically formsets help you in having a list of forms. Imagine your single form now turned into a list of forms.
Checkout this link for a tutorial
Let me know if you want more explanation
I want that the landing page of my homepage is a form with an input and the user puts in stuff. So I followed a couple of tutorials and now I have this:
views.py:
def create2(request):
if request.method =='POST':
form = LocationForm(request.POST)
if form.is_valid():
form.save()
return HttpResponseRedirect('')
else:
form = LocationForm()
args = {}
args.update(csrf(request))
args['form'] = form
return render_to_response('location/index.html', args)
and in my urls.py:
url(r'^$', 'core.views.create2'),
which works perfectly fine, if I go to 127.0.0.1:8000 I get to index.html and when put in something in the input it gets saved in the database. However, the old part of my homepage looks like this
class LandingView(TemplateView):
model = Location
template_name="location/index.html"
def search
...
and the urls.py:
url(r'^$', core.views.LandingView.as_view(), name='index'),
which has a function search I So my question is, is there a way how I can merge the def create2 into my LandingView. I tried several things, but I am always ending up having the index.html without the input field. I also tried
def create2
...
def search
...
but didn't work.
Does anyone know how to merge that together?
EDIT
Thank you the working solution looks like this now
class Create(CreateView):
model = coremodels.Location
template_name = 'location/test.html'
fields = ['title']
def form_valid(self, form):
form.save()
return HttpResponseRedirect('')
return super(Create, self).form_valid(form)
Depending on the results you are looking for, there are multiple ways to solve this:
1. Use CreateView and UpdateView
Django already provides some classes that render a form for your model, submit it using POST, and re-render the form with errors if form validation was not successful.
Check the generic editing views documentation.
2. Override get_context_data
In LandingView, override TemplateView's get_context_data method, so that your context includes the form you are creating in create2.
3. Use FormView
If you still want to use your own defined form instead of the model form that CreateView and UpdateView generate for you, you can use FormView, which is pretty much the same as TemplateView except it also handles your form submission/errors automatically.
In any case, you can keep your search function inside the class-based view and call it from get_context_data to include its results in the template's context.
I want to 'attach' a manytomany relationship on form submit.
The example is the classic blog tags-post relation: a post can have multiple tags related
In django-admin it works, but i can't figure how to do in views...
my code:
def add_post(request):
if request.method == 'POST':
form = PostForm(data=request.POST)
if form.is_valid():
model_instance = form.save(commit=False)
model_instance.author = request.user
newentry = model_instance.save()
#some magic needed here, this will never works
for tag in model_instance.tags.all():
t = Tag.objects.get_or_create(author=request.user, title=tag.title, slug=slugify(tag.title))
model_instance.tags.add(t)
#end of magic
return HttpResponseRedirect("/blog/")
else:
form = PostForm()
return render_to_response(
'blog/add_post.html',
{'form' : form },
context_instance=RequestContext(request))
I'm using the automatic tokenization from select2.js in the template, so i can to add tags "on the fly", but i'm not sure how to handle it with django...
newentry = model_instance.save()
The save() method on a model instance will not return anything, unlike the same method on a form. You should reuse model_instance instead of using newentry.
I'd also take a look at get_or_create() to create the tag if it doesn't exist already.
I have a blog where I have a ManyToManyField between posts and projects, and I select the projects to create a relationship to in the post form.
When you use commit=False on form.save(), you need to use form.save_m2m() after the form is saved using post.save().
This is what part of my view function looks like:
form = PostForm(request.POST)
if form.is_valid():
post = form.save(commit=False)
post.author = request.user
post.save()
# This saves the project relation
form.save_m2m()
For your usage, I would try moving the model_instance.save() and form.save_m2m() after your magic.
Another thing about get_or_create() is that it returns a tuple with the object that was gotten or created, and a boolean in regards to whether it created the object. So you need to only pass model_instance.tags.add() the created object.
form = PostForm(data=request.POST)
if form.is_valid():
model_instance = form.save(commit=False)
model_instance.author = request.user
#some magic needed here, this will never works
for tag in model_instance.tags.all():
t, created = Tag.objects.get_or_create(author=request.user, title=tag.title, slug=slugify(tag.title))
model_instance.tags.add(t)
#end of magic
model_instance.save()
form.save_m2m()
As a database programmer (with a little django experience) I would argue that you should normalize your models. IE, add a third table (call it something like Post Tags) and set it up as an intermediary between posts and tags. So the relationship from Post to Post Tags would be 1:M and the relationship from Tags to Post Tags would be 1:M
I am trying to get my head around Class based views (I'm new to Django). I currently have a project that uses function based views. My 'create' view renders a form and successfully submits to the database. However, I need an edit/update function so the obvious option is to re-use the 'create' function I made but I'm struggling to work it out and adhere to the DRY principle.
Is using Class based views the right way to go?
Do they handle the creation of all the 'CRUD' views?
I'm currently working my way through the GoDjano tutorials on Class based views but its still not sinking in.
Any help/pointers would be, as usual, much appreciated.
As you can see in the source code, a CreateView and an UpdateView are very similar. The only difference is that a CreateView sets self.object to None, forcing the creation of a new object, while UpdateView sets it to the updated object.
Creating a UpdateOrCreateView would be as simple as subclassing UpdateView and overriding the get_object method to return None, should a new object be created.
class UpdateOrCreateView(UpdateView):
def get_object(self, queryset=None):
# or any other condition
if not self.kwargs.get('pk', None):
return None
return super(UpdateOrCreateView, self).get_object(queryset)
The GoDjango tutorials don't seem to be out of date (CBVs have barely changed since their introduction), but they do seem to be missing some of the essential views in their tutorials.
CBV is in my opinion never the solution. A dry FBV is (assuming you have created an imported a form RecordForm and a model Record, imported get_object_or_404 and redirect):
#render_to('sometemplate.html')
def update(request, pk=None):
if pk:
record = get_object_or_404(Record, pk=pk)
else:
record = None
if request.POST:
form = RecordForm(request.POST)
if form.is_valid():
form.save()
return redirect('somepage')
else:
// ....
elif record:
form = RecordForm(instance=record)
else:
form = RecordForm()
return { 'form': form, 'record': record }
I also integrate the messages framework to for example add an error message when form.is_valid() is False.
I use a render_to decorator but that's not necessary (but then you have to return the view results differently).
I've made a nice form, and a big complicated 'add' function for handling it. It starts like this...
def add(req):
if req.method == 'POST':
form = ArticleForm(req.POST)
if form.is_valid():
article = form.save(commit=False)
article.author = req.user
# more processing ...
Now I don't really want to duplicate all that functionality in the edit() method, so I figured edit could use the exact same template, and maybe just add an id field to the form so the add function knew what it was editing. But there's a couple problems with this
Where would I set article.id in the add func? It would have to be after form.save because that's where the article gets created, but it would never even reach that, because the form is invalid due to unique constraints (unless the user edited everything). I can just remove the is_valid check, but then form.save fails instead.
If the form actually is invalid, the field I dynamically added in the edit function isn't preserved.
So how do I deal with this?
If you are extending your form from a ModelForm, use the instance keyword argument. Here we pass either an existing instance or a new one, depending on whether we're editing or adding an existing article. In both cases the author field is set on the instance, so commit=False is not required. Note also that I'm assuming only the author may edit their own articles, hence the HttpResponseForbidden response.
from django.http import HttpResponseForbidden
from django.shortcuts import get_object_or_404, redirect, render, reverse
#login_required
def edit(request, id=None, template_name='article_edit_template.html'):
if id:
article = get_object_or_404(Article, pk=id)
if article.author != request.user:
return HttpResponseForbidden()
else:
article = Article(author=request.user)
form = ArticleForm(request.POST or None, instance=article)
if request.POST and form.is_valid():
form.save()
# Save was successful, so redirect to another page
redirect_url = reverse(article_save_success)
return redirect(redirect_url)
return render(request, template_name, {
'form': form
})
And in your urls.py:
(r'^article/new/$', views.edit, {}, 'article_new'),
(r'^article/edit/(?P<id>\d+)/$', views.edit, {}, 'article_edit'),
The same edit view is used for both adds and edits, but only the edit url pattern passes an id to the view. To make this work well with your form you'll need to omit the author field from the form:
class ArticleForm(forms.ModelForm):
class Meta:
model = Article
exclude = ('author',)
You can have hidden ID field in form and for edit form it will be passed with the form for add form you can set it in req.POST e.g.
formData = req.POST.copy()
formData['id'] = getNewID()
and pass that formData to form