I have a view function that resubmits data when I refresh the page.
def home(request):
if request.method == 'POST':
form = ListForm(request.POST or None)
if form.is_valid():
form.save()
all_items = List.objects.all
messages.success(request,('Item has been added to List'))
return render(request, 'home.html', {'all_items': all_items})
else:
all_items = List.objects.all
return render(request, 'home.html',{'all_items':all_items})
Any ideas on how to prevent this please. render_to_response is now deprecated from what Ive read.
Thank you
Preventing form resubmission is nothing new, the canonical solution is the post-redirect-get pattern: after a successful post, you return a redirect HTTP response, forcing the user's browser to do a get. The canonical Django "form handler" view (in it's function version) is:
def yourview(request):
if request.method == "POST":
form = YourForm(request.POST)
if form.is_valid():
do_something_with_the_form_data_here()
return redirect("your_view_name")
# if the form isn't valid we want to redisplay it with
# the validation errors, so we just let the execution
# flow continue...
else:
form = YourForm()
# here `form` will be either an unbound form (if it's a GET
# request) or a bound form with validation errors.
return render(request, "yourtemplate.html", {'form': form, ...})
Related
OK im probably doing this all wrong!
I am trying to run a function in a view which calls another view.
This seems to pass my request into the next function as a POST method before loading the form from the second function.
my views.py
''' This section of hte code seems to function correctly '''
#login_required()
def joinLeague(request):
if request.method == 'POST':
league = JoinLeagueQueue(user=request.user)
form = JoinLeagueForm(instance=league, data=request.POST)
if form.is_valid():
form.save()
context = int(league.id) # displays id of model, JoinLeagueQueue
return HttpResponseRedirect(confirmLeague(request, context))
else:
form = JoinLeagueForm()
context = {'form':form}
return render(request, 'userteams/joinleagueform.html', context)
This section of the views file is not working correctly.
it seems to run the POST request without displaying the GET request with the form first.
#login_required()
def confirmLeague(request, league):
# gets ID of application to join league
joinleagueid=JoinLeagueQueue.objects.get(id=league)
pin = joinleagueid.pin # gets pin from application
user = joinleagueid.user # get user from application
leagueinquestion=League.objects.get(leaguePin=pin) # gets the league record for applied league
manager=leagueinquestion.leagueManager # Gets the league manager for league applied for
leaguename=leagueinquestion.leagueName # Gets the league name for league applied for
if request.method == 'POST':
if 'accept' in request.POST:
LeaguesJoinedTo.objects.create(
leaguePin = pin,
playerjoined = user,
)
return redirect('punterDashboard')# user homepage
else:
print("Error in POST request")
else:
context = {'leaguename':leaguename, 'pin':pin, 'manager':manager}
return render(request, 'userteams/confirmleague.html', context)
I now get an error saying Page not found (404)
Request Method: GET
Request URL: http://127.0.0.1:8000/userteams/None
Using the URLconf defined in fanfoo_proj.urls, Django tried these URL patterns, in this order:
... im skipping a list of the patterns.
10. userteams/ confirmLeague [name='confirmLeague']
Ok i think the better way would be a HttpRedirect to the second view:
return confirmLeague(request, context)
should change to something like:
return redirect(confirmLeague,args=league)
django doc to urlresolvers: https://docs.djangoproject.com/en/3.0/topics/http/shortcuts/#redirect
def joinLeague(request):
if request.method == 'POST':
league = JoinLeagueQueue(user=request.user)
form = JoinLeagueForm(instance=league, data=request.POST)
if form.is_valid():
form.save()
context = league.id
return HttpResponseRedirect( reverse("your_confirmLeague_url",kwargs={'league':context}) )
else:
form = JoinLeagueForm()
context = {'form':form}
return render(request, 'userteams/joinleagueform.html', context)
def confirmLeague(request, league):
league = get_object_or_404(JoinLeagueQueue, pk=league)
pin = league.pin
if request.method == 'POST':
if 'accept' in request.POST: # This refers to the action from my form which is waiting for a button press in a html form.
LeaguesJoinedTo.objects.create(
leaguePin = pin,
playerjoined = request.user.id,
)
return redirect('punterDashboard')
else:
context = {'league':league}
return render(request, 'userteams/confirmleague.html', context)
I m facing error in Django :invalid syntax (views.py).
def deals(request):
form = deals()
if request.method == "POST":
form = deals(request.POST, request.FILES)
if form.is_valid():
form.save()
else:
return render_to_response("deals.html", {'form':form}, context_instance=RequestContext(request))
else:
form = deals()
return render_to_response("deals.html", {'form':form}, context_instance=RequestContext(request))
The problem is actually an issue with indentation, which manifests as a syntax error. The four lines beginning if form.is_valid() should be indented one level.
However, this would still not be the recommended pattern. You don't need the inner else at all, and you must redirect after a successful post.
def deals(request):
form = DealsForm()
if request.method == "POST":
form = DealsForm(request.POST, request.FILES)
if form.is_valid():
form.save()
return redirect('/') # or wherever
else:
form = DealsForm()
return render(request "deals.html", {'form':form})
Also I've used the render shortcut instead of render_to_response, as that uses a RequestContext automatically.
Note that all this is explicitly given in the docs; there's no reason to do anything else.
I've used Django forms. I have this function in views.py:
def func(request):
if request.method == "POST":
form = MyForm(request.POST)
if form.is_valid():
//do processing
return HttpResponseRedirect('/')
else:
form = MyForm()
return render_to_response("checkbox.html", RequestContext(request, {'form':form}))
but when form is invalid, it shows me the error: The view didn't return an HttpResponse object. I've searched and realized every where the view functions are like this, but I don't know why mine has error. It seems it doesn't know what to do, while form in invalid!!! Why it doesn't show the page and show user the form errors? can you please help me?
When the form is invalid, the view just returns since else part of the if statement is only evaluated when the request.method == "POST" is False, which it is not...
To fix this, the following is the usual pattern for making form views:
def func(request):
if request.method == "POST":
form = MyForm(request.POST)
if form.is_valid():
//do processing
return HttpResponseRedirect('/')
else:
form = MyForm()
# outside of the else clause
# if the form is invalid, then it will also show the error messages to the user
return render_to_response("checkbox.html", RequestContext(request, {'form':form}))
You already have your answer on #miki725 post. Just a suggestion you might want to consider GET as the default behaviour to avoid those if .. else:
def func(request):
# GET is the default behaviour
form = MyForm()
if request.method == "POST":
form = MyForm(request.POST)
if form.is_valid():
//do processing
return HttpResponseRedirect('/')
return render_to_response("checkbox.html", RequestContext(request, {'form':form}))
I have a form which contains an imagefield and some other fields.
my view looks like this:
def post_view(request):
def errorHandle(errors,form):
return render_to_response('post_form.html', {
'errors':errors,
'form' : form,
},context_instance=RequestContext(request))
if request.method == 'POST': # If the form has been submitted...
form = PostForm(request.POST, request.FILES) # A form bound to the POST data
if form.is_valid(): # All validation rules pass
#save
else:
errors = form.errors
return errorHandle(errors,form)
else:
form = PostForm() # An unbound form
sucess = ''
return render_to_response('post_form.html', {
'form': form,
}, context_instance=RequestContext(request))
When errorHandle is called, it returns to the page with the form, errors and the values entered except for the value entered on an ImageField.
tell me if you need to look at my form and model. thanks in advance.
I think it's normal.
Path of a client image is secure for a backend, so, it was not sent. It's an official HTTP feature.
I have a simple view in which I'm saving a form. The code seems 'clean', but I can't get rid of the error:
"The view didn't return an HttpResponse object."
Though I've searched on the web, I did not find a relevant indication.
def classroom_privacy(request,classname):
theclass = Classroom.objects.get(classname=classname)
if request.method == 'POST':
form = PrivacyClass(request.POST)
if form.is_valid():
new_obj = form.save(commit=False)
new_obj.save()
return HttpResponseRedirect('.')
else:
form = PrivacyClass()
return render_to_response('classroom/classroom_privacy.html', {'form': form},
context_instance=RequestContext(request))
verify the indentation of your code
def classroom_privacy(request, classname):
theclass = Classroom.objects.get(classname=classname)
if request.method == 'POST':
form = PrivacyClass(request.POST)
if form.is_valid():
new_obj = form.save(commit=False)
new_obj.save()
return HttpResponseRedirect('.')
else:
form = PrivacyClass()
return render_to_response('classroom/classroom_privacy.html', {'form': form}, context_instance=RequestContext(request))
if it is get request, render a unbound form
if it is post request and invalid form render a bound form
if it is post request and valid form redirect the page
All view functions must return some kind of HttpResponse object. There exists a code path in your function where None will be returned instead. This will occur when request.method != 'POST' and you'll simply "fall off the end" of your function (which will return None).
If you are using the Django Rest framework. Use the below code to return the HTTP response to resolve this issue.
from django.http import HttpResponse
def TestAPI(request):
# some logic
return HttpResponse('Hello')
JSON Response return example:
def TestAPI(request):
your_json = [{'key1': value, 'key2': value}]
return HttpResponse(your_json, 'application/json')
For more details about HttpResponse:
https://docs.djangoproject.com/en/3.1/ref/request-response/#django.http.HttpResponse