Can't advance Django paginator after formset submit - django

Question

[** found a fix, see below **]
I'm having trouble getting Django 2 Paginator to work with a modelformset. There are three models, Place & Hit (one-to-many), and Link. The 'validator' view pages through Place objects 1 at a time, builds a queryset of Hits filtered by the FK placeid. The context sent to the template includes 1) the formset=HitFormSet, 2) a 'records' list with only the one Place object, and 3) the Paginator page.
The template renders the single Place record on the left side, and a scrolling list of Hit forms on the right. The Hit form has two added fields, 'match' (3 radio buttons) and 'flag' (checkbox). The user selects those if one or more Hits match the Place. Upon submitting, a new Link record is created with a placeid, a hitid, and values from the radios and checkbox. Also, a 'reviewed' field in the Place record is set to True.
The code below works to load Place #1, then page through the records - displaying a Place and its Hits. Clicking the Save button creates a new Link record as desired. The problem is that after the save, although the next Page loads on the left, its corresponding hits don't. By displaying pprint(locals()) I can see the correct hits are in the queryset, but the Hit fields in the formset all retain the values from the previous set of forms. The Paginator is advancing and the next Place loads, but not its Hit formset.
I've banged at this for a couple days, read docs, searched, etc. Any ideas?
view.py
def validator(request):
record_list = Place.objects.order_by('placeid').filter(reviewed=False)
paginator = Paginator(record_list, 1)
page = request.GET.get('page')
records = paginator.get_page(page)
count = len(record_list)
context = {
'records': records,
'page': page if request.method == 'GET' else str(int(page)-1)
}
placeid = records[0].placeid
hitid = records[0].hitid
q = Hit.objects.filter(placeid=placeid)
HitFormset = modelformset_factory(
Hit, fields = ['id','hitid', ],form=HitModelForm,extra=0)
formset = HitFormset(request.POST or None, queryset=q)
context['formset'] = formset
if request.method == 'GET':
method = request.method
print('a GET')
else:
if formset.is_valid():
print('formset is valid')
for x in range(len(formset)):
link = Link.objects.create(
placeid = placeid,
hitid = formset[x].cleaned_data['hitid'],
match = formset[x].cleaned_data['match'],
flag = formset[x].cleaned_data['flag'],
)
# flag Place record as reviewed
matchee = get_object_or_404(Place, placeid = placeid)
matchee.reviewed = True
matchee.save()
else:
print('formset is NOT valid')
print(formset.errors)
pprint(locals())
return render(request, 'validator/template.html', context=context)
template.html
{% block content %}
<div class="pagination">
<span class="step-links">
... all standard, works fine
</span>
</div>
{% for record in records %}
{% if records.has_next %}
<!-- <form id="form_related" method="POST" action="" > -->
<form id="form_related" method="POST" action="?page={{ records.next_page_number }}" >
{% else %}
<form id="form_related" method="POST" action="" >
{% endif %}
{% csrf_token %}
{{ formset.management_form }}
<input type="hidden" name="placeid" value="{{ record.placeid }}" />
{% for form in formset %}
<div class="row">
<div class="col-sm-4 id="place-record">
<!-- Place attributes -->
</div>
<div class="col-sm-8" id="hit-forms">
<div id="review">
<span>{{ form.match }} flag: {{ form.flag_geom }}</span>
</div>
<div id="hit">
<!-- Hit attributes -->
</div>
</div>
</div>
{% endfor %}
{% endfor %}
{% endblock%}

Answer 1

The answer (or an answer) turned out to be doing a redirect immediately after the save/POST. The save of Link record removes the Place from the queue, so the page is always "1"
view.py
...
if formset.is_valid():
for x in range(len(formset)):
link = Link.objects.create(
placeid = placeid,
tgnid = formset[x].cleaned_data['tgnid'],
match = formset[x].cleaned_data['match'],
flag_geom = formset[x].cleaned_data['flag_geom'],
)
matchee = get_object_or_404(Place, placeid = placeid)
matchee.reviewed = True
matchee.save()
return redirect('/formset/?page='+page)
else:
print('formset is NOT valid')
print(formset.errors)
...