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How can I avoid repetition of code within a function-based view in Django?

I have been researching how can I avoid using snippet of code over and over. The answer probably will involve using (generic) Class-based functions. However, I am a beginner in Django and this seems confusing. Here is my view in views.py:
#login_required(login_url='/login')
def view_list(request, listing_id):
bid = Bid.objects.all().filter(listing=listing_id).order_by('-id')
b_u = bid[0].user
listing = Listing.objects.get(pk=listing_id)
if request.method == "GET":
return render(request, "auctions/view_list.html", {
"form": BidForm(),
"total_bids": bid.count(),
"bid": None if bid == 0 else bid[0].bid,
"listing": listing,
"bid_user": "Your bid is the current bid." if request.user == b_u else None
})
else:
form = BidForm(request.POST)
if form.is_valid():
value = form.cleaned_data
if value['bid'] <= bid[0].bid:
error_check = True
return render(request, "auctions/view_list.html", {
"error_check": error_check,
"alert": f"Your bid is lower than the current bid $({bid[0].bid})! Try placing a higher one.",
"form": BidForm(),
"total_bids": bid.count(),
"bid": None if bid == 0 else bid[0].bid,
"listing": listing,
"bid_user": "Your bid is the current bid." if request.user == b_u else None
})
else:
error_check = False
new_bid = form.save(commit=False)
new_bid.user_id = request.user.id
new_bid.listing_id = listing.id
new_bid.save()
return render(request, "auctions/view_list.html", {
"error_check": error_check,
"alert": "Your bid was successfully placed!",
"form": BidForm(),
"total_bids": bid.count(),
"bid": None if bid == 0 else bid[0].bid,
"listing": listing,
"bid_user": "Your bid is the current bid." if request.user == b_u else None
})
And here is my template code:
{% extends "auctions/layout.html" %}
{% load humanize %}
{% load crispy_forms_tags %}
{% block body %}
{% if error_check == True %}
<div class="alert alert-warning" role="alert">
{{ alert }}
</div>
{% elif error_check == False %}
<div class="alert alert-success" role="alert">
{{ alert }}
</div>
{% endif %}
<div>
<h3>Listing: {{ listing.title }}</h3>
<img src="{{ listing.image }}" alt="Listings' Images">
<p>{{ listing.description }}</p>
{% if not bid %}
<strong>${{ listing.price|stringformat:"1.2f" }}</strong>
{% else %}
<strong>${{ bid|stringformat:"1.2f" }}</strong>
{% endif %}
<p> {{ total_bids }} bid(s) so far. {% if bid_user %} {{ bid_user }} {% endif %}</p>
<form method="POST" name="bidding" action="{% url 'view_list' listing.id %}">
{% csrf_token %}
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">$</span>
</div>
<div style="margin: 0; padding: 0 2px; height: 6px;">
{% crispy form %}
</div>
<div class="input-group-append" >
<span class="input-group-text">.00</span>
</div>
<input type="submit" class="btn btn-primary" value="Place Bid">
</div>
</form>
<h4>Details</h4>
<li>Listed by: {{ listing.user }} </li>
<li>Category: {{ listing.category }} </li>
<li>Listing created at: {{ listing.created_at }} </li>
</div>
{% endblock %}
So how can I avoid all this repetition and make the code more succinct. Also, this way when the user places a successful bid, the rendered template does not contain the new information from the form.

The pattern is very simple
def some_view(request):
form = SomeForm(request.POST or None)
if request.method == 'POST' and form.is_valid():
# Form processing
return render(request, "auctions/view_list.html", {
"form": form
})

Can't get past Django MultiValueDictKeyError on specific form id?

So, everytime I submit my form, I always get this error
MultiValueDictKeyError at /template/ 'form-21-id'
Here is my views.py:
class SomeTemplate(TemplateView):
template_name = 'template/index.html'
def get_context_data(self, **kwargs):
context = super(AttendanceTemplate, self).get_context_data(**kwargs)
instruction = Instruction(self.request.user.username)
sections_list = self.request.GET.getlist('sections_list')
term = self.request.GET.get('term', instruction.term)
enrollments = Enrollment.objects.using('api').prefetch_related('profile').filter(section_id__in=['111111'], term=term)
attendanceQuery = Enrollment.objects.using('api').prefetch_related('student').filter(section_id__in=['111111'], term=term)
#logger.error(dir(attendanceQuery))
#logger.error(attendanceQuery.values())
for enrollment in attendanceQuery:
#logger.error(enrollment.student.first_name)
attendance, created = Attendance.objects.update_or_create(
section_id=enrollment.section_id,
term=enrollment.term,
first_name=enrollment.student.first_name,
last_name=enrollment.student.last_name,
email_address=enrollment.student.email_address,
meeting_date=timezone.now(),
section_info=3,
)
something = Attendance.objects.filter(section_id__in=['111111'], term=term)
formset = AttendanceFormSet(queryset=something)
combined = zip(enrollments, formset)
context['combined'] = combined
context['formset'] = formset
return context
def post(self, request):
formset = AttendanceFormSet(request.POST)
logger.error(formset.errors)
if formset.is_valid():
formset = formset.save();
return render_to_response("template/index.html", {'formset': formset},context_instance=RequestContext(request))
else:
return HttpResponse(request.POST)
Here is my index.html file:
<form method="POST" action="">
{% csrf_token %}
{{ formset.management_form }}
{% for enrollment, form in combined %}
{{ form.id }}
{% for hidden in combined %}
{{ hidden.hidden_fields }}
{% endfor %}
<div class="wrapper-formset">
<div>
{{ form.first_name.value }}
{{ form.last_name.value }}
{{ form.email_address.value }}
</div>
<div class="clear-all"></div>
</div>
{% endfor %}
<button type="submit" class="save btn btn-default">Save</button>
</form>
I've included the following key form properties in my template as well:
form.id
management form
hidden fields
What am I missing? Doing it wrong? DB issue?

I can't figure why I'm getting unboundLocalError

I am using django 1.8 and python 2.7 but I keep on getting unbounLocalError. It looks all is ok with the code in my views.py. But it keep on local variable 'cd' referenced before assignment. I will be glad if someone could provide the solution
def post_search(request):
form = SearchForm()
if 'query' in request.GET:
form = SearchForm(request.GET)
if form.is_valid():
cd = form.cleaned_data
results = SearchQuerySet().models(Post).filter(content=cd['query']).load_all()
# count total results
total_results = results.count()
return render(request, 'blog/post/search.html', {'form': form,
'cd': cd,
'results': results,
'total_results': total_results})
search.html
{% extends "blog/base.html" %}
{% block title %}Search{% endblock %}
{% block content %}
{% if "query" in request.GET %}
<h1>Posts containing "{{ cd.query }}"</h1>
<h3>Found {{ total_results }} result{{ total_results|pluralize }}</h3>
{% for result in results %}
{% with post=result.object %}
<h4> {{ post.title }}</h4>
{{ post.body|truncatewords:5 }}
{% endwith %}
{% empty %}
<p>There are no results for your query.</p>
{% endfor %}
<p>Search again</p>
{% else %}
<h1>Search for posts</h1>
<form action="." method="get">
{{ form.as_p }}
<input type="submit" value="Search">
</form>
{% endif %}
{% endblock %}

The problem is that you try to return a context dictionary containing cd, results, and total_results even if your if clauses are not satisified. You should fix your indentation:
def post_search(request):
form = SearchForm()
if 'query' in request.GET:
form = SearchForm(request.GET)
if form.is_valid():
cd = form.cleaned_data
results = SearchQuerySet().models(Post).filter(content=cd['query']).load_all()
# count total results
total_results = results.count()
# Indent this line:
return render(request, 'blog/post/search.html', {'form': form,
'cd': cd,
'results': results,
'total_results': total_results})

Django error / value too long for type character varying(1)

I'm trying to add new formset field to my model/forms, but when i want save it, i gets an error " value too long for type character varying(1)".
Can anyone help me with that? I'm begginer at django.
This error is start's show up when i add "study_1" field
in views.
if university and field:
new_obj.append(UserLink(user=user, university=university, city_1=city_1, grade=grade, field=field, description_1 = description_1, study_1 = study_1))
Here's my code:
views.py:
#login_required
def profile_settings(request):
user = request.user
LinkFormSet = formset_factory(LinkForm, formset=BaseLinkFormSet)
# Get our existing link data for this user. This is used as initial data.
user_links = UserLink.objects.filter(user=user)
link_data = [{'university': l.university, 'city_1': l.city_1, 'grade': l.grade, 'field': l.field, 'description_1': l.description_1, 'study_1': l.study_1,}
for l in user_links]
#lfs = formset_factory(NameForm)
if request.method == 'POST':
#postedformset = lfs(request.POST)
#return HttpResponseRedirect('/edit_profile/')
link_formset = LinkFormSet(request.POST)
if link_formset.is_valid():
# Now save the data for each form in the formset
new_obj = []
for link_form in link_formset:
university = link_form.cleaned_data.get('university')
city_1 = link_form.cleaned_data.get('city_1')
grade = link_form.cleaned_data.get('grade')
field = link_form.cleaned_data.get('field')
description_1 = link_form.cleaned_data.get('description_1')
study_1 = link_form.cleaned_data.get('study_1')
if university and field:
new_obj.append(UserLink(user=user, university=university, city_1=city_1, grade=grade, field=field, description_1 = description_1, study_1 = study_1))
try:
with transaction.atomic():
#Replace the old with the new
UserLink.objects.filter(user=user).delete()
UserLink.objects.bulk_create(new_obj)
# And notify our users that it worked
messages.success(request, 'You have updated your profile.')
except IntegrityError: #If the transaction failed
messages.error(request, 'There was an error saving your profile.')
return redirect(reverse('profile_settings'))
else:
#form = NameForm()
link_formset = LinkFormSet(initial=link_data)
context = {
'link_formset': link_formset,
#'form':lfs,
}
return render(request, 'edit_profile.html', context)
forms.py:
YEARS_CHOICES = tuple((str(n), str(n)) for n in range(1990, datetime.now().year + 1))
class LinkForm(forms.Form):
university = forms.CharField(
max_length=100,
widget = forms.TextInput(attrs = {'placeholder': 'University',}), required = False)
grade = forms.CharField(
max_length = 50,
widget = forms.TextInput(attrs = {'placeholder': 'Grade',}), required = False)
field = forms.CharField(
max_length = 50,
widget = forms.TextInput(attrs = {'placeholder': 'Field of study',}), required = False)
city_1 = forms.CharField(
max_length = 50,
widget = forms.TextInput(attrs = {'placeholder': 'City',}), required = False)
description_1 = forms.CharField(
max_length = 500,
widget=forms.Textarea(attrs={'placeholder': ('Add some details about your education...'),'rows': '5', 'cols': '40',}), required=False)
study_1 = forms.ChoiceField(
choices=YEARS_CHOICES,
required=False)
models.py:
YEARS_CHOICES = tuple((str(n), str(n)) for n in range(1925, datetime.now().year + 1))
class UserLink(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, verbose_name=('user'), related_name='links')
university = models.CharField(max_length = 100)
grade = models.CharField(max_length = 50)
field = models.CharField(max_length = 50)
city_1 = models.CharField(max_length=50)
description_1 = models.TextField(max_length=350)
study_1 = models.CharField(max_length=1, default=0)
def __str__(self):
return self.university
def save(self, *args, **kwargs):
super(UserLink, self).save(*args, **kwargs)
and edit_profile.html:
<form method="post">
{% csrf_token %}
{{ link_formset.management_form }}
{{ form.management_form }}
<legend style="font-size: 23px;"> Update your education part</legend>
{% for link_form in link_formset %}
<div class="link-formset">
<div style="border-style:groove; border-radius: 8px; padding: 12px 0 0 7px;">
<p style="font-size:15px">University:
{{ link_form.university }}
{% if link_form.university.errors %}
{% for error in link_form.university.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
<p style="font-size:15px">City:
{{ link_form.city_1 }}
{% if link_form.city_1.errors %}
{% for error in link_form.city_1.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
<p style="font-size:15px">Grade:
{{ link_form.grade }}
{% if link_form.grade.errors %}
{% for error in link_form.grade.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
<p style="font-size:15px">Field of study:
{{ link_form.field }}
{% if link_form.field.errors %}
{% for error in link_form.field.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
<p style="font-size:15px">Description:
{{ link_form.description_1 }}
{% if link_form.description_1.errors %}
{% for error in link_form.description_1.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
<p style="font-size:15px">Rok:
{{ link_form.study_1 }}
{% if link_form.study_1.errors %}
{% for error in link_form.study_1.errors %}
{{ error|escape }}
{% endfor %}
{% endif %}</p>
{{ form }}
</div>
</div>
{% endfor %}
{% if link_formset.non_form_errors %}
{% for error in link_formset.non_form_errors %}
{{ error|escape }}
{% endfor %}
{% endif %}
<input type="submit" value="Update Profile" class="button"/>
</form>
Thanks for any help!
:)

You've declared study_1 to be a character field with a maximum length of 1 character, but you're setting it with four-digit strings representing years.

change the max_length of study_1 to 4 or more and then make a migration of your changes by python manage.py makemigrations. Finally apply changes by python manage.py migrate.

Next and Before Links for a django paginated query

I'm trying to make a search form for Django.
Its a typical search form and then returns a table of matches. I wish to paginate the tables returned.
The problem lies in the Previous and Next buttons.
The links for the return query goes to /records/search/?query=a (search sample is a)
The page outputs the table and its previous and next links. However the links redirect to /records/search/?page=2 and the page displays a blank table.
Any help on which links I should pass for Prev/Next?
search.html:
{% extends 'blank.html' %}
{% block content %}
<div class="row">
<form id="search-form" method="get" action=".">
{{ form.as_p }}
<input type="submit" value="Search" />
</form>
</div>
<br><br>
//display table code//
{% if is_paginated %}
<div class="pagination">
<span class="step-links">
{% if agent_list.has_previous %}
forrige
{% endif %}
<span class="current">
Page {{ agent_list.number }} of {{ agent_list.paginator.num_pages }}.
</span>
{% if agent_list.has_next %}
Next
{% endif %}
</span>
</div>
{% endif %}
{% endblock %}
and the search view:
def search_page(request):
form = SearchForm()
agents = []
show_results=False
if request.GET.has_key('query'):
show_results=True
query=request.GET['query'].strip()
if query:
form=SearchForm({'query': query})
agents = \
Agent.objects.filter(Q(name__icontains=query))
paginator = Paginator(agents, 10)
page = request.GET.get('page')
try:
agents = paginator.page(page)
except PageNotAnInteger:
agents = paginator.page(1)
except EmptyPage:
agents = paginator.page(paginator.num_pages)
variables = RequestContext(request,
{ 'form': form,
'agent_list': agents,
'show_results': show_results,
'is_paginated': True,
}
)
return render_to_response('search.html', variables)
I've seen the similar questions but I can't understand/make them work. Any help?
Edit:
For a quickfix (haven't really looked at the cons)
I added a variable in my view:
variables = RequestContext(request,
{ 'form': form,
'agent_list': agents,
'show_results': show_results,
'is_paginated': True,
**'query': query,**
}
)
Where query without the quotes is the recieved query variable.
Then simply change the URL to:
Previous
If you have a better way of answering the question, please do or appending a URL to your currently opened URL.

I would recommend putting the solution in a template tag like so:
myapp/templatetags/mytemplatetags.py:
from django import template
register = template.Library()
#register.simple_tag
def url_replace(request, field, value):
d = request.GET.copy()
d[field] = value
return d.urlencode()
#register.simple_tag
def url_delete(request, field):
d = request.GET.copy()
del d[field]
return d.urlencode()
Then from templates do:
{% load mytemplatetags %}
...
previous

you can use {{ request.get_full_path }} this tag to get current url.
Next
this worked for me

The below works before and after a search form has been submitted:
Views.py
class PostListView(ListView):
model = Post #.objects.select_related().all()
template_name = 'erf24/home.html' # <app>/<model>_<viewtype>.html
context_object_name = 'posts' # default >> erf24/post_list.html
ordering = ['date_posted']
paginate_by = 3
def is_valid_queryparam(param):
return param != '' and param is not None
def invalid_queryparam(param):
return param == '' and param is None
class SearchView(ListView):
model = Post #.objects.select_related().all()
template_name = 'erf24/home.html' # <app>/<model>_<viewtype>.html
context_object_name = 'posts' # default >> erf24/post_list.html
ordering = ['date_posted']
paginate_by = 3
def get_queryset(self): # new
key = self.request.GET.get('key')
minp = self.request.GET.get('min')
maxp = self.request.GET.get('max')
if is_valid_queryparam(key):
obj = Post.objects.filter(Q(content__icontains=key) | Q(location__icontains=key)).distinct().order_by('date_posted')
if is_valid_queryparam(minp):
obj = Post.objects.filter(Q(price__gte=minp)).distinct().order_by('date_posted')
if is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(price__lte=maxp)).distinct().order_by('date_posted')
if is_valid_queryparam(minp) & is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(price__gte=minp) & Q(price__lte=maxp)).distinct().order_by('date_posted')
if is_valid_queryparam(key) & is_valid_queryparam(minp) & is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(content__icontains=key) | Q(location__icontains=key)).distinct()
obj = obj.filter(Q(price__gte=minp) & Q(price__lte=maxp)).order_by('date_posted')
if invalid_queryparam(key) & invalid_queryparam(minp) & invalid_queryparam(maxp):
obj = Post.objects.all()
return obj
url.py
urlpatterns = [
path('', PostListView.as_view(), name='erf24-home'),
path('search/', SearchView.as_view(), name='erf24-search'),
]
Home.html
<form action="{% url 'erf24-search' %}" method="GET">
<div class="form-group">
<label for="inputAddress">Search keyword</label>
<input type="text" class="form-control" id="key" name="key" placeholder="keyword">
</div>
<label for="">Price</label>
<div class="form-row">
<div class="form-group col-md-6">
<input type="number" class="form-control" id="min" name="min" placeholder="min price">
</div>
<div class="form-group col-md-6">
<input type="number" class="form-control" id="max" name="max" placeholder="max price">
</div>
</div>
<button type="submit" class="btn btn-primary btn-sm mt-1 mb-1">Search</button>
<button type="reset" class="btn btn-secondary btn-sm mt-1 mb-1">Clear</button>
</form>
{% for post in posts %}
<article class="media content-section">
<div class="media-body">
<div class="article-metadata">
<img class="rounded-circle article-img" src="{{ post.author.profile.image.url }}" alt="">
{{ post.author }}
<small class="text-muted">{{ post.date_posted }}</small>
<!-- use |date: "specs" to filter date display -->
</div>
<h2>
{{ post.price }}
</h2>
<p class="article-content">{{ post.content }}</p>
<p class="article-content">{{ post.location }}</p>
<p><a class="like-btn" data-href="{{ post.get_api_like_url }}" href="">{{ post.likes.count }}
{% if user in post.likes.all %} Unlike
{% else %} Like
{% endif %}
</a></p>
</div>
{% for image in post.image_set.all %}
<img class="account-img" src="{{ image.image.url }}" alt="">
{% endfor %}
</article>
{% endfor %}
{% if is_paginated %}
{% if page_obj.has_previous %}
First
Previous
{% endif %}
{% for num in page_obj.paginator.page_range %}
{% if page_obj.number == num %}
{{ num }}
{% elif num > page_obj.number|add:'-3' and num < page_obj.number|add:'3' %}
{{ num }}
{% endif %}
{% endfor %}
{% if page_obj.has_next %}
Next
Last
{% endif %}
{% endif %}
Worked like a charm :) Enjoy!

You can use {{ request.get_full_path }} template tag
Next

you can use this, I use it because I use filters in the url itself, so all the url params are used to build the next or previous url
import re
from django import template
register = template.Library()
PAGE_NUMBER_REGEX = re.compile(r'(page=[0-9]*[\&]*)')
#register.simple_tag
def append_page_param(value,pageNumber=None):
'''
remove the param "page" using regex and add the one in the pageNumber if there is one
'''
value = re.sub(PAGE_NUMBER_REGEX,'',value)
if pageNumber:
if not '?' in value:
value += f'?page={pageNumber}'
elif value[-1] != '&':
value += f'&page={pageNumber}'
else:
value += f'page={pageNumber}'
return value
then, in your pagination nav you can call it like this:
{% append_page_param request.get_full_path page_obj.previous_page_number %}