My Django project has a field for "Tags," where users can add tags for their posts. Currently this is stored in a models.CharField(max_length=200) field in my model.
What I'd like to do is have it so that when the post is displayed, each word is printed with its own URL to sort the posts by that particular tag. For example, each post also has a "Category" models.CharField where they can select a category from a dropdown list, which is made into a URL in the post.
For example in my Views.py:
#login_required
def category(request, category):
thisuser = request.user
if request.method == "POST":
category = request.POST['category']
else:
category = ''
following = Follow.objects.filter(follower=thisuser).order_by('-pubdate')
followers = Follow.objects.filter(who_following=thisuser).order_by('-pubdate')
posts = Post.objects.filter(category__contains=category)
args = {'posts': posts, 'thisuser': thisuser, 'following': following, 'followers': followers}
args.update(csrf(request))
args['category'] = category
return render_to_response('lobby.html', args)
and in my template:
Category: {{post.category}}
Is there a {% for %} template tag I can use to split the values in the tags field by comma and then render each of them as their own instance? Or would I have to do something else, like make a relational database for Tags (since a post can have multiple tags) and then iterate them all by Post ID?
Database design-wise, the best option is to have a separate model for Tags. This will let you search/sort/filter by tags more easily.
However, if you need a quick fix, you'll have to push that "split by comma" logic to your view/model, like so:
class Post(models.Model):
tags = models.CharField(...)
def split_tags(self):
return self.tags.split(',')
# in your template:
{% for tag in post.split_tags %} {{ tag }} {% endfor %}
You should do something like
class Post(models.Model):
def categories(self):
return self.category.split(',')
and then
{% for category in post.categories %}
but I strongly advice using a m2m relationship in your case. You can use an app like django-taggit to help you with that.
Related
I have a simple m2m relationship as below:
class Category(ModelBase):
name = models.CharField(max_length=255)
icon = models.CharField(max_length=50)
class Course(ModelBase):
name = models.CharField(max_length=255, unique=True)
categories = models.ManyToManyField(Category, related_name="courses")
I am using ListView to show all the courses in a category or all courses if no category provided.
views.py
class CourseListView(ListView):
model = Course
paginate_by = 15
template_name = "courses.html"
context_object_name = "courses"
def get_queryset(self):
queryset = (
super()
.get_queryset()
.select_related("tutor")
.prefetch_related("categories")
.filter(active=True)
)
category_id = self.kwargs.get("category_id")
return (
queryset
if not category_id
else queryset.filter(categories__in=[category_id])
)
def get_context_data(self, *args, **kwargs: Any) -> Dict[str, Any]:
context = super().get_context_data(**kwargs)
category_id = self.kwargs.get("category_id")
if category_id:
context["current_category"] = Category.objects.get(id=category_id)
context["categories"] = Category.objects.all()
return context
Django is making duplicate calls as I am doing something like this in the template.
<div class="icon"><span class="{{ course.categories.first.icon }}"></span></div>
Not sure why, help much appreciated. Thanks!
When you do .prefetch_related('categories') the result of this prefetch will be used when you access course.categories.all. Any other queryset on course.categories will do a fresh query. Since course.categories.first is a new queryset, it does not use the prefetched result.
What you want to access in your template is the first result from course.categories.all(). But this is not easy in the template. I would recommend a method on the Course model:
class Course(...):
...
def first_category(self):
# Equivalent to self.categories.first(), but uses the prefetched categories
categories = self.categories.all()
if len(categories):
return categories[0]
else:
return None
And then in your template you can call this method
<div class="icon"><span class="{{ course.first_category.icon }}"></span></div>
You can also access the first value like:
{{ course.categories.all.0.icon }}
It is not necessary to write a method.
because categories is ManyToMany which means one category may appear in many courses, but in the template you just calling the first category's icon, so there maybe more than two course with the same first category, and it will retrieve them all, i recommend using another for loop to loops through categories too.
{% for course in courses %}
<div>
<h1>{{ course.name</h1>
......
<h4>categories</h4>
{% for category in course.categories %}
<div class="icon"><span class="{{ category.icon }}"></span></div>
{% endfor %}
</div>
{% endfor %}
In models:
class Match(models.Model):
hot_league = models.ManyToManyField(HotLeague, blank=True)
class HotLeague(models.Model):
user = models.ManyToManyField(User, blank=True)
price_pool = models.IntegerField()
winner = models.IntegerField()
In Views:
match = get_object_or_404(Match, pk=pk)
Here i need to access this Match queryset.
that's why
In template:
{% for hot_league in match.hot_league.all %}
By writing match.hot_league.all in template I can get all queryset of HotLeague class. But I want to use filter here with user. Like in views we can use HotLeague.objects.filter(user=request.user). But {% for hot_league in match.hot_league.filter(user=request.user) %} is not working on template.
How can I do that kind of filter in template?
How can I do that kind of filter in template?
Templates are deliberately restricted to avoid that. Some template processors, like Jinja can make function calls, but usually if you have to do that, something is wrong with the design. Views should determine what to render, and templates should render that content in a nice format.
In your view, you thus can render this as:
def some_view(request, pk):
match = get_object_or_404(Match, pk=pk)
hot_leagues = match.hot_league.filter(user=request.user)
return render(
request,
'some_template.html',
{'match': match, 'hot_leagues': hot_leagues}
)
In your template, you can then render this like:
{% for hot_league in hot_leagues %}
<!-- -->
{% endfor %}
I want to display data from 2 tables (and more in the future), but something doesnt work in my code.
my views.py:
**imports**
def home(request):
context = {'users': Person.object.all(),
'emails': Email.object.all()
}
return render(request,'app/home.html',context)
class PersonListView(ListView):
model = Person
template_name = 'app/home.html'
context_object_name = 'users'
and in my home.html
{% extends "app/base.html" %}
{% block content %}
{% for user in users %}
Displaying user attributes works fine
{% endfor %}
Here should be emails
{% for email in emails %}
This displaying doesnt work
{% endfor %}
{% endbock content %}
So, displaying users works without any problem, but cant display anything form emails, but if I do it in shell, everything works well
A ListView [Django-doc] is designed to display only one queryset at a time. If you need to pass extra querysets, you can override the get_context_data(..) method [Django-doc]:
class PersonListView(ListView):
model = Person
template_name = 'app/home.html'
context_object_name = 'users'
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context.update(emails=Email.objects.all())
return context
Here we thus pass an extra variable emails to the template rendering engine. Note however that this queryset will not be paginated (or at least not without adding some pagination yourself).
my models.py:
Note that those are views, you need to write these in views.py.
Models:
class Instructional_Cycle(models.Model):
date_started = models.DateField()
date_finished = models.DateField()
standard_tested = models.OneToOneField(Standard, on_delete=models.CASCADE)
class Standard(models.Model):
subject = models.CharField(max_length=14, choices=subjects)
grade_level = models.IntegerField(choices=gradeLevels)
descriptor = models.CharField(max_length=15)
description = models.TextField()
essential_status = models.BooleanField(default=False)
View:
class CycleCreateView(CreateView):
model = Instructional_Cycle
template_name = 'cycle_new.html'
fields = '__all__'
success_url = reverse_lazy('student_progress:cycles')
Template:
<!-- student_progress/cycle_new.html -->
{% extends 'base.html' %}
{% block content %}
<h1>Add a new instructional cycle:</h1>
<form action="{% url 'student_progress:cycle_new' %}" method="post">
{% csrf_token %}
{{ form.as_p }}
<button name="submit">add cycle</button>
</form>
{% endblock content %}
The problem I'm having with this form is that the dropdown to select Instructional_Cycle.standard_tested has literally 1000 records from Standard. There's no way that the user can scroll through all of those and find the one record they want.
What I need is some way to click a link and filter the dropdown list by subject or grade_level and/or a search box, similar to what's achieved on the admin side by creating a custom admin model in admin.py like so:
class StandardAdmin(admin.ModelAdmin):
list_display = ('descriptor', 'description', 'essential_status')
list_filter = ('subject', 'grade_level', 'essential_status')
search_fields = ('descriptor',)
inlines = [MilestoneInLine]
def get_search_results(self, request, queryset, search_term):
queryset, use_distinct = super().get_search_results(request, queryset, search_term)
try:
search_term_as_int = int(search_term)
except ValueError:
pass
else:
queryset |= self.model.objects.filter(age=search_term_as_int)
return queryset, use_distinct
Please "dumb it down" for this newbie. I just finished working through Django for Beginners, and my conceptual model of how this all fits together is still full of holes. Please assume that I know hardly anything. Thanks!
That amount of reactive work on one page will require you to be comfortable with Javascript, Ajax, etc. If that is the case, there are a number of approaches you could take that let you refresh the form with the desired options.
Alternatively, you could ask the user for the necessary data one step earlier in the process and let Django build the correct form for you in the first place by overriding the form's default queryset.
You should look into using something like django-ajax-select. https://github.com/crucialfelix/django-ajax-selects
I understand that it is possible to override the default queryset 'used' by the modelformset. This just limits the objects for which a form is created.
I also found a Stack Overflow question about filtering ForeignKey choices in a Django ModelForm, but not a ModelForm Set and about limiting available choices in a Django formset, but not a Model FormSet. I have included my version of this code below.
What I want to do is render a ModelFormSet, for a school class ('teachinggroup' or 'theclass' to avoid clashing with the 'class' keyword) with one field limited by a queryset. This is for a teacher's class-editing form, to be able to reassign pupils to a different class, but limited to classes within the same cohort.
My models.py
class YearGroup(models.Model):
intake_year = models.IntegerField(unique=True)
year_group = models.IntegerField(unique=True, default=7)
def __unicode__(self):
return u'%s (%s intake)' % (self.year_group, self.intake_year)
class Meta:
ordering = ['year_group']
class TeachingGroup(models.Model):
year = models.ForeignKey(YearGroup)
teachers = models.ManyToManyField(Teacher)
name = models.CharField(max_length=10)
targetlevel = models.IntegerField()
def __unicode__(self):
return u'Y%s %s' % (self.year.year_group, self.name)
class Meta:
ordering = ['year', 'name']
My views.py
def edit_pupils(request, teachinggroup):
theclass = TeachingGroup.objects.get(name__iexact = teachinggroup)
pupils = theclass.pupil_set.all()
PupilModelFormSet = modelformset_factory(Pupil)
classes_by_year = theclass.year.teachinggroup_set.all()
choices = [t for t in classes_by_year]
# choices = [t.name for t in classes_by_year] #### I also tried this
if request.method == 'POST':
formset = PupilModelFormSet(request.POST,queryset=pupils)
if formset.is_valid():
formset.save()
return redirect(display_class_list, teachinggroup = teachinggroup)
else:
formset = PupilModelFormSet(queryset=pupils)
for form in formset:
for field in form:
if 'Teaching group' == field.label:
field.choices = choices
return render_to_response('reassign_pupils.html', locals())
As you can see, I am limiting the choices to the queryset classes_by_year, which is only classes which belong to the same year group. This queryset comes out correctly, as you can see in the rendered page below, but it doesn't affect the form field at all.
My template
{% for form in formset %}
<tr>
{% for field in form.visible_fields %}
<td> {# Include the hidden fields in the form #}
{% if forloop.first %}
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
{% endif %}
<p><span class="bigtable">{{ field }}</span>
{% if field.errors %}
<p><div class="alert-message error">
{{field.errors|striptags}}</p>
</div>
{% endif %}
</td>
{% endfor %}
</tr>
{% endfor %}
</table>
<input type="submit" value="Submit changes"></p>
</form>
{{ choices }} <!-- included for debugging -->
The page renders with all teaching groups (classes) visible in the select widget, but the tag at the bottom of the page renders as: [<TeachingGroup: Y8 82Ma2>, <TeachingGroup: Y8 82Ma3>], accurately showing only the two classes in Year 8.
Note that I've also read through James Bennett's post So you want a dynamic form as recommended by How can I limit the available choices for a foreign key field in a django modelformset?, but that involves modifying the __init__ method in forms.py, and yet the only way I know how to create a ModelFormSet is with modelformset_factory, which doesn't involve defining any classes in forms.py.
Further to help from Luke Sneeringer, here is my new forms.py entry. After reading Why do I get an object is not iterable error? I realised that some of my problems came from giving a tuple to the field.choices method, when it was expecting a dictionary. I used the .queryset approach instead, and it works fine:
class PupilForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(PupilForm, self).__init__(*args, **kwargs)
thepupil = self.instance
classes_by_year = thepupil.teaching_group.year.teachinggroup_set.all()
self.fields['teaching_group'].queryset = classes_by_year
class Meta:
model = Pupil
As best as I can tell, you've actually put all the pieces together except one. Here's the final link.
You said you read the dynamic form post, which involves overriding the __init__ method in a forms.Form subclass, which you don't have. But, nothing stops you from having one, and that's where you can override your choices.
Even though modelformset_factory doesn't require an explicit Form class (it constructs one from the model if none is provided), it can take one. Use the form keyword argument:
PupilModelFormset = modelformset_factory(Pupil, form=PupilForm)
Obviously, this requires defining the PupilForm class. I get the impression you already know how to do this, but it should be something like:
from django import forms
class PupilForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
super(PupilForm, self).__init__(*args, **kwargs)
self.fields['teaching_group'].choices = ______ # code to generate choices here
class Meta:
model = Pupil
The last problem you might have is that a modelformset_factory just takes the class, which means that the constructor will be called with no arguments. If you need to send an argument dynamically, the way to do it is to make a metaclass that generates the form class itself, and call that metaclass in your modelformset_factory call.
You can accomplish this by setting field choices of a form in a formset is in the forms init and overwriting the self.fields['field_name'].choices. This worked fine for me but I needed more logic in my view after the formset was initialized. Here is what works for me in Django 1.6.5:
from django.forms.models import modelformset_factory
user_choices = [(1, 'something'), (2, 'something_else')] # some basic choices
PurchaserChoiceFormSet = modelformset_factory(PurchaserChoice, form=PurchaserChoiceForm, extra=5, max_num=5)
my_formset = PurchaserChoiceFormSet(self.request.POST or None, queryset=worksheet_choices)
# and now for the magical for loop and override each desired fields choices
for choice_form in my_formset:
choice_form.fields['model'].choices = user_choices
I wasn't able to find the answer for this but tried it out and it works in Django 1.6.5. I figured it out since formsets and for loops seem to go so well together :)