I am currently using the django-mptt Django package, and I am trying to run .order_by() against a filter but it is not working - more specifically, the order stays the same no matter what order_by() I use. Here is my current code:
views.py
class ArticleModalView(View):
def get(self, request):
article_id = request.GET['article_id']
article = get_object_or_404(Article, id=article_id)
article_comments_recent = ArticleComment.objects.filter(article=article).order_by('-created')
return render(request, '_includes/_article-modal.html', {'article': article, 'article_comments_recent': article_comments_recent})
_article-modal.html
<ul class="root">
{% recursetree nodes %}
<li>
{{ node.name }}
{% if not node.is_leaf_node %}
<ul class="children">
{{ children }}
</ul>
{% endif %}
</li>
{% endrecursetree %}
</ul>
So I just figured it out! I had to mix a few different answers, but it looks like the solution is as follows:
I've done lots of .filter().order_by() chains just as you have them there, and nothing jumps out to me as out of place. I've never tried to carry that ordering over to the template without further processing the objects though (usually iterate over them), so I wonder if the order_by() is lost as part of django's lazy evaluation? Maybe try wrapping the filter().order_by() line in a list() to force evaluation there instead of it being put off till some later time?
via StackOverflow Question: "order_by() doesn't work with filter() in
Django view"
article_comments_recent = ArticleComment.objects.filter(article=article).order_by('-created')
Should be:
article_comments_recent = list(ArticleComment.objects.filter(article=article).order_by('tree_id', 'level', '-created'))
Related
I'm trying to build a website that has products and categories.
When you are on the page of a product, you can click a button to see a list of all the categories it falls under.
You can click another button, that appears on all pages, to see a list of all the categories overall.
In the html page see_all_categories, I wrote a simple block like this:
{% extends 'base.html' %}
{% load staticfiles %}
{% block content%}
{{Category.all}}
{% endblock content %}
I expect to see a messy printout of all the categories but I don't. It doesn't return an error, but it produces nothing, other than the base.html.
What am I doing wrong?
You want to display a list of the categories. I assume your Category model owns an attribute named "title" which is the representation of your Category.
If you're using Django template engine or Jinja2, you can make a for loop inside your template like this :
{% for cat in Category.objects.all %}
{{ cat.title }}
{% endfor %}
As a troubleshooting, I'd suggest you didn't pass your Category model to your template, that is not done automatically. You have to add your model to the context before rendering the template.
As mentionned in the comments, here is doc for template rendering with Django templates.
Django Template Guide
To add your model to the context you can follow this guide.
I don't intend to help you further because I lack of information and that may vary a LOT according to your settings. (Class Based views ? Function based views ? What kind of template are you using... And so on)
I figured out the solution after many long annoying hours of trying everything. I feel dumb but I want to spare the next guy the massive pain in the two-pack.
This is what I did:
In the Views.py, I changed the view function for this page FROM this:
def view_all_categories(request):
context = {'Category' : Category}
return render(request, 'store/see_all_categories.html', context)
TO this
def view_all_categories(request):
all_cats = Category.objects.all().order_by('id')
context = {'all_categories' : all_cats}
return render(request, 'store/see_all_categories.html', context)
and in the page see_all_categories.html itself, I changed it (from the question) TO this:
{% extends 'base.html' %}
{% load staticfiles %}
{% block content%}
{% for cat in all_categories %}
<p>{{ cat.name }}</p>
{% endfor %}
{% endblock content %}
And now it works!!
I am hitting a brick wall when it comes to solving this problem. I have a template that is being included in an other template, but I am unable to render any template variables in the included template. I have a separate template tag file for the included template. I am at a total loss right now how to resolve this problem.
I would like to be able to render the field values from my model in the template (which consist of an image, a short description, etc.) I am fairly certain that I am going about this in the wrong way.
Below is my code:
The model:
class AddOnItem(models.Model):
base_product = models.ForeignKey(Product)
base_price = models.DecimalField(max_digits=8, decimal_places=2, default=0.0)
addon_image = models.ImageField(upload_to='uploads/shop/product/images/',
default='uploads/shop/product/images/', help_text='Max width: 450px')
short_description = models.CharField(max_length=255, blank=True)
def __unicode__(self):
return self.base_product.name
The template:
{% load addon_tags %}
{% if items_to_add %}
{% for items in items_to_add %}
<div id="addon-container">
<div id="left-addon" class="addon-container">
<img src="#" class="addon-image">
<p class="addon-description">{{items.short_description}}</p>
</div>
</div>
{% endfor %}
{% endif %}
addon_tags.py:
from django import template
from sho.models import AddOnItem
register = template.Library()
#register.inclusion_tag("foo/templates/v/sho/addon.html", takes_context=True)
def add_on_render():
context['items_to_add'] = AddOnItem()
return context
I imagine I am doing either a lot wrong (my assumption at the moment) or I am missing some minor bit. I have been working on this for several days and have gone over the docs repeatedly. I am simply completely missing something and this has become a major blocker for me. Any help would be appreciated.
Django version 1.4
Edit:
I ended up rewriting the view and did away with the templatetag. Thanks to both Daniel Roseman and Odif Yltsaeb for their replies.
1) From your post you are adding empty, new item into the context in add_on_render templateag.
2) I cant see in your post, WHERE you are using {% add_on_render %} templatetag. You have created templattag, but do not seem to be using it anywhere.
It is bit hard to understand what exactly are you trying to do or why you even need templatetag there.
If you want to display models field value, you do not need templateag for this and all the stuff that you show in your "template" part of this post, could be very well in your main template, which i assume, is not shown in your post.
If you want to use templatetag, then this templatetag should probably recieve AddOnItem istance as parameter like this:
#register.inclusion_tag("foo/templates/v/sho/addon.html", takes_context=True)
def add_on_render(item):
context['items_to_add'] = item
return context
And You could use it in some template like this:
{% load addon_tags %}
{% if items_to_add %}
{% for items in items_to_add %}
<div id="addon-container">
<div id="left-addon" class="addon-container">
<img src="#" class="addon-image">
<p class="addon-description">{% add_on_render items %}</p>
</div>
</div>
{% endfor %}
{% endif %}
and your foo/templates/v/sho/addon.html
would like like this:
{{ items_to_add.short_description }}
But doing it this way seems very unnecessary as you could achieve all that without templatag by using the template code that you already have outside your "main" template.
You haven't posted the template that you are attempting to include the tag in. I suspect you're not calling it at all, because there are a couple of errors that would cause exceptions if you did try and use the tag. You need to do {% add_on_render %} somewhere in your main template.
As I say though there are a couple of errors. Firstly, you don't define context (as an empty dict) before adding the items_to_add key. You can shortcut this by just doing it in one go.
Secondly you've made items_to_add a single, blank, AddOnItem. So in your included template, iterating through items_to_add does nothing at all. Not sure what you are trying to do there. Perhaps you want to pass all AddOnItem instances?
context = {'items_to_add': AddOnItem.objects.all()}
Or maybe you want to filter them by some criteria, in which case you probably want to pass those criteria to the inclusion tag itself:
def add_on_render(product):
context = {'items_to_add': AddOnItem.objects.filter(base_product=product)}
and you would call it from the main template like this:
{% add_on_render my_product %}
if you set "takes_context=True" you should take context as the first argument in decorated function:
#register.inclusion_tag("foo/templates/v/sho/addon.html", takes_context=True)
def add_on_render(context):
context['items_to_add'] = AddOnItem()
....
I am new to Django and I've been impressed so far by its capabilities. I am playing with more complex models and I am have problem to use them properly. Using Django 1.3, I am trying to write a summary page which would present the three models below with the following structure. In other words, a list of trips with their destinations and activities.
Trip 1
Destination 1
Destination 2
Activity 1
Trip 2
Destination 1
Activity 2
Models
Trip <-> TripDestination <-> Destination (a trip can have multiple destinations)
Activity -> Trip, Activity -> Destination (an activity is defined for a trip at a specific location/destination)
class Destination(models.Model):
city_name=models.CharField()
class Trip(models.Model):
departing_on=models.DateField()
returning_on=models.DateField()
destinations=models.ManyToManyField(Destination)
class Activity(models.Model):
destination=models.ForeignKey(Destination, null=False)
trip=models.ForeignKey(Trip, null=False)
I am trying to write a view which would generate a page with the structure presented above. The main problem I am having right now is to display the activities for a specific trip and destination. As you can see in the code below, I am building a dictionary and I doubt it is the right thing to do. In addition, the view becomes
View
def list_trip(request, template_name = 'trip-list.html'):
trips = Trip.objects.all()
# Build a dictionary for activities -- Is this the right thing to do?
activities = Activity.objects.filter(trip__in=trips)
activities_by_trips = dict()
for activity in activities:
if activity.trip_id not in activities_by_trips:
activities_by_trips[activity.trip_id] = dict()
if activity.destination_id not in activities_by_trips[activity.trip_id]:
activities_by_trips[activity.trip_id][activity.destination_id] = []
activities_by_trips[activity.trip_id][activity.destination_id].append(activity)
return render_to_response(template_name, {
'page_title': 'List of trips',
'trips': trips,
'activities_by_trips': activities_by_trips,
})
Template
{% block content %}
{% for trip in trips %}
{{ trip.id }} - {{ trip.name }}
{% for destination in trip.destinations.all %}
{{ destination.city_name }}
** This is terrible code -- How to fix that **
{% for key, value in activities_by_trips|dict_lookup:trip.id %}
{% if value %}
{% for key_prime, value_prime in value|dict_lookup:destination.id %}
{{ value_prime.description }}
{% endfor %}
{% endif %}
{% endfor %}
{% endfor %}
{% endfor %}
{% endblock %}
In brief, can someone please help me to get a summary of all the trips and activities? What's the best way to accomplish that? Is the model correct?
Thanks!
There is plenty of room for improvement. By using through on ManyToManyField you can explicitly define the join table, which we can conveniently consider as a single visit to a city during a particular trip. During that visit we had activities, so activity should have a foreignkey to a visit.
For each foreignkey in a table, Django will add API convenience manager for sets of objects on the opposite side of the relationship. Destination will have a visit_set, but so will Trip. Similarly, because of visit foreignkey in Activity each visit will have an activity_set.
First start with the models:
from django.db import models
# Create your models here.
class Destination(models.Model):
city_name=models.CharField(max_length=50)
class Trip(models.Model):
departing_on=models.DateField()
returning_on=models.DateField()
destinations=models.ManyToManyField(Destination, through='Visit')
class Visit(models.Model):
destination=models.ForeignKey(Destination)
trip=models.ForeignKey(Trip)
class Activity(models.Model):
name=models.CharField(max_length=50)
visit=models.ForeignKey(Visit)
Then lets change list_trip a bit, added print_trip for clarity of what is going on in template:
def list_trip(request, template_name = 'trip-list.html'):
return render_to_response(template_name, {
'page_title': 'List of trips',
'trips': Trip.objects.all(),
})
def print_trips():
for trip in Trip.objects.all():
for visit in trip.visit_set.select_related().all():
print trip.id, '-', visit.destination.city_name
for act in visit.activity_set.all():
print act.name
And finally the improved template:
{% block content %}
{% for trip in trips %}
{{ trip.id }} - {{ trip.name }}
{% for visit in trip.visit_set.select_related.all %}
{{ visit.destination.city_name }}
{% for act in visit.activity_set.all %}
{{ act.name }}
{% endfor %}
{% endfor %}
{% endfor %}
{% endblock %}
There is still some more room for improvement performance wise. Notice I used select_related. That will prefetch all destinations at the time visits are fetched, so that visit.destination.city_name will not incur another db call. However this doesn't work for reverse ManyToMany relationships (in our case all members of activity_set). Django 1.4 will come out with new method called prefetch_related which will resolve that as well.
In the mean time, read up on Efficient reverse lookups for an idea how to even further reduce the number of DB hits. In the comments few readily available solutions are mentioned as well.
So the title is a bit obtuse, I know, but I couldn't think of a more succinct way to state it. Here's the issue:
I've created two proxy models for "user types", both inheriting from django.contrib.auth.User. Each has a custom manager limiting the queryset to items belonging to a particular Group. Specifically, there's a PressUser which is any user belonging to the "Press" group and StaffUser which is any user in any other group than "Press".
The issue is that when I add 'groups' to list_filters on my StaffUsers modeladmin, the resulting filter options are every group available, including "Press", and not just groups available to StaffUsers.
I've research a bit online and came up with a custom filterspec that should produce the behavior I want, but the problem is that the User model's 'groups' attribute is actually a related_name applied from the Group model. As a result, I can't attach my filterspec to 'groups' in my proxy model.
Is there any other way to apply the filterspec? Alternatively, is there a better approach to filtering the items returned by the default filterspec?
So, I was able to solve my own problem. For those that might run into a similar situation, here are the steps:
The approach I took is to modify the change_list.html template and manually filter out the items I didn't want to be included. There's quite a number of changes to make, though.
First, add a changelist_view method to your ModelAdmin:
# myproject/account/admin.py
class StaffUserAdmin(models.ModelAdmin):
...
def changelist_view(self, request, extra_context=None):
groups = Group.objects.exclude(name__in=['Press',]).values_list('name')
extra_context = {
'groups': [x[0] for x in groups],
}
return super(StaffUserAdmin, self).changelist_view(request,
extra_context=extra_context)
Basically, all we're doing here is passing in the filtered list of Groups we want to use into the context for the template.
Second, create a change_list.html template for your app.
# myproject/templates/admin/auth/staffuser/change_list.html
{% extends "admin/change_list.html" %}
{% load admin_list %}
{% load i18n %}
{% load account_admin %}
{% block filters %}
{% if cl.has_filters %}
<div id="changelist-filter">
<h2>{% trans 'Filter' %}</h2>
{% for spec in cl.filter_specs %}
{% ifequal spec.title 'group' %}
{% admin_list_group_filter cl spec groups %}
{% else %}
{% admin_list_filter cl spec %}
{% endifequal %}
{% endfor %}
</div>
{% endif %}
{% endblock filters %}
This one deserves a little explanation. First, the template tag loads: admin_list is used for the default Django template tag responsible for rendering the filters, admin_list_filter, i18n is used for trans, and account_admin is for my custom template tag (discussed in a sec), admin_list_group_filter.
The variable spec.title holds the title of the field that's being filtered on. Since I'm trying to alter how the Groups filter is displayed, I'm checking if it equals 'groups'. If it does, then I use my custom template tag, otherwise, it falls back to the default Django template tag.
Third, we create the template tag. I basically just copied the default Django template tag and made the necessary modifications.
# myproject/account/templatetags/account_admin.py
from django.template import Library
register = Library()
def admin_list_group_filter(cl, spec, groups):
return {'title': spec.title, 'choices' : list(spec.choices(cl)), 'groups': groups }
admin_list_group_filter = register.inclusion_tag('admin/auth/group_filter.html')(admin_list_group_filter)
The only things that I've changed here are adding a new argument to the method called 'groups' so I can pass in my filtered list of groups from before, as well as adding a new key to the dictionary to pass that list into the context for the template tag. I've also changed the template the tag uses to a new one that we're about to create now.
Fourth, create the template for the template tag.
# myproject/templates/admin/auth/group_filter.html
{% load i18n %}
<h3>{% blocktrans with title as filter_title %} By {{ filter_title }} {% endblocktrans %}</h3>
<ul>
{% for choice in choices %}
{% if choice.display in groups %}
<li{% if choice.selected %} class="selected"{% endif %}>
{{ choice.display }}</li>
{% endif %}
{% endfor %}
</ul>
No big surprises here. All we're doing is putting all the pieces together. Each choice is a dictionary with all the values needed to construct the filter link. Specifically, choice.display holds the actual name of the instance that will be filtered by. Obviously enough, I've set up a check to see if this value is in my filtered list of groups I want to show, and only render the link if it is.
So, it's a bit involved but works remarkably well. Just like that, you have a list of filters that is exactly what you want instead of the default ones generated by Django.
I'm going to tell you off the bat that I've never done this before myself, so take it with a grain of salt.
What I'd suggest would be to override get_changelist on your ModelAdmin, to return a custom ChangeList class, which you can define somewhere in your admin module.
Your custom ChangeList class would simply override get_filters, so you can map your custom FilterSpec for the group field.
Another thing that might interest you are patches from the feature request ticket for specifying custom filter specs. The latest patch doesn't work for Django 1.3rc1 yet, although #bendavis78 recently posted that he's working on a new one, but depending on your version of Django it may apply cleanly.
It looks like it barely missed the cut to get included into the 1.3 milestone, so I figure it's going to make it into the trunk as soon as work beings on Django 1.4.
I'm writing a simple blog-like application for Django and am trying to get the effect of having a front page with posts limited to 5, with a comprehensive archive that lists something like 100 posts at a time. (100 is not realistic, just throwing a number out there)
Since the blog post blocks will look exactly the same between the two pages minus the number being shown, I'd like to put the corresponding HTML in a separate template that I can include or link to from the actual templates being rendered. I've looked over the documentation, and the include tag looked promising, but it apparently renders outside of the current context, which is not helpful to my cause, since it wouldn't get the objects to loop through. Outside of that, I can't see any other way to do what I want. Is this possible or am I just out of luck and going to have to violate DRY? Code is below to give you an idea of what I want.
Thanks
#######################
# news/frontpage.html #
#######################
{% extends "news/base.html" %}
{% block site_title %} - Front Page{% endblock %}
{% block center_col %}
{{ block.super }}
View Older Blog Posts
{% endblock %}
{% block blog_rows %}
{% for object in object_list %}
# Blog post content would go here, however it is to be included.
{% endfor %}
{% endblock %}
You're looking for an inclusion tag.
Why don't you filter for the blog posts you want to show in your view? That way you can keep the template the same:
{% for object in blogposts %}
# ...
{% endfor %}
You define blogposts in your view, which either includes 5 or 100 posts.
Ignacio is right that you want an inclusion tag, but you should know that the include tag does not render outside the current context - it very definitely uses the same context as the block it's in.
Your problem is probably that you're trying to call blogpost_set on the object_list - but the relationship is not with the list of objects, it's with each individual object in the list. You'd need to iterate through object_list and then through blogpost_set.all on each one.