I've passed 'Tango with Django' tutorial but still don't get one thing - why we need to use hidden fields in Django template.
For example, if I have a code
class CategoryForm(forms.ModelForm):
name = forms.CharField(max_length=128, help_text="Please enter the category name.")
views = forms.IntegerField(widget=forms.HiddenInput(), initial=0)
likes = forms.IntegerField(widget=forms.HiddenInput(), initial=0)
Ok, here I get, that views and likes won't be filled by user in form, so they are hidden.
But, in template, inside the form we have something like:
{% csrf_token %}
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
{% for field in form.visible_fields %}
{{ field.errors }}
{{ field.help_text }}
{{ field }}
{% endfor %}
Why do we need 2-nd and 3-rd rows? And do we need them?
It's difficult to say exactly why, because the reasons could be pretty numerous.
But broadly speaking, it is probably so that those two fields can be modified or accessed client-side by javascript, and then also be submitted back to the server.
If you're not doing any of that, then you probably don't need them :) But you might have to worry about not overwriting those values when you save changes to the other fields.
Check the generated HTML. Even if hidden, those fields need to be present in the HTML, so that they get sent to the server on form submit. They are "hidden", not "absent".
And, indeed, quite often they are manipulated by the client-side javascript, as well, typically to put a value there.
Related
I've got a modelform_factory which works perfect for what I need.
I call it like this:
dep_formset = modelformset_factory(
Dependent,
fields=('has_medical', 'med_group_id'),
max_num = dep_count
)
As you might guess, Dependent has additional fields that I want to use simply for display purposes (first_name and last_name respectively) I want to show the first_name and last_name of the dependent person - but have it be simply for display, not edit.
If I add 'first_name' and 'last_name' to the fields in the above, I can then access them in my template - but the form fails against .is_valid() because I'm displaying them simply as text and not as an input, so they're not being POST'ed
Is there some clever way to get access to the first_name and last_name of the dependent objects without adding them to fields for the formset_factory?
The template looks like this (partial snippet so you can see what I'm trying to do with the first_name, last_name):
{% for form in dep_formset %}
{{ form.id }}
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
<div class="g">
<h4>{{ form.first_name.value }} {{form.last_name.value}}</h4>
</div>
<div class="g dependent-option">
<div class="g-1-4 dependent-option-check">
{% if form.has_medical %}
Based on provided information it looks like the formset is tied to an instance which you can access in template:
{{ form.instance.first_name }}
I have a django form that I can iterate over, for example, through a for loop:
{% for field in form %}
...
{% endfor %}
Now I'm trying to find out the total number form fields outside of the for loop. I have tried the following, but it just returns 0, even though I have 2 form fields:
{{ form|length }}
Is there any way to do this?
PS: This is in the context of django-cms 3.1.3, if this helps.
You'll need to explicitly count the fields, rather than just the form itself, such as:
{{ form.fields|length }}
As seen in the Django form documentation
Try this :
{{ form.hidden_fields|length + form.visible_fields|length }}
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 have a variable:
m2m_links = mymodel._meta.many_to_many
This has all of the fields that are m2m in a particular model. I want the template to display the names of the models that are linked. Within my view, I can list the tables like so:
for f in m2m_links:
print f.related.parent_model
But in my template, if I try
{% for table in m2m_links %}
{{ table.related.parent_model }}<br>
{% endfor %}
I get an error: "Caught DoesNotExist while rendering"
How do I get the names of the tables to render in the template? And a further question, how do I get just the name, not something like
<class 'myapp.models.ModelName'>
which is what I have showing in my terminal from the "print" statement.
There's no reason, based on the template code you've provided that you should be getting that error. Most likely, there's something else going on in your template that is causing that.
As for your second question, the way to get a class' name is:
some_class.__name__
However, the Django template engine will not allow you to use underscored properties in the template, so your best bet is to prepare a proper list in your view:
linked_models = [m2m.related.parent_model.__name__ for m2m in mymodel._meta.many_to_many]
Then, just loop through that in your template and the all the work is already done.
UPDATE (based on comment)
You do it mostly the same way, though you have a couple of choices.
You can do a list of tuples and unpack it in the template:
linked_models = [(m2m.related.parent_model.__name__, m2m.related.parent_model._meta.verbose_name) for m2m in mymodel._meta.many_to_many]
Then, in your template:
{% for class_name, verbose_name in linked_models %}
{{ class_name }} {{ verbose_name }}
{% endfor %}
Create a list of dictionaries and reference the keys in the template:
linked_models = [{'class_name': m2m.related.parent_model.__name__, 'verbose_name': m2m.related.parent_model._meta.verbose_name} for m2m in mymodel._meta.many_to_many]
Them, in your template:
{% for model in linked_models %}
{{ model.class_name }} {{ model.verbose_name }}
{% endfor %}
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.