Using variables with a django template - python

I have a developed a filter which does alot of database queries in my django templete. I have several uses for the same filter with the same values which will provide the same result on the same templete. I wish to save the filter result in a variable within the templete so I can make sure I dont re-run the same queries over again.
I cant send this from my view because I am doing this filter call in a for loop for each object in my model.
an example of what I need can be seen in the url tag :
{% url 'path.to.view' arg arg2 as the_url %}
I need the "as" operation over a filter.

{% with bla=arg|foo %}
{% url 'view' bla %}
{% endwith %}

Related

fetch a specific item in database into Django template if it's certain type

I've been trying to use if statement in Django template to check if the type is equals to something in my database.
I used this code for the if statement:
{% if product.type == 'tshirt'%}
<strong>{{product.name}}</strong>
<span>{{product.price}}IQD</span>
{% endif %}
But it doesn't seem to work also my back-end has no problem it can handle and load products from the database into the html template very well but the if statement is what I'm struggling with and it doesn't seem to work like that
I just want to render the product into the template if it's a certain type.
The problem is that you are trying to compare a string with a non string type. product.type and 'tshirt' are different objects so format product.type to string
{% if product.type|stringformat:'s' == 'tshirt' %}
<strong>{{product.name}}</strong>
<span>{{product.price}}IQD</span>
{% endif %}

Django/Wagtail - How to create a conditional in template that checks for url path?

I'm struggling to finding a quick and easy solution to show HTML content based on a conditional that checks if the wagtail page is at root, aka '/'.
According to the Wagtail docs, I can also make this work using original request object from Django:
Additionally request. is available and contains Django’s request
object.
This is essentially what I want to do. I use the page object here from wagtail but it might be better if I used the request object from Django instead. How can I
{% if page.request.path == '/' %}
<div> show something </div>
{% else %}
#show nothing
{% endif %}
How can I structure a conditional to solve what I'm trying to do?
Access request
The request object can be accessed via request and not page.request.
A helpful tip is to add {% debug %} to see ALL the context that is available to the current template while working locally and debugging.
{% if request.path == '/' %}
<div> show something </div>
{% else %}
#show nothing
{% endif %}
More info
Within Wagtail the request object should be available to all templates, however you may need to enable this by following the instructions about Using RequestContext in the Django docs.
Alternatively this Django request in template answer provides a clear example of what to update in your settings file.

Show url link only if condition meet using data in model - Django

I am using template to render basic html in django and specify link as below.
<li>Geometry</li>
I want to hide this link based on condition using model information.
Does anyone know how to do this?
You can surround the html in an if statement using the Django template language:
{% if object.something %}
<li>Geometry</li>
{% endif %}
You can use operators, filters or complex expressions if object.something is not a boolean
Django has an if template tag, see:
https://docs.djangoproject.com/en/2.1/ref/templates/builtins/#if
from the docs:
{% if not athlete_list %}
There are no athletes.
{% endif %}

Flask redirect on select onchange

I'm a beginner to flask and I'm making a small web scraper app. What I've done so far has created a dropdown with a list of elements. Now I want to be able to render another page when the user selects a value from the list and I want to pass that value to the next page as well.
{% extends "base.html" %}
{% block content %}
<select id = "foo" onchange="">
{% for item in Citydata %}
<option value = {{ item.link }}> {{ item.name }} </option>
{% endfor %}
</select>
{% endblock %}
This makes the list and adds in all the links and values. I know that what should happen is that when an option is selected a new route is selected/used and a new template file is loaded. But I don't know how to do it.
If you are trying to do a form submission, follow colidyre's suggestion.
It seems to me, however, that you're looking to add a variable in your path, so you will need to use Flask's Variable Rules
It is unclear what item.link is, however if you have formatted that to be associated with an item's id such as /item/1, you could create an <a> tag like so:
{% for item in Citydata %}
{{ item.name }}
{% endfor %}
That would handle populating the href properly on the front-end, next you will need to set up the proper route on the server to handle the path:
#app.route('/item/<int:item_id>')
def item_route(item_id):
# do some stuff
NOTE: you don't have to create <a> tags, but it is a bit more straight forward than <option>. To stick with <option> you would just need to add some JavaScript client-side to call the back-end service based on the selected <option>'s value attribute instead.

Possible to limit filters ManyToMany/Foreign Key in Django admin for a model where the relationship is defined on the other model?

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.

Categories