Django inclusion tag with configurable template - django

I've created an inclusion tag, however I'd like to be able to make the template optionally configurable. There doesn't seem to be support for this out of the box, so I'd like to see how people did this - maybe a method search the templates directory first for a specific template name and then falling back to the default template.
#register.inclusion_tag('foo.html', takes_context=True)

I use simple_tag when i need to do that:
from django.template import Library, loader, Context
#register.simple_tag(takes_context=True)
def my_tag(context, template_name):
var1 = ...
t = loader.get_template(template_name)
return t.render(Context({
'var1': var1,
...
}))

This post saved my life: http://djangosnippets.org/snippets/1329/
The key is to add to a "dummy template":
{% extends template %}

The inclusion_tag decorator is just a shortcut - it's meant as a simple way of rendering a specific template with a specific context. As soon as you want to move outside of that, it can no longer help you. But that just means you'll have to write the tag the long way, as explained in the documentation, and pass the template you want as a parameter.

I had to do something like this for a project and since we needed more than one of this kind of inclusion tag I made a decorator based on django inclusion_tag decorator. This is the code:
# -*- coding: utf-8 -*-
from django import template
from inspect import getargspec
from django.template.context import Context
from django.template import Node, generic_tag_compiler, Variable
from django.utils.functional import curry
def inclusion_tag(register, context_class=Context, takes_context=False):
def dec(func):
params, xx, xxx, defaults = getargspec(func)
if takes_context:
if params[0] == 'context':
params = params[1:]
else:
raise TemplateSyntaxError("Any tag function decorated with takes_context=True must have a first argument of 'context'")
class InclusionNode(Node):
def __init__(self, vars_to_resolve):
self.vars_to_resolve = map(Variable, vars_to_resolve)
def render(self, context):
resolved_vars = [var.resolve(context) for var in self.vars_to_resolve]
if takes_context:
args = [context] + resolved_vars
else:
args = resolved_vars
file_name, extra_context = func(*args)
from django.template.loader import get_template, select_template
if not isinstance(file_name, basestring) and is_iterable(file_name):
t = select_template(file_name)
else:
t = get_template(file_name)
self.nodelist = t.nodelist
new_context = context_class(extra_context, autoescape=context.autoescape)
# Copy across the CSRF token, if present, because inclusion
# tags are often used for forms, and we need instructions
# for using CSRF protection to be as simple as possible.
csrf_token = context.get('csrf_token', None)
if csrf_token is not None:
new_context['csrf_token'] = csrf_token
return self.nodelist.render(new_context)
compile_func = curry(generic_tag_compiler, params, defaults, getattr(func, "_decorated_function", func).__name__, InclusionNode)
compile_func.__doc__ = func.__doc__
register.tag(getattr(func, "_decorated_function", func).__name__, compile_func)
return func
return dec
You have to return a tuple with the template (or template list) and the context dict. Note that you have to pass the register (Library instance) in the decorator call:
from somewhere import inclusion_tag
#inclusion_tag(register)
def display_formset(formset):
template_name = FORMSET_TEMPLATES.get(formset.model,
'includes/inline_formset.html')
return (template_name, {'formset': formset})
Hope this helps

A solution could be a regular inclusion_tag which pass dynamic template name to context.
Like this :
# templatetags/tags.py
#register.inclusion_tag('include_tag.html', takes_context=True)
def tag_manager(context):
context.update({
'dynamic_template': resolve_template(context),
})
return context
And the template:
<!-- include_tag.html -->
{% include dynamic_template %}
The tricks here is, when I call {% tag_manager %}, it includes include_tag.html which in turn includes the template returned by resolve_template() (not included for brevity).
Hope this helps...

Related

Publish a custom Django Flatpage at a set date and time

I have a custom Flatpage model:
from django.contrib.flatpages.models import FlatPage
class MyFlatPage(FlatPage):
publish = models.DateTimeField()
so that I can add a publish date in the future.
Now, I don't have a proper list of flatpages on the front end, my use for frontpages is more like 'one-offs', where I specific the URL and all that. For example, 'about', '2019prize', 'Today's walk', stuff like that.
The urls.py is set up to catch all the flatpages with:
from django.contrib.flatpages import views
re_path(r'^(?P<url>.*/)$', views.flatpage)
How can I set these pages I create to be displayed only after the publish date has arrived? I know that I can filter them by looking up something like pages.filter(publish__lte=now). Where and how should I put that code though?
Additional information
I suppose I need to create a custom view, is that correct? The original view is in ../lib/python3.8/site-packages/django/contrib/flatpages/views.py:
def flatpage(request, url)
if not url.startswith('/'):
url = '/' + url
site_id = get_current_site(request).id
try:
f = get_object_or_404(FlatPage, url=url, sites=site_id)
except Http404:
if not url.endswith('/') and settings.APPEND_SLASH:
url += '/'
f = get_object_or_404(FlatPage, url=url, sites=site_id)
return HttpResponsePermanentRedirect('%s/' % request.path)
else:
raise
return render_flatpage(request, f)
#csrf_protect
def render_flatpage(request, f):
if f.registration_required and not request.user.is_authenticated:
from django.contrib.auth.views import redirect_to_login
return redirect_to_login(request.path)
if f.template_name:
template = loader.select_template((f.template_name, DEFAULT_TEMPLATE))
else:
template = loader.get_template(DEFAULT_TEMPLATE)
f.title = mark_safe(f.title)
f.content = mark_safe(f.content)
return HttpResponse(template.render({'flatpage': f}, request))
How can I extend this, adding my if publish__lte=now code?
What I did is copy-paste the view code from ../lib/python3.8/site-packages/django/contrib/flatpages/views.py to my app.views, rename the two functions, and add the following to render_myflatpage:
def render_myflatpage(request, f):
[...]
if f.publish > now:
f.content = 'This content will be published on ' + str(f.publish)
I then assigned the new view in the catch-all urls.py code:
re_path(r'^(?P<url>.*/)$', myflatpage)
I know this goes against the DRY protocol; this works for me for the time being. If there's a more elegant solution please do let me know.

Django - If my template tag takes the context and the context is changed, are its new variables accessible in the rest of my page?

I have a template tag that takes the context. In it I add a variable to my context. It seems this variable prints correctly in the template which includes my template tag (let's call it "desktop"). But in the the template which includes THAT template, it no longer has the variable.
I've googled the django docs because I'm curious as to what's going on here. Is my template tag's context variable only available within the template that includes it and not beyond, as it seems?
In the Django library, django.template.base you have the parse_bits function. In this function, the view context is copied into a new variable.
if takes_context:
if params[0] == 'context':
params = params[1:]
else:
raise TemplateSyntaxError(
"'%s' is decorated with takes_context=True so it must "
"have a first argument of 'context'" % name)
And in the class InclusionNode class render function, a new context object is created to render the template of the template tag:
class InclusionNode(TagHelperNode):
def render(self, context):
"""
Renders the specified template and context. Caches the
template object in render_context to avoid reparsing and
loading when used in a for loop.
"""
resolved_args, resolved_kwargs = self.get_resolved_arguments(context)
_dict = func(*resolved_args, **resolved_kwargs)
t = context.render_context.get(self)
if t is None:
if isinstance(file_name, Template):
t = file_name
elif isinstance(getattr(file_name, 'template', None), Template):
t = file_name.template
elif not isinstance(file_name, six.string_types) and is_iterable(file_name):
t = context.template.engine.select_template(file_name)
else:
t = context.template.engine.get_template(file_name)
context.render_context[self] = t
new_context = context.new(_dict)
# Copy across the CSRF token, if present, because
# inclusion tags are often used for forms, and we need
# instructions for using CSRF protection to be as simple
# as possible.
csrf_token = context.get('csrf_token', None)
if csrf_token is not None:
new_context['csrf_token'] = csrf_token
return t.render(new_context)
So it should not propagate the templatetag context to the calling template.

Render a Django CMS Placeholder to variable in view

I try to render a Django CMS Placeholder from a page to a variable, to return the rendered code as JSON.
So what I do is:
from cms.models.placeholdermodel import Placeholder
from cms.models.pagemodel import Page
def render(self, page_id, placeholder_slot, request):
page = Page.objects.get(id=page_id)
placeholder = page.placeholders.get(slot=placeholder_slot)
Now I want to render the placeholder to a variable. Which function do I have to call in which way to get this?
The Placeholder can be called manually and rendered like that, a few examples:
from cms import models
from django import template
def render(request):
placeholder = models.Placeholder.objects.get_or_create(slot='some_slot')
context = template.RequestContext(request)
return placeholder.render(request, width=None)
Or for json/javascript/etc. where you don't want full html but just the value:
def render_basic(request):
placeholder = models.Placeholder.objects.get_or_create(slot='some_slot')
context = template.RequestContext(request)
return placeholder.render(request, width=None, editable=False)
It's also possible (and even easier) to use the StaticPlaceholder:
from cms import models
def render(request):
placeholder = models.StaticPlaceholder.objects.get_or_create(name='name of the placeholder')
return placeholder.code
You can render it using Placeholder.render. Note that the context must contain a valid HttpRequest object under the 'request' key. width may be None. See the {% render_placeholder %} implementation for an example.

Creating PDFs with django (wkhtmltopdf)

Could someone please provide me with a comprehensive example of how to get a view in django to return a PDF using wkhtmltopdf. There are limited number of examples that come with django-wkhtmltopdf and they presume a level of knowledge I just don't have. I have looked through the source code but I can't make heads or tails of how to use it (for example whats the difference between PDFTemplateView and PDFTemplateResponse?!?)
I would be very grateful for any help.
BTW(I'm using templates for the header and footer as well)
EDIT
def some_view(request,sID):
something = get_object_or_404(Something,id=sID)
return render_to_response('something.html', {'something':something}, context_instance=RequestContext(request))
How would I get the following simple view to provide me with a pdf instead of an html file?
EDIT 2
I am currently playing around with:
def pdf_view(request,sID):
template = 'pdf.html'
something = get_object_or_404(Something,id=sID)
context = {
'something' : Something,
'object_for_header_and_footer': something.object_for_header_and_footer,
}
cmd_options = settings.WKHTMLTOPDF_CMD_OPTIONS
return PDFTemplateResponse(request=request,
context=context,
template=template,
filename='something',
header_template='header.html',
footer_template='footer.html',
cmd_options=cmd_options)
but I am getting 'str' object has no attribute 'update' in /usr/local/lib/python2.7/dist-packages/wkhtmltopdf/utils.py in wkhtmltopdf, line 74. I don't know whether to starting hacking wkhtmltopdf?!?!
The difference between PDFTemplateView and PDFTemplateResponse is that the view is a class-based view. And PDFTemplateResponse renders the pdf data and sets the right response headers. To add header and footer:
# urls.py
from django.conf.urls.defaults import *
from wkhtmltopdf.views import PDFTemplateView
urlpatterns = patterns('',
...
url(r'^pdf/$', PDFTemplateView.as_view(template_name='my_template.html',
filename='my_pdf.pdf',
header_template='my_header_template.html',
footer_template='my_footer_template.html',
...
), name='pdf'),
)
Opening pdf/ in your browser will start a download of my_pdf.pdf based on the my_template.html, my_header_template.html and my_footer_template.html.
The advanced example shows how to subclass PDFTemplateView extending and changing the logic of PDFTemplateView. To understand what happens read Using class based views.
Like header_template and footer_template you can define a response_class. Because PDFTemplateResponse is the default, you don't have to define it.
EDIT
The following simple view provides you with a pdf instead of an html. This is not using django-wkhtmltopdf. You could use wkhtmltopdf in your html2pdf function.
def some_view(request):
t = loader.get_template('myapp/template.html')
c = RequestContext(request, {'foo': 'bar'})
html = t.render(c)
pdf_data = html2pdf(html) # Your favorite html2pdf generator
response = HttpResponse(pdf_data, content_type='application/pdf')
response['Content-Disposition'] = 'attachment; filename="some_filename.pdf"'
return response
EDIT 2
A simple view with context:
template.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Untitled</title>
</head>
<body>
<h1>{{ title }}</h1>
</body>
</html>
urls.py
from views import MyPDFView
urlpatterns = patterns('',
(r'^pdf/', MyPDFView.as_view()),
)
views.py
from django.views.generic.base import View
from wkhtmltopdf.views import PDFTemplateResponse
class MyPDFView(View):
template='template.html'
context= {'title': 'Hello World!'}
def get(self, request):
response = PDFTemplateResponse(request=request,
template=self.template,
filename="hello.pdf",
context= self.context,
show_content_in_browser=False,
cmd_options={'margin-top': 50,},
)
return response
EDIT 3
If you use a DetailView, you can add the object to context:
url(r'^books/(?P<pk>\d+)/$', MyPDFView.as_view(), name='book-detail'),
class MyPDFView(DetailView):
template='pdftestapp/template.html'
context= {'title': 'Hello World!'}
model = Book
def get(self, request, *args, **kwargs):
self.context['book'] = self.get_object()
response=PDFTemplateResponse(request=request,
template=self.template,
filename ="hello.pdf",
context=self.context,
show_content_in_browser=False,
cmd_options={'margin-top': 50,}
)
return response
Hmm the error indicates that you're passing string somewhere that you shouldn't.
After checking its source code, I guess in settings.py you have WKHTMLTOPDF_CMD_OPTIONS as a string, something like
WKHTMLTOPDF_CMD_OPTIONS = 'some_option_here'
But you should assign a dict there:
WKHTMLTOPDF_CMD_OPTIONS = {
'quiet': True,
}
Otherwise your code should work fine.

Django DRY Feeds

I'm using the Django Feeds Framework and it's really nice, very intuitive and easy to use. But, I think there is a problem when creating links to feeds in HTML.
For example:
<link rel="alternate" type="application/rss+xml" title="{{ feed_title }}" href="{{ url_of_feed }}" />
Link's HREF attribute can be easily found out, just use reverse()
But, what about the TITLE attribute? Where the template engine should look for this? Even more, what if the feed is build up dinamically and the title depends on parameters (like this)?
I can't come up with a solution that "seems" DRY to me... All that I can come up with is using context processors o template tags, but it gets messy when the context procesor/template tag has to find parameters to construct the Feed class, and writing this I realize I don't even know how to create a Feed instance myself within the view.
If I put all this logic in the view, it would not be just one view. Also, the value for TITLE would be in the view AND in the feed.
Just a guess (as I have not used feeds yet in my django app), but you could add a special template_context for your feed with your feed object and use it in your base.html.
I'm not fully satisfied with this solution, it may break feeds using Request and depends on a magic method. There it goes:
#coding:utf-8
# Author: Armando Pérez Marqués <mandx#rbol.org>
# Purpose: Django TemplateTag to output feed links in templates in a DRY way
# Created: 05/07/2010
import re
from django import template
from django.conf import settings
from django.contrib.syndication.views import Feed
from django.core.urlresolvers import reverse, resolve, NoReverseMatch
from django.template import Node
from django.template import TemplateSyntaxError
from django.utils.encoding import smart_str
from django.utils.html import escape as html_escape
from django.utils.safestring import mark_safe
register = template.Library()
kwarg_re = re.compile(r"(?:(\w+)=)?(.+)")
class FeedInfoNode(Node):
def __init__(self, view_name, args, kwargs, asvar):
self.view_name = view_name
self.args = args
self.kwargs = kwargs
self.asvar = asvar
def render(self, context):
args = [arg.resolve(context) for arg in self.args]
kwargs = dict([(smart_str(k,'ascii'), v.resolve(context))
for k, v in self.kwargs.items()])
# Try to look up the URL twice: once given the view name, and again
# relative to what we guess is the "main" app. If they both fail,
# re-raise the NoReverseMatch unless we're using the
# {% feed_info ... as var %} construct in which cause return nothing.
url = ''
try:
url = reverse(self.view_name, args=args, kwargs=kwargs, current_app=context.current_app)
except NoReverseMatch, e:
if settings.SETTINGS_MODULE:
project_name = settings.SETTINGS_MODULE.split('.')[0]
try:
url = reverse(project_name + '.' + self.view_name,
args=args, kwargs=kwargs, current_app=context.current_app)
except NoReverseMatch:
if self.asvar is None:
# Re-raise the original exception, not the one with
# the path relative to the project. This makes a
# better error message.
raise e
else:
if self.asvar is None:
raise e
if 'request' in context:
request = context['request']
else:
request = None
feed_instance, feed_args, feed_kwargs = resolve(url)
if not isinstance(feed_instance, Feed):
raise NoReverseMatch, \
'feed_info can only reverse class-based feeds'
feed_obj = feed_instance.get_object(request, *feed_args, **feed_kwargs)
feed_data = {
'url': url,
'obj': feed_instance,
'args': feed_args,
'kwargs': feed_kwargs,
#'title': html_escape(feed_instance.__get_dynamic_attr('title', obj)),
'title': html_escape(
feed_instance._Feed__get_dynamic_attr('title', feed_obj)
),
'type': feed_instance.feed_type.mime_type,
}
if self.asvar:
context[self.asvar] = feed_data
return ''
else:
return mark_safe(
'<link rel="alternate" type="%(type)s" title="%(title)s" href="%(url)s" />' \
% feed_data
)
def feed_info(parser, token):
"""
Returns an mapping containing populated info about the reversed feed
Works exactly as the url tag, but the mapping is not returned, instead
a variable is always set in the context.
This is a way to define links that aren't tied to a particular URL
configuration::
{% feed_info path.to.some_feed_view_class arg1 arg2 as feed_info_var %}
or
{% feed_info path.to.some_feed_view_class name1=value1 name2=value2 as feed_info_var %}
"""
bits = token.split_contents()
if len(bits) < 2:
raise TemplateSyntaxError("'%s' takes at least one argument"
" (path to a feed view)" % bits[0])
viewname = bits[1]
args = []
kwargs = {}
asvar = None
bits = bits[2:]
if len(bits) >= 2 and bits[-2] == 'as':
asvar = bits[-1]
bits = bits[:-2]
# Backwards compatibility: check for the old comma separated format
# {% url urlname arg1,arg2 %}
# Initial check - that the first space separated bit has a comma in it
if bits and ',' in bits[0]:
check_old_format = True
# In order to *really* be old format, there must be a comma
# in *every* space separated bit, except the last.
for bit in bits[1:-1]:
if ',' not in bit:
# No comma in this bit. Either the comma we found
# in bit 1 was a false positive (e.g., comma in a string),
# or there is a syntax problem with missing commas
check_old_format = False
break
else:
# No comma found - must be new format.
check_old_format = False
if check_old_format:
# Confirm that this is old format by trying to parse the first
# argument. An exception will be raised if the comma is
# unexpected (i.e. outside of a static string).
match = kwarg_re.match(bits[0])
if match:
value = match.groups()[1]
try:
parser.compile_filter(value)
except TemplateSyntaxError:
bits = ''.join(bits).split(',')
# Now all the bits are parsed into new format,
# process them as template vars
if len(bits):
for bit in bits:
match = kwarg_re.match(bit)
if not match:
raise TemplateSyntaxError("Malformed arguments to url tag")
name, value = match.groups()
if name:
kwargs[name] = parser.compile_filter(value)
else:
args.append(parser.compile_filter(value))
return FeedInfoNode(viewname, args, kwargs, asvar)
feed_info = register.tag(feed_info)
I'm starting with the code of the {% url %} template tag, and then, after obtaining the feed's URL, use resolve() to get the Feed subclass instance, and then get the needed attributes.
Caveats
Requires Django 1.2 Class Feeds, don't know exactly how to do this with the old way of feeds.
If the feed class uses the request object, the request context processor must be configured, since None is passed if it isn't present in the context.
There's an oddity with Feed.__get_dynamic_attr(). The Feed subclass instance doesn't have this method; instead, it appears with another name. Don't know how to figure the name out at runtime...