Front-end prototype/skeleton in Django - django

Often I create a static html prototype/skeleton for back-end developers I work with. This helps to find mistakes in the UI/IA and costly re-writes before the site is implemented.
I would like to take this a step further and create these prototypes/skeletons in Django. By a prototype/skeleton I mean linked static pages that can be easily hooked up to back-end later.
I would like to get some suggestions/ideas how I should set up my templates/links so they are easy to work with later during the implementation stage.
Short list of requirements that come to my mind:
Organization of templates while the entire project will consist of multiple apps
Clean URL dispatcher and link creation
Ability to display logged-in/ logged-out states

I guess in a more traditional approach, the UI designers and back-end developers work on two ends of the development spectrum and hopefully converge somewhere in the middle in a gracious manner. If you'd be willing to get your hands dirty with writing a few lines of code, you could lay out the whole application architecture for the developers because you have the upper hand—your immediately concerned with the users, the data they consume and the interactions they need to perform. That would take out much of the guesswork for the developers, now with only having to fill in the holes, connect the dots or what have you.
The first thing you should do is get together and set some common grounds. Typically, that includes performing modularization at the very beginning. Take all the major features and break them into several Django apps that are going to wrap template, view and model triads relevant to a certain feature the application provides. The more the better holds true here, so don't worry if you end up with a lot of applications, because you never want to have a single application providing too many features/hosting too many components. Commonly you start with apps such as registration, authentication, profiles (user) and work you way outwards. As an example, you could cram the three into a single application, but you end up with a lot of templates, a lot of views, two or three models perhaps, but the tests are really going to be a real choking point. So, break everything into these app buckets until you feel that every part of the system naturally falls into place on a conceptual level. If your ever find yourself thinking where something should be placed, or your looking at a module that's several pages long and feel tempted to break the module (models.py, views.py, test.py) into a package with many intra-package modules, you should probably refactor the architecture immediately. Always remember that your efforts here are to strike simplicity with your architecture.
Once that's done, you've really done half of the work. Great thing about Django is that you have loose coupling between URLs and views. The views themselves provide the application behavior and streamline the presentation. If you can properly pave out the main URLs and stub out the views to just churn out static templates, you've just done some fine work.
This is how it's accomplished. You can abstract URLs and the views they're mapped to by naming your patterns, such as authentication:login, authentication:logout, registration:register, registration:confirm, registration:activate, etc. This is how you tie your internals to all the behaviors that are provided and these shouldn't be subject to change. You can then always change the URL pattern for authentication:login, change the view that pattern maps to, but your referencing it by an internal name, so you can, say, swap out the views that just churned out static templates with a full blown view without having to do any additional modifications to your code.
So here's how it works in real life:
Brainstorm, decide on the apps and the features they'll provide and review your decisions.
Start of with a core application that's going to host some project specific features, such as base templates and the root / view.
Create a /core/templates/core/base.html that's going to load all the common CSS/JS files that are going to be used site-wide, that'll define the header, contents and footer sections (template blocks) and that's going to use context variables for page metadata, such as title, description, keywords and robots. Your typical "One Template To Rule Them All", the bits that are going to be present in structure/presentation for all of your pages.
Create a simple /core/temaplates/core/welcome.html, that extends the core template and prints "Hello world!" in the content area.
Add the following to /core/urls.py:
from django.conf.urls.defaults import *
from django.views.generic import TemplateView
urlpatterns = patterns('',
# Welcome
url(
r'^$', TemplateView.as_view(template_name='core/welcome.html'),
name='welcome'
),
)
Hook it up in the main /urls.py:
from django.conf.urls.defaults import *
from django.contrib import admin
admin.autodiscover()
urlpatterns = patterns('',
url(ur'^', include('core.urls', namespace='core')),
url(ur'^admin/doc/', include('django.contrib.admindocs.urls')),
url(ur'^admin/', include(admin.site.urls)),
)
Hit http://localhost:8080/, see the "Hello World!", revel in the warm fuzzy feeling.
Repeat the same for the rest of the apps: create the app, create the patterns, name them, map them to a static template, hook it to a namespace in the main urlconf.
You can push the views even further to production readiness for the developers. It might depend on the devs and their style guidelines, but I like to keep my /urls.py clean of everything else but patterns, names and view mappings. Your /core/urls.py could look like:
from django.conf.urls.defaults import *
from core import views
urlpatterns = patterns('',
# Welcome
url(
r'^$', views.Welcome.as_view(),
name='welcome'
),
)
Edit /core/views.py with the following:
from django.core.views.generic import TemplateView
class WelcomeView(TemplateView):
template_name='core/welcome.html'
extra_context={
'page_title': 'Welcome!',
'page_keywords': 'relevant,page,keywords',
'page_description': 'Something equally relevant',
}
def get_context_data(self, **kwargs):
context = super(WelcomeView, self).get_context_data(**kwargs)
context.update(self.extra_context)
return context
And that's one sturdy stubbed-out view, packed with page metadata! Definitely the stuff that'll earn you a beer from the devs. Keep on doing this for all of the views to pump out static templates. When someone approaches to finalizing the views, they'd just have to inherit from a different view class, add the missing features, extend the context, modify the template and voila--it's ready for production.
There's not a lot of upfront learning you'd have to do to make this possible, but it really takes out a lot of the guesswork for devs, which are naturally more concerned with building the rest of the application. It's also simple enough to get really good at, I would guess no one would mind letting you do all of this work. As added beef, you'll probably not be kept in the dark as to how the template context gets populated in the views, so even you can start rolling out more complex views, or at least be able to read them.

When I start an application, I usually make a prototype version as well in Django. I just use direct_to_template generic views, which can later be replaced with the views that the developers create. Since you have multiple apps, you can store app specific templates in a folder in your templates folder that has the same name as the app.
The end result is that you have all the screens displaying at the right urls and can link between them. All developers need to do is replace each url with the custom view they create. Makes it easy.
You may have to do a bit of code if you want the logged in/out status to display, but it is definitely doable.

Related

Determine which templates are used by which views/ URLs in django

I have a fairly large django project consisting of several individual apps. I am farming out some of the front-end work (CSS, HTML tweaks) to people who aren't over-familiar with django. To that end I'd like to generate a list of templates for each URL pattern any given engineer is working on. This will save much time that would otherwise be spent manually tracking down the templates used during a view's render phase.
For example, if Bob is working on URLs beginning with /accounts/ then I'd like to generate a list of all the templates used by any view that handles requests to those URLs.
My initial thought is to use something in the test framework since that has access to the templates rendered during a request. However, I can't guarantee that all URLs or views will be exercised (sadly I don't have 100% test coverage), and a missed template is unlikely to be noticed. I don't mind writing a set of tests that simply exercise each view, but don't want to duplicate existing efforts. Also certain views require POSTed data or authentication to function correctly - although I suspect that's an issue I'll have to face no matter what approach is used.
Are there any utilities or snippets that will do what I need?
django-debug-toolbar is a must for developing with Django, It includes a panel detailing all templates used during a request.
I've found the SQL panel is the most helpful for improving page load times as it details slow and duplicate queries.
It can slow down requests when enabled, disabling all panels but those that you use helps.

How can I automate urls for django generic views?

I have subclassed Django's generic views for my project. I use them extensively to create basic CRUD views on our front-end site. Some models have just a create view, some have a read and update, etc.
This works well but I still write a line of code for each URL. ie:
url(r'^referrer/create/$',ReferrerCreateView.as_view(), name='referrer_create'),
url(r'^referrer/$',ReferrerListView.as_view(), name='referrer_list'),
url(r'^referrer/(?P<pk>\d+)/update/$',ReferrerUpdateView.as_view(),
name='referrer_update'),
I then do this for every model and the views that model has. This doesn't seem to be a very DRY approach to me. Is there a good approach to automating these urls for any generic view that has been created for a model?
The solution is to create a method that will return a list of url() calls given a set of views. Something like
views = {
'base_name': 'referrer',
'create_view': ReferrerCreateView,
'list_view': ReferrerListView,
'update_view': ReferrerUpdateView,
}
def generate_urls(views):
return [
url(r'^%s/create/$' % views['base_name'], views['create_view'].as_view(), '%s_create' % views['base_name'],
# and so on
]
Then you just need to do
urlpatterns = patterns('', *generate_urls(views))
For every set of views you have.
That being said I believe you shouldn't do this. This solution (or any different implementations) is over complicated and will add an extra layer you'll need to go through if things go wrong.
There's nothing wrong of having some boilerplate code, especially configuration code, because it makes your life much easier to debug in the future.
I have the same very concern and I shared it here before
One answer was the use of django rest framework as it implements such url patterns on its own!?! I didn't experience this solution yet.
My workaround is to have a dedicated file for crud operations for every model.
By that solution I decreased the matching time , and grouped related model pattern in one file.
BUT I understand that wont fully solve your question

The true meaning of django project and individual apps in it

What really is the true meaning of django project and individual apps in it?
I mean - AFAIK you cannot create a project and live entirely in that project you created, you have to create an app in that project to be able to actually do something in django. Please correct me if I'm wrong.
Now what should really be the structure of a django project? I'm writing an e-shop. Let's say my project is named foo:
/foo
/foo
/settings.py
/templates
/urls.py
/wsgi.py
/shop
/__init__.py
/admin.py
/models.py
/tests.py
/views.py
and do everything entirely in /foo/shop/, but I edit urls.py inside /foo/foo/ etc.
I was following the Django Book, but I've begun to gain that strange feeling that /foo/foo/ is just for a main folder "stitching the thing together" but individual stuff should be done only in /foo/shop/, but not limited to. Preferably in /foo/web/, /foo/products/, /foo/forum/, /foo/controlpanel/, /foo/shop/, /foo/helpdesk/, /foo/backoffice/ etc.
Is that correct? Should I put everything products-related in /foo/products/, that including storage management, shipping, dealers, prices etc., then put management of those products (from the employee side) to /foo/backoffice/, which will serve as some sort of "django.contrib.admin" for this? Is that correct? Then if I want to host multiple instances of this (with completely separate databases and stuff) for multiple customers, should i only create a barebone project, that will put these things together, to configure the settings and then just move individual components in some sort of central repository and call them back in the project via INSTALLED_APPS? Because that would be cool as hell! I mean - making all the changes globally, not touching users data and configuration, unless necessary (adding columns in models and such). Is this how django is really supposed to be used? Or am I completely off the track and do things ENTIRELY wrong and this paragraph just doesn't make any django-sense?
I'm relatively new to this. I've been using PHP before and even though Django was a pain-in-the-ass to get basic grip of, I don't regret that and plan to deprecate and make offline any PHP project I created to date and replace them all with django. Well - where it makes sense and is not a single-purpose site. Not only because Django is awesome and versatile, but i cas I can scale it easily as well…
So… How should I really design Django projects, apps, and how to use them in production, providing them to multiple customers?
Thank you!
I mean - AFAIK you cannot create a project and live entirely in that project you created, you have to create an app in that project to be able to actually do something in django. Please correct me if I'm wrong.
You can do plenty of things on just a project, but you need an app for models to be auto discovered.
For example, I have a project with just this in urls.py:
class Homepage(generic.TemplateView):
template_name = 'homepage.html'
def get_context_data(self):
context = cache.get('homepage')
if not context:
management.call_command('reset_cache')
context = cache.get('homepage')
return context
urlpatterns = patterns("",
url(r"^$", Homepage.as_view(), name="home"),
)
You guessed it, it's a really basic website.
and do everything entirely in /foo/shop/, but I edit urls.py inside /foo/foo/ etc.
I was following the Django Book, but I've begun to gain that strange
feeling that /foo/foo/ is just for a main folder "stitching the thing
together" but individual stuff should be done only in /foo/shop/, but
not limited to. Preferably in /foo/web/, /foo/products/, /foo/forum/,
/foo/controlpanel/, /foo/shop/, /foo/helpdesk/, /foo/backoffice/ etc.
Well, you should define /foo/shop/urls.py, and import it from /foo/foo/urls.py ie.:
urlpatterns = patterns("",
url(r"^shop/", include("shop.urls")),
)
The point is to make your apps more convenient to reuse in other django projects.
Is that correct? Should I put everything products-related in
/foo/products/, that including storage management, shipping, dealers,
prices etc., then put management of those products (from the employee
side) to /foo/backoffice/, which will serve as some sort of
"django.contrib.admin" for this? Is that correct?
You should take a look at open source projects and see how they divided that.
According to the directory tree that you represented, you seem to have understood the point, but your statement seems fuzzy so I'll attempt to clarify it.
Apps are generally oriented around models. So if I make a product app it will probably contain:
Product model,
Product list, edit, create, delete and detail view
urls for the views,
Product admin,
tests for Product and views,
other things which are used by other django apps like product/admin.py would be used by django.contrib.admin, but also external apps like django-autocomplete-light would use product/autcomplete_light_registry.py and django-rules-light would use product/rules_light_registry
Then if I want to host multiple instances of this (with completely
separate databases and stuff) for multiple customers, should i only
create a barebone project, that will put these things together, to
configure the settings and then just move individual components in
some sort of central repository and call them back in the project via
INSTALLED_APPS?
There are many ways to do SaaS with django. But I agree that the easiest and most convenient is to maintain generic apps and build a project per customer that reuses (and eventually override parts of) these apps.

how to make interaction between different django apps in a single site?

I have just learnt about Django apps. I want to know that within one site, if I make different apps. like, users, profiles, polls, blogs,comments, jobs , applications then how can I manage them to make them intereactive? And is it how the concept of app should be? I want to have things loosely coupled that's why asking? Rails work on the way of REST, so do Django support that also with the use of apps? May be my questions seems a bit ambiguous because I am new to django and some of my concepts are still messed up.
Please tell what ever you know.
The general idea is that apps should be as loosely coupled as possible. The goal is to have completely self-contained functionality. Now, of course, that's not always possible and many times it even makes sense to bring in functionality from another app. To do that, you simply import whatever you need. For example, if your "blogs" app needed to work with your Comment model in your "comments" app you'd simply add the following to the top of the python file you're working in:
from comments.models import Comment
You can then use Comment as if it were defined right in the same file.
As far as REST goes, Django's views are much more fluid. You can name your view whatever you like; you need only hook it up to the right urlpattern in urls.py. Django views can return any content type, you just prepare the response and tell it what mimetype to serve it as (the default is HTML).

Alternate URL router for Django

How would you go about using django models and templates, but not the URL routing system? I'd like to swap out the urls.py system for something like PHP where the URL tells you exactly where the code is that's running. Or maybe something more automagic like rails uses -- where the URL always includes the same components like app name, model name and view name.
I just disagree with the line from the django philosophy statement that "Tying URLs to Python function names is a Bad And Ugly Thing." Pretty URLs just aren't all that important to me, and IMVHO not worth the complexity of climbing through a maze of indirection in multiple urls.py files and dozens of regexes to find out what code runs behind a particular URL. It's a personal choice, right? Django is generally pretty modular allowing you to swap out the major components for other ones. So, how would I swap out the part which takes the request URL and decides which view to run?
Are there any alternate URL routers for django out there?
All you need is one line in your urls.py that matches everything, and then just write your handler/dispatcher as a view. That handler does whatever you want based on the parts of the URL....
I've never heard of anyone successfully swapping out Django's URL routing system. There's certainly no hook for it - core.handlers.base.BaseHandler.get_response calls urlresolvers.RegexURLResolver directly. Conceivably, you could add a middleware at the bottom of the stack that dispatches to your own URL resolution system and returns the response, thus bypassing the Django system, but it's a bit kludgy.
If you're after something more like Rails, you might want to try one of the other frameworks - Pyramid, for example, uses a system of Routes very similar to Rails'. Pyramid is much more pluggable than Django, so you should be able to plug in the Jinja2 templating system, which is based on Django's. However, there's no way to use Django's ORM seperately, so you'd need to use SQLAlchemy (which can be used in a way that's not massively different).