I'm relatively new to Django and I'm designing a website that primarily needs usability experience, speaking of optimized CSS, HTML5 and UI stuff.
It's very easy to use Django for data/Model centric design. Just designing a couple of Python classes and ./manage.py syncdb - there's your Model.
But I'm dealing with a significant amount of View centric challenges. (Different user classes, different tasks, different design challenges.)
The official Django tutorial cursorily goes through using a "Template".
Is there any Design centric guide for Django, or a set of Templates that are ready and useable? I don't want to start from scratch using JS, HTML5, Ajax and everything. From the Model layer perspective Django is very rapid and delivering a working base system. I wonder whether there's something like that for the Views.
Probably django-blocks (http://code.google.com/p/django-blocks/) is aiming a bit into this direction! But otherwise I guess your only choice is to assort to some other 3rdparty html/css + js/aja frameworks depending on the functionality you need! There are also some snippets out, that implement templatetags that output common used html, but nothing big in general!
Is there any Design centric guide for Django, or a set of Templates that are ready and useable?
Django templates alone aren't that much reusable, since their are tied to specific views and variables defined in that views. In my personal experience, I found templating still rapid with an average size of my templates around 50 lines. Of course, this application wasn't heavy on the UI.
Inheritance and fragments will save you from repetition.
Inheritance:
{% extends base.html %}
Fragments:
{% for location in locations %}
{% include "_location_item.html" %}
{% endfor %}
I don't want to start from scratch using JS, HTML5, Ajax and everything.
Well, at a point, you'll start from scratch.
Version-control your project, so you could extract intermediate states for the coming project, if appropriate,
use efficient libraries like jQuery to write less, and do more,
use some CSS scaffolding tool like blueprintcss.
I agree that there is an overhead at the beginning of a project. My justification of that overhead so far has been the fact, that the UI wasn't a modified template (like modified typo3 or so templates, hence more tailored to the applications needs), that it was fast and looked good in the end, too.
Related
I have been using Django for many years (since Django 1.2). and in the past, I used different type of web frameworks (such as CakePHP, Rails, ASP.NET MVC, and some other full-stack framework). Django wasn't my first framework.
Different frameworks have differences in their approaches and benefits. There are certain part of those framework I like and I don't. In this context, I'd like to look at the design of Django Framework in more specific.
After transition to Django, I like how it design its framework. When learning a new language (such as Go, Scala, Ruby, Haskell), I try to looks for a framework that has some similarity in its design especially those I mentioned later.
The following are the 2 Django framework design decision that is very different:
it encourage pluggable apps or apps reusability.
Hence:
moving away from monolithic design by Jacob Kaplan-Moss
using multiple apps to create a full feature site, without any model or logic
writing a Project-less Django mentioned in Practical Django Projects by James Bennett
it uses Model View Template instead of classical MVC:
mentioned in FAQ.
view describes which data is presented
template describes how the data is presented
a view normally delegates to a template
controller is probably the framework itself: the machinery that sends a request to the appropriate view, according to the Django URL configuration.
I would not believe that Django pioneer such features. I believed this pattern is very common in Framework Design. Just that I have no idea, what is this (design) pattern called? This concept is very useful to be applied in other framework. I believed knowing the name of the pattern could help me understand or even build a new framework on different language with the same concept.
Currently there are tons of web framework, most of them are following the classic MVC pattern. Some use the concept of plugin to add certain capability. Plugin however solve the reusability in different approach depending on the context.
So I did tried to learn as many framework I could in order to find an alternative framework in different languages. Hoping that I could find out the pattern that Django use. However, it is very difficult for me to learn all of them. In fact, I haven't found one so far.
I have been searching for:
Django like framework in 'ruby'
Django like framework in 'Java'
Django like framework in 'Haskell'
Django like framework in 'Go-Lang'
Django like framework in 'Scala'
Unfortunately, none of them really, highlight the concept that I'm interested in.
In this Q&A, I would like to know what do people call such framework? (Or What pattern is Django use?) Would be good if you could give a references in this design which other framework might have been using it too?
Looking at Django design philosophies
I think they use/combine a lot of different design patterns trying to fulfill the philosophies. It's difficult to map to a single concept.
Tip is to look at Software Design Pattern and it should be possible to identify many patterns are used in django. Many patterns are of course common in other frameworks as well.
For example (patterns more or less used):
modelform_factory maps to "Builder"
QuerySet can be mapped to "Lazy initialization"
The ORM/database mapped to "Adapter"
What is it about django that you cannot do in other languages?
is it the access to the database, or the models? - no, python also has SQLAlchemy; ruby has Active Record...
is it the views, or web framework? - no, you can provide views with Flask, Pyramid, rails, php ...
it is the templating system? - no, you also have Jinja; mustache, Liquid...
is it the admin contrib packages? - no, you have phpmyadmin, workbench ...
is it a set of libraries to make your development easy? a toolkit?
django has great tooling, many packages you can use; it is a platform, meaning it has enough of a core to be the starting point of many projects, and enough community behind it to have many packages to make integration into a turn-key solution a breeze.
django uses the DRY (Don't Repeat Yourself) principle as a design philosophy. From the point of reusability, keeping clear responsibilities for each piece / app makes it easy to reuse components. But that doesn't take a well-designed platform; the emphasis should be on the components that are written in a way to be reused. E.g. generic tagging, configuration / data-driven components...
Django is MVC.
MVC is a pattern not a strict rule frameworks have to apply. The pattern tries to give a commonly accepted solution to a frequent problem. The problem is "How to properly organize a web framework" and the solution is "by separating data, logic and UI" in meaningful modules.
Therefore Django is MVC. Django logically separates those concepts (and many others) in modules. That's what matters IMO. Django view is not the same as MVC view, but... poteto potato...
About app reusability:
Django is The web framework for perfectionists(...) and perfectionists (or simply good developers) write reusable code. This is expressed by Django DRY philosophy and materializes in Django apps.
I'm pretty sure you can design app-like components with other web frameworks. Of course, since apps are in Django's nature since many years, it has much better support!
Let's say I'm writing a complex site in django with wikis, forums, ... or writing my own apps that I intend to reuse from different sites.
I really want to create, for example, a wiki page that has a forum at the bottom, or reuse my previously written wiki app with a different graphical layout.
What is the best way to structure my app to allow this kind of reuse?
So far, I have been giving apps their own urls in urls.py. This however does not work if I want to combine multiple apps together in a single page.
Additionally, most of the apps I found online come with their own templates, which has the full html, and do not separate the logic of creating / preparing a context from that of handling a request and generating a reply.
What is the best practice here? What do you do? edit the templates that come from applications you download online? refactor them to fit in your application?
what should I do for my own applications? structure them so they have a method to get the context, and a method to render it?
Django hasn't great support out of the box to component-oriented architectures. I find this problematic some times too. You'll face to problems here.
Architecture
Code
Architecture: As Django is not component oriented, all the apps aren't component oriented neither. The designers and coders for those apps haven't thought about that. So they've just built "views" to interface with their apps. You'll need to get something more "pluggable".
Code: Once you decide to build that, you'll have to find what support you have for that. Most Django apps are pretty well coded, so you won't have much code in views, but abstracted in other places. That way you could reuse that code and build your own components.
Example: Suppose you're working with a third-party Wiki app. That wiki has a view to display highest ranked Tags and other view to create a wiki entry. If the code is good enough (that I'm assuming it is because Django has a pretty good community), you could refactor that to use components. The view to create an entry must be using some Form, that you can plug in your own site. And the view to get highest ranked tags probably uses some utility function, or some Tag manager's method. In that case you could refactor it to your own needs.
Hope it helps.
I am a computer programmer by training but have been away from web development for a while. I am doing a little bit of background research on various Python web development frameworks. I understand that Django, Grok / Zope 3, and Pylons are all good solid frameworks, but have little in the way of background working with them. Can someone explain to me the difference in approach of the each of the frameworks, and where one shines when compared to the others?
My specific use case is in building a web application that will recommend products to users based on a variety of user supplied information. Thus, it will take a fair bit of user input in the shape of a basic profile, product preferences, attempt to establish social relationships between users. It will also need to support staff uploading products into the system with labeled features that can be then matched to users.
On the last point, would parts of Plone help with providing an interface for non-tech people to upload products and descriptions of the products? Are piece of Plone easy to borrow? Seems like I shouldn't have to reinvent the wheel in terms of having a way for people to upload items for sale / recommendation along with some metadata to describe the items. Thanks for the help.
Based on your background and requirements, I'd advise you to go with something like http://pinaxproject.com/ which is based on Django.
Pyramid (the successor to Pylons) is a very low-level framework and you need to either choose the libraries or write all your application code yourself. For someone experienced this makes sense and gives you full control over your code. But it is a bit of a hurdle if you start from scratch and aren't familiar with the available libraries.
Django and Grok are both high level frameworks, with Django being the more popular choice. If you aren't familiar yet with using object databases or URL traversal, Grok is more time consuming to learn.
Plone is not suited for your use-case. It's a content management system and not a general web framework. Very little of the libraries it uses can be reused in a different context, certainly none of its UI. If you want to provide an engaging user experience with personalized content, Plone isn't for you - that's not what its been build to handle.
Disclaimer: I'm a release manager for Plone and Zope 2 / Zope Toolkit and have used Pyramid but not Django.
Dolmen project is a CMS built on top of Grok. Is very simple, but there are very few that use it. If you go with Grok, you could be able to reuse the GUI.
But As Hanno said, Grok is more time-consuming to learn than Django. Also Django has far more users than Grok.
The advantage of using Grok is that you can profit from Zope Component Architecture almost without writing ZCML and using decorators instead.
With Pyramid/Pylons you get a very simple framework and nothing else. It is a decoupled framework, so you are free to use whatever templating enginge you want (Mako, Genshi, Jinja, Cheetah), you are free to choose sqlalchemy, zodb, mongoDb, etc., and you are also free to choose the url mapping scheme (traversal vs. django-style mapping or a combination of both). You can also use ZCA here if you want. For starters this might become quite confusing or verbose.
Django is a kind of monolithic framework that gives you one way to do stuff. That's why it's easy to learn and a very good option. But, in my experience, you sometimes get to a point where you want to deviate from Django standards and it simply cannot be done without patching a bunch of stuff.
And, as for Zope3, I'd recommend you to download a copy of BlueBream and se how it does for you.
As a Plone user I can say that creating Content Objects in Plone is difficult. There is not much documentation on how to do it and it is complicated. Some recommend using UML and specialized Plone products to make it easier but that introduces yet another dependency.
I mention the problem with content objects because your "products" (not the same as a Plone product) would probably be represented in Plone as a content object which you would need to write yourself.
Plone is best when users and editors are entering and approving text in the form of news articles, press releases, photos etc. When that is the use case there are predefined content objects for such things so one does not need to write them oneself.
--Jonathan Mark
After reading the Jinja2 documentation, I'm interested in employing it in future Django projects. However, I'm wondering if anyone has encountered any drawbacks or gotchas when using Jinja2 templates with Django? If so, how did you work around them?
I wouldn't mind hearing about positive experiences either, just to get a good cross section of the best and worst of Jinja2.
I use Jinja2 in some of my projects and love the extra expressiveness it gives me. I can keep my presentation logic and application logic separate, but I don't have to bend over backwards to call into a function/method I've designed specifically for my presentation layer.
In addition to what's already been listed by other posters, here are some things that I've found:
The Admin app is tightly coupled to Django templates
The default views and decorators that come with the Auth app (and elsewhere) are coupled to Django templates, so you may have to duplicate the effort if you want to use your Jinja2 templates for login/logout/etc
Behaviorally, Django templates will escape its output by default whereas Jinja2 will not. I think either approach has its own merits, but you have to keep this in mind if you are switching between the two.
I've documented several of the syntax, config, filter, and interoperability considerations for Django -> Jinja2 on my wiki
I haven't used Jinja2 with an actual Django site yet, but I did convert an application using Django templates in standalone mode over to Jinja2 templates. The only (very minor) problem I encountered was lack of the {% spaceless %} template tag.
Extending Jinja2 is much harder than Django template system (I'm talking about templatetags). While most of inclusion tags functionality can be achieved using macros in Jinja (they even seem to be more appropriate), writing bit more complicated tags is really hard in Jinja (see the docs for yourself).
Other than that, the only obstacle are Django-based habits... ;)
There's been some new code added in the Django trunk that lets you write TemplateLoaders and Template classes that can be used to work with different template languages. Docs have been added for it at http://docs.djangoproject.com/en/dev/ref/templates/api/#using-an-alternative-template-language, and it will be in the 1.2 release. This should cut out most of the gotchas with things like using custom templates for login, logout, admin etc.
An alternate solution is to use a layer on top of Django, like Chouwa or Djinja2. You will have issues getting Django's builtin views to use your templates, but it works if you don't want to use Django trunk.
Once you've done either of those, the only really major issue is that most of the stuff Django exposes to templates (especially for the comments framework) is exposed in custom tags, which don't translate to Jinja2. Sadly, backwards-compatibility concerns don't see this changing anytime soon.
For me, the most annoying thing from using Jinja2 in Django is that you won't be able to use some Django apps when they come with their own templates or template tags (e.g. django-uni-forms).
This can be frustrating some times, when you find a great app that solves your problems but you can't use it because it's not compatible with Jinja2.
BTW, it seems that Armin Ronacher (the author of Jinja2) will be working on a new template engine backend that will sit behind both Jinja2 and Django, replacing the current infrastructure but preserving backwards-compatibility. https://www.djangoproject.com/weblog/2011/apr/25/gsoc/
re: the lack of {% spaceless %} in jinja2, check out the jinja2htmlcompress module:
# In shell:
fetch -o myapp/jinja2htmlcompress.py https://raw.github.com/mitsuhiko/jinja2-htmlcompress/master/jinja2htmlcompress.py
# In your app:
app = Flask(__name__, static_path='/static')
app.config.from_object('myapp.default_settings')
app.jinja_env.add_extension('myapp.jinja2htmlcompress.HTMLCompress')
As April 2015, Django 1.8 supports rendering templates with multiple engines within the same project, and has built-in support for Jinja2. So it doesn't have to be an all-or-nothing decision anymore.
(While this isn't directly answering the question, since this was previously the case I thought it merited more than just a comment).
I had some issues getting crispy-forms to work with Jinja2. There is a pretty easy way to solve this however.
django crispy forms with jinja2
I think in general downside will most likely be similar often used Django packages that just don't play with Jinja2
First, some background information... I'm coming up on a medium-scale website for a non-profit that will require both English and Korean translations. Feature-set includes: CMS for normal content, a blog, some form submission/handling (including CSV/PDF exports), a job posting board, a directory of related businesses and non-profits (that accepts visitor submissions), and a basic (probably blog-driven) newsroom.
I have a fairly strong development background, and I've done some sites using Drupal, built some basic custom CMSes using frameworks like CodeIgniter, and I've recently started getting into Django. These are the primary options that I am exploring, and I would consider using different tools for different portions of the project, but what I'm mainly interested in, is if anyone has any experience to share with regards to localization/internationalization. I haven't yet put together a site that supports multiple languages, so before I get in trouble by underestimating the task, or making poor assumptions, I'd like to get some input to help guide my decision-making process.
Do you have any recommendations for frameworks (Drupal, Django, CodeIgniter) that handle localization/internationalization/translation well for a CMS? I know they all support it, but I'm looking for real-world experience here (or suggestions for modules/plugins given explanations).
Sorry for the longwinded question, but I wanted to be clear as possible. Thanks in advance!
There is a distinction between "site" translation and content translation. Django handles the site translation great, out of the box. The content translation, however, requires making some decisions (there's no one right way at this point). This probably makes sense, because of the very nature of Django as a lower level framework (when compared to something like Drupal, which is intended to serve as a complete CMS).
There are applications for Django which are meant to add this functionality (in the form of translations configured at the model level):
Django-multilingual
Transmeta
Also, I found this question that is related.
The bottom line though, is that this is still being explored in the Django world, and neither approach has been decided upon for the framework. Also, although I haven't used it, Drupal has module support for this in the form of the i18n module.
I will update with more conclusions as I come to them. If you have anything to add about content translation in Django or in Drupal, feel free to add your own answer as well.
You probably already know that the native i18n support in django is quite good. As for translation, you might try the django-rosetta app which allows you to grant translation rights to a subset of users, who are then able to translate through an admin-like interface.
Zend_Translate is pretty comprehensive. And if you decide to use PHP, I suggest you take a look at it. It provides multiple interfaces (e.g. an Array, CSV, Gettext, etc.) to manage your translations, which makes it IMHO unmatched when it comes to PHP.
I'm not sure how well it plays with Drupal, since Drupal is hardly a framework but more a CMS -- or maybe a CMS framework. I'm pretty sure that Drupal either has a thing build in or that there is a plugin for it.
With CodeIgniter you would start from scratch and Zend_Translate plays well with it.
I liked Drupal over Joomla. You should also look into DotNetNuke, out of the box it has lot of things that will meet your needs.
Checkout django-blocks. Has multi-language Menu, Flatpages and even has a simple Shopping Cart!!