Setting a baseline for your django projects
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This document discusses setting a baseline for Django projects by preventing repetitive code. It describes iterating on a book store project to add models, views, forms and authentication. It introduces the touchtechnology-public library which provides reusable model and form fields, widgets and mixins. It also addresses migrations by adding a SouthTripleMixin to custom fields to represent them as built-in fields for migrations.
Setting a baseline for your django projects
- 1. Setting a baseline for your Django projects Gary Reynolds Touch Technology @goodtune bitbucket.org/goodtune github.com/goodtune
- 2. DRY principle Django has loads of ways to prevent repetitive boilerplate ModelForm Class Based Views django.contrib.admin Then do I 鍖nd myself writing code like this?
- 3. from django import forms from .models import Book BOOLEAN_CHOICES = ((1, 'Yes'), (0, 'No')) class BookForm(forms.ModelForm): for_sale = forms.ChoiceField( choices=BOOLEAN_CHOICES) class Meta: model = Book
- 4. Iteration 0 Our example project is for a book store Books will need to have a title a published date are either for sale or not Well start with an empty project
- 5. Iteration 1 Add our Book model Add a front end view to output a list of books Register the model with django.contrib.admin Use south for schema migration
- 6. Iteration 2 Add the published date to the Book model Add a view to edit our Book items in the front end
- 7. Better Form Fields Default form 鍖elds for some model 鍖elds are a poor choice BooleanField as a checkbox DateField, TimeField, DateTimeField are all text 鍖elds Depending on your project, there will be others We can easily override these, build a library, and reuse across all our applications to suit our preferences
- 8. touchtechnology-public A backport of useful model & form 鍖elds, widgets, mixins, etc that have evolved over the past 5 years More coming soon, Ive kept it light for this talk Available to install from pypi, source is on bitbucket.org
- 9. Iteration 3 Change our model 鍖elds to implement our library Without a single custom form de鍖ned in our project, our form 鍖elds have now been 鍖avoured to our taste Add a view to create from the front end as well
- 10. Authentication Do we really want just anyone editing our books? from django.contrib.auth.decorators import login_required from django.http import HttpResponseRedirect from django.shortcuts import get_object_or_404 from django.template.response import TemplateResponse @login_required def book_edit(request, pk): book = get_object_or_404(Book, pk=pk) if request.method == 'POST': form = BookForm(data=request.POST, instance=book) if form.is_valid(): form.save() return HttpResponseRedirect('..') else: form = BookForm(instance=book) context = {'form': form, 'book': book} return TemplateResponse( request, 'example/book_form.html', context)
- 11. Iteration 4 Change our views to implement our library Without any other changes to our project, our views have now been protected from unauthenticated users
- 12. Migrations When you use simple inheritance of built-in Django model 鍖elds and South for migrations, you usually need to do some extra work for each 鍖eld http://south.readthedocs.org/en/latest/tutorial/ part4.html#simple-inheritance Oh no, thats more boilerplate!
- 13. SouthTripleMixin Add to your custom 鍖elds inheritance structure when you subclass a built-in Django 鍖eld Were just altering the way we markup our 鍖eld in forms, not its database internal representation Migrations will represent your 鍖eld as the built-in 鍖eld This code is stand alone, you can copy it into any project
- 14. Questions?
- 15. Sample project and touchtechnology-public can be obtained from bitbucket.org bitbucket.org/touchtechnology/public bitbucket.org/goodtune/sydjango-example This presentation can be downloaded from 際際滷Share slideshare.net/goodtune/setting-a-baseline-for-your- django-projects