2013-11-17 22:26:41 +04:00
<!DOCTYPE html>
< html lang = "en" >
< head > < meta http-equiv = "Content-Type" content = "text/html; charset=UTF-8" >
< meta charset = "utf-8" >
2013-12-23 16:37:56 +04:00
< title > Tutorial 3: Class Based Views - Django REST framework< / title >
2014-08-02 18:29:15 +04:00
< link href = "http://www.django-rest-framework.org/img/favicon.ico" rel = "icon" type = "image/x-icon" >
< link rel = "canonical" href = "http://www.django-rest-framework.org/tutorial/3-class-based-views" / >
2013-11-17 22:26:41 +04:00
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< meta name = "description" content = "Django, API, REST, Tutorial 3: Class Based Views" >
< meta name = "author" content = "Tom Christie" >
<!-- Le styles -->
2014-08-02 18:29:15 +04:00
< link href = "http://www.django-rest-framework.org/css/prettify.css" rel = "stylesheet" >
< link href = "http://www.django-rest-framework.org/css/bootstrap.css" rel = "stylesheet" >
< link href = "http://www.django-rest-framework.org/css/bootstrap-responsive.css" rel = "stylesheet" >
< link href = "http://www.django-rest-framework.org/css/default.css" rel = "stylesheet" >
2013-11-17 22:26:41 +04:00
<!-- Le HTML5 shim, for IE6 - 8 support of HTML5 elements -->
<!-- [if lt IE 9]>
< script src = "http://html5shim.googlecode.com/svn/trunk/html5.js" > < / script >
<![endif]-->
< script type = "text/javascript" >
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-18852272-2']);
_gaq.push(['_trackPageview']);
(function() {
var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
})();
< / script >
2014-07-15 18:02:49 +04:00
< style >
span.fusion-wrap a {
display: block;
margin-top: 10px;
color: black;
}
a.fusion-poweredby {
display: block;
margin-top: 10px;
}
@media (max-width: 767px) {
div.promo {display: none;}
}
< / style >
2013-11-17 22:26:41 +04:00
< / head >
< body onload = "prettyPrint()" class = "3-class-based-views-page" >
< div class = "wrapper" >
< div class = "navbar navbar-inverse navbar-fixed-top" >
< div class = "navbar-inner" >
< div class = "container-fluid" >
< a class = "repo-link btn btn-primary btn-small" href = "https://github.com/tomchristie/django-rest-framework/tree/master" > GitHub< / a >
2014-08-02 18:29:15 +04:00
< a class = "repo-link btn btn-inverse btn-small " href = "../tutorial/4-authentication-and-permissions" > Next < i class = "icon-arrow-right icon-white" > < / i > < / a >
< a class = "repo-link btn btn-inverse btn-small " href = "../tutorial/2-requests-and-responses" > < i class = "icon-arrow-left icon-white" > < / i > Previous< / a >
2013-11-17 22:26:41 +04:00
< a class = "repo-link btn btn-inverse btn-small" href = "#searchModal" data-toggle = "modal" > < i class = "icon-search icon-white" > < / i > Search< / a >
< a class = "btn btn-navbar" data-toggle = "collapse" data-target = ".nav-collapse" >
< span class = "icon-bar" > < / span >
< span class = "icon-bar" > < / span >
< span class = "icon-bar" > < / span >
< / a >
2014-08-02 18:29:15 +04:00
< a class = "brand" href = "http://www.django-rest-framework.org" > Django REST framework< / a >
2013-11-17 22:26:41 +04:00
< div class = "nav-collapse collapse" >
< ul class = "nav" >
2014-08-02 18:29:15 +04:00
< li > < a href = "http://www.django-rest-framework.org" > Home< / a > < / li >
2013-11-17 22:26:41 +04:00
< li class = "dropdown" >
< a href = "#" class = "dropdown-toggle" data-toggle = "dropdown" > Tutorial < b class = "caret" > < / b > < / a >
< ul class = "dropdown-menu" >
2014-08-02 18:29:15 +04:00
< li > < a href = "http://www.django-rest-framework.org/tutorial/quickstart" > Quickstart< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/1-serialization" > 1 - Serialization< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/2-requests-and-responses" > 2 - Requests and responses< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/3-class-based-views" > 3 - Class based views< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/4-authentication-and-permissions" > 4 - Authentication and permissions< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/5-relationships-and-hyperlinked-apis" > 5 - Relationships and hyperlinked APIs< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/tutorial/6-viewsets-and-routers" > 6 - Viewsets and routers< / a > < / li >
2013-11-17 22:26:41 +04:00
< / ul >
< / li >
< li class = "dropdown" >
< a href = "#" class = "dropdown-toggle" data-toggle = "dropdown" > API Guide < b class = "caret" > < / b > < / a >
< ul class = "dropdown-menu" >
2014-08-02 18:29:15 +04:00
< li > < a href = "http://www.django-rest-framework.org/api-guide/requests" > Requests< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/responses" > Responses< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/views" > Views< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/generic-views" > Generic views< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/viewsets" > Viewsets< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/routers" > Routers< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/parsers" > Parsers< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/renderers" > Renderers< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/serializers" > Serializers< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/fields" > Serializer fields< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/relations" > Serializer relations< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/authentication" > Authentication< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/permissions" > Permissions< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/throttling" > Throttling< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/filtering" > Filtering< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/pagination" > Pagination< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/content-negotiation" > Content negotiation< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/format-suffixes" > Format suffixes< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/reverse" > Returning URLs< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/exceptions" > Exceptions< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/status-codes" > Status codes< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/testing" > Testing< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/api-guide/settings" > Settings< / a > < / li >
2013-11-17 22:26:41 +04:00
< / ul >
< / li >
< li class = "dropdown" >
< a href = "#" class = "dropdown-toggle" data-toggle = "dropdown" > Topics < b class = "caret" > < / b > < / a >
< ul class = "dropdown-menu" >
2014-08-02 18:29:15 +04:00
< li > < a href = "http://www.django-rest-framework.org/topics/documenting-your-api" > Documenting your API< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/ajax-csrf-cors" > AJAX, CSRF & CORS< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/browser-enhancements" > Browser enhancements< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/browsable-api" > The Browsable API< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/rest-hypermedia-hateoas" > REST, Hypermedia & HATEOAS< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/contributing" > Contributing to REST framework< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/rest-framework-2-announcement" > 2.0 Announcement< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/2.2-announcement" > 2.2 Announcement< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/2.3-announcement" > 2.3 Announcement< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/kickstarter-announcement" > Kickstarter Announcement< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/release-notes" > Release Notes< / a > < / li >
< li > < a href = "http://www.django-rest-framework.org/topics/credits" > Credits< / a > < / li >
2013-11-17 22:26:41 +04:00
< / ul >
< / li >
< / ul >
< ul class = "nav pull-right" >
<!-- TODO
< li class = "dropdown" >
< a href = "#" class = "dropdown-toggle" data-toggle = "dropdown" > Version: 2.0.0 < b class = "caret" > < / b > < / a >
< ul class = "dropdown-menu" >
< li > < a href = "#" > Trunk< / a > < / li >
< li > < a href = "#" > 2.0.0< / a > < / li >
< / ul >
< / li >
-->
< / ul >
< / div > <!-- /.nav - collapse -->
< / div >
< / div >
< / div >
< div class = "body-content" >
< div class = "container-fluid" >
<!-- Search Modal -->
< div id = "searchModal" class = "modal hide fade" tabindex = "-1" role = "dialog" aria-labelledby = "myModalLabel" aria-hidden = "true" >
< div class = "modal-header" >
< button type = "button" class = "close" data-dismiss = "modal" aria-hidden = "true" > × < / button >
< h3 id = "myModalLabel" > Documentation search< / h3 >
< / div >
< div class = "modal-body" >
<!-- Custom google search -->
< script >
(function() {
var cx = '015016005043623903336:rxraeohqk6w';
var gcse = document.createElement('script');
gcse.type = 'text/javascript';
gcse.async = true;
gcse.src = (document.location.protocol == 'https:' ? 'https:' : 'http:') +
'//www.google.com/cse/cse.js?cx=' + cx;
var s = document.getElementsByTagName('script')[0];
s.parentNode.insertBefore(gcse, s);
})();
< / script >
< gcse:search > < / gcse:search >
< / div >
< div class = "modal-footer" >
< button class = "btn" data-dismiss = "modal" aria-hidden = "true" > Close< / button >
< / div >
< / div >
< div class = "row-fluid" >
< div class = "span3" >
<!-- TODO
< p style = "margin-top: -12px" >
< a class = "btn btn-mini btn-primary" style = "width: 60px" > « previous< / a >
< a class = "btn btn-mini btn-primary" style = "float: right; margin-right: 8px; width: 60px;" > next » < / a >
< / p >
-->
< div id = "table-of-contents" >
< ul class = "nav nav-list side-nav well sidebar-nav-fixed" >
< li class = "main" > < a href = "#tutorial-3-class-based-views" > Tutorial 3: Class Based Views< / a > < / li >
< li > < a href = "#rewriting-our-api-using-class-based-views" > Rewriting our API using class based views< / a > < / li >
< li > < a href = "#using-mixins" > Using mixins< / a > < / li >
< li > < a href = "#using-generic-class-based-views" > Using generic class based views< / a > < / li >
2014-07-15 18:02:49 +04:00
< div class = "promo" >
< / div >
2014-01-03 17:26:35 +04:00
< / ul >
2013-11-17 22:26:41 +04:00
< / div >
< / div >
< div id = "main-content" class = "span9" >
< h1 id = "tutorial-3-class-based-views" > Tutorial 3: Class Based Views< / h1 >
< p > We can also write our API views using class based views, rather than function based views. As we'll see this is a powerful pattern that allows us to reuse common functionality, and helps us keep our code < a href = "http://en.wikipedia.org/wiki/Don't_repeat_yourself" > DRY< / a > .< / p >
< h2 id = "rewriting-our-api-using-class-based-views" > Rewriting our API using class based views< / h2 >
< p > We'll start by rewriting the root view as a class based view. All this involves is a little bit of refactoring of < code > views.py< / code > .< / p >
< pre class = "prettyprint lang-py" > < code > from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from django.http import Http404
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status
class SnippetList(APIView):
"""
List all snippets, or create a new snippet.
"""
def get(self, request, format=None):
snippets = Snippet.objects.all()
serializer = SnippetSerializer(snippets, many=True)
return Response(serializer.data)
def post(self, request, format=None):
serializer = SnippetSerializer(data=request.DATA)
if serializer.is_valid():
serializer.save()
return Response(serializer.data, status=status.HTTP_201_CREATED)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
< / code > < / pre >
< p > So far, so good. It looks pretty similar to the previous case, but we've got better separation between the different HTTP methods. We'll also need to update the instance view in < code > views.py< / code > . < / p >
< pre class = "prettyprint lang-py" > < code > class SnippetDetail(APIView):
"""
Retrieve, update or delete a snippet instance.
"""
def get_object(self, pk):
try:
return Snippet.objects.get(pk=pk)
except Snippet.DoesNotExist:
raise Http404
def get(self, request, pk, format=None):
snippet = self.get_object(pk)
serializer = SnippetSerializer(snippet)
return Response(serializer.data)
def put(self, request, pk, format=None):
snippet = self.get_object(pk)
serializer = SnippetSerializer(snippet, data=request.DATA)
if serializer.is_valid():
serializer.save()
return Response(serializer.data)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
def delete(self, request, pk, format=None):
snippet = self.get_object(pk)
snippet.delete()
return Response(status=status.HTTP_204_NO_CONTENT)
< / code > < / pre >
< p > That's looking good. Again, it's still pretty similar to the function based view right now.< / p >
< p > We'll also need to refactor our < code > urls.py< / code > slightly now we're using class based views.< / p >
< pre class = "prettyprint lang-py" > < code > from django.conf.urls import patterns, url
from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views
urlpatterns = patterns('',
url(r'^snippets/$', views.SnippetList.as_view()),
url(r'^snippets/(?P< pk> [0-9]+)/$', views.SnippetDetail.as_view()),
)
urlpatterns = format_suffix_patterns(urlpatterns)
< / code > < / pre >
< p > Okay, we're done. If you run the development server everything should be working just as before.< / p >
< h2 id = "using-mixins" > Using mixins< / h2 >
< p > One of the big wins of using class based views is that it allows us to easily compose reusable bits of behaviour.< / p >
< p > The create/retrieve/update/delete operations that we've been using so far are going to be pretty similar for any model-backed API views we create. Those bits of common behaviour are implemented in REST framework's mixin classes.< / p >
< p > Let's take a look at how we can compose the views by using the mixin classes. Here's our < code > views.py< / code > module again.< / p >
< pre class = "prettyprint lang-py" > < code > from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import mixins
from rest_framework import generics
class SnippetList(mixins.ListModelMixin,
mixins.CreateModelMixin,
generics.GenericAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer
def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)
def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
< / code > < / pre >
< p > We'll take a moment to examine exactly what's happening here. We're building our view using < code > GenericAPIView< / code > , and adding in < code > ListModelMixin< / code > and < code > CreateModelMixin< / code > .< / p >
< p > The base class provides the core functionality, and the mixin classes provide the < code > .list()< / code > and < code > .create()< / code > actions. We're then explicitly binding the < code > get< / code > and < code > post< / code > methods to the appropriate actions. Simple enough stuff so far.< / p >
< pre class = "prettyprint lang-py" > < code > class SnippetDetail(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
generics.GenericAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer
def get(self, request, *args, **kwargs):
return self.retrieve(request, *args, **kwargs)
def put(self, request, *args, **kwargs):
return self.update(request, *args, **kwargs)
def delete(self, request, *args, **kwargs):
return self.destroy(request, *args, **kwargs)
< / code > < / pre >
< p > Pretty similar. Again we're using the < code > GenericAPIView< / code > class to provide the core functionality, and adding in mixins to provide the < code > .retrieve()< / code > , < code > .update()< / code > and < code > .destroy()< / code > actions.< / p >
< h2 id = "using-generic-class-based-views" > Using generic class based views< / h2 >
< p > Using the mixin classes we've rewritten the views to use slightly less code than before, but we can go one step further. REST framework provides a set of already mixed-in generic views that we can use to trim down our < code > views.py< / code > module even more.< / p >
< pre class = "prettyprint lang-py" > < code > from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import generics
class SnippetList(generics.ListCreateAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer
class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer
< / code > < / pre >
< p > Wow, that's pretty concise. We've gotten a huge amount for free, and our code looks like good, clean, idiomatic Django.< / p >
2014-08-02 18:29:15 +04:00
< p > Next we'll move onto < a href = "4-authentication-and-permissions" > part 4 of the tutorial< / a > , where we'll take a look at how we can deal with authentication and permissions for our API.< / p >
2013-11-17 22:26:41 +04:00
< / div > <!-- /span -->
< / div > <!-- /row -->
< / div > <!-- /.fluid - container -->
< / div > <!-- /.body content -->
< div id = "push" > < / div >
< / div > <!-- /.wrapper -->
< footer class = "span12" >
< p > Sponsored by < a href = "http://dabapps.com/" > DabApps< / a > .< / a > < / p >
< / footer >
<!-- Le javascript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
2014-08-02 18:29:15 +04:00
< script src = "http://www.django-rest-framework.org/js/jquery-1.8.1-min.js" > < / script >
< script src = "http://www.django-rest-framework.org/js/prettify-1.0.js" > < / script >
< script src = "http://www.django-rest-framework.org/js/bootstrap-2.1.1-min.js" > < / script >
2014-07-15 18:02:49 +04:00
2013-11-17 22:26:41 +04:00
< script >
//$('.side-nav').scrollspy()
var shiftWindow = function() { scrollBy(0, -50) };
if (location.hash) shiftWindow();
window.addEventListener("hashchange", shiftWindow);
$('.dropdown-menu').on('click touchstart', function(event) {
event.stopPropagation();
});
// Dynamically force sidenav to no higher than browser window
$('.side-nav').css('max-height', window.innerHeight - 130);
$(function(){
$(window).resize(function(){
$('.side-nav').css('max-height', window.innerHeight - 130);
});
});
< / script >
< / body > < / html >
