python django rest framework Serialization 的学习

创建一个新的app

python manage.py startapp snippets

修改settings文件

注意:使用Django <1.9，则需要用snippets替换snippets.apps.SnippetsConfig。

INSTALLED_APPS = (
...
'rest_framework',
'snippets.apps.SnippetsConfig',
)

创建一个模型对象

编辑snippets/models.py

from django.db import models
from pygments.lexers import get_all_lexers
from pygments.styles import get_all_styles

LEXERS = [item for item in get_all_lexers() if item[1]]
LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in LEXERS])
STYLE_CHOICES = sorted((item, item) for item in get_all_styles())

class Snippet(models.Model):
created = models.DateTimeField(auto_now_add=True)
title = models.CharField(max_length=100, blank=True, default='')
code = models.TextField()
linenos = models.BooleanField(default=False)
language = models.CharField(choices=LANGUAGE_CHOICES, default='python', max_length=100)
style = models.CharField(choices=STYLE_CHOICES, default='friendly', max_length=100)

class Meta:
ordering = ('created',)

同步数据库

python manage.py makemigrations snippets
python manage.py migrate

创建序列化类

编辑snippets/serializers.py(没有的话自行创建)

from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES

class SnippetSerializer(serializers.Serializer):
id = serializers.IntegerField(read_only=True)
title = serializers.CharField(required=False, allow_blank=True, max_length=100)
code = serializers.CharField(style={'base_template': 'textarea.html'})
linenos = serializers.BooleanField(required=False)
language = serializers.ChoiceField(choices=LANGUAGE_CHOICES, default='python')
style = serializers.ChoiceField(choices=STYLE_CHOICES, default='friendly')

def create(self, validated_data):
"""
Create and return a new `Snippet` instance, given the validated data.
"""
return Snippet.objects.create(**validated_data)

def update(self, instance, validated_data):
"""
Update and return an existing `Snippet` instance, given the validated data.
"""
instance.title = validated_data.get('title', instance.title)
instance.code = validated_data.get('code', instance.code)
instance.linenos = validated_data.get('linenos', instance.linenos)
instance.language = validated_data.get('language', instance.language)
instance.style = validated_data.get('style', instance.style)
instance.save()
return instance

使用序列化类

python manage.py shell

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser

snippet = Snippet(code='foo = "bar"\n')
snippet.save()

snippet = Snippet(code='print "hello, world"\n')
snippet.save()

serializer = SnippetSerializer(snippet)
serializer.data
# {'id': 2, 'title': u'', 'code': u'print "hello, world"\n', 'linenos': False,
# 'language': u'python', 'style': u'friendly'}

# 为了完成序列化过程，我们把数据转换成json。
content = JSONRenderer().render(serializer.data)
content
# '{"id": 2, "title": "", "code": "print \\"hello, world\\"\\n", "linenos":
# false, "language": "python", "style": "friendly"}'

# 反序列化
from django.utils.six import BytesIO

stream = BytesIO(content)
data = JSONParser().parse(stream)
serializer = SnippetSerializer(data=data)
serializer.is_valid()
# True
serializer.validated_data
# OrderedDict([('title', ''), ('code', 'print "hello, world"\n'), ('linenos',
# False), ('language', 'python'), ('style', 'friendly')])
serializer.save()
# <Snippet: Snippet object>

serializer = SnippetSerializer(Snippet.objects.all(), many=True)
serializer.data
# [OrderedDict([('id', 1), ('title', u''), ('code', u'foo = "bar"\n'),
# ('linenos', False), ('language', 'python'), ('style', 'friendly')]),
# OrderedDict([('id', 2), ('title', u''), ('code', u'print "hello, world"\n'),
# ('linenos', False), ('language', 'python'), ('style', 'friendly')]),
# OrderedDict([('id', 3), ('title', u''), ('code', u'print "hello, world"'),
# ('linenos', False), ('language', 'python'), ('style', 'friendly')])]

使用ModelSerializers

修改 serializers.py中的文件如下

class SnippetSerializer(serializers.ModelSerializer): # 需要注意一下这里不再是serializers.Serializer而是serializers.ModelSerializer
class Meta:
model = Snippet
fields = ('id', 'title', 'code', 'linenos', 'language', 'style')

使用我们的序列化程序编写常规的Django视图

编辑snippets/views.py

from django.http import HttpResponse, JsonResponse
from django.views.decorators.csrf import csrf_exempt
from rest_framework.renderers import JSONRenderer
from rest_framework.parsers import JSONParser
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer

@csrf_exempt
def snippet_list(request):
"""
List all code snippets, or create a new snippet.
"""
if request.method == 'GET':
snippets = Snippet.objects.all()
serializer = SnippetSerializer(snippets, many=True)
return JsonResponse(serializer.data, safe=False)

elif request.method == 'POST':
data = JSONParser().parse(request)
serializer = SnippetSerializer(data=data)
if serializer.is_valid():
serializer.save()
return JsonResponse(serializer.data, status=201)
return JsonResponse(serializer.errors, status=400)

@csrf_exempt
def snippet_detail(request, pk):
"""
Retrieve, update or delete a code snippet.
"""
try:
snippet = Snippet.objects.get(pk=pk)
except Snippet.DoesNotExist:
return HttpResponse(status=404)

if request.method == 'GET':
serializer = SnippetSerializer(snippet)
return JsonResponse(serializer.data)

elif request.method == 'PUT':
data = JSONParser().parse(request)
serializer = SnippetSerializer(snippet, data=data)
if serializer.is_valid():
serializer.save()
return JsonResponse(serializer.data)
return JsonResponse(serializer.errors, status=400)

elif request.method == 'DELETE':
snippet.delete()
return HttpResponse(status=204)

修改urls

编辑snippets/urls.py

urlpatterns = [
url(r'^snippets/$', views.snippet_list),
url(r'^snippets/(?P<pk>[0-9]+)/$', views.snippet_detail),
]

编辑tutorial/urls.py

from django.conf.urls import url, include

urlpatterns = [
url(r'^', include('snippets.urls')),
]

测试运行

退出 shell

启动项目

1.通过http访问,安装httpie

pip install httpie

访问

http http://127.0.0.1:8000/snippets/

结果