Django rest framework学习笔记1

参考
Django rest framework官网http://www.django-rest-framework.org/
httpie工具使用简介http://blog.csdn.net/pzw_0612/article/details/46521965

一.序列化

安装

pip install django
pip install djangorestframework
pip install pygments # We'll be using this for the code highlighting

Getting Started

django-admin startproject turorial   创建turorial项目
python manage.py snippets            创建snippets  APP

把APP snippets和rest_framework 添加到turorial/settings.py中的INSTALLED_APP

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

然后在turorial/urls.py中添加如下代码

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

Creating a model to work with

在app 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',)

然后创建数据库

python manage.py makemigrations snippets
python manage.py migrate

Create a Serializer class创建数列化类

在snippet文件夹中创建serializers.py， 此处继承的是Serializer类，非常像django中的form， 但是这里必须要实现一个create方法，update方法.
当然还有一种继承ModelSerializer的方法

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

class SnippetSerializer(serializers.Serializer): 
  pk = 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

Working with Serializers

在shell中测试上述序列化api

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

#Snippet数据库中创建两条数据
snippet = Snippet(code='foo = "bar"\n')
snippet.save()

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

#创建一个序列化的对象
serializer = SnippetSerializer(snippet)
serializer.data
>>>{'pk': 2, 'title': u'', 'code': u'print "hello, world"\n', 'linenos': False, 'language': u'python', 'style': u'friendly'}


#使用JSONRenderer().render(serializer.data)吧数据渲染成json数据
content = JSONRenderer().render(serializer.data)
content
>>>'{"pk": 2, "title": "", "code": "print \\"hello, world\\"\\n", "linenos": false, "language": "python", "style": "friendly"}'


#反序列化

#吧流数据转化成python数据
from django.utils.six import BytesIO

stream = BytesIO(content)
data = JSONParser().parse(stream)

#把数据转化成实例
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>

Using ModelSerializer

序列化中的modelserializerf非常像django form表单中涉及到的ModelForm， 上述继承serializers.Serializer的代码可以改成

class SnippetSerializer(serializers.ModelSerializer): 
  class Meta: 
    model = Snippet 
    fields = ('id', 'title', 'code', 'linenos', 'language', 'style')

非常简洁，优雅 有没有

Writing regular Django views using our Serializer

使用serializers

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

class JSONResponse(HttpResponse): 
""" An HttpResponse that renders its content into JSON. """ 
def __init__(self, data, **kwargs):
  content = JSONRenderer().render(data) 
  kwargs['content_type'] = 'application/json' 
  super(JSONResponse, self).__init__(content, **kwargs)

@csrf_exemptdef 
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) 
  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)

最后在snippets/urls.py中添加

from django.conf.urls import url
from snippets import views

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

使用httpie测试api

pip install httpie

http http://127.0.0.1:8000/snippets/
http http://127.0.0.1:8000/snippets/2/