Django-rest-framework学习(-)Serialization
2016-03-30 16:45
585 查看
Django-rest-framework学习(-)Serialization
标签(空格分隔): 互联网 API DjangoDjango-rest-framework学习Serialization
前提
虚拟环境搭建
安装相应的一些包
正式开始
创建模型
创建serializer类
反序列化
使用内置的模型序列类ModelSerializers
使用serializer与views结合
总结
前提
Python (2.7, 3.2, 3.3, 3.4, 3.5)Django (1.7+, 1.8, 1.9)
虚拟环境搭建
pip install virtualenv virtualenv frankstar //会在当前目录下创建一个目录 即改虚拟环境里所需要的一些资源都会在这个目录下 cd frankstar source ./bin/activate //进入虚拟环境 deactivate // 退出虚拟环境 (frankstar) ➜ frankstar
安装相应的一些包
(1)可以将一些你觉得合适的包放在一个文件中,使用 pip install -r <filename> 统一安装 例: requirements.txt django == 1.8.0 djangorestframework pygments mysql-python == 1.2.5 (2)当然也可以选择想起一个安装一个这样的方式
正式开始
django-admin.py startproject tutorial cd tutorial python manage.py startapp snippets
我们需要将我们的应用snippets和rest-framework 加入到自带的配置文件中INSTALLED_APPS 如下:
INSTALLED_APPS = ( 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'snippets.apps.SnippetsConfig', 'rest_framework', )
顺便将数据库的配置也添加进去, 如下:
DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'tutorial', 'USER': 'root', 'PASSWORD': '', 'HOST': '127.0.0.1', 'PORT': '3306', } }
创建模型
# coding:utf-8 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): """docstring for Snippet""" # 定义该模型的字段及相应的类型 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',)
执行以下命令:
python manage.py makemigrations snippets //创建模型snippets python manage.py migrate //将模型转化为数据库表存到数据库中
创建serializer类
在提供web API时,我们常常需要将我们的实例对象转换为相应的数据格式,序列化或者反序列化。Django框架中其实带有了这个功能的库,我们先手试着动创建一个这样的类。
在snippets文件夹下创建一个文件serializers.py,其中定义如下:
#coding:utf-8 from rest_framework import serializers from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES class SnippetSerializer(serializers.Serializer): """docstring for SnippetSerializer""" 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): ''' 通过给定的有效数据创建并返回一个Snippet对象 ''' return Snippet.objects.create(**validated_data) def update(self, instance, validated_data): ''' 通过给定的有效数据更新并返回一个Snippet对象 ''' 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
打开Django的shell,试着创建几个Snippet实例
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()
接着调用为这个类创建的序列化类SnippetSerializer,输出json对象
serializer = SnippetSerializer(snippet) serializer.data #output: {'style': 'friendly', 'code': u'print "hello,world"\n', 'language': 'python', 'title': u'', 'linenos': False, 'pk': 2} content = JSONRenderer().render(serializer.data) content #output: '{"pk":2,"title":"","code":"print \\"hello,world\\"\\n","linenos":false,"language":"python","style":"friendly"}'
反序列化
反序列化也是类似的处理,紧接着上述的步骤,还是在Django shell中处理
from django.utils.six import BytesIO stream = BytesIO(content) data = JSONParser.parse(stream) serializer = SnippetSerializer(data=data) serializer.is_valid() //判断是否是有效的json对象 #output: True serializer.validate_data #output: OrderedDict([(u'title', u''), (u'code', u'print "hello,world"'), (u'linenos', False), (u'language', 'python'), (u'style', 'friendly')]) serializer.save() #output: <Snippet: Snippet object>
我们可以同时处理多个Snippet实例,只需要在它的构造方法中加入many=True这个参数即可,如下:
serializer = SnippetSerializer(Snippet.objects.all(), many=True) serializer.data #output: [OrderedDict([('pk', 1), ('title', u''), ('code', u'foo = "bar"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')]), OrderedDict([('pk', 2), ('title', u''), ('code', u'print "hello,world"\n'), ('linenos', False), ('language', 'python'), ('style', 'friendly')]), OrderedDict([('pk', 3), ('title', u''), ('code', u'print "hello,world"'), ('linenos', False), ('language', 'python'), ('style', 'friendly')])]
使用内置的模型序列类ModelSerializers
打开serializer.py,找到SnippetSerializer类定义的地方(create()与update()方法暂时不需要改动),改成如下代码:
class SnippetSerializer(serializers.ModelSerializer): """docstring for SnippetSerializer""" # 此处添加你所需要序列化元类的模型和相应的字段 class Meta: model = Snippet fields = ('id', 'title', 'code', 'linenos', 'language', 'style')
打开django manage.py shell输入以下命令
from snippets.serializers import SnippetSerializer serializer = SnippetSerializer() print(repr(serializer)) #output: SnippetSerializer(): id = IntegerField(label='ID', read_only=True) title = CharField(allow_blank=True, max_length=100, required=False) code = CharField(style={'base_template': 'textarea.html'}) linenos = BooleanField(required=False) ...
使用serializer与views结合
首先在snippets文件下新建一个文件views.py,创建如下代码:
#coding:utf-8 from django.shortcuts import render from django.views.decorators.csrf import csrf_exempt from django.http import HttpResponse from rest_framework.renderers import JSONRenderer from rest_framework.parsers import JSONParser from snippets.models import Snippet from snippets.serializers import SnippetSerializer # Create your views here. class JSONResponse(HttpResponse): """docstring for JSONRenderer""" ''' 将HttpResponse对象相应的内容转化为json ''' def __init__(self, data, **kwargs): content = JSONRenderer().render(data) kwargs['content_type'] = 'application/json' super(JSONResponse, self).__init__(content, **kwargs) @csrf_exempt def snippet_list(request): ''' 显示所有的snippets的对象,或者创建一个新的对象 ''' if request.method == 'GET': snippets = Snippet.objects.all() serializers = SnippetSerializer(snippets, many=True) return JSONResponse(serializers.data) elif request.method == 'POST': data = JSONParser().parse(request) serializers = SnippetSerializer(data=data) if serializers.is_valid(): serializers.save() return JSONResponse(serializers.data, status=201) return JSONResponse(serializers.errors, status=400) @csrf_exempt def snippet_detail(request, pk): ''' 查找、更新或者删除一个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)
然后在该文件夹(snippets)下再添加一个文件urls.py,部署访问路由:
#coding:utf-8 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), ]
最后再将改路由文件添加到总路由文件中,如下:
from django.conf.urls import include, url from django.contrib import admin urlpatterns = [ # Examples: # url(r'^$', 'tutorial.views.home', name='home'), # url(r'^blog/', include('blog.urls')), url(r'^admin/', include(admin.site.urls)), url(r'^', include('snippets.urls')), #将其包含进来即可 ]
打开命令行,输入python manage.py runserver,浏览器中输入:http://127.0.0.1:8000/snippets/, 输出如下:
[ { id: 1, title: "", code: "foo = "bar" ", linenos: false, language: "python", style: "friendly" }, { id: 2, title: "", code: "print "hello,world" ", linenos: false, language: "python", style: "friendly" }, { id: 3, title: "", code: "print "hello,world"", linenos: false, language: "python", style: "friendly" } ]
输入某个具体的ID,还可以显示某条具体的内容如:http://127.0.0.1:8000/snippets/2/,输出如下:
{ id: 2, title: "", code: "print "hello,world" ", linenos: false, language: "python", style: "friendly" }
总结
这个案例可以从官网上找到,这只是其中一个部分,算是开个头,后续的会不定期的补上,可能细心的人会发现在snippet_list和snippet_detail接口定义中,会有PUT,DELETE,GET,POST等Http方法,但是相应路由只有相应的一条记录,这其中涉及到restful-api的一些知识。虽是同一条路由,但是调用的Http方法不同,相应自然不会相同。相关文章推荐
- mongotemplate做插入时怎样去掉多余字段
- 【干货】Go语言开发常见陷阱,你遇到过几个?
- Django REST 异常处理
- Google带WiFi的热气球或首次商用
- Google带WiFi的热气球或首次商用
- Go net包介绍
- Django Models的数据类型 汇总
- Google推荐的图片加载库Glide介绍
- 百度地图缩放、比例尺、logo操作
- mongostat
- CodeForces - 368C Sereja and Algorithm (找规律&模拟)
- Django1.8静态文件配置
- Go语言学习五:数组与传递到函数的数组
- go on
- GoAhead 2.1.8嵌入式webserver源码分析学习(二)---源码文件结构分析
- Django orm总结
- 使用google map v3添加经纬度信息
- 20160329 -- for/while/do while/goto/ 递归
- 利用 Google API 调用谷歌地图 演示1
- google多语言通信框架gRPC