序列化與反序列化例子

序列化與反序列化

把自定義的某個類 序列化 成基本類型 如 字段清單

建立虛拟環境
virtualenv env
source env/bin/activate


安裝django
pip install django
pip install djangorestframework
pip install pygments  # 我們将使用這個代碼突出顯示 高亮 highlighting


建立項目 和app

cd ~
django-admin.py startproject tutorial
cd tutorial

python manage.py startapp snippets





tutorial/settings.py

ALLOWED_HOSTS = ['10.8.152.31']


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'snippets',
    'rest_framework',
    'snippets.apps.SnippetsConfig',
]
           

建立一個用于存儲代碼片段的簡單代碼段模型
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',)
        
        
python manage.py makemigrations snippets
python manage.py migrate







snippets/serializers.py

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):
        """
        給定驗證後的資料，建立并傳回一個新的“片段”執行個體.
        """
        return Snippet.objects.create(**validated_data)

    def update(self, instance, validated_data):
        """
       在已驗證的情況下，更新并傳回現有的“片段”執行個體
        """
        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


           

python manage.py shell
序列化
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework.renderers import JSONRenderer json渲染器
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'}

轉為json資料 
content = JSONRenderer().render(serializer.data)
content 
# '{"id": 2, "title": "", "code": "print \\"hello, world\\"\\n", "linenos": false, "language": "python", "style": "friendly"}'

反序列化： 其他類型轉化為python基本類型
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


           

snippets/serializers.py   可以代替之前的内容
#使用下面代碼替換掉SnippetSerializer類
#序列化的對象 和字段
class SnippetSerializer(serializers.ModelSerializer):
    class Meta:
        model = Snippet
        fields = ('id', 'title', 'code', 'linenos', 'language', 'style')
        
        
 python manage.py shell

from snippets.serializers import SnippetSerializer
serializer = SnippetSerializer()
print(repr(serializer))
# 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)
#    language = ChoiceField(choices=[('Clipper', 'FoxPro'), ('Cucumber', 'Gherkin'), ('RobotFramework', 'RobotFramework'), ('abap', 'ABAP'), ('ada', 'Ada')




snippets/views.py


from django.http import HttpResponse, JsonResponse
from django.views.decorators.csrf import csrf_exempt 取消身份驗證的作用局部取消csrf認證
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):
    """
    列出所有代碼段，或者建立一個新的代碼段
    """
    if request.method == 'GET':
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)  結果序列化
        return JsonResponse(serializer.data, safe=False)
           #JsonResponse     把類似字典的資料轉化為json資料
    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):
    """
   檢索、更新或删除代碼段。
    """
    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)
           

snippets/urls.py


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),
]



tutorial/urls.py
from django.conf.urls import url,include
from django.contrib import admin

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

python manage.py makemigrations  
python manage.py migrate
python manage.py createsuperuser

pip install httpie
測試 python manage.py runserver 0.0.0.0:8888
http http://10.8.152.31:8888/snippets/2/
http http://10.8.152.31:8888/snippets/