Django REST framework(序列化)

時間  2019-11-30
標籤 django rest framework 序列 欄目 Python 简体版
原文   原文鏈接

準備工做html

 

一丶配置虛擬環境python

1.安裝虛擬包:pip install virtualenv linux

2.建立一個用於虛擬環境的目錄,並進入到目錄下shell

3.執行 python -m venv 虛擬環境名django

4.執行 virtualenv 虛擬環境名json

5.在目錄下激活虛擬環境  瀏覽器

windos下:source env\Scripts\activateapp

linux下:source env/bin/activate測試

6.中止虛擬環境 deactivate指令或者關閉終端ui

二丶用於代碼高亮顯示pip install pygments

 

開始

 

一丶建立一個項目

1.新建一個項目目錄,在目錄中建立一個Django項目

cd 項目目標目錄
django-admin.py startproject 項目名
cd 項目目錄下

2.建立一個Django應用

python manage.py startapp snippets

3.將rest_framework和新建的應用註冊到settings.py的INSTALLED_APPS中

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

 

二丶編輯模型層

1.編輯模型層文件

應用下的models.py文件

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',)

2.遷移數據

項目根目錄下
python manage.py makemigrations 應用名
python manage.py migrate

 

三丶序列化

1.應用下創建serializers.py文件

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

 

四丶使用序列化器

一丶序列化

1.進入python shell: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()

2.查看實例化的數據

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

3.轉換爲json數據

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

 

二丶反序列化

1.解析字符串爲python原生的數據類型

from django.utils.six import BytesIO

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

2.將原生數據類型變爲對象實例

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>

3.序列化querysets實例,將many=True參數加入序列化器

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')])]

 

五丶使用ModelSerializers

REST framework包括Serializer類和ModelSerializer類,這樣能夠使代碼更加的整潔.

ModelSerializer就像是Django的表單,不會有特別的功能可是是序列化的一個快捷方式.

1.找到應用下的serializers.py文件,替換代碼

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

2.查看序列化器的全部字段

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')...
#    style = ChoiceField(choices=[('autumn', 'autumn'), ('borland', 'borland'), ('bw', 'bw'), ('colorful', 'colorful')...

 

六丶編寫序列化試圖

1.編輯應用下的views.py文件

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

2.加入如下方法

@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)

3.上述代碼的升級版,用於增刪改查數據

@csrf_exempt #跨越csrf令牌,進行POST請求
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)

4.url設置

建立應用的urls.py文件
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), ]
項目的urls.py文件

from django.conf.urls import url, include

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

 

七丶測試Web API

1.運行Django服務:python manage.py runserver

2.安裝httpie:pip install httpie,這是一個http客戶端用python編寫對客戶很是友好

3.獲得全部的數據列表

http http://127.0.0.1:8000/snippets/

HTTP/1.1 200 OK
...
[
  {
    "id": 1,
    "title": "",
    "code": "foo = \"bar\"\n",
    "linenos": false,
    "language": "python",
    "style": "friendly"
  },
  {
    "id": 2,
    "title": "",
    "code": "print \"hello, world\"\n",
    "linenos": false,
    "language": "python",
    "style": "friendly"
  }
]

4.經過id獲得列表

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

HTTP/1.1 200 OK
...
{
  "id": 2,
  "title": "",
  "code": "print \"hello, world\"\n",
  "linenos": false,
  "language": "python",
  "style": "friendly"
}

5.也能夠經過瀏覽器來訪問Django項目　

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