Django-DRF(ModelViewSet)及自定义函数的使用

rest_framework中Serialization、 ModelViewSet学习

1.环境搭建

为了区分之前内容，新建应用snippets，独立操作。

python manage.py startapp snippets

1.1 model准备

准备了一格5列的数据表

from django.db import models

# Create your models here.
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']

1. 2数据库准备

当然installed_apps种需要加应用名snippets

python manage.py startapp snippets
python manage.py makemigrations snippets
python manage.py migrate snippets

2.组装

2.1序列化

依葫芦画瓢，调用serializers接口初始化。

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

2.2 views设置

• 列表函数
• 细节展示函数

from django.shortcuts import render

# Create your views here.
from django.http import HttpResponse, JsonResponse
from django.views.decorators.csrf import csrf_exempt
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)

2.3 添加urls

可以单独在应用下加urls，然后再引用到project的总urls里，这样层次比较清晰。

from django.urls import path
from snippets import views

urlpatterns = [
    path('snippets/', views.snippet_list),
    path('snippets/<int:pk>/', views.snippet_detail),
]

from django.contrib import admin
from django.urls import path
from app01.views import *
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    # path('filtergoodscategory/', FilterGoodsCategory),
    # path('insertgoodscategory/', InsertGoodsCategory),
    path("filetgoodscategoryapi/", FilterGoodsCategoryAPI.as_view()),
    # path("insertgoodscategory/", InsertGoodsCategory),
    path('getgoods/', GetGoods.as_view()),
    path('', include('snippets.urls')),
]

2.4 shell调试

python manage.py shell
#进入后可以进行数据增删改查
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
content = JSONRenderer().render(serializer.data)
content

import io

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

serializer = SnippetSerializer(data=data)
serializer.is_valid()

serializer = SnippetSerializer(Snippet.objects.all(), many=True)
serializer.data

2.5 http调试

那个postman登录有时候半天登陆不上去（QTMD外网），用httpie很方便

pip install httpie
http http://127.0.0.1:8000/snippets/

(py10) PS D:\work> http http://127.0.0.1:8000/snippets/2/
HTTP/1.1 200 OK
Content-Length: 120
Content-Type: application/json
Cross-Origin-Opener-Policy: same-origin
Date: Sun, 22 Oct 2023 01:54:38 GMT
Referrer-Policy: same-origin
Server: WSGIServer/0.2 CPython/3.10.12
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

{
    "code": "print(\"hello, world\")\n",
    "id": 2,
    "language": "python",
    "linenos": false,
    "style": "friendly",
    "title": ""
}

(py10) PS D:\work> http http://127.0.0.1:8000/snippets/
HTTP/1.1 200 OK
Content-Length: 234
Content-Type: application/json
Cross-Origin-Opener-Policy: same-origin
Date: Sun, 22 Oct 2023 02:12:34 GMT
Referrer-Policy: same-origin
Server: WSGIServer/0.2 CPython/3.10.12
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

[
    {
        "code": "foo = \"bar\"\n",
        "id": 1,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
    {
        "code": "print(\"hello, world\")\n",
        "id": 2,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    }
]

3. requests-responses

3.1新建views_new.py

from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


@api_view(['GET', 'POST'])
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 Response(serializer.data)

    elif request.method == 'POST':
        serializer = SnippetSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)



@api_view(['GET', 'PUT', 'DELETE'])
def snippet_detail(request, pk):
    """
    Retrieve, update or delete a code snippet.
    """
    try:
        snippet = Snippet.objects.get(pk=pk)
    except Snippet.DoesNotExist:
        return Response(status=status.HTTP_404_NOT_FOUND)

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

    elif request.method == 'PUT':
        serializer = SnippetSerializer(snippet, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    elif request.method == 'DELETE':
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

3.2 urls.py

from django.urls import path
from snippets import views_new

urlpatterns = [
    path('snippets/', views_new.snippet_list),
    path('snippets/<int:pk>/', views_new.snippet_detail),
]

3.3 调试

(py10) PS D:\work> http http://127.0.0.1:8000/snippets/ Accept:application/json
HTTP/1.1 200 OK
Allow: POST, GET, OPTIONS
Content-Length: 211
Content-Type: application/json
Cross-Origin-Opener-Policy: same-origin
Date: Sun, 22 Oct 2023 02:38:07 GMT
Referrer-Policy: same-origin
Server: WSGIServer/0.2 CPython/3.10.12
Vary: Accept, Cookie
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

[
    {
        "code": "foo = \"bar\"\n",
        "id": 1,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    },
    {
        "code": "print(\"hello, world\")\n",
        "id": 2,
        "language": "python",
        "linenos": false,
        "style": "friendly",
        "title": ""
    }
]

或者http http://127.0.0.1:8000/snippets/ Accept:text/html

或者

http http://127.0.0.1:8000/snippets.json  # JSON suffix
http http://127.0.0.1:8000/snippets.api   # Browsable API suffix

4.class-based views

好处是代码很干，没水份，多余的都给框架弄了。

4.1创建views_new_classbased.py

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from django.http import Http404
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status
class SnippetList(APIView):
    """
    List all snippets, or create a new snippet.
    """
    def get(self, request, format=None):
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        serializer = SnippetSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

class SnippetDetail(APIView):
    """
    Retrieve, update or delete a snippet instance.
    """
    def get_object(self, pk):
        try:
            return Snippet.objects.get(pk=pk)
        except Snippet.DoesNotExist:
            raise Http404

    def get(self, request, pk, format=None):
        snippet = self.get_object(pk)
        serializer = SnippetSerializer(snippet)
        return Response(serializer.data)

    def put(self, request, pk, format=None):
        snippet = self.get_object(pk)
        serializer = SnippetSerializer(snippet, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def delete(self, request, pk, format=None):
        snippet = self.get_object(pk)
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

4.2 修改urls.py

from django.urls import path
from snippets import views_new_classbased

from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views_new_classbased

urlpatterns = [
    path('snippets/', views_new_classbased.SnippetList.as_view()),
    path('snippets/<int:pk>/', views_new_classbased.SnippetDetail.as_view()),
]
urlpatterns = format_suffix_patterns(urlpatterns)

4.3 使用mixins

views简化了

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import mixins
from rest_framework import generics


class SnippetList(mixins.ListModelMixin,
                  mixins.CreateModelMixin,
                  generics.GenericAPIView):
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer

    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)


class SnippetDetail(mixins.RetrieveModelMixin,
                    mixins.UpdateModelMixin,
                    mixins.DestroyModelMixin,
                    generics.GenericAPIView):
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer

    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):
        return self.update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):
        return self.destroy(request, *args, **kwargs)

urls.py

from django.urls import path
from snippets import views_new_classbased

from rest_framework.urlpatterns import format_suffix_patterns
# from snippets import views_new_classbased
from snippets import views_mixins

urlpatterns = [
    path('snippets/', views_mixins.SnippetList.as_view()),
    path('snippets/<int:pk>/', views_mixins.SnippetDetail.as_view()),
]
urlpatterns = format_suffix_patterns(urlpatterns)

结果并无区别

知识点	请求	url	特点
GenericViewSet			提供一组通用的视图方法，方便实现特定功能
ListModelMixin	get	127.0.0.1:8000/book/	提供 list 方法，用于获取资源列表
RetrieveModelMixin	get	127.0.0.1:8000/book/{1}/	提供 retrieve 方法，用于获取单个资源的详细信息
CreateModelMixin	post	127.0.0.1:8000/book/	提供 create 方法，用于创建资源
UpdateModelMixin	put	127.0.0.1:8000/book/{1}/	提供 update 方法，用于更新资源
DestroyModelMixin	detete	127.0.0.1:8000/book/{1}/	提供 destroy 方法，用于删除资源
自定义	get/post	127.0.0.1:8000/book/自定义	用户自定义方法/函数

5. 鉴权

5.1 model.py

from django.db import models

# Create your models here.
from django.db import models
from pygments.lexers import get_all_lexers
from pygments.styles import get_all_styles
from pygments.lexers import get_lexer_by_name
from pygments.formatters.html import HtmlFormatter
from pygments import highlight

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)
    owner = models.ForeignKey('auth.User', related_name='snippets', on_delete=models.CASCADE)
    highlighted = models.TextField()

    class Meta:
        ordering = ['created']


def save(self, *args, **kwargs):
    """
    Use the `pygments` library to create a highlighted HTML
    representation of the code snippet.
    """
    lexer = get_lexer_by_name(self.language)
    linenos = 'table' if self.linenos else False
    options = {'title': self.title} if self.title else {}
    formatter = HtmlFormatter(style=self.style, linenos=linenos,
                              full=True, **options)
    self.highlighted = highlight(self.code, lexer, formatter)
    super().save(*args, **kwargs)

5.2 数据库生成

del -f db.sqlite3
rmdir -r snippets/migrations
python manage.py makemigrations snippets
python manage.py migrate

python manage.py createsuperuser

5.3 序列号

from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES
from django.contrib.auth.models import User

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


class UserSerializer(serializers.ModelSerializer):
    snippets = serializers.PrimaryKeyRelatedField(many=True, queryset=Snippet.objects.all())

    class Meta:
        model = User
        fields = ['id', 'username', 'snippets']