django的rest framework框架——版本、解析器、序列化

时间 2019-11-10

标签 django rest framework 框架版本解析序列栏目 Python 繁體版

原文原文链接

1、rest framework的版本使用git

一、版本能够写在URL中，经过GET传参，如 http://127.0.0.1:8082/api/users/?version=v1django

（1）自定义类获取版本信息：json

from django.http import JsonResponse
from rest_framework.views import APIView


class ParamVersion(object):
    """获取版本"""

    def determine_version(self, request, *args, **kwargs):
        version = request.query_params.get("version")  # 获取请求里面的版本信息
        return version


class UsersView(APIView):
    """用户中心"""
    versioning_class = ParamVersion  # 获取版本信息

    def get(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        version = request.version
        print(version)
        return JsonResponse(res)

views.py

（2）经过内置类来获取版本api

from django.http import JsonResponse
from rest_framework.views import APIView
from rest_framework.versioning import QueryParameterVersioning


class UsersView(APIView):
    """用户中心"""
    versioning_class = QueryParameterVersioning  # 获取版本信息

    def get(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        version = request.version
        print(version)
        return JsonResponse(res)

views.py

在项目的settings中进行参数配置：app

二、也能够写在URL的路径中，如 http://127.0.0.1:8082/api/v1/users/ide

能够经过内置类来获取：函数

from django.http import JsonResponse
from rest_framework.views import APIView
from rest_framework.versioning import URLPathVersioning

class UsersView(APIView):
    """用户中心"""
    versioning_class = URLPathVersioning  # 获取版本信息

    def get(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        version = request.version
        print(version)
        return JsonResponse(res)

views.py

推荐使用第二种方法来配置版本信息。post

三、能够将版本类写到配置文件中，进行全局控制：ui

在项目的settings中进行设置：this

from django.http import JsonResponse
from rest_framework.views import APIView

class UsersView(APIView):
    """用户中心"""

    def get(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        version = request.version  # 获取版本
        print(version)
        return JsonResponse(res)

views.py

四、源码流程

路由→as_view()→rest framework的dispatch()→initial()→determine_version()

能够经过request.version获取版本信息

经过request.versioning_scheme获取处理版本的对象，能够利用这个对象调用reverse()方法来反向生成url:

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/users/$', views.UsersView.as_view(), name="userView"),
]

urls.py

from django.http import JsonResponse
from rest_framework.views import APIView

class UsersView(APIView):
    """用户中心"""

    def get(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        version = request.version  # 获取版本
        scheme = request.versioning_scheme  # 处理版本的对象

        # 反向生成URL
        url = scheme.reverse(viewname="userView", request=request)
        print(url)

        return JsonResponse(res)

views.py

2、解析器

解析器：对请求体的数据进行解析

一、Django的解析器

from django.core.handlers.wsgi import WSGIRequest

在Django内部会跟据不一样的状况将request.body里面的数据解析到request.POST：

因此只有当 Content_type='application/x-www-form-urlencoded' 时，才会去解析request.body里面的数据，另外，数据格式必须是 name=amy&age=18 这种格式才能被解析，

基于如上两个条件才能使得request.POST有值。

二、rest framework的解析器

一、示例

from django.http import JsonResponse
from rest_framework.views import APIView
from rest_framework.parsers import JSONParser


class ExampleView02(APIView):
    """"""
    parser_classes = [JSONParser]  # 解析器类JSONParser：表示容许用户发送json格式的数据{"name":"amy", "age":18}

    def post(self, request, *args, **kwargs):
        res = {"code": 1000, "msg": None, "data": None}
        data = request.data  # 获取解析后的数据

        res["data"] = data
        return JsonResponse(res)

views.py

JSONParser类只能解析Content-type为applicaton/json的数据,

FormParser类只能解析Content-type为applicaton/x-www-form-urlencoded的数据,

三、rest framework的解析器源码流程

执行dispatch()中的initialize_request()方法：

全局解析器配置：

视图中配置：

在视图中调用requst.data触发：

request的data方法调用_load_data_and_files()：

以JSONParser类为例：

3、rest framework序列化处理数据

一、示例1 序列化类的使用

from django.db import models


class UserGroup(models.Model):
    title = models.CharField(max_length=32)


class UserInfo(models.Model):
    user_type_choices = (
        (1, "普通用户"),
        (2, "vip"),
        (3, "svip"),
    )
    user_type = models.IntegerField(choices=user_type_choices)
    username = models.CharField(max_length=32, unique=True)
    password = models.CharField(max_length=64)
    group = models.ForeignKey(to="UserGroup", on_delete=models.CASCADE, null=True, blank=True)
    roles = models.ManyToManyField(to="Role", blank=True)


class UserToken(models.Model):
    user = models.OneToOneField(to="UserInfo")
    token = models.CharField(max_length=64)


class Role(models.Model):
    title = models.CharField(max_length=32)


class Order(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    create_time = models.DateTimeField(auto_now_add=True)
    user = models.ForeignKey(to="UserInfo", on_delete=models.CASCADE, null=True, blank=True)

models.py

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/roles/$', views.RolesView.as_view()),
]

api/urls.py

import json

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers

from api import models


class RolesSerializer(serializers.Serializer):
    """对获取的数据进行序列化操做"""
    # 要与数据表中的字段向对应
    id = serializers.CharField()
    title = serializers.CharField()


class RolesView(APIView):
    """获取角色"""

    def get(self, request, *args, **kwargs):

        # 方法一：
        # roles = models.Role.objects.all().values("id", "title")
        # roles = list(roles)
        # res = json.dumps(roles, ensure_ascii=False)

        # 方法二：使用序列化类
        # roles = models.Role.objects.all()
        # # 实例化序列化类  若是是对多条数据进行序列化要设置 many=True
        # serl = RolesSerializer(instance=roles, many=True)
        # res = serl.data  # 获取序列化后的结果
        # res = json.dumps(res, ensure_ascii=False)

        role = models.Role.objects.all().first()
        # 实例化序列化类  若是是对一条数据进行序列化要设置 many=False
        serl = RolesSerializer(instance=role, many=False)
        res = serl.data  # 获取序列化后的结果
        res = json.dumps(res, ensure_ascii=False)

        return HttpResponse(res)

views.py

二、序列化自定义字段

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/userInfo/$', views.UserInfoView.as_view()),
]

urls.py

import json

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers

from api import models


class UserInfoSerializer(serializers.Serializer):
    """对获取的数据进行序列化操做"""
    username = serializers.CharField()
    password = serializers.CharField()
    user_type = serializers.CharField(source="get_user_type_display")  # 获取choices字段的文本
    group = serializers.CharField(source="group.title")  # 获取ForeignKey字段
    roles = serializers.SerializerMethodField()  # 自定义显示ManyToMany字段

    def get_roles(self, row):
        """获取角色对象信息"""
        role_obj_list = row.roles.all()
        res = []
        for item in role_obj_list:
            res.append({"id": item.id, "title": item.title})
        return res


class UserInfoView(APIView):
    """获取用户信息"""

    def get(self, request, *args, **kwargs):
        users = models.UserInfo.objects.all()
        serl = UserInfoSerializer(instance=users, many=True)
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)

views.py

三、除了继承Serializer类实现序列化，还可使用ModelSerializer类来实现。ModelSerializer继承了Serializer

import json

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers

from api import models


class UserInfoSerializer(serializers.ModelSerializer):
    """对获取的数据进行序列化操做"""
    class Meta:
        model = models.UserInfo
        fields = "__all__"  # 对全部的字段作序列化


class UserInfoView(APIView):
    """获取用户信息"""

    def get(self, request, *args, **kwargs):
        users = models.UserInfo.objects.all()
        serl = UserInfoSerializer(instance=users, many=True)
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)

views.py

这种方式生成的数据比较”简陋“，能够根据需求定制：

class UserInfoSerializer(serializers.ModelSerializer):
    """对获取的数据进行序列化操做"""
    user_type = serializers.CharField(source="get_user_type_display")
    group = serializers.CharField(source="group.title")
    roles = serializers.SerializerMethodField()  # 自定义显示ManyToMany字段

    def get_roles(self, row):
        """获取角色对象信息"""
        role_obj_list = row.roles.all()
        res = []
        for item in role_obj_list:
            res.append({"id": item.id, "title": item.title})
        return res

    class Meta:
        model = models.UserInfo
        fields = ["id", "username", "password", "user_type", "group", "roles"]  


class UserInfoView(APIView):
    """获取用户信息"""

    def get(self, request, *args, **kwargs):
        users = models.UserInfo.objects.all()
        serl = UserInfoSerializer(instance=users, many=True)
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)

views.py

四、序列化深度控制

自动序列化实现连表操做

class UserInfoSerializer(serializers.ModelSerializer):
    """对获取的数据进行序列化操做"""

    class Meta:
        model = models.UserInfo
        fields = "__all__"
        depth = 1  # 深度控制  建议取0~10层，层数越多响应速度也会受到影响


class UserInfoView(APIView):
    """获取用户信息"""

    def get(self, request, *args, **kwargs):
        users = models.UserInfo.objects.all()
        serl = UserInfoSerializer(instance=users, many=True)
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)

views.py

五、序列化生成HyperMediaLink

需求：经过查看用户信息页面获取到查看分组信息的URL

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/userInfo/$', views.UserInfoView.as_view()),
    url(r'^(?P<version>[v1|v2]+)/group/(?P<pk>\d+)$', views.GroupView.as_view(), name="groupView"),
]

urls.py

import json

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers

from api import models


class GroupSerializer(serializers.ModelSerializer):
    """对获取的数据进行序列化操做"""

    class Meta:
        model = models.UserGroup
        fields = "__all__"


class UserInfoSerializer(serializers.ModelSerializer):
    """对获取的数据进行序列化操做"""
    # 反向生成查看group的URL
    group = serializers.HyperlinkedIdentityField(view_name="groupView", lookup_field="group_id", lookup_url_kwarg="pk")

    class Meta:
        model = models.UserInfo
        fields = ["id", "username", "password", "user_type", "group"]


class GroupView(APIView):
    """获取分组信息"""

    def get(self, request, *args, **kwargs):
        pk = kwargs.get("pk")
        group_obj = models.UserGroup.objects.filter(id=pk).first()
        serl = GroupSerializer(instance=group_obj, many=False)
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)


class UserInfoView(APIView):
    """获取用户信息"""

    def get(self, request, *args, **kwargs):
        users = models.UserInfo.objects.all()
        serl = UserInfoSerializer(instance=users, many=True, context={"request": request})
        res = json.dumps(serl.data, ensure_ascii=False)
        return HttpResponse(res)

views.py

六、序列化源码流程

若是是处理QuerySet数据，就会执行many_init()方法：

至关于在内部，若是是处理对象(一条数据)，就使用Serializer进行处理；若是是处理QuerySet（多条数据），就用ListSerializer处理。

实例化完成后，能够经过“对象名.data”方法获取数据：

父类的data方法：

若是是处理对象(一条数据)，就到Serializer类里面找to_representation()方法；若是是处理QuerySet（多条数据），就去ListSerializer里面找。

get_attribute()方法的具体实现：

循环字段列表获取字段对应的值：

　　获取instance对象对应的字段的属性值，而后把这个属性值赋值给instance，而后继续循环，直到instance从字段里面获取不到值为止，即取数据表中真正的数值，

如 UserInfo 表中有外键group，想要获取到group字段对应的表对象的title字段:group = serializers.CharField(source="group.title"),则此时attrs=['group', 'title'],

第一轮循环时：instance=getattr(UserInfo object,group)=UserGroup object，

第二轮循环时instance=getattr(UserGroup object,title)=A组，此时便经过外键获取到UserGroup表中的title字段的值了。

　　当字段是一个能够被调用的对象（如函数或方法）时，就在这个字段后面加上“（）”，直接执行这个函数或者方法，将返回值赋值给instance。

如获取一个choices字段的文本：user_type=serializers.CharField(source="get_user_type_display") ，这个get_user_type_display就是一个可调用的方法。

对于字段是serializers.HyperlinkedIdentityField()对象的时候执行的to_representation()方法：

因此，咱们在使用HyperlinkedIdentityField()的时候要传递参数：

4、rest framework序列化验证用户请求数据

一、自定义类验证用户请求数据

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/userGroup/$', views.UserGroupView.as_view()),
]

urls.py

import json

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers

from api import models


class MyValidator(object):
    """自定制校验规则"""
    def __init__(self, base):
        self.base = base

    def __call__(self, value):
        # 设置一个必须以self.base开头的规则
        if not value.startswith(self.base):
            message = "this field must start with %s." % self.base
            raise serializers.ValidationError(message)

    def set_context(self, serializer_field):
        pass


class UserGroupSerializer(serializers.Serializer):
    title = serializers.CharField(
        error_messages={"required": "标题不能为空"},
        validators=[MyValidator("a-")],
    )  # 校验的字段：title


class UserGroupView(APIView):
    """验证用户请求数据"""

    def post(self, request, *args, **kwargs):
        # request.data ：用户提交过来的数据
        serl = UserGroupSerializer(data=request.data)

        # 若是请求数据是合法的，就获取到的数据，不然打印错误信息
        if serl.is_valid():
            print(serl.validated_data["title"])
        else:
            print(serl.errors)
        return HttpResponse("xxx")

views.py

二、源码

在Serializer类中实现了请求数据校验：

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

urlpatterns = [
    url(r'^(?P<version>[v1|v2]+)/userGroup/$', views.UserGroupView.as_view()),
]

urls.py

from django.shortcuts import HttpResponse
from rest_framework.views import APIView
from rest_framework import serializers
from api import models


class UserGroupSerializer(serializers.Serializer):
    title = serializers.CharField(
        error_messages={"required": "标题不能为空"},
        # validators=[MyValidator("a-")],
    )  # 校验的字段：title

    def validate_title(self, value):
        """自定义title字段钩子方法"""
        if not value.startswith("a-"):
            message = "值必须以'a-'开头."
            raise serializers.ValidationError(message)
        return value


class UserGroupView(APIView):
    """验证用户请求数据"""

    def post(self, request, *args, **kwargs):
        # request.data ：用户提交过来的数据
        serl = UserGroupSerializer(data=request.data)

        # 若是请求数据是合法的，就获取到的数据，不然打印错误信息
        if serl.is_valid():
            print(serl.validated_data["title"])
        else:
            print(serl.errors)
        return HttpResponse("xxx")

views.py