如何将复杂的Django模型序列化为json?

时间:2015-11-27 10:35:09

标签: python django django-rest-framework

我正在尝试使用djangoRestframework django-rest在我的django应用程序中创建REST服务。

我在MyModels.py中有模型学生,后面是

from django.db import models

class Student(object) :
    def __init__(self,first_name,middle_name,last_name,subject_list=None):
            self.first_name = first_name
            self.last_name = last_name
            self.middle_name = middle_name
            self.subject_list = subject_list

class Subject(object) :
    def __init__(self,name):
            self.name = name

以下代码来自views.py

def getStudentList(request):
my_list = []
my_list.append(Student(first_name="Alajandro",middle_name="Santana",last_name="Gonzales"))
my_list.append(Student(first_name="Timothy",middle_name="Carlos",last_name="Robins"))
my_list.append(Student(first_name="Nathan",middle_name="Nick",last_name="Mathews"))
my_list.append(Student(first_name="John",middle_name="Nelson",last_name="Kennedy"))
my_list.append(Student(first_name="Tom",middle_name="Kenny",last_name="Cruise"))
my_list.append(Student(first_name="Jerry",middle_name="Sanvile",last_name="McGuire"))
my_list.append(Student(first_name="Jason",middle_name="San",last_name="Statham"))

student_list = []

for student in my_list:
    student_ser = rest.StudentSerialize(student)
    student_list.append(student_ser.data.copy())

json = JSONRenderer().render(student_list)
return HttpResponse(json)

urls.py中的网址映射是

 url(r'^studentList/', views.getStudentList),

响应来自URL     http://127.0.0.1:8083/studentList/

[{"first_name":"Alajandro","middle_name":"Santana","last_name":"Gonzales"},{"first_name":"Timothy","middle_name":"Carlos","last_name":"Robins"},{"first_name":"Nathan","middle_name":"Nick","last_name":"Mathews"},{"first_name":"John","middle_name":"Nelson","last_name":"Kennedy"},{"first_name":"Tom","middle_name":"Kenny","last_name":"Cruise"},{"first_name":"Jerry","middle_name":"Sanvile","last_name":"McGuire"},{"first_name":"Jason","middle_name":"San","last_name":"Statham"}]

现在如果我有兴趣在json中传递主题。我想做的是学生和科目之间的一对多关系。即一名学生可以有很多科目。

所以我期待这个json作为输出

 [{
      "name" : "Tom",
      "subject_list" : [{..},{},{},....]
  },{},{}...]

为此,我在代码中进行了以下更改

我的MyModel.py文件

from django.db import models

class Student(object) :

    def __init__(self,first_name,middle_name,last_name,subject_list=None):
            self.first_name = first_name
            self.last_name = last_name
            self.middle_name = middle_name
            if subject_list is None:
                    self.subject_list = subject_list

class Subject(object) :
    def __init__(self,name):
            self.name = name

我的MyREST.py包含

from MyModels import Student
from MyModels import Subject
from rest_framework import serializers


class StudentSerialize(serializers.Serializer):
    first_name = serializers.CharField(max_length=200)
    middle_name = serializers.CharField(max_length=200)
    last_name = serializers.CharField(max_length=200)

我的views.py包含

def get_student_list(request):

my_list = []
my_list.append(Student(first_name="Alajandro",middle_name="Santana",last_name="Gonzales"))
my_list.append(Student(first_name="Timothy",middle_name="Carlos",last_name="Robins"))
my_list.append(Student(first_name="Nathan",middle_name="Nick",last_name="Mathews"))
my_list.append(Student(first_name="John",middle_name="Nelson",last_name="Kennedy"))


subject_list = []
subject_list.append(Subject(name="Computer Science"))
subject_list.append(Subject(name="Physics"))
subject_list.append(Subject(name="Chemistry"))

my_list.append(Student(first_name="Jason",middle_name="San",last_name="Statham",subject_list=subject_list))
my_list.append(Student(first_name="Tom",middle_name="Kenny",last_name="Cruise",subject_list=subject_list))
my_list.append(Student(first_name="Jerry",middle_name="Sanvile",last_name="McGuire",subject_list=subject_list))

student_list = []
for student in my_list:
    student_ser = rest.StudentSerialize(student)
    student_list.append(student_ser.data.copy())


json = JSONRenderer().render(student_list)
return HttpResponse(json)

在urls.py中我添加了

 url(r'^student_list/', views.get_student_list),

现在,如果我点击了URL,我仍然会将json输出为

[{"first_name":"Alajandro","middle_name":"Santana","last_name":"Gonzales"},{"first_name":"Timothy","middle_name":"Carlos","last_name":"Robins"},{"first_name":"Nathan","middle_name":"Nick","last_name":"Mathews"},{"first_name":"John","middle_name":"Nelson","last_name":"Kennedy"},{"first_name":"Jason","middle_name":"San","last_name":"Statham"},{"first_name":"Tom","middle_name":"Kenny","last_name":"Cruise"},{"first_name":"Jerry","middle_name":"Sanvile","last_name":"McGuire"}]

但我没有得到这些科目。

我应该在课程SudentSerialize中添加什么,这样如果我在学生的对象中设置subject_list,我将获得学生的json属性subject_list将具有主题json数组。

2 个答案:

答案 0 :(得分:1)

您必须使用嵌套的关系来完成这项工作:

这是一个例子:

class SubjectSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=200)

    class Meta:
        fields = [
            'name',
        ]

class StudentSerializer(serializers.Serializer):
    first_name = serializers.CharField(max_length=200)
    middle_name = serializers.CharField(max_length=200)
    last_name = serializers.CharField(max_length=200)
    # nested relationship
    subjects = SubjectSerializer(many=True)

    class Meta:
        fields = [
            'first_name',
            'last_name',
            'middle_name',
            'subjects'
        ]

阅读Django Rest Framework - Nested relationships了解更多信息

答案 1 :(得分:0)

您正在寻找nested serializers。 文档应涵盖您需要了解的所有内容。

请花一些时间来运行tutorial的6个步骤。它将为您提供有关如何使用DRF的提示。