[Django rest-framework] 2-ModelSerializers

将上一节中SnippetSerializer继承的父类换为serializers.ModelSerializer

修改代码为：

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

 打开Django shell

python manage.py shell

 执行

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')...

 很神奇的只用了两行代码就实现了上一节的功能

将view中的代码改为

# Create your views here.
@csrf_exempt
def snippet_list(request):
    """
    list all snippets
    or create a snippet
    :param request:
    :return:
    """
    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)
        else:
            return JsonResponse(serializer.errors, status=400)


@csrf_exempt
def snippet_detail(request, pk):
    try:
        snippet = Snippet.objects.get(pk=pk)
    except:
        return HttpResponse(404)
    if request.method == "GET":
        serializer = SnippetSerializer(snippet)
        return JsonResponse(serializer.data)
    if request.method == "PUT":
        data = JSONParser().parse(request)
        serializer = SnippetSerializer(data=data)
        if serializer.is_valid():
            serializer.save()
            return JsonResponse(serializer.data)
        else:
            return JsonResponse(serializer.errors, status=400)
    if request.method == 'DELETE':
        snippet.delete()
        return HttpResponse(204)

 url 修改为

urlpatterns = [
    url(r'^snippets/$', views.snippet_list),
    url(r'^snippets/(?P<pk>[0-9]+)/$', views.snippet_detail),
]

 当然，tutorail中的url修改为

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

 打开postman试试吧

GET: /snippets/

[{"id": 1, "title": "", "code": "foo=\"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, 
{"id": 3, "title": "", "code": "foo = \"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, 
{"id": 4, "title": "", "code": "print \"hello, world\"\n", "linenos": false, "language": "python", "style": "friendly"}, {"id": 5, "title": "", "code": "foo = \"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, {"id": 6, "title": "", "code": "print \"hello, world\"\n", "linenos": false, "language": "python", "style": "friendly"}, {"id": 7, "title": "", "code": "foo = \"bar\"\n", "li......

GET中的　　return JsonResponse(serializer.data,safe=False)这一句中的safe必须设置为False，因为我们返回的并不是一个dict而是一个数组 

POST: /snippets/

request body

{}

response

{"code": ["This field is required."]}

 

 POST: /snippets/

request body

{"code":"console.log('ok')"}

response

{"id": 18, "title": "", "code": "console.log('ok)", "linenos": false, "language": "python", "style": "friendly"}

 

修改serializer.py中meta元类中的fields包含的字段看到，这里定义了需要关注的字段

删除id

GET: /snippets/

[{"title": "", "code": "foo=\"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, 
{"title": "", "code": "foo = \"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, 
{"title": "", "code": "print \"hello, world\"\n", "linenos": false, "language": "python", "style": "friendly"},
 {"title": "", "code": "foo = \"bar\"\n", "linenos": false, "language": "python", "style": "friendly"}, {"title": "", "code": "print \"hello, world\"\n", "linenos": false, "language": "python", "style": "friendly"},...

 着实很方便

但实际情况中，有时候数据库定义的字段和我们想返回的字段名不同，比如id我们想返回为userId;

有时候我们不想返回所有字段，比如我们只想返回title 和 code

目前就不知道改怎么办了，看看下一节能不能解决这个问题

参考资料：http://www.django-rest-framework.org/tutorial/1-serialization/#using-modelserializers