01 REST框架原始写法，与表单Form类似，实例

1. 创建模型(models.py)

from django.db import models# 高亮文本， 两种风格from pygments.lexers import get_all_lexersfrom pygments.styles import get_all_stylesLEXERS = [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. 创建自定义的Serializer类（serializers.py）

from rest_framework import serializersfrom snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICESclass SnippetSerializer(serializers.Serializer):    # read_only 只读    id = serializers.IntegerField(read_only=True)    # required：必要， allow_blank:允许为空，    title = serializers.CharField(required=False, allow_blank=True, max_length=100)    # style: 设置显示样式，控制如何显示可浏览的API    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')    # 一般是与model一一对应的，一般可以少，但不可以多，如果想增加需要另外进行处理！    # 字段设置是为了验证前端通过get等方法传递过来的数据    def create(self, validated_data):        """        根据传入的数据创建一个实例        """        return Snippet.objects.create(**validated_data)    def update(self, instance, validated_data):        """        更新一个实例，若没有传值，就使用原来的数据        """        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

3. 序列化与反序列化

from rest_framework.renderers import JSONRendererfrom rest_framework.parsers import JSONParser# 序列化，将数据转化成json格式serializer = SnippetSerializer(snippet)content = JSONRenderer().render(serializer.data)# 反序列化，转换成本机类型from django.utils.six import BytesIOstream = BytesIO(content)# 首先将数据转化成二进制流，然后再将其渲染成python中的字典data = JSONParser().parse(stream)

4. 简便的ModelSerializer，要求不高的数据，不用自定义

class SnippetSerializer(serializers.ModelSerializer):    class Meta:        model = Snippet        fields = ('id', 'title', 'code', 'linenos', 'language', 'style')    # 默认实现了create()和 update()方法

5.重点，编写我们的视图处理函数（views.py）

from django.http import HttpResponse, JsonResponsefrom django.views.decorators.csrf import csrf_exemptfrom rest_framework.renderers import JSONRendererfrom rest_framework.parsers import JSONParserfrom snippets.models import Snippetfrom snippets.serializers import SnippetSerializer# 不用进行csrf验证@csrf_exemptdef snippet_list(request):    # 删除多个对象的方法    if request.method == 'GET':        # 获取所有的对象        snippets = Snippet.objects.all()        # 序列化所有的查询集，必须设置many=True，模型对象不用设置        serializer = SnippetSerializer(snippets, many=True)        return JsonResponse(serializer.data, safe=False)    elif request.method == 'POST':        data = JSONParser().parse(request)        serializer = SnippetSerializer(data=data)        # 验证我们的数据        if serializer.is_valid():            serializer.save()            return JsonResponse(serializer.data, status=201)        return JsonResponse(serializer.errors, status=400)# 处理单个对象的方法（get, put, delete）@csrf_exemptdef 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':        # 序列化数据        serializer = SnippetSerializer(snippet)        # 将数据转换成json格式，作为响应返回给客户端        return JsonResponse(serializer.data)    elif request.method == 'PUT':        # 将请求对象反序列化为python对象        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)        

6. serializer支持的字段

models.AutoField: IntegerField,models.BigIntegerField: IntegerField,models.BooleanField: BooleanField,models.CharField: CharField,models.CommaSeparatedIntegerField: CharField,models.DateField: DateField,models.DateTimeField: DateTimeField,models.DecimalField: DecimalField,models.EmailField: EmailField,models.Field: ModelField,models.FileField: FileField,models.FloatField: FloatField,models.ImageField: ImageField,models.IntegerField: IntegerField,models.NullBooleanField: NullBooleanField,models.PositiveIntegerField: IntegerField,models.PositiveSmallIntegerField: IntegerField,models.SlugField: SlugField,models.SmallIntegerField: IntegerField,models.TextField: CharField,models.TimeField: TimeField,models.URLField: URLField,models.GenericIPAddressField: IPAddressField,models.FilePathField: FilePathField,

7. 自定义字段，支持的参数

LIST_SERIALIZER_KWARGS = ('read_only', 'write_only', 'required', 'default', 'initial', 'source','label', 'help_text', 'style', 'error_messages', 'allow_empty','instance', 'data', 'partial', 'context', 'allow_null')