14 DRF返回值的自定义

django中的返回值可以分为：

• 异常返回值
• 正常返回值

1. Djanog中常见的异常返回值有如下

• 序列化校验错误
  
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  {     "age": [         "A valid integer is required."     ] }

• 数据不存在
  http://127.0.0.1:8000/api/demon/11/
  
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  {     "detail": "Not found." }

• 认证错误
  
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  {     "detail": "Incorrect authentication credentials." }

• 权限错误
  
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  {     "detail": "Authentication credentials were not provided." }

• 限流错误
  
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  {     "detail": "Request was throttled" }

• 其他错误：python的语法错误等

2.异常处理源码分析

　　上面的这些错误都会在dispath函数中进行捕获和处理

 

 

 

 

 

 

 

 

 最后通过配置文件可以找到处理异常的函数

 

 

 

 

 

 这个函数就是对常见的异常进行捕获处理，并且这个函数只能处理基于APIException的类，对于python法人语法错误是无法捕获的，只能继续上报，导致程序报错

3. 自定义异常处理方法

为此我们可以自定义该类如下

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# encoding:utf-8 # author:kunmzhao # email:1102669474@qq.com from django.core.exceptions import PermissionDenied from django.http import Http404   from rest_framework import exceptions, status from rest_framework.response import Response from rest_framework.views import set_rollback from rest_framework.exceptions import AuthenticationFailed, NotAuthenticated, Throttled, ValidationError     def exception_handler(exc, context):     """     Returns the response that should be used for any given exception.       By default we handle the REST framework `APIException`, and also     Django's built-in `Http404` and `PermissionDenied` exceptions.       Any unhandled exceptions may return `None`, which will cause a 500 error     to be raised.     """     if isinstance(exc, Http404):         exc = exceptions.NotFound()         exc.ret_code = 1001     elif isinstance(exc, PermissionDenied):         exc = exceptions.PermissionDenied()         exc.ret_code = 1002       elif isinstance(exc, (AuthenticationFailed, NotAuthenticated)):         exc.ret_code = 1003     elif isinstance(exc, Throttled):         exc.ret_code = 1004     elif isinstance(exc, ValidationError):         exc.ret_code = 1005       headers = {}     if getattr(exc, 'auth_header', None):         headers['WWW-Authenticate'] = exc.auth_header     if getattr(exc, 'wait', None):         headers['Retry-After'] = '%d' % exc.wait     code = getattr(exc, "ret_code", -1)     if isinstance(exc, exceptions.APIException):         detail = exc.detail     else:         detail = "请求错误"     print(detail)     if isinstance(detail, (list, dict)):         data = {"code": code, 'error': detail}     else:         data = {"code": code, 'error': detail}       set_rollback()     return Response(data, headers=headers)

 

 配置如下

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REST_FRAMEWORK = {     'EXCEPTION_HANDLER': 'utils.exception_handler', }

 以后我们也可以自定义一些异常，放入该函数中，对异常进行分类，便于前端根据异常ma进行处理

 

4.正常返回值源码分析

 

 

我们可以重写该方法，返回我们需要的数据格式，如下

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class DemonView(ModelViewSet):     queryset = models.Student.objects.all()     serializer_class = DemonDModelSerializers       # authentication_classes = [DemonAuthentication, ]     # permission_classes = [DemonPermission, ]     # throttle_classes = [DemonThrottle, ]       def finalize_response(self, request, response, *args, **kwargs):         super().finalize_response(request, response, *args, **kwargs)         if not response.exception: // 对于异常的response不做处理             response.data = {"code": 0, "data": response.data}         return response

 

 

通过以上的方式就可以很好的自定义我们返回的数据格式了！！！