rest-framework之解析器

rest-framework之解析器

本文目录

• 一 解析器的作用
• 二 全局使用解析器
• 三 局部使用解析器
• 四 源码分析

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一 解析器的作用

根据请求头 content-type 选择对应的解析器对请求体内容进行处理。

有application/json，x-www-form-urlencoded，form-data等格式

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二 全局使用解析器

setting里

REST_FRAMEWORK = {'DEFAULT_PARSER_CLASSES':['rest_framework.parsers.JSONParser''rest_framework.parsers.FormParser''rest_framework.parsers.MultiPartParser']}

路由：

urlpatterns = [url(r'test/', TestView.as_view()),
]

视图函数：

from rest_framework.views import APIView
from rest_framework.response import Responseclass TestView(APIView):def post(self, request, *args, **kwargs):print(request.content_type)# 获取请求的值，并使用对应的JSONParser进行处理print(request.data)# application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值print(request.POST)print(request.FILES)return Response('POST请求，响应内容')def put(self, request, *args, **kwargs):return Response('PUT请求，响应内容')

 

 

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三 局部使用解析器

a. 仅处理请求头content-type为application/json的请求体

from django.conf.urls import url, include
from web.views.s5_parser import TestView urlpatterns = [ url(r'test/', TestView.as_view(), name='test'), ]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.request import Request from rest_framework.parsers import JSONParser class TestView(APIView): parser_classes = [JSONParser, ] def post(self, request, *args, **kwargs): print(request.content_type) # 获取请求的值，并使用对应的JSONParser进行处理 print(request.data) # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值 print(request.POST) print(request.FILES) return Response('POST请求，响应内容') def put(self, request, *args, **kwargs): return Response('PUT请求，响应内容')

b. 仅处理请求头content-type为application/x-www-form-urlencoded 的请求体

from django.conf.urls import url, include
from web.views import TestView urlpatterns = [ url(r'test/', TestView.as_view(), name='test'), ]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.request import Request from rest_framework.parsers import FormParser class TestView(APIView): parser_classes = [FormParser, ] def post(self, request, *args, **kwargs): print(request.content_type) # 获取请求的值，并使用对应的JSONParser进行处理 print(request.data) # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值 print(request.POST) print(request.FILES) return Response('POST请求，响应内容') def put(self, request, *args, **kwargs): return Response('PUT请求，响应内容')

c. 仅处理请求头content-type为multipart/form-data的请求体

from django.conf.urls import url, include
from web.views import TestView urlpatterns = [ url(r'test/', TestView.as_view(), name='test'), ]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.request import Request from rest_framework.parsers import MultiPartParser class TestView(APIView): parser_classes = [MultiPartParser, ] def post(self, request, *args, **kwargs): print(request.content_type) # 获取请求的值，并使用对应的JSONParser进行处理 print(request.data) # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值 print(request.POST) print(request.FILES) return Response('POST请求，响应内容') def put(self, request, *args, **kwargs): return Response('PUT请求，响应内容')

"en">
"UTF-8">    
"http://127.0.0.1:8000/test/" method="post" enctype="multipart/form-data"> "text" name="user" /> "file" name="img"> "submit" value="提交">   

d. 仅上传文件

from django.conf.urls import url, include
from web.views import TestView urlpatterns = [ url(r'test/(?P[^/]+)', TestView.as_view(), name='test'), ]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.request import Request from rest_framework.parsers import FileUploadParser class TestView(APIView): parser_classes = [FileUploadParser, ] def post(self, request, filename, *args, **kwargs): print(filename) print(request.content_type) # 获取请求的值，并使用对应的JSONParser进行处理 print(request.data) # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值 print(request.POST) print(request.FILES) return Response('POST请求，响应内容') def put(self, request, *args, **kwargs): return Response('PUT请求，响应内容')

"en">
"UTF-8">    
"http://127.0.0.1:8000/test/f1.numbers" method="post" enctype="multipart/form-data"> "text" name="user" /> "file" name="img"> "submit" value="提交">   

e. 同时多个Parser

当同时使用多个parser时，rest framework会根据请求头content-type自动进行比对，并使用对应parser

 

from django.conf.urls import url, include
from web.views import TestView urlpatterns = [ url(r'test/', TestView.as_view(), name='test'), ]

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView from rest_framework.response import Response from rest_framework.request import Request from rest_framework.parsers import JSONParser, FormParser, MultiPartParser class TestView(APIView): parser_classes = [JSONParser, FormParser, MultiPartParser, ] def post(self, request, *args, **kwargs): print(request.content_type) # 获取请求的值，并使用对应的JSONParser进行处理 print(request.data) # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值 print(request.POST) print(request.FILES) return Response('POST请求，响应内容') def put(self, request, *args, **kwargs): return Response('PUT请求，响应内容')

 

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四 源码分析

1 在调用request.data时，才进行解析，由此入手@propertydef data(self):if not _hasattr(self, '_full_data'):self._load_data_and_files()return self._full_data2 查看self._load_data_and_files()方法---->self._data, self._files = self._parse()def _parse(self):#用户请求头里content_type的值media_type = self.content_type#self.parsers 就是用户配置的parser_classes = [FileUploadParser,FormParser ]#self里就有content_type，传入此函数parser = self.negotiator.select_parser(self, self.parsers)3 查看self.negotiator.select_parser(self, self.parsers)def select_parser(self, request, parsers):#同过media_type和request.content_type比较，来返回解析器，然后调用解析器的解析方法#每个解析器都有media_type = 'multipart/form-data'属性for parser in parsers:if media_type_matches(parser.media_type, request.content_type):return parserreturn None4 最终调用parser的解析方法来解析parsed = parser.parse(stream, media_type, self.parser_context)

 

1 Request实例化，parsers=self.get_parsers()Request(request,parsers=self.get_parsers(),authenticators=self.get_authenticators(),negotiator=self.get_content_negotiator(),parser_context=parser_context)
2 get_parsers方法，循环实例化出self.parser_classes中类对象def get_parsers(self):return [parser() for parser in self.parser_classes]            3 self.parser_classes 先从类本身找，找不到去父类找即APIVIew 中的parser_classes = api_settings.DEFAULT_PARSER_CLASSES
4 api_settings是一个对象，对象里找DEFAULT_PARSER_CLASSES属性，找不到，会到getattr方法def __getattr__(self, attr):if attr not in self.defaults:raise AttributeError("Invalid API setting: '%s'" % attr)try:#调用self.user_settings方法，返回一个字典，字典再取attr属性val = self.user_settings[attr]except KeyError:# Fall back to defaultsval = self.defaults[attr]# Coerce import strings into classesif attr in self.import_strings:val = perform_import(val, attr)# Cache the result
            self._cached_attrs.add(attr)setattr(self, attr, val)return val5 user_settings方法 ，通过反射去setting配置文件里找REST_FRAMEWORK属性，找不到，返回空字典@propertydef user_settings(self):if not hasattr(self, '_user_settings'):self._user_settings = getattr(settings, 'REST_FRAMEWORK', {})return self._user_settings