基于Django的Rest Framework框架的解析器
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
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 Response class 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')
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')
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="http://127.0.0.1:8000/test/" method="post" enctype="multipart/form-data">
<input type="text" name="user" />
<input type="file" name="img">
<input type="submit" value="提交">
</form>
</body>
</html>
d. 仅上传文件
from django.conf.urls import url, include
from web.views import TestView
urlpatterns = [
url(r'test/(?P<filename>[^/]+)', 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')
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="http://127.0.0.1:8000/test/f1.numbers" method="post" enctype="multipart/form-data">
<input type="text" name="user" />
<input type="file" name="img">
<input type="submit" value="提交">
</form>
</body>
</html>
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')
四 源码分析
1 在调用request.data时，才进行解析，由此入手 @property def data(self): if not _hasattr(self, '_full_data'): self._load_data_and_files() return self._full_data 2 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 parser return None 4 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 defaults val = self.defaults[attr] # Coerce import strings into classes if attr in self.import_strings: val = perform_import(val, attr) # Cache the result self._cached_attrs.add(attr) setattr(self, attr, val) return val 5 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 @property def user_settings(self): if not hasattr(self, '_user_settings'): self._user_settings = getattr(settings, 'REST_FRAMEWORK', {}) return self._user_settings
