基于Django的Rest Framework框架的解析器

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

回到目录

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

回到目录

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')

回到目录

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')

回到目录

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

解析器

基于Django的Rest Framework框架的解析器

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

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