02-03 解析模块

Django-rest framework框架,第二章：请求响应组件

256 字

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2 分钟

解析模块

1、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

2、全局使用解析器

settings.py配置

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

urls.py配置

 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')

3、局部使用解析器

3-1 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')

3-2 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')

3-3 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>
 
    <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>

3-4 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>
 
    <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>

3-5 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')

4、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

jQuery

 >: cnpm install jquery

vue/cli 3 配置jQuery：在vue.config.js中配置(没有，手动项目根目录下新建)

 const webpack = require("webpack");
 
module.exports = {
    configureWebpack: {
        plugins: [
            new webpack.ProvidePlugin({
                $: "jquery",
                jQuery: "jquery",
                "window.jQuery": "jquery",
                Popper: ["popper.js", "default"]
            })
        ]
        }
};

BootStrap

 >: cnpm install bootstrap@3

vue/cli 3 配置BootStrap：在main.js中配置

 import "bootstrap"
import "bootstrap/dist/css/bootstrap.css"