rest framework 之解析器

朱雀 2023-06-02 10:53 130阅读 0赞

## 一、示例 ##

1、`api/urls.py`

from django.urls import path, re_path
    from api.views import UserView, ParserView
    
    urlpatterns = [
        # path('users/', UserView.as_view()),
        re_path('(?P<version>[v1|v2]+)/users/', UserView.as_view(), name='api_user'),
    
        path('parser/', ParserView.as_view(), name='api_parer'),        # 添加这句
    ]

2、`api/views.py`

*  `JSONParser`：只能解析`content-type:application/json`的头
 *  `FormParser`：只能解析`content-type:application/x-www-form-urlencoded`的头

from rest_framework.parsers import JSONParser, FormParser
    
    
    class ParserView(APIView):
        parser_classes = [JSONParser, FormParser]
    
        def post(self, request, *args, **kwargs):
            print(request.data)
    
            return HttpResponse('解析')

3、使用 postman 发送 json 数据测试后台是否能解析：

（1）、设置为 post 方式，headers 中添加数据类型为 json

（2）、body 中选择 raw，然后选择 json 类型，最后就是在空白处构建要发送的 json 数据（记得是双引号）：

后台结果：

如果是 `content-type:application/x-www-form-urlencoded` 类型数据，不需要设置请求头，默认就是。但是 `body` 中需要设置为 `x-www-form-urlencoded` 。

## 二、源码分析 ##

1、`dispatch()`

def dispatch(self, request, *args, **kwargs):
        """
        `.dispatch()` is pretty much the same as Django's regular dispatch,
        but with extra hooks for startup, finalize, and exception handling.
        """
        self.args = args
        self.kwargs = kwargs
        # 对原生的 request 对象进行加工，丰富了
        # request= Request(request,parsers=self.get_parsers(),authenticators=self.get_authenticators(),negotiator=self.get_content_negotiator(),parser_context=parser_context)
        # 第一个参数为原生的 request 对象，封装原生 request
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?
    
        try:
    
            self.initial(request, *args, **kwargs)
    
            # Get the appropriate handler method
            if request.method.lower() in self.http_method_names:
                handler = getattr(self, request.method.lower(),
                                  self.http_method_not_allowed)
            else:
                handler = self.http_method_not_allowed
    
                response = handler(request, *args, **kwargs)
    
        except Exception as exc:
            response = self.handle_exception(exc)
    
            self.response = self.finalize_response(request, response, *args, **kwargs)
            return self.response

2、`initialize_request()`

def initialize_request(self, request, *args, **kwargs):
        """
        Returns the initial request object. 封装原生 request 对象
        """
        parser_context = self.get_parser_context(request)
    
        return Request(
            request,
            # 获取所有解析器
            parsers=self.get_parsers(),
            authenticators=self.get_authenticators(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

3、`get_parsers()`

def get_parsers(self):
        """
        Instantiates and returns the list of parsers that this view can use.
        返回次视图可以使用的解析器列表
        """
        return [parser() for parser in self.parser_classes]

4、`parser_classes`

class APIView(View):
    
        # The following policies may be set at either globally, or per-view.
        renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES
        # 从 settings 中获取解析器
        parser_classes = api_settings.DEFAULT_PARSER_CLASSES
    
        # Allow dependency injection of other settings to make testing easier.
        settings = api_settings

5、全局配置解析器 `settings`：

REST_FRAMEWORK = {
        # 解析器
        "DEFAULT_PARSER_CLASSES":["rest_framework.parsers.JSONParser","rest_framework.parsers.FormParser"]
    }

**源码流程图**

--------------------

根据请求头 `content-type` 选择对应的解析器就**请求体内容**进行处理。

## 三、仅处理请求头 content-type 为 application/json 的请求体 ##

1、`urls.py`

from django.urls import path, re_path, include
    from api.views import TestView2
    
    urlpatterns = [
        re_path(r'(?P<version>[v1|v2]+)/test2', TestView2.as_view()),
    ]

2、`views.py`

rom rest_framework.views import APIView
    from rest_framework.parsers import JSONParser, FormParser
    from rest_framework.response import Response
    
    
    class TestView2(APIView):
        parser_classes = [JSONParser]
    
        def post(self, request, *args, **kwargs):
            print(request.content_type)    # application/json
    
            # 获取请求值，并发 JSONParser  处理
            print(request.data)     # {'name': 'rose', 'age': 18}
    
            # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值
            print(request.POST)         # <QueryDict: {}>
            print(request.FILES)        # <MultiValueDict: {}>
    
            return Response('响应内容')

![20190731101614.png][]

## 四、仅处理请求头 content-type 为 application/x-www-form-urlencoded 的请求体 ##

1、`urls.py`

from django.urls import path, re_path, include
    from api.views import TestView2
    
    urlpatterns = [
        re_path(r'(?P<version>[v1|v2]+)/test2', TestView2.as_view()),
    ]

2、`views.py`

rom rest_framework.views import APIView
    from rest_framework.parsers import JSONParser, FormParser
    from rest_framework.response import Response
    
    
    class TestView2(APIView):
        parser_classes = [FormParser]
    
        def post(self, request, *args, **kwargs):
            print(request.content_type)    # application/x-www-form-urlencoded
    
            # 获取请求值，并发 JSONParser  处理
            print(request.data)     # <QueryDict: {'123': ['']}>
    
            # application/x-www-form-urlencoded 或 multipart/form-data时，request.POST中才有值
            print(request.POST)         # <QueryDict: {'123': ['']}>
            print(request.FILES)        # <MultiValueDict: {}>
    
            return Response('响应内容')

## 五、仅处理请求头content-type为multipart/form-data的请求体 ##

1、`urls.py`

from django.urls import path, re_path, include
    from api.views import TestView2
    
    urlpatterns = [
        re_path(r'(?P<version>[v1|v2]+)/test2', TestView2.as_view()),
    ]

2、`views.py`

rom rest_framework.views import APIView
    from rest_framework.parsers import JSONParser, FormParser, MultiPartParser
    from rest_framework.response import Response
    
    
    class TestView2(APIView):
        parser_classes = [MultiPartParser]
    
        def post(self, request, *args, **kwargs):
            print(request.content_type)    # multipart/form-data
    
            # 获取请求值，并发 JSONParser  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('响应内容')

3、`upload.html`

<!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>

## 六、仅上传文件 ##

1、`urls.py`

from django.urls import path, re_path, include
    from api.views import TestView2
    
    urlpatterns = [
        re_path(r'(?P<version>[v1|v2]+)/test2', TestView2.as_view()),
    ]

2、`views.py`

rom rest_framework.views import APIView
    from rest_framework.parsers import JSONParser, FormParser, MultiPartParser, FileUploadParser
    from rest_framework.response import Response
    
    
    class TestView2(APIView):
        parser_classes = [FileUploadParser]
    
        def post(self, request, *args, **kwargs):
            print(request.content_type)    
    
            # 获取请求值，并发 JSONParser  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('响应内容')

3、`upload.html`

## 七、其他 ##

**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`

#!/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')

--------------------

**全局使用**

`settings.py`

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

> **Tips: 个别特殊的值可以通过Django的request对象 request.\_request 来进行获取**

**总结**

*  `JSONParser`，解析数据类型：`content-type:application/json`
 *  `FormParser`，解析数据类型：`content-type:application/x-www-form-urlencoded`
 *  支持全局配置解析器类型

转载于:https://www.cnblogs.com/midworld/p/11380172.html

[20190731101614.png]: /images/20230601/d3a180a565134c998155b1553946f33e.png