django restframework框架一

@(python之路)[django restframework框架初識]
django restframework框架初識

- @(python之路)[django restframework框架初識] django restframework框架初識
1.restframework框架
2.基于django CBV實現接口
- 2.1 源碼刨析
3django restframwork小試牛刀
- 源碼刨析
4.rest framework組件
- 4.1 版本
  - 重點

1.restframework框架

django-rest-framework框架，基于django的REST框架，是一個強大靈活的構建Web API的工具包。
環境準備：

python3.6 
pip install django==1.11.7
pip install djangorestframework

2.基于django CBV實現接口

urls.py

from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
    # url(r'^admin/', admin.site.urls),
    url(r'^user/', views.UserView.as_view()),
]

views.py

from django.shortcuts import render,HttpResponse
from django.views import View

class UserView(View):
    def get(self,request,*args,**kwargs):
        return HttpResponse("get")
    def post(self,request,*args,**kwargs):
        return HttpResponse("post")

    def put(self,request,*args,**kwargs):
        return HttpResponse("put")
    def delete(self,request,*args,**kwargs):
        return HttpResponse("delete")

這樣的化我們就可以通過發送不同的請求來，根據不同請求做出不同響應。

2.1 源碼刨析

問題：為什么他會根據不同請求做出響應？
我們需要查看as_view都做了什么，思路。我們首先先要找到as_view的父類，也就是View.

from django.views import View
class UserView(View):
	pass

分析源碼：

@classonlymethod
   def as_view(cls, **initkwargs):

       for key in initkwargs:
           if key in cls.http_method_names:
               raise TypeError("You tried to pass in the %s method name as a "
                               "keyword argument to %s(). Don't do that."
                               % (key, cls.__name__))
           if not hasattr(cls, key):
               raise TypeError("%s() received an invalid keyword %r. as_view "
                               "only accepts arguments that are already "
                               "attributes of the class." % (cls.__name__, key))

       def view(request, *args, **kwargs):
           self = cls(**initkwargs)
           if hasattr(self, 'get') and not hasattr(self, 'head'):
               self.head = self.get
           self.request = request
           self.args = args
           self.kwargs = kwargs
           return self.dispatch(request, *args, **kwargs)
       view.view_class = cls
       view.view_initkwargs = initkwargs


       update_wrapper(view, cls, updated=())


       update_wrapper(view, cls.dispatch, assigned=())
       return view

我們整體來看，這就是一個閉包

def as_view():
	def view():
		pass
	return view

所以，我們先分析源碼中的view()

def view(request, *args, **kwargs):
		  # 這里的self=UserView()
          self = cls(**initkwargs)
          if hasattr(self, 'get') and not hasattr(self, 'head'):
              self.head = self.get
          # 請求相關的數據
          self.request = request
          # 參數相關的數據
          self.args = args
          self.kwargs = kwargs
          # self=UserView()
          # self.dispath    這里dispath返回什么用戶就看到什么。
          return self.dispatch(request, *args, **kwargs)
      view.view_class = cls
      view.view_initkwargs = initkwargs
      update_wrapper(view, cls, updated=())
      update_wrapper(view, cls.dispatch, assigned=())
      return view

dispath詳解

 http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']


def dispatch(self, request, *args, **kwargs):
	# 他會看你請求的方法是不是在http_method_names里邊。
	# 根據在不在里邊去做出相應的相應。
    if request.method.lower() in self.http_method_names:
	    # self=UserView
	    # 他會執行get/post/put/delete/方法，
	    # getattr找到UserView中http_method_names 中對應的方法執行。
        handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
    else:
        handler = self.http_method_not_allowed
    return handler(request, *args, **kwargs)

3django restframwork小試牛刀

urls.py

from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
    # url(r'^admin/', admin.site.urls),
    url(r'^user/', views.UserView.as_view()),
]

views.py

from rest_framework.views import APIView

class UserView(APIView):
    def get(self,request,*args,**kwargs):
        return HttpResponse("get")
    def post(self,request,*args,**kwargs):
        return HttpResponse("post")
    def put(self,request,*args,**kwargs):
        return HttpResponse("put")
    def delete(self,request,*args,**kwargs):
        return HttpResponse("delete")

源碼刨析

這里是繼承了APIview。我們需要從APIview中尋找as_view，查看他是如何工作的。

def as_view(cls, **initkwargs):
      if isinstance(getattr(cls, 'queryset', None), models.query.QuerySet):
          def force_evaluation():
              raise RuntimeError(
                  'Do not evaluate the `.queryset` attribute directly, '
                  'as the result will be cached and reused between requests. '
                  'Use `.all()` or call `.get_queryset()` instead.'
              )
          cls.queryset._fetch_all = force_evaluation

      view = super(APIView, cls).as_view(**initkwargs)
      view.cls = cls
      view.initkwargs = initkwargs

      return csrf_exempt(view)

?我們首先來看一下view = super(APIView, cls).as_view(**initkwargs)這條語句。補充：super會根據mro表的繼承順序查找方法。
?他會查找原來的as_view方法。原來的as_view返回的是原來的內部的view函數。
?往下走，我們發現return csrf_exempt(view),這里我們可以認為，他注釋了django的csrf_token。所以，rest framework不用csrf_token認證。其他事沒有做，還是正常走。找到view在找到dispatch。我們發現父類APIview有自己的dispatch。
dispatch分析

def dispatch(self, request, *args, **kwargs):
	 # 這里的request還是還是原來的request
	 # arg傳遞的參數
     self.args = args
     self.kwargs = kwargs
     # 將request替換，這里的替換是指將request加了一層封裝；下面將詳細說明，
     # 1. 封裝視圖函數
     request = self.initialize_request(request, *args, **kwargs)
     self.request = request
     self.headers = self.default_response_headers  # deprecate?

     try:
	     # 這里是視圖函數觸發之前就做的操作。
	     # 2. 在視圖函數值前
         self.initial(request, *args, **kwargs)
		 # 3. 執行視圖函數
         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
		 # 此處做了一個反射，找到視圖函數。
         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

?這里的request包括：

_request = 老的request(以后要用的化就需要.出來)

authenticators = 認證的對象列表

注意：這里的self.request是新的request
response = handler(request, *args, **kwargs)此處做了一個反射，找到視圖函數。
2.self.initial

def initial(self, request, *args, **kwargs):
    self.format_kwarg = self.get_format_suffix(**kwargs)
    neg = self.perform_content_negotiation(request)
    request.accepted_renderer, request.accepted_media_type = neg
    # 2.1 處理版本信息
    version, scheme = self.determine_version(request, *args, **kwargs)
    request.version, request.versioning_scheme = version, scheme
    self.perform_authentication(request)
    self.check_permissions(request)
    self.check_throttles(request)

version, scheme = self.determine_version(request, *args, **kwargs)這里邊就是處理版本相關的信息的。

def determine_version(self, request, *args, **kwargs):
    if self.versioning_class is None:
        return (None, None)
    # 實例化處理版本的對象，obj = URLPathVersioning()
    scheme = self.versioning_class()
    # 返回的結果
	    # - 方法取得東西obj.determine_version()-->幫助我們拿版本的。
	    # - 對象本身;obj
    return (scheme.determine_version(request, *args, **kwargs), scheme)

如果我們在View.py中UserView中寫versioning_class = ‘ ’他會優先執行這里的
版本具體操縱請看4.1版本

1.request處理：
我們可以先看一下，request是怎么處理的。

 def __init__(self, request, parsers=None, authenticators=None,
              negotiator=None, parser_context=None):
     assert isinstance(request, HttpRequest), (
         'The `request` argument must be an instance of '
         '`django.http.HttpRequest`, not `{}.{}`.'
         .format(request.__class__.__module__, request.__class__.__name__)
     )

     self._request = request
     self.parsers = parsers or ()
     self.authenticators = authenticators or ()
     self.negotiator = negotiator or self._default_negotiator()
     self.parser_context = parser_context
     self._data = Empty
     self._files = Empty
     self._full_data = Empty
     self._content_type = Empty
     self._stream = Empty

     if self.parser_context is None:
         self.parser_context = {}
     self.parser_context['request'] = self
     self.parser_context['encoding'] = request.encoding or settings.DEFAULT_CHARSET

     force_user = getattr(request, '_force_auth_user', None)
     force_token = getattr(request, '_force_auth_token', None)
     if force_user is not None or force_token is not None:
         forced_auth = ForcedAuthentication(force_user, force_token)
         self.authenticators = (forced_auth,)

initialize_request：這里將request做了封裝。詳解一下。

def initialize_request(self, request, *args, **kwargs):

      parser_context = self.get_parser_context(request)
	  # 這的request包括認證對像，
      return Request(
          request,
          parsers=self.get_parsers(),
          # 我們先看這里
          # 這里的 authenticators就是一個一個列表，里邊放的是我們自己寫的類的
          #一個一個對象。并且把對象封裝到request中了。
          authenticators=self.get_authenticators(),
          negotiator=self.get_content_negotiator(),
          parser_context=parser_context
      )

?這里的 authenticators就是一個一個列表，里邊放的是我們自己寫的類的一個一個對象。并且把對象封裝到request中了。這就是認證相關的對象。
get_authenticators：詳解
?這是一個列表生成式；

    def get_authenticators(self):
        return [auth() for auth in self.authentication_classes]

我們再看一下，authentication_classes

authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES

?authentication_classe默認取配置文件里讀.如果我們在自己定義的類class UserView:pass中設置，authentication_classes=[ ],那么它的優先級會比他自己定義的要高。

我們在views.py中看一下request。

class UserView(APIView):


    def get(self,request,*args,**kwargs):
        print(request)
        print(request._request)
        print(request.authenticators)
############### 打印 #####################
<rest_framework.request.Request object at 0x06D20BD0>
<WSGIRequest: GET '/user/'>
[<rest_framework.authentication.SessionAuthentication object at 0x07255670>, <rest_framework.authentication.BasicAuthentication object at 0x07255690>]

?我們可以發現，reqeust是rest_framework做好封裝的；而request._request是原來的request.request.authenticators是我們傳遞過去的幾類個對象。

4.rest framework組件

4.1 版本

urls.py

from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
    # url(r'^admin/', admin.site.urls),
    url(r'^(?P<version>\w+)/user/', views.UserView.as_view()),
]

views.py

from rest_framework.versioning import URLPathVersioning

class UserView(APIView):
    versioning_class = URLPathVersioning

    def get(self,request,*args,**kwargs):
        return HttpResponse("get")
    def post(self,request,*args,**kwargs):
        return HttpResponse("post")
    def put(self,request,*args,**kwargs):
        return HttpResponse("put")
    def delete(self,request,*args,**kwargs):
        return HttpResponse("delete")

我們需要在user前邊加上東西
?如果是versioning_class = URLPathVersioning我們來看一下他都做了什么

class URLPathVersioning(BaseVersioning):
	  invalid_version_message = _('Invalid version in URL path.')
	
	  def determine_version(self, request, *args, **kwargs):
	      version = kwargs.get(self.version_param, self.default_version)
	      if not self.is_allowed_version(version):
	          raise exceptions.NotFound(self.invalid_version_message)
	      return version

version_param

class BaseVersioning(object):
    default_version = api_settings.DEFAULT_VERSION
    allowed_versions = api_settings.ALLOWED_VERSIONS
    version_param = api_settings.VERSION_PARAM

當我們打印的時候他就會打印版本信息

class UserView(APIView):
    versioning_class = URLPathVersioning

    def get(self,request,*args,**kwargs):
        print(request.version)
        return HttpResponse("get")
  ############# 打印 ##############
v1

方式二
urls.py

from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [

    url(r'^user/', views.UserView.as_view()),
]

views.py

from rest_framework.versioning import URLPathVersioning,QueryParameterVersioning

class UserView(APIView):
	# 訪問方式http://127.0.0.1:8000/user/?version=v2
    versioning_class = QueryParameterVersioning
    def get(self,request,*args,**kwargs):
        print(request.version)
		return HttpResponse("get")
################# 打印 ########################
v2

QueryParameterVersioning

class QueryParameterVersioning(BaseVersioning):
    invalid_version_message = _('Invalid version in query parameter.')

    def determine_version(self, request, *args, **kwargs):
        # 版本信息是在query_params中拿到的
        # query_params = self._request.GET
        #def query_params(self):
	    #  return self._request.GET
        
        version = request.query_params.get(self.version_param, self.default_version)
        if not self.is_allowed_version(version):
            raise exceptions.NotFound(self.invalid_version_message)
        return version

注意推薦用第一種方式：URLPathVersioning

重點

&emsp:我們所用的都是rest_framework默認寫好的配置文件我們需要自己定義一下。我們首先找到然后它的配置文件命，我們在重新定義。

class APIView(View):
    renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES
    parser_classes = api_settings.DEFAULT_PARSER_CLASSES
    authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
    throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES
    permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
    content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS
    metadata_class = api_settings.DEFAULT_METADATA_CLASS
    # 版本
    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS

一步、urls.py

from django.conf.urls import url
from django.contrib import admin
from app01 import views
urlpatterns = [
    url(r'^(?P<version>\w+)/user/', views.UserView.as_view()),
]

所以我們需要在配置settings.py最下邊添加
二步、settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'app01.apps.App01Config',
    'rest_framework',
]



REST_FRAMEWORK = {
  "DEFAULT_VERSIONING_CLASS":"rest_framework.versioning.URLPathVersioning",
    "ALLOWED_VERSIONS":["v1","v2"],
    "DEFAULT_VERSION":"v1"

}
# rest_framework.versioning.URLPathVersioning 是URLPathVersioning 模塊調用的路徑
# ALLOWED_VERSIONS 限制版本號，只能訪問v1和v2兩個版本號
# DEFAULT_VERSION 如果沒有取到，默認取v1

ALLOWED_VERSIONS 由來


class URLPathVersioning(BaseVersioning):
    invalid_version_message = _('Invalid version in URL path.')
    def determine_version(self, request, *args, **kwargs):
        version = kwargs.get(self.version_param, self.default_version)
        if not self.is_allowed_version(version):
            raise exceptions.NotFound(self.invalid_version_message)
        return version
#####################################################################
version_param
class BaseVersioning(object):
    default_version = api_settings.DEFAULT_VERSION
    allowed_versions = api_settings.ALLOWED_VERSIONS
    version_param = api_settings.VERSION_PARAM

?當然版本也可以放在視圖局部，根據需求設置；版本可以有好多中可以是請求頭，url；子域名中；這里推薦用我們實現的方式之中。

三步、views.py

from rest_framework.versioning import URLPathVersioning

class UserView(APIView):

    # versioning_class = URLPathVersioning   如果在這里添加，優先級會高于全局

    def get(self,request,*args,**kwargs):
        return HttpResponse("get")
    def post(self,request,*args,**kwargs):
        return HttpResponse("post")
    def put(self,request,*args,**kwargs):
        return HttpResponse("put")
    def delete(self,request,*args,**kwargs):
        return HttpResponse("delete")

這里我們需要注意一下；
在視圖函數執行之前，我們執行的操作為：

版本控制

認證

權限

訪問頻率控制

posted @ 2018-05-30 17:19 zz小公子閱讀(835) 評論(0) 收藏舉報

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cameron

django restframework框架一

@(python之路)[django restframework框架初識]
django restframework框架初識

1.restframework框架

2.基于django CBV實現接口

2.1 源碼刨析

3django restframwork小試牛刀

源碼刨析

4.rest framework組件

4.1 版本

重點

公告

cameron

django restframework框架一

@(python之路)[django restframework框架初識] django restframework框架初識

1.restframework框架

2.基于django CBV實現接口

2.1 源碼刨析

3django restframwork小試牛刀

源碼刨析

4.rest framework組件

4.1 版本

重點

公告

@(python之路)[django restframework框架初識]
django restframework框架初識