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Django REST framework中的版本控制

1.REST framework版本控制的流程分析

1.1 determine_version方法的執行流程

首先,請求到達

REST framework

的CBV,執行CBV中的

dispatch

方法再次封裝完成request後,執行

initial

方法.

在

REST framework

中的版本控制就是在

initial

函數中調用

determine_version

方法完成的

來看看源碼

initial

方法的源碼:

def initial(self, request, *args, **kwargs):
    """
    Runs anything that needs to occur prior to calling the method handler.
    """
    self.format_kwarg = self.get_format_suffix(**kwargs)

    # Perform content negotiation and store the accepted info on the request
    neg = self.perform_content_negotiation(request)
    request.accepted_renderer, request.accepted_media_type = neg

    # Determine the API version, if versioning is in use.
    version, scheme = self.determine_version(request, *args, **kwargs)
    request.version, request.versioning_scheme = version, scheme

    # Ensure that the incoming request is permitted
    self.perform_authentication(request)
    self.check_permissions(request)
    self.check_throttles(request)

determine_version

方法的源碼

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

    if self.versioning_class is None:    # 如果versioning_class為空則傳回一個None的元組
        return (None, None) 
    scheme = self.versioning_class()
    return (scheme.determine_version(request, *args, **kwargs), scheme)

determine_version

方法中的

versioning_class

方法又是從哪裡來的呢

1.2 versioning_class的由來

在UserView視圖函數中沒有定義versioning_class,那就要到UserView的父類APIView中去找

在APIView類中定義了versioning_class的資訊

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
    versioning_class = api_settings.DEFAULT_VERSIONING_CLASS

在視圖函數中列印versioning_class

None

可以看到預設設定的

versioning_class的值是None

,這說明我們

可以在視圖函數中為versioning_class設定一個值

detemine_version

函數的源碼中,可以看到versioning_class後面加了一個括号,是以

versioning_class是一個函數或一個類

 
如果versioning_class是一個函數,那麼執行versioning_class後會有一個傳回值
如果versioning_class是一個類,那麼versioning_class加括号就執行個體化一個類

從rest_framework中導入versioning子產品

from rest_framework import versioning

然後進入versioning子產品,可以看到這個versioning中定義了6個類

這6個類是

BaseVersioning

,

AcceptHeaderVersioning

URLPathVersioning

NamespaceVersioning

HostNameVersioning

QueryParameterVersioning

而且還可以看到

BaseVersioning類

是其餘5個類的父類.

并且這其餘的5個類,每個類中都有一個

determine_version

方法

在項目的視圖函數中導入其中任意一個類,列印

versioning_class

 
from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from django.views import View
from rest_framework.versioning import QueryParameterVersioning

class UsersView(APIView):
    versioning_class=QueryParameterVersioning

    def get(self,request,*args,**kwargs):
        print(self.versioning_class)        #列印versioning_class

        return HttpResponse("aaaa")

列印結果

<class 'rest_framework.versioning.QueryParameterVersioning'>

是以versioning_class是一個類,并且

versioning_class類中有一個determine_version方法

1.3 REST framework版本控制的流程總結

initial

方法中,執行完

determine_version

後的傳回值被指派給version, scheme這兩個變量

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

    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)

這兩個變量又把

determine_version

方法的傳回值指派給

request.version

request.versioning_scheme

這兩個變量

在視圖函數中列印這兩個變量

from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import QueryParameterVersioning

class UsersView(APIView):
    versioning_class=QueryParameterVersioning

    def get(self,request,*args,**kwargs):
        print(self.versioning_class)
        print("request.version:",request.version)
        print("request.versioning_scheme:",request.versioning_scheme)

        return HttpResponse("aaaa")           
<class 'rest_framework.versioning.QueryParameterVersioning'>
request.version: None
request.versioning_scheme: <rest_framework.versioning.QueryParameterVersioning object at 0x00000000057722B0>

2. REST framework擷取版本的方法

在上面的流程分析中,versioning子產品中定義了6個類

BaseVersioning

AcceptHeaderVersioning

URLPathVersioning

NamespaceVersioning

HostNameVersioning

QueryParameterVersioning

BaseVersioning類

是其餘5個類的父類,

REST framework

擷取版本調用的就是這5個類

2.1 QueryParameterVersioning:基于url的get傳參方式

在settings.py檔案的

INSTALLED_APPS

配置項中引入rest-framework

INSTALLED_APPS = [
    ...
    'rest_framework',
]

配置路由表

from django.conf.urls import url
from django.contrib import admin
from app01 import views

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^users/$',views.UsersView.as_view()),
]

視圖函數配置擷取版本方式為

QueryParameterVersioning

 
from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import QueryParameterVersioning

class UsersView(APIView):
    versioning_class=QueryParameterVersioning

    def get(self,request,*args,**kwargs):
        # print("request:",request.__dict__)
        print("request.version:",request.version)       # 列印版本
        # print(request.version.scheme)
        # print(request.versioning_scheme.reverse("test1",request=request))
        # print(request.versioning_scheme.reverse(viewname="test1",request=request))

        return HttpResponse("aaaa")

在浏覽器中輸入

http://127.0.0.1:8000/users/?version=v1

位址,服務端列印結果

request.version: v1

再把浏覽器中的url位址更換為

http://127.0.0.1:8000/users/?version=v5

,重新整理浏覽器,服務端列印結果

request.version: v5

2.2 URLPathVersioning:基于url的正則方式

配置url路由資訊

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^(?P<version>\w+)/users/$',views.UsersView.as_view()),
]

URLPathVersioning

 
from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import URLPathVersioning

class UsersView(APIView):
    versioning_class=URLPathVersioning

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

        print("request.version:",request.version)   # 列印版本

        return HttpResponse("aaaa")

http://127.0.0.1:8000/v1/users/

 
request.version: v1

http://127.0.0.1:8000/v10/users/

 
request.version: v10

2.3 AcceptHeaderVersioning:基于accept請求頭方式擷取版本資訊

在settings.py檔案中添加如下配置

REST_FRAMEWORK = {
    'VERSION_PARAM': "version",     # 版本的參數,在url中可以展現
    'DEFAULT_VERSION': 'V1',        # 預設的版本
    'ALLOWED_VERSIONS': ['v1', 'v2','v3']  # 允許的版本
}

urls.py設定為

from django.conf.urls import url
from django.contrib import admin
from app01 import views

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^users/$',views.UsersView.as_view()),
]

視圖函數定義

from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import AcceptHeaderVersioning

class UsersView(APIView):
    versioning_class=AcceptHeaderVersioning

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

        print("request.version:",request.version)   # 擷取版本資訊

        return HttpResponse("aaaa")

用浏覽器打開

http://127.0.0.1:8000/users/

的url位址

request.version: V1

由于在settings.py檔案中已經設定了預設的版本是v1,是以在服務端背景擷取到的版本是v1

把settings.py中定義的預設版本更改變v2或者v3,再次重新整理浏覽器,背景列印的版本資訊又會跟着改變

request.version: V2

2.4 NamespaceVersioning:基于django路由系統的namespace 

from django.conf.urls import url
from django.contrib import admin
from app01 import views

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^v1/users/',([url(r'test/',views.UsersView.as_view(),name='test1')],None,'v1')),
    url(r'^v2/users/',([url(r'test/',views.UsersView.as_view(),name='test2')],None,'v2')),
]           
from django.shortcuts import render,HttpResponse
from rest_framework.views import APIView
from rest_framework.versioning import NamespaceVersioning

class UsersView(APIView):
    versioning_class=NamespaceVersioning

    def get(self,request,*args,**kwargs):
        print("request.version:",request.version)   # 擷取版本資訊

        return HttpResponse("aaaa")

http://127.0.0.1:8000/v1/users/test/

 
request.version: V1

把url的位址更換為

http://127.0.0.1:8000/v2/users/test/

,重新整理浏覽器,背景列印資訊如下

request.version: V2

2.5 HostNameVersioning由于要更換電腦的主機名稱,是以這裡不再進行測試

3. versioning_class的全局配置

在視圖函數中定義

versioning_class

,隻能作用于單個類,

如果想整個項目都使用同一種方法來進行版本控制,就可以在settings.py檔案中定義全局的

versioning_class

settings.py

中配置預設的

versioning_class

為

URLPathVersioning

 
REST_FRAMEWORK={
    'DEFAULT_VERSIONING_CLASS':'rest_framework.versioning.URLPathVersioning',
}

在前面檢視到

BaseVersioning

的源碼時,可以看到還有幾個參數可以在settings.py檔案中定義的

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

再來看看這幾個參數配置項的作用

REST_FRAMEWORK={            # 預設使用URLPathVersioning類來擷取版本資訊
    'DEFAULT_VERSIONING_CLASS':'rest_framework.versioning.URLPathVersioning',
    'VERSION_PARAM':"version",          # 版本的參數,在url中可以展現
    'DEFAULT_VERSION':'V1',             # 預設的版本
    'ALLOWED_VERSIONS':['v1','v2']      # 允許的版本
}

修改urls.py檔案,使url可以比對任意長度的字元url

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+)/users/$',views.UsersView.as_view()),
]

在浏覽器中分别輸入

http://127.0.0.1:8000/v1/users/

和

http://127.0.0.1:8000/v2/users/

都可以擷取到正确的響應資訊

再在浏覽器中輸入

http://127.0.0.1:8000/v3/users/

時,浏覽器中出現了報錯

Django REST framework中的版本控制

從這裡可以知道,在settings.py檔案中設定的url中允許的版本隻能是v1或v2,在浏覽器中輸入的版本是v3,是以就會出現錯誤了

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