1. 瀏覽器解析輸入的url
2. 尋找url對應的ip位址
3. 透過ip位址存取我們的伺服器
a . 請求進入wsgi伺服器（我在這裡省略了可能存在的代理伺服器，例如nginx）
b. wsgi伺服器將請求包裝後，傳遞給django應用
c. django應用根據請求路徑找到對應的處理函數進行處理
d. 處理完成後，django應用程式將回應傳回給wsgi伺服器
e. wsgi伺服器將django套用傳回的回應包裝後，回傳回應
4. 伺服器回傳回應內容，瀏覽器渲染輸出
wsgi服務透過wsgi協定和django應用程式進行通信，wsgi服務是server端，django應用是application，server端透過django提供的application_callable函數去呼叫djano應用，application_callable函數處理完成後，將回應傳回給server
django的application_callable函式在django.core.handlers.wsgi.py檔案中，server服務端處理每個請求時會呼叫WSGIHandler這個類別
#wsgi.py文件
class WSGIHandler(base.BaseHandler):
request_class = WSGIRequest
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.load_middleware()
def __call__(self, environ, start_response):
set_script_prefix(get_script_name(environ))
signals.request_started.send(sender=self.__class__, environ=environ)
request = self.request_class(environ)
response = self.get_response(request)
response._handler_class = self.__class__
status = '%d %s' % (response.status_code, response.reason_phrase)
response_headers = list(response.items())
for c in response.cookies.values():
response_headers.append(('Set-Cookie', c.output(header='')))
start_response(status, response_headers)
if getattr(response, 'file_to_stream', None) is not None and environ.get('wsgi.file_wrapper'):
response = environ['wsgi.file_wrapper'](response.file_to_stream)
return responseWSGIHandler類別在初始化時，先載入中間件，將要請求的函數_get_response用中間件封裝起來（中間件相當於裝飾器），執行的時候，中間件就會執行
# wsgi.py文件
# wsgi.py文件
def load_middleware(self):
...
self._view_middleware = []
self._template_response_middleware = []
self._exception_middleware = []
handler = convert_exception_to_response(self._get_response)
for middleware_path in reversed(settings.MIDDLEWARE):
middleware = import_string(middleware_path)
try:
mw_instance = middleware(handler)
except MiddlewareNotUsed as exc:
...
handler = convert_exception_to_response(mw_instance)
self._middleware_chain = handler接下來，就是請求調用WSGIHandler
1. 實例化一個request_class
2. 透過get_response取得請求，get_response最終會呼叫被中間件封裝後的函式_get_response
def _get_response(self, request):
response = None
if hasattr(request, 'urlconf'):
urlconf = request.urlconf
set_urlconf(urlconf)
resolver = get_resolver(urlconf)
else:
resolver = get_resolver()
resolver_match = resolver.resolve(request.path_info)
callback, callback_args, callback_kwargs = resolver_match
request.resolver_match = resolver_match
...
if response is None:
wrapped_callback = self.make_view_atomic(callback)
try:
response = wrapped_callback(request, *callback_args, **callback_kwargs)
except Exception as e:
response = self.process_exception_by_middleware(e, request)
...
return response_get_response函數中，首先會根據url找到要呼叫的視圖函數 resolver_match = resolver.resolve(request.path_info)，然後呼叫視圖函數 response = wrapped_callback(request, *callback_args, **callback_kwargs)kwargs)
回傳response（在_get_response裡面也是會呼叫一些的中間件的）至此再將response回傳給server，整個請求流程完畢四、總結django對於一個請求，主要過程就是尋找請求對應的視圖函數，呼叫被中間件封裝後的視圖函數，回傳回應。【推薦課程：Django影片教學
】###以上是django源碼分析之請求流程的詳細內容。更多資訊請關注PHP中文網其他相關文章！
