聲明：本文為轉載 django有兩種運行方式
1，通過python manage.py runserver運行內建的web server
2，通過mod_python兩種方式但最後的request產生方法都是繼承自django.http.HttpReques
第一種方式， runserver參數最後實際執行的是django.core.management.commands.runserver模組
runserver.py中關鍵代碼為
run(addr, int(port), handler) run函數詳細定義(django.core.servers.basehttp.py)：
def run(addr, port, wsgi_handler):
server_address = (addr, port)
httpd = WSGIServer(server_address, WSGIRequestHandler)
httpd.set_app(wsgi_handler)
httpd.serve_forever()
不難發現，產生一httpServer對象，並將wsgi_handler作為http請求handle 第二種方式，以Apache為例那更簡明了 <Location "/">
SetHandler python-program
PythonHandler django.core.handlers.modpython
SetEnv DJANGO_SETTINGS_MODULE mysite.settings
PythonDebug On
</Location>
PythonHandler指明django.core.handlers.modpython為處理每個http請求的handle
django.core.handlers.modpython定義了ModPythonHandler和ModPythonRequest
ModPythonHandler和WSGIHandler內容基本相同
首先產生request對象，然後處理各中介軟體和返回response，關鍵代碼如下：
try:
try:
request = self.request_class(environ)
except UnicodeDecodeError:
response = http.HttpResponseBadRequest()
else:
response = self.get_response(request)
# Apply response middleware
for middleware_method in self._response_middleware:
response = middleware_method(request, response)
response = self.apply_response_fixes(request, response)
finally:
signals.request_finished.send(sender=self.__class__)
get_response定義在django.core.handlers.base.py BaseHandler類中：
def get_response(self, request)
該函數關鍵代碼如下：
resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)
try:
callback, callback_args, callback_kwargs = resolver.resolve(
request.path_info) #此處為尋找view函數，即urls.py中定義的每個url具體的處理函數
# Apply view middleware #處理中介軟體
for middleware_method in self._view_middleware:
response = middleware_method(request, callback, callback_args, callback_kwargs)
if response:
return response
try:
response = callback(request, *callback_args, **callback_kwargs) #執行view函數
except Exception, e:
# If the view raised an exception, run it through exception
# middleware, and if the exception middleware returns a
# response, use that. Otherwise, reraise the exception.
for middleware_method in self._exception_middleware:
response = middleware_method(request, e)
if response:
return response
raise
if response is None:
try:
view_name = callback.func_name # If it's a function
except AttributeError:
view_name = callback.__class__.__name__ + '.__call__' # If it's a class
raise ValueError, "The view %s.%s didn't return an HttpResponse object." % (callback.__module__, view_name)
return response #返回response
有一張圖很明了，對理解django處理流程很有協助
先寫到這，分析原始碼對自己理解django確實協助大，發現django源碼很易懂，我想這也跟python語言本身有很大的關係
|
