Django源码分析--引导

声明：本文为转载   django有两种运行方式 1，通过python manage.py runserver运行自带的web server 2，通过mod_python 两种方式但最后的request生成方法都是继承自django.http.HttpReques 第一种方式， runserver参数最后实际执行的是django.core.management.commands.runserver模块 runserver.py中关键代码为 run(addr, int(port), handler) run函数详细定义(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() 不难发现，生成一httpServer对象，并将wsgi_handler作为http请求handle 第二种方式，以Apache为例那更简明了 <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为处理每个http请求的handle django.core.handlers.modpython定义了ModPythonHandler和ModPythonRequest ModPythonHandler和WSGIHandler内容基本相同 首先生成request对象，然后处理各中间件和返回response，关键代码如下： 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定义在django.core.handlers.base.py BaseHandler类中： def get_response(self, request) 该函数关键代码如下： resolver = urlresolvers.RegexURLResolver(r'^/', urlconf) try: callback, callback_args, callback_kwargs = resolver.resolve( request.path_info) #此处为寻找view函数，即urls.py中定义的每个url具体的处理函数 # Apply view middleware #处理中间件 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) #执行view函数 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 有一张图很明了，对理解django处理流程很有帮助 先写到这，分析源代码对自己理解django确实帮助大，发现django源码很易懂，我想这也跟python语言本身有很大的关系