[Oldboy-django] [2 in-depth Django] Django a request lifecycle + WSGI + middleware

1 WSGI

#WSGI (is a set of protocols, many things such as Wsgiref, uwsgiref follow this set of protocols)-the Django system is essentially someone's socket (wsgiref or uwsgiref)+Django-The simple definition of WSGI (Web server Gateway Interface) is a specification that defines the interface format between Web apps and Web servers written in Python, enabling Web apps and Web Ser    Decoupling between the Ver. -more complete Web request life-cycle requests--Follow the WSGI socket server (WSGIREF)--->django middleware---> Routing system--->View Function View functions---> Routing systems---> Middleware--->wsgi--->Client-examples of Django-borrowed WSGIREF servers fromWsgiref.simple_serverImportMake_serverdefrunserver (environ, start_response):"""@params: Information about the environ request @params: Start_response container that returns the contents as a message header to the user @ret The contents returned by the urn are returned as the body of the message to the user"""Start_response ('OK', [('Content-type','text/html')])            return[Bytes ('', encoding='Utf-8'), ]        if __name__=='__main__': httpd= Make_server ("', 8000, Runserver) httpd.serve_forever ()#wait for the socket request of the service, execute the Runserver function when the request comes over-a simple socket serverImportSocketdefhandle_request (client): BUF= CLIENT.RECV (1024) Client.send ("http/1.1 ok\r\n\r\n") Client.send ("Hello, Seven.")        defMain (): Sock=Socket.socket (socket.af_inet, socket. Sock_stream) Sock.bind (('localhost', 8000)) Sock.listen (5)             whiletrue:connection, Address=sock.accept () handle_request (connection) connection.close ()if __name__=='__main__': Main ()

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2 Django Full life cycle of a request

   - Django The lifecycle of a request        is simply: Wsgi and Django        client -->request--->wsgi---> All middleware (middleware process_request)--->process_view----> Views---        >urls---> All middleware ( Middleware process_response)--->wsgi---> client        PS: Process_ in middleware The request already knows which view function to execute (according to request, get the URL, get the corresponding view function according to the URL)

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3 middleware

#Middleware-the life cycle of a Django request is simply: Wsgi and the Django client-->request--->wsgi---> All middleware (middleware process_request)--->process_view----> views--->urls---> All middleware (middleware process_response)--->wsgi--->Client PS: In the middleware process_request already know which view function to execute (according to request has obtained the URL, according to the URL to get the corresponding view function)-Define your own middleware class Mymiddle (middleware is a class) fromDjango.utils.deprecationImportmiddlewaremixin fromDjango.shortcutsImportRender,httpresponseclassMyMiddle1 (middlewaremixin):defprocess_request (self, request):Print('m1.process.request')            defProcess_view (self, request,callback, Callback_args, Callback_kwargs):Print('M1.process_view')                Print(callback)#This callback, is the URL corresponding to the view function                #return callback (Request, *callback_args, **callback_kwargs)            defProcess_response (self, request, response):Print('M1.processs.response')                returnResponse#You must have this, or you'll get an error.            defprocess_exception (self, request, exception):Print('m1.process_exception')                #print (Exception)        classMyMiddle2 (middlewaremixin):defprocess_request (self, request):Print('m2.process.request')            defProcess_view (Self,request, Callback, Callback_args, Callback_kwargs):Print('M2.process_view')            defProcess_response (self, request, response):Print('M2.processs.response')                returnResponse#You must have this, or you'll get an error.            defprocess_exception (self, request, exception):Print('m2.process_exception')                #print (Exception)-Register Middleware Middleware= [            #omit the previous section, append the next two            'Mid. MyMiddle1',            'Mid. MyMiddle2',        ]    -Full lifecycle HTTPS for a request:www.processon.com/diagraming/5a0ce2bae4b06bed41d126e1 Normal Flow: m1.process.request m2.process.request M1.proce        Ss_view m2.process_view views M2.processs.response m1.processs.response If there is exception:m1.process.request m2.process.request M1.process_view m2.proces            S_view views M2.process_exception m1.process_exception M2.processs.response M1.processs.response-Middleware Applications unify all requests (or part of a request) (such as caching)--can use the middleware implementation of each request to make a judgment, if the cache has, return, otherwise to the views read the database,

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[Oldboy-django] [2 in-depth Django] Django a request lifecycle + WSGI + middleware