Re: creating django middleware
On Fri, 2008-11-14 at 00:39 -0800, ershadul wrote: > Dear Steve Holden, > Please consider the following block i wrote: > > def process_request(self, request): > request.db_session = session() > request.db_session.time_stamp = str(datetime.datetime.now()) > print 'process_request', request.db_session.time_stamp > > def process_response(self, request, response): > try: > print 'process_response', request.db_session.time_stamp > session_destroy(request.db_session) > except AttributeError: > print 'process_response: db_session not found' > #pass > return response > > For some links i got the message 'db_session not found' , not for > all request. > that is for some requests process_response is called at first. > Look at the output at console: > These are OK. > Django version 1.0-alpha-SVN-unknown, using settings > 'divineba.settings' > Development server is running at http://127.0.0.1:8000/ > Quit the server with CTRL-BREAK. > process_request 2008-11-14 14:33:07.437000 > process_response 2008-11-14 14:33:07.437000 > [14/Nov/2008 14:33:07] "GET /journal/view HTTP/1.1" 200 22616 > process_request 2008-11-14 14:33:07.734000 > process_response 2008-11-14 14:33:07.734000 > [14/Nov/2008 14:33:07] "GET /js/jquery.js HTTP/1.1" 304 0 > process_request 2008-11-14 14:33:07.781000 > process_response 2008-11-14 14:33:07.781000 > [14/Nov/2008 14:33:07] "GET /js/jquery.autocomplete.js HTTP/1.1" 304 0 > > But for some links we got the following output: > > Django version 1.0-alpha-SVN-unknown, using settings > 'divineba.settings' > Development server is running at http://127.0.0.1:8000/ > Quit the server with CTRL-BREAK. > process_response process_response: db_session not found > [14/Nov/2008 14:36:14] "GET /account/chart HTTP/1.1" 301 0 > process_request 2008-11-14 14:36:14.531000 > process_response 2008-11-14 14:36:14.531000 > [14/Nov/2008 14:36:14] "GET /account/chart/ HTTP/1.1" 200 6717 > > Look at the 4th line: > "process_response process_response: db_session not found" > > Why for some links process_response is called before process_request? > Logically each process_request is called before process_response. > Can you provide any suggestion please ? There's no guarantee that the request method is going to be called. If another middleware earlier in the stack returned a response, the remainder of the middleware stack (including your process_request() method) is skipped -- in the request processing path. However, at that point, the full response processing path, including all middleware functions, is executed. So if something, say, the cache middleware intercepted the request before it got to your middleware, your request handler won't be run. But your response handler will be. You need to be able to handle that situation (your response handler needs to check that something like db_session exists before accessing it). Regards, Malcolm --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: creating django middleware
Dear Steve Holden, Please consider the following block i wrote: def process_request(self, request): request.db_session = session() request.db_session.time_stamp = str(datetime.datetime.now()) print 'process_request', request.db_session.time_stamp def process_response(self, request, response): try: print 'process_response', request.db_session.time_stamp session_destroy(request.db_session) except AttributeError: print 'process_response: db_session not found' #pass return response For some links i got the message 'db_session not found' , not for all request. that is for some requests process_response is called at first. Look at the output at console: These are OK. Django version 1.0-alpha-SVN-unknown, using settings 'divineba.settings' Development server is running at http://127.0.0.1:8000/ Quit the server with CTRL-BREAK. process_request 2008-11-14 14:33:07.437000 process_response 2008-11-14 14:33:07.437000 [14/Nov/2008 14:33:07] "GET /journal/view HTTP/1.1" 200 22616 process_request 2008-11-14 14:33:07.734000 process_response 2008-11-14 14:33:07.734000 [14/Nov/2008 14:33:07] "GET /js/jquery.js HTTP/1.1" 304 0 process_request 2008-11-14 14:33:07.781000 process_response 2008-11-14 14:33:07.781000 [14/Nov/2008 14:33:07] "GET /js/jquery.autocomplete.js HTTP/1.1" 304 0 But for some links we got the following output: Django version 1.0-alpha-SVN-unknown, using settings 'divineba.settings' Development server is running at http://127.0.0.1:8000/ Quit the server with CTRL-BREAK. process_response process_response: db_session not found [14/Nov/2008 14:36:14] "GET /account/chart HTTP/1.1" 301 0 process_request 2008-11-14 14:36:14.531000 process_response 2008-11-14 14:36:14.531000 [14/Nov/2008 14:36:14] "GET /account/chart/ HTTP/1.1" 200 6717 Look at the 4th line: "process_response process_response: db_session not found" Why for some links process_response is called before process_request? Logically each process_request is called before process_response. Can you provide any suggestion please ? On Nov 13, 6:18 am, Steve Holden <[EMAIL PROTECTED]> wrote: > ershadul wrote: > > Dear , > > I dont know whether my process_request() is being called or not? > > Can you inform me please, how can i verify that mymiddleware's > > process_request() is called ? > > > On Nov 12, 4:42 am, Steve Holden <[EMAIL PROTECTED]> wrote: > >> ershadul wrote: > >>> Dear all, > >>> please consider the following code-block: > >>> class SQLAlchemySessionMiddleware(object): > >>> """ > >>> This class instantiates a sqlalchemy session and destroys > >>> """ > >>> def process_request(self, request): > >>> request.db_session = session() > >>> return None > >> The last statement in your method is completely redundant, and I'd > >> suggest you remove it. > > >> How are you verifying that yourmiddleware's"process_request()" method > >> is being called? > >> [...] > > Try putting print statements in your code. Running the test server, of > course, so you will see any console output. > > regards > Steve > -- > Steve Holden +1 571 484 6266 +1 800 494 3119 > Holden Web LLC http://www.holdenweb.com/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: creating django middleware
ershadul wrote: > Dear , > I dont know whether my process_request() is being called or not? > Can you inform me please, how can i verify that my middleware's > process_request() is called ? > > On Nov 12, 4:42 am, Steve Holden <[EMAIL PROTECTED]> wrote: >> ershadul wrote: >>> Dear all, >>> please consider the following code-block: >>> class SQLAlchemySessionMiddleware(object): >>> """ >>> This class instantiates a sqlalchemy session and destroys >>> """ >>> def process_request(self, request): >>> request.db_session = session() >>> return None >> The last statement in your method is completely redundant, and I'd >> suggest you remove it. >> >> How are you verifying that your middleware's "process_request()" method >> is being called? >> [...] Try putting print statements in your code. Running the test server, of course, so you will see any console output. regards Steve -- Steve Holden+1 571 484 6266 +1 800 494 3119 Holden Web LLC http://www.holdenweb.com/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: creating django middleware
Dear , I dont know whether my process_request() is being called or not? Can you inform me please, how can i verify that my middleware's process_request() is called ? On Nov 12, 4:42 am, Steve Holden <[EMAIL PROTECTED]> wrote: > ershadul wrote: > > Dear all, > > please consider the following code-block: > > > class SQLAlchemySessionMiddleware(object): > > """ > > This class instantiates a sqlalchemy session and destroys > > """ > > def process_request(self, request): > > request.db_session = session() > > return None > > The last statement in your method is completely redundant, and I'd > suggest you remove it. > > How are you verifying that your middleware's "process_request()" method > is being called? > [...] > > regards > Steve --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: creating django middleware
I also wrote middleware for SQLAlchemy--I'd post it, but it depends on other libraries that I wrote that I can't really share. What I found is that, at least while using the dev server, the process_response method would get called when serving media files, even if the process_request hadn't. So, simple solution: wrap the session_destroy call in a try/except block. Here's mine: def process_response(self, request, response): try: request.db_session.commit() request.db_session.close() except AttributeError: pass return response Also, may I suggest adding a process_exception method? Here's mine: def process_exception(self, request, exception): request.db_session.rollback() request.db_session.close() -Jeff On Nov 12, 7:18 am, ershadul <[EMAIL PROTECTED]> wrote: > Dear all, > please consider the following code-block: > > class SQLAlchemySessionMiddleware(object): > """ > This class instantiates a sqlalchemy session and destroys > """ > def process_request(self, request): > request.db_session = session() > return None > > def process_response(self, request, response): > session_destroy(request.db_session) > return response > > Consider that session() is method that returns a new object sqlalchemy > session. > I want to inject it before view is processed and destroy it upon > exiting the view. > > I have added the path of this middleware class before XView > middleware in settings.py. > But i got a error that > request has not attribute 'db_session' ( process_response function) > How can i do it? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: creating django middleware
ershadul wrote: > Dear all, > please consider the following code-block: > > class SQLAlchemySessionMiddleware(object): > """ > This class instantiates a sqlalchemy session and destroys > """ > def process_request(self, request): > request.db_session = session() > return None > > The last statement in your method is completely redundant, and I'd suggest you remove it. How are you verifying that your middleware's "process_request()" method is being called? [...] regards Steve --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
creating django middleware
Dear all, please consider the following code-block: class SQLAlchemySessionMiddleware(object): """ This class instantiates a sqlalchemy session and destroys """ def process_request(self, request): request.db_session = session() return None def process_response(self, request, response): session_destroy(request.db_session) return response Consider that session() is method that returns a new object sqlalchemy session. I want to inject it before view is processed and destroy it upon exiting the view. I have added the path of this middleware class before XView middleware in settings.py. But i got a error that request has not attribute 'db_session' ( process_response function) How can i do it? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
