[mod_python] The DOs and DONTs of mod_python: second problem maybe cornered.

Hi,

If any of you wish to look at this: this code works in command line, and 
crashes with apache. Something I'm doing is really anoying minidom.


you can fetch the xml file responsible at: www.snakecard.com/mod_python

Any help is greatly appreciated.

Regards,

Philippe
if __name__ != "__main__":
     from mod_python import apache
import os
import sys
if os.name == 'nt':
     sys.path.append("Z:\\dev")
else:
     sys.path.append('/home/philippe/dev')

import xml
import xml.dom
from xml.dom import minidom


def test():
     l_doc = minidom.parse('/var/www/html/mp/templates/sc_template.xml')
     print l_doc
     

def world(req):


     
     l_doc = minidom.parse('/var/www/html/mp/templates/sc_template.xml')

     return 'OK' #let's stop here for now


     ls = SC_Script_Processor() #INSTANTIATE A _BIG_ OBJECT ==> *** HIS IS THE 
KILLER ***
     ll = ls.Reader_List() # get the reader list

     #Grab ATR from card - assume first reader
     l_appli_conn = ls.Get_Connection(ll[0] )
     
     
     
     req.send_http_header()
     req.write("RETURN CARD ATR= " +  l_appli_conn.Get_Connection_ATR() )

     

     
     return apache.OK
 



#*******************************************************************************
if __name__ == "__main__":
     test()

     




On Wednesday 19 October 2005 12:00 am, Philippe C. Martin wrote:
> Hi,
>
> It took me a while to understand that although I had apache configured to
> run as me "philippe", doing an os.getenv still returned the root
> environment variables.
>
> Maybe forcing a source of ~/.bashrc ?
>
> Regards,
>
> Philippe
>
> On Tuesday 18 October 2005 11:40 pm, Philippe C. Martin wrote:
> > On Tuesday 18 October 2005 11:33 pm, Graham Dumpleton wrote:
> >
> > Thanks,
> >
> > The one good thing is that I cannot afford all of these threads to attack
> > the only hardware resource (the smart card) at the same time: ISO7816
> > simply is not ready for it.
> >
> > So I will have to find a way to keep the people waiting and avoid
> > concurent access.
> >
> > Regards,
> >
> > Philippe
> >
> > > A few additional comments on top of what Jorey has already said.
> > >
> > > Philippe C. Martin wrote ..
> > >
> > > > Please note that, although I must have bugs, the code I'm calling
> > > > _seems_ to
> > > > work flawlessly under Linux and Windows.
> > >
> > > Besides issues with multiple interpreters, if using a multithread
> > > Apache MPM, such as is the case for Win32 systems and "worker" MPM on
> > > UNIX, you have to contend with multithreading. Your system may work
> > > quite happily if you trickle requests in serially, but get requests
> > > come in at the same time and they can trample all over each other if
> > > your module isn't multithread safe.
> > >
> > > There are also various issues because of mod_python's module reloading
> > > system. Problems can also arise if you use a module which has a C code
> > > component and it uses the simplified threading C APIs in Python.
> > >
> > > There are a lot of gotchas.
> > >
> > > > from mod_python import apache
> > > > import os
> > > > import sys
> > > > if os.name == 'nt':
> > > >      sys.path.append("Z:\\dev")
> > > > else:
> > > >      sys.path.append('/home/philippe/dev')
> > >
> > > You shouldn't extend sys.path in Python code when mod_python is used.
> > > The main reason is that if mod_python reloads the module, everytime
> > > that occurs then sys.path will be extended even if the directory is
> > > already in there. Thus, sys.path could grow and grow. This is made
> > > worse by bugs in mod_python.publisher in versions of mod_python < 3.2.
> > >
> > > > from SC.pilot.SC_Script_Processor import *
> > > >
> > > >
> > > > def world(req):
> > > >      ls = SC_Script_Processor() #INSTANTIATE A _BIG_ OBJECT ==> ***
> > > > THIS IS
> > > > THE KILLER THAT CRASHES APACHE ***
> > > >      ll = ls.Reader_List() # get the reader list
> > > >
> > > >      #Grab ATR from card - assume first reader
> > > >      l_appli_conn = ls.Get_Connection(r1)
> > > >
> > > >
> > > >
> > > >      req.send_http_header()
> > >
> > > You don't set req.content_type. How is the browser mean't to know what
> > > to do with the response. You perhaps want:
> > >
> > >   req.content_type = 'text/plain'
> > >   req.send_http_header()
> > >
> > > Although, in 3.X the call to 'req.send_http_header()' is actually
> > > redundant. It was only required in 2.7.X.
> > >
> > > >      req.write("RETURN CARD ATR= " + 
> > > > l_appli_conn.Get_Connection_ATR() )
> > > >
> > > >      return apache.OK
> > >
> > > I have presumed that mod_python.publisher was being used because
> > > you weren't using "handler()" for the function, but "world()". If this
> > > is the case, you shouldn't be returning "apache.OK" as it will result
> > > in the string "0" being appended to the response sent back to the
> > > browser.
> > >
> > > Overall, better off perhaps saying:
> > >
> > >   req.content_type = 'text/plain'
> > >   return "RETURN CARD ATR= " +  l_appli_conn.Get_Connection_ATR()
> > >
> > > Graham

-- 
*************************************
Philippe C. Martin
SnakeCard, LLC
www.snakecard.com
+1 405 694 8098
*************************************