win32print how to lower cpu load?

From: Guy Robinson (guy_at_NOSPAM.r-e-d.co.nz)
Date: 11/30/03

  • Next message: Jules Dubois: "Re: Bug in glob.glob for files w/o extentions in Windows" 
    Date: Sun, 30 Nov 2003 21:26:57 +1300

    Hello,

    I've got this working print queue monitor and currently it checks the
    queues every 1 second. I'm worried that I might miss events if I set
    the delay to more than this. Particularly as I would like to perform
    functions depending on status codes. When I don't have a delay set, the
    CPU usage is huge 70%.

    My question is, is there an 'intelligent' way of monitoring the spooler?
    I guess what I'm thinking is some low cpu method of watching for
    activity on the spooler, and triggering my program as the spooler stops
    and starts.

    Suggestions?

    Regards,

    Guy

    Here's my code so far:

    try:
         import win32print
    except:
         print 'win32all required .'

    import time

    #constants

    wp = win32print

    # lists and dictionaries of constants
    ptypelist =
    [(wp.PRINTER_ENUM_SHARED,'shared'),(wp.PRINTER_ENUM_LOCAL,'local'),(wp.PRINTER_ENUM_CONNECTIONS,'network')]
    cmds = {'Pause':wp.JOB_CONTROL_PAUSE, 'cancel':wp.JOB_CONTROL_CANCEL,
    'resume':wp.JOB_CONTROL_RESUME,
    'prior_low':wp.MIN_PRIORITY,'prior_high':wp.MAX_PRIORITY,'prior_normal':wp.DEF_PRIORITY
    }
    status codes =
    {'deleting':wp.JOB_STATUS_DELETING,'error':wp.JOB_STATUS_ERROR,'offline':wp.JOB_STATUS_OFFLINE,'paper
    out':wp.JOB_STATUS_PAPEROUT,'paused':wp.JOB_STATUS_PAUSED,'printed':wp.JOB_STATUS_PRINTED,'printing':wp.JOB_STATUS_PRINTING,'spooling':wp.JOB_STATUS_SPOOLING}

    class PMFuncs:

         def __init__(self):

             # initialise the list of printers
             self.PList =[]

         def PrinterList(self):

             # returns a list of dicts.
             # this gets the default printer
             tmpdic ={}
             DefPName = win32print.GetDefaultPrinter()

             # Get the default printer firstso we can add this to the list
    of printers

             for pt in ptypelist:

                 try:

                     for (Flags,pDescription,pName,pComment) in
    list(win32print.EnumPrinters(pt[0],None,1)):
                         tmpdic ={}
                         tmpdic['PType'] = pt[1]
                         tmpdic['Flags'] = Flags
                         tmpdic['Description'] = pDescription
                         #test for if this is the default printer
                         if pName == DefPName:
                             tmpdic['DefPrinter':True]
                         else:
                             tmpdic['DefPrinter':False]
                         tmpdic['Name'] = pName
                         tmpdic['Comment'] = pComment
                         self.PList.append(tmpdic)
                 except:
                     pass #no printers of this type so don't add anything

             return self.PList #list of installed printers

         def GetJobList(self,printer):

             phandle = win32print.OpenPrinter(printer)
             #now get all the print jobs (start at job 0 and -1 for all jobs)
             jlist = win32print.EnumJobs(phandle,0,-1,1)
             win32print.ClosePrinter(phandle)
             return jlist # this lists all jobs on all printers

         def GetJobInfo(self,printer,jobID):

             phandle = win32print.OpenPrinter(printer)
             ilist = win32print.GetJob(phandle,jobID,1)
             win32print.ClosePrinter(phandle)
             return ilist #this lists all info available at level 1 for
    selected job.

         def SetJobCmd(self, printer, jobID , JobInfo , RCmd ):

             phandle = win32print.OpenPrinter(printer)
             win32print.SetJob(phandle,jobID,1,JobInfo,Cmds[RCmd])
             win32print.ClosePrinter(phandle)

    # test functions
    e = PMFuncs()
    while 1:

         time.sleep(1)
         e = PMFuncs()
         for i in e.PrinterList():

             try:
                 p = e.GetJobList(i['Name'])
                 for w in p:
                     print e.GetJobInfo(i['Name'],w['JobID'])

             except:
                 pass

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