printing - How to catch printer event in python

Question

I want to catch the signal when the printer started to print. That would be fine if you tell me how to get the path of document that will print.

pywin32print looks like useful but I don't know how to use.

Answer 1

To be notified of new print jobs, you can use FindFirstPrinterChangeNotification, FindNextPrinterChangeNotification, and a wait function from kernel32 such as WaitForSingleObject.

Here's an example to set a filter that waits for a new print job on the local print server. There's much more work to be done if you want the JOB_NOTIFY_FIELD_DOCUMENT value out of a PRINTER_NOTIFY_INFO_DATA structure.

Edit: Malik Brahimi requested information about obtaining the print job ID, so I've decided to flesh this out as a more complete example. The new code adds a wait_for_print_job_info function that waits for notifications specified using the PRINTER_NOTIFY_OPTIONS structure. Windows returns the data in an array of the above-mentioned PRINTER_NOTIFY_INFO_DATA structures, each of which has the print job Id for the given data.

The data has to be freed by calling FreePrinterNotifyInfo, which I handle automatically in the __del__ finalizer of the PPRINTER_NOTIFY_INFO_GC class.

import ctypes
from ctypes import wintypes

kernel32 = ctypes.WinDLL('kernel32.dll', use_last_error=True)
winspool = ctypes.WinDLL('winspool.drv', use_last_error=True)

# define LPHANDLE, PDWORD, and PWORD for Python 2
if not hasattr(wintypes, 'LPHANDLE'):
    setattr(wintypes, 'LPHANDLE', ctypes.POINTER(wintypes.HANDLE))
if not hasattr(wintypes, 'PDWORD'):
    setattr(wintypes, 'PDWORD', ctypes.POINTER(wintypes.DWORD))
if not hasattr(wintypes, 'PWORD'):
    setattr(wintypes, 'PWORD', ctypes.POINTER(wintypes.WORD))

INFINITE = -1
WAIT_OBJECT_0 = 0x00000000
WAIT_TIMEOUT  = 0x00000102
WAIT_FAILED   = 0xFFFFFFFF
INVALID_HANDLE_VALUE = wintypes.HANDLE(-1).value

PRINTER_CHANGE_ADD_PRINTER               = 0x00000001
PRINTER_CHANGE_SET_PRINTER               = 0x00000002
PRINTER_CHANGE_DELETE_PRINTER            = 0x00000004
PRINTER_CHANGE_FAILED_CONNECTION_PRINTER = 0x00000008
PRINTER_CHANGE_PRINTER                   = 0x000000FF

PRINTER_CHANGE_ADD_JOB                   = 0x00000100
PRINTER_CHANGE_SET_JOB                   = 0x00000200
PRINTER_CHANGE_DELETE_JOB                = 0x00000400
PRINTER_CHANGE_WRITE_JOB                 = 0x00000800
PRINTER_CHANGE_JOB                       = 0x0000FF00

PRINTER_CHANGE_ADD_FORM                  = 0x00010000
PRINTER_CHANGE_SET_FORM                  = 0x00020000
PRINTER_CHANGE_DELETE_FORM               = 0x00040000
PRINTER_CHANGE_FORM                      = 0x00070000

PRINTER_CHANGE_ADD_PORT                  = 0x00100000
PRINTER_CHANGE_CONFIGURE_PORT            = 0x00200000
PRINTER_CHANGE_DELETE_PORT               = 0x00400000
PRINTER_CHANGE_PORT                      = 0x00700000

PRINTER_CHANGE_ADD_PRINT_PROCESSOR       = 0x01000000
PRINTER_CHANGE_DELETE_PRINT_PROCESSOR    = 0x04000000
PRINTER_CHANGE_PRINT_PROCESSOR           = 0x07000000
PRINTER_CHANGE_SERVER                    = 0x08000000 # NT 6.1+

PRINTER_CHANGE_ADD_PRINTER_DRIVER        = 0x10000000
PRINTER_CHANGE_SET_PRINTER_DRIVER        = 0x20000000
PRINTER_CHANGE_DELETE_PRINTER_DRIVER     = 0x40000000
PRINTER_CHANGE_PRINTER_DRIVER            = 0x70000000

PRINTER_CHANGE_ALL                       = 0x7F77FFFF
PRINTER_CHANGE_TIMEOUT                   = 0x80000000

PRINTER_NOTIFY_CATEGORY_ALL = 0x00
PRINTER_NOTIFY_CATEGORY_3D  = 0x01

PRINTER_NOTIFY_TYPE = 0x00
JOB_NOTIFY_TYPE     = 0x01

PRINTER_NOTIFY_FIELD_SERVER_NAME            = 0x00 # not supported
PRINTER_NOTIFY_FIELD_PRINTER_NAME           = 0x01
PRINTER_NOTIFY_FIELD_SHARE_NAME             = 0x02
PRINTER_NOTIFY_FIELD_PORT_NAME              = 0x03
PRINTER_NOTIFY_FIELD_DRIVER_NAME            = 0x04
PRINTER_NOTIFY_FIELD_COMMENT                = 0x05
PRINTER_NOTIFY_FIELD_LOCATION               = 0x06
PRINTER_NOTIFY_FIELD_DEVMODE                = 0x07
PRINTER_NOTIFY_FIELD_SEPFILE                = 0x08
PRINTER_NOTIFY_FIELD_PRINT_PROCESSOR        = 0x09
PRINTER_NOTIFY_FIELD_PARAMETERS             = 0x0A
PRINTER_NOTIFY_FIELD_DATATYPE               = 0x0B
PRINTER_NOTIFY_FIELD_SECURITY_DESCRIPTOR    = 0x0C
PRINTER_NOTIFY_FIELD_ATTRIBUTES             = 0x0D
PRINTER_NOTIFY_FIELD_PRIORITY               = 0x0E
PRINTER_NOTIFY_FIELD_DEFAULT_PRIORITY       = 0x0F
PRINTER_NOTIFY_FIELD_START_TIME             = 0x10
PRINTER_NOTIFY_FIELD_UNTIL_TIME             = 0x11
PRINTER_NOTIFY_FIELD_STATUS                 = 0x12
PRINTER_NOTIFY_FIELD_STATUS_STRING          = 0x13 # not supported
PRINTER_NOTIFY_FIELD_CJOBS                  = 0x14
PRINTER_NOTIFY_FIELD_AVERAGE_PPM            = 0x15
PRINTER_NOTIFY_FIELD_TOTAL_PAGES            = 0x16 # not supported
PRINTER_NOTIFY_FIELD_PAGES_PRINTED          = 0x17 # not supported
PRINTER_NOTIFY_FIELD_TOTAL_BYTES            = 0x18 # not supported
PRINTER_NOTIFY_FIELD_BYTES_PRINTED          = 0x19 # not supported
PRINTER_NOTIFY_FIELD_OBJECT_GUID            = 0x1A
PRINTER_NOTIFY_FIELD_FRIENDLY_NAME          = 0x1B # NT 6.0+
PRINTER_NOTIFY_FIELD_BRANCH_OFFICE_PRINTING = 0x1C # NT 6.2+

JOB_NOTIFY_FIELD_PRINTER_NAME        = 0x00
JOB_NOTIFY_FIELD_MACHINE_NAME        = 0x01
JOB_NOTIFY_FIELD_PORT_NAME           = 0x02
JOB_NOTIFY_FIELD_USER_NAME           = 0x03
JOB_NOTIFY_FIELD_NOTIFY_NAME         = 0x04
JOB_NOTIFY_FIELD_DATATYPE            = 0x05
JOB_NOTIFY_FIELD_PRINT_PROCESSOR     = 0x06
JOB_NOTIFY_FIELD_PARAMETERS          = 0x07
JOB_NOTIFY_FIELD_DRIVER_NAME         = 0x08
JOB_NOTIFY_FIELD_DEVMODE             = 0x09
JOB_NOTIFY_FIELD_STATUS              = 0x0A
JOB_NOTIFY_FIELD_STATUS_STRING       = 0x0B
JOB_NOTIFY_FIELD_SECURITY_DESCRIPTOR = 0x0C # not supported
JOB_NOTIFY_FIELD_DOCUMENT            = 0x0D
JOB_NOTIFY_FIELD_PRIORITY            = 0x0E
JOB_NOTIFY_FIELD_POSITION            = 0x0F
JOB_NOTIFY_FIELD_SUBMITTED           = 0x10
JOB_NOTIFY_FIELD_START_TIME          = 0x11
JOB_NOTIFY_FIELD_UNTIL_TIME          = 0x12
JOB_NOTIFY_FIELD_TIME                = 0x13
JOB_NOTIFY_FIELD_TOTAL_PAGES         = 0x14
JOB_NOTIFY_FIELD_PAGES_PRINTED       = 0x15
JOB_NOTIFY_FIELD_TOTAL_BYTES         = 0x16
JOB_NOTIFY_FIELD_BYTES_PRINTED       = 0x17
JOB_NOTIFY_FIELD_REMOTE_JOB_ID       = 0x18

PRINTER_NOTIFY_OPTIONS_REFRESH = 0x01
PRINTER_NOTIFY_INFO_DISCARDED  = 0x01

JOB_STATUS_PAUSED            = 0x00000001
JOB_STATUS_ERROR             = 0x00000002
JOB_STATUS_DELETING          = 0x00000004
JOB_STATUS_SPOOLING          = 0x00000008
JOB_STATUS_PRINTING          = 0x00000010
JOB_STATUS_OFFLINE           = 0x00000020
JOB_STATUS_PAPEROUT          = 0x00000040
JOB_STATUS_PRINTED           = 0x00000080
JOB_STATUS_DELETED           = 0x00000100
JOB_STATUS_BLOCKED_DEVQ      = 0x00000200
JOB_STATUS_USER_INTERVENTION = 0x00000400
JOB_STATUS_RESTART           = 0x00000800
JOB_STATUS_COMPLETE          = 0x00001000
JOB_STATUS_RETAINED          = 0x00002000
JOB_STATUS_RENDERING_LOCALLY = 0x00004000
JOB_STATUS_ALL               = 0x00007FFF

JOB_STATUS_STRING = {
    JOB_STATUS_PAUSED:   'PAUSED',
    JOB_STATUS_ERROR:    'ERROR',
    JOB_STATUS_DELETING: 'DELETING',
    JOB_STATUS_SPOOLING: 'SPOOLING',
    JOB_STATUS_PRINTING: 'PRINTING',
    JOB_STATUS_OFFLINE:  'OFFLINE',
    JOB_STATUS_PAPEROUT: 'PAPEROUT',
    JOB_STATUS_PRINTED:  'PRINTED',
    JOB_STATUS_DELETED:  'DELETED',
    JOB_STATUS_BLOCKED_DEVQ: 'BLOCKED_DEVQ',
    JOB_STATUS_USER_INTERVENTION: 'USER_INTERVENTION',
    JOB_STATUS_RESTART:  'RESTART',
    JOB_STATUS_COMPLETE: 'COMPLETE',
    JOB_STATUS_RETAINED: 'RETAINED',
    JOB_STATUS_RENDERING_LOCALLY: 'RENDERING_LOCALLY'}

class SYSTEMTIME(ctypes.Structure):
    _fields_ = (('wYear',         wintypes.WORD),
                ('wMonth',        wintypes.WORD),
                ('wDayOfWeek',    wintypes.WORD),
                ('wDay',          wintypes.WORD),
                ('wHour',         wintypes.WORD),
                ('wMinute',       wintypes.WORD),
                ('wSecond',       wintypes.WORD),
                ('wMilliseconds', wintypes.WORD))
    @property
    def as_datetime(self):
        from datetime import datetime
        return datetime(self.wYear, self.wMonth, self.wDay,
                        self.wHour, self.wMinute, self.wSecond,
                        self.wMilliseconds * 1000)

class PRINTER_NOTIFY_OPTIONS_TYPE(ctypes.Structure):
    _fields_ = (('Type',      wintypes.WORD),
                ('Reserved0', wintypes.WORD),
                ('Reserved1', wintypes.DWORD),
                ('Reserved2', wintypes.DWORD),
                ('Count',     wintypes.DWORD),
                ('_pFields',  wintypes.PWORD))
    def __init__(self, Type=JOB_NOTIFY_TYPE, pFields=None):
        super(PRINTER_NOTIFY_OPTIONS_TYPE, self).__init__(Type)
        if pFields is not None:
            self.pFields = pFields
    @property
    def pFields(self):
        ptr_t = ctypes.POINTER(wintypes.WORD * self.Count)
        return ptr_t(self._pFields.contents)[0]
    @pFields.setter
    def pFields(self, pFields):
        self.Count = len(pFields)
        self._pFields = pFields

PPRINTER_NOTIFY_OPTIONS_TYPE = ctypes.POINTER(PRINTER_NOTIFY_OPTIONS_TYPE)

class PRINTER_NOTIFY_OPTIONS(ctypes.Structure):
    _fields_ = (('Version', wintypes.DWORD),
                ('Flags',   wintypes.DWORD),
                ('Count',   wintypes.DWORD),
                ('_pTypes', PPRINTER_NOTIFY_OPTIONS_TYPE))
    def __init__(self, Flags=0, pTypes=None):
        super(PRINTER_NOTIFY_OPTIONS, self).__init__(2, Flags)
        if pTypes is not None:
            self.pTypes = pTypes
    @property
    def pTypes(self):
        ptr_t = ctypes.POINTER(PRINTER_NOTIFY_OPTIONS_TYPE * self.Count)
        return ptr_t(self._pTypes.contents)[0]
    @pTypes.setter
    def pTypes(self, types):
        if isinstance(types, PRINTER_NOTIFY_OPTIONS_TYPE):
            self.Count = 1
            self._pTypes = ctypes.pointer(types)
        else:
            self.Count = len(types)
            self._pTypes = types

PPRINTER_NOTIFY_OPTIONS = ctypes.POINTER(PRINTER_NOTIFY_OPTIONS)

class PRINTER_NOTIFY_INFO_DATA(ctypes.Structure):
    class _NOTIFY_DATA(ctypes.Union):
        class  _DATA(ctypes.Structure):
            _fields_ = (('cbBuf', wintypes.DWORD),
                        ('pBuf',  wintypes.LPVOID))
        _fields_ = (('adwData', wintypes.DWORD * 2),
                    ('Data',    _DATA))
    _fields_ = (('Type',        wintypes.WORD),
                ('Field',       wintypes.WORD),
                ('Reserved',    wintypes.DWORD),
                ('Id',          wintypes.DWORD),
                ('_NotifyData', _NOTIFY_DATA))
    @property
    def _data_as_string(self):
        if self._NotifyData.Data.pBuf:
            return ctypes.c_wchar_p(self._NotifyData.Data.pBuf).value
        return u""
    @property
    def _data_as_datetime(self):
        if self._NotifyData.Data.pBuf:
            t = SYSTEMTIME.from_address(self._NotifyData.Data.pBuf)
        else:
            t = SYSTEMTIME()
        return t.as_datetime
    @property
    def NotifyData(self):
        if self.Type == JOB_NOTIFY_TYPE:
            if self.Field == JOB_NOTIFY_FIELD_PRINTER_NAME:
                return 'job_printer_name', self._data_as_string
            if self.Field == JOB_NOTIFY_FIELD_MACHINE_NAME:
                return 'job_machine_name', self._data_as_string
            if self.Field == JOB_NOTIFY_FIELD_USER_NAME:
                return 'job_user_name', self._data_as_string
            elif self.Field == JOB_NOTIFY