Monitoring Print Jobs (Question to Jose Roca)

[Peter Redei]

Jose,

I modified your WMI code to write log for print jobs completed as follows:

#COMPILE EXE
#DIM ALL
#INCLUDE "win32api.inc"
#INCLUDE "TB_WMI.INC"

GLOBAL bFinish AS LONG
GLOBAL TerminateAt AS STRING

SUB DoWMI(strComputer AS ASCIIZ, sLogFile AS ASCIIZ)
    LOCAL hr AS LONG                     ' // HRESULT
    LOCAL CLSID_WbemLocator AS GUID      ' // IWbemLocator interface CLSID
    LOCAL IID_IWbemLocator AS GUID       ' // IWbemLocator interface IID
    LOCAL ppLocator AS DWORD PTR         ' // IWbemLocator interface reference
    LOCAL sThis AS STRING                ' // Error message to log
    LOCAL ppEnum AS DWORD PTR            ' // IEnumWbemClassObject collection reference
    LOCAL ppObject AS DWORD PTR          ' // IWbemClassObject interface reference
    LOCAL ppServices AS DWORD PTR        ' // IWbemServices interface reference
    LOCAL puReturned AS DWORD            ' // Number of returned references
    LOCAL varRecord AS VARIANT           ' // PrintJob record
    LOCAL oPrintJob AS DISPATCH          ' // PrintJob object
    LOCAL vProperty AS VARIANT           ' // The property value of a printjob property (variant)
    LOCAL sPrintJobName AS STRING        ' // The name of the printjob (string)
    LOCAL sPrintJobCaption AS STRING     ' // The caption property of the printJob
    LOCAL sPrintJobDataType AS STRING
    LOCAL sPrintJobDescription AS STRING
    LOCAL sPrintJobDocument AS STRING
    LOCAL sPrintJobDriverName AS STRING
    LOCAL sPrintJobElapsedTime AS STRING
    LOCAL sPrintJobHostPrintQueue AS STRING
    LOCAL sPrintJobInstallDate AS STRING
    LOCAL sPrintJobJobId AS LONG
    LOCAL sPrintJobJobStatus AS STRING
    LOCAL sPrintJobNotify AS STRING
    LOCAL sPrintJobOwner AS STRING
    LOCAL sPrintJobPagesPrinted AS LONG
    LOCAL sPrintJobPaperLength AS LONG
    LOCAL sPrintJobPaperSize AS STRING
    LOCAL sPrintJobPaperWidth AS LONG
    LOCAL sPrintJobParameters AS STRING
    LOCAL sPrintJobPrintProcessor AS STRING
    LOCAL sPrintJobPriority AS LONG
    LOCAL sPrintJobSize AS LONG
    LOCAL sPrintJobStartTime AS STRING
    LOCAL sPrintJobStatus AS STRING
    LOCAL sPrintJobStatusMask AS LONG
    LOCAL sPrintJobTimeSubmitted AS STRING
    LOCAL sPrintJobTotalPages AS LONG
    LOCAL sPrintJobUntilTime AS STRING
    LOCAL v AS LONG

    IF LEN(strComputer) = 0 THEN strComputer = "."
    ' // registers security and sets the default security values for the process
    hr = CoInitializeSecurity(BYVAL %NULL, -1, %NULL, %NULL, _
                            %RPC_C_AUTHN_LEVEL_CONNECT, %RPC_C_IMP_LEVEL_IMPERSONATE, %NULL, _
                            %EOAC_NONE, BYVAL %NULL)
    IF hr <> %S_OK THEN
        sThis = "CoInitializeSecurity failed with an error code of &H" & HEX$(hr)
        'log the error here
        EXIT SUB
    END IF

    ' // create a WbemLocator object
    CLSID_WbemLocator = $CLSID_WbemLocator
    IID_IWbemLocator = $IID_IWbemLocator
    hr = CoCreateInstance(CLSID_WbemLocator, BYVAL %NULL, %CLSCTX_INPROC_SERVER, _
                         IID_IWbemLocator, ppLocator)
    sThis = "ppLocator = " & STR$(ppLocator)
    'log the error here
    IF ISTRUE hr OR ppLocator = %NULL THEN
        v = FREEFILE
        OPEN sLogFile FOR APPEND AS #v
        PRINT #v, "Unable to load WbemLocator"
        CLOSE #v
        GOTO Terminate  'log the error before
    END IF

    hr = IWbemLocator_ConnectServer(ppLocator, "root\cimv2", BYVAL %NULL, BYVAL %NULL, _
                                BYVAL %NULL, 0, BYVAL %NULL, %NULL, ppServices)
    sThis = "ppServices = " & STR$(ppServices)
    IF ISTRUE hr OR ppServices = %NULL THEN
        v = FREEFILE
        OPEN sLogFile FOR APPEND AS #v
        PRINT #v, "Unable to connect to service"
        CLOSE #v
        GOTO Terminate  'log the error before
    END IF
    hr = IWbemServices_ExecNotificationQuery(ppServices, "WQL", "Select * From __InstanceCreationEvent " _
                & "Within 10 Where TargetInstance ISA 'Win32_PrintJob'", _
                %WBEM_FLAG_FORWARD_ONLY OR %WBEM_FLAG_RETURN_IMMEDIATELY, %NULL, ppEnum)

    IF ISTRUE hr OR ppEnum = %NULL THEN
        v = FREEFILE
        OPEN sLogFile FOR APPEND AS #v
        PRINT #v, "Unable to load PrintJobs"
        CLOSE #v
        GOTO Terminate  'log the error before
    END IF
    DO WHILE ISTRUE(bFinish)
        ON ERROR RESUME NEXT
        IF TIME$ > TerminateAt THEN bFinish = %FALSE
        ppObject = %NULL
        'hr = IEnumWbemClassObject_Next(ppEnum, 10, 1, BYVAL VARPTR(ppObject), puReturned)
        hr = WMIEXTENSIONLibISWbemEventSource_NextEvent(ppEnum, 5, BYVAL VARPTR(ppObject))
        IF NOT ppObject = %NULL THEN
             ' // get the PrintJob
            hr = IWbemClassObject_Get(ppObject, "TargetInstance", 0, varRecord, %NULL, %NULL)
            SET oPrintJob = varRecord
            OBJECT GET oPrintJob.Name TO vProperty: sPrintJobName = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Caption TO vProperty: sPrintJobCaption = VARIANT$(vProperty)
            OBJECT GET oPrintJob.DataType TO vProperty: sPrintJobDataType = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Description TO vProperty: sPrintJobDescription = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Document TO vProperty: sPrintJobDocument = VARIANT$(vProperty)
            OBJECT GET oPrintJob.DriverName TO vProperty: sPrintJobDriverName = VARIANT$(vProperty)
            OBJECT GET oPrintJob.ElapsedTime TO vProperty: sPrintJobElapsedTime = VARIANT$(vProperty)    'datetime
            OBJECT GET oPrintJob.HostPrintQueue TO vProperty: sPrintJobHostPrintQueue = VARIANT$(vProperty)
            OBJECT GET oPrintJob.InstallDate TO vProperty: sPrintJobInstallDate = VARIANT$(vProperty)    'datetime
            OBJECT GET oPrintJob.JobId TO vProperty: sPrintJobJobId = VARIANT#(vProperty)
            OBJECT GET oPrintJob.JobStatus TO vProperty: sPrintJobJobStatus = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Notify TO vProperty: sPrintJobNotify = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Owner TO vProperty: sPrintJobOwner = VARIANT$(vProperty)
            OBJECT GET oPrintJob.PagesPrinted TO vProperty: sPrintJobPagesPrinted = VARIANT#(vProperty)
            OBJECT GET oPrintJob.PaperLength TO vProperty: sPrintJobPaperLength = VARIANT#(vProperty)
            OBJECT GET oPrintJob.PaperSize TO vProperty: sPrintJobPaperSize = VARIANT$(vProperty)
            OBJECT GET oPrintJob.PaperWidth TO vProperty: sPrintJobPaperWidth = VARIANT#(vProperty)
            OBJECT GET oPrintJob.Parameters TO vProperty: sPrintJobParameters = VARIANT$(vProperty)
            OBJECT GET oPrintJob.PrintProcessor TO vProperty: sPrintJobPrintProcessor = VARIANT$(vProperty)
            OBJECT GET oPrintJob.Priority TO vProperty: sPrintJobPriority = VARIANT#(vProperty)
            OBJECT GET oPrintJob.Size TO vProperty: sPrintJobSize = VARIANT#(vProperty)
            OBJECT GET oPrintJob.StartTime TO vProperty: sPrintJobStartTime = VARIANT$(vProperty)    'datetime
            OBJECT GET oPrintJob.Status TO vProperty: sPrintJobStatus = VARIANT$(vProperty)
            OBJECT GET oPrintJob.StatusMask TO vProperty: sPrintJobStatusMask = VARIANT#(vProperty)
            OBJECT GET oPrintJob.TimeSubmitted TO vProperty: sPrintJobTimeSubmitted = VARIANT$(vProperty)    'datetime
            OBJECT GET oPrintJob.TotalPages TO vProperty: sPrintJobTotalPages = VARIANT#(vProperty)
            OBJECT GET oPrintJob.UntilTime TO vProperty: sPrintJobUntilTime = VARIANT$(vProperty)    'datetime

            v = FREEFILE
            OPEN sLogFile FOR APPEND AS #v
            PRINT #v, "<PrintJob Name=""" & sPrintJobName & """ Document=""" & sPrintJobDocument & """ ElapsedTime=""" & sPrintJobElapsedTime & """";
            PRINT #v, " JobId=""" & FORMAT$(sPrintJobJobId) & """ JobStatus=""" & sPrintJobJobStatus & """ Owner=""" & sPrintJobOwner & """ PagesPrinted=""" & FORMAT$(sPrintJobPagesPrinted) & """";
            PRINT #v, " PaperLength=""" & FORMAT$(sPrintJobPaperLength) & """ PaperWidth=""" & FORMAT$(sPrintJobPaperWidth) & """ PaperSize=""" & sPrintJobPaperSize & """";
            PRINT #v, " JobSize=""" & FORMAT$(sPrintJobSize) & """ StartTime=""" & sPrintJobStartTime & """ TimeSubmitted=""" & sPrintJobTimeSubmitted & """ TotalPages=""" & FORMAT$(sPrintJobTotalPages) & """";
            PRINT #v, " UntilTime=""" & sPrintJobUntilTime & """/>"
            CLOSE #v
            ' // release the collection's object
            IWbemClassObject_Release ppObject
        END IF
        DIALOG DOEVENTS
    LOOP
    ' // release the collection
    IF ISTRUE ppEnum THEN IEnumWbemClassObject_Release ppEnum
Terminate:

   IF ISTRUE ppServices THEN IWbemServices_Release ppServices
   IF ISTRUE ppLocator THEN IWbemLocator_Release ppLocator
   LOCAL tTimer AS LONG
   tTimer = GetTickCount
   DO
   LOOP UNTIL GetTickCount - tTimer > 20000
END SUB

FUNCTION PBMAIN()
    LOCAL strComputer AS ASCIIZ * %MAX_PATH
    LOCAL sLogfile AS ASCIIZ * %MAX_PATH
    bFinish = %TRUE
    TerminateAt = "15:00:00" '<---------------- adjust the value as needed to unload!
    sLogfile    = "c:\apu\printlog.txt" '<----- adjust the value to your computer!
    DoWMI strComputer, sLogfile
    MSGBOX "Done"
END FUNCTION

In order to incorporate the NextEvent method I modified TB_WMI.INC, added reference to the WMIExtensionLib as
#INCLUDE "WMIExtensionLib.inc"

and I created the include file using your utility.

However, NextEvent never returns a valid object even when I am printing something. Doing the same in VB works. What am I doing wrong?

Thanks,

Peter Redei

[José Roca]

Doing the same in VB works.

Are you also using a timeout of 5 milliseconds with VB or are you using something like Set objEventObject = objEventSource.NextEvent() ? With VB, if you don't specify the timeout it defaults to -1 (infinite).

Which value returns this call in hr?

hr = WMIEXTENSIONLibISWbemEventSource_NextEvent(ppEnum, 5, BYVAL VARPTR(ppObject))

If hr = &H80043001 it means that the equested event did not arrive in the amount of time specified in iTimeoutMs.

[Peter Redei]

Hi Jose,

I tried it with different timeouts and I always got the same hr=&H40004 response that I believe means 'There is no connection for this connection ID', but I am not sure. In VB I got the response with 10 milliseconds timeout. I used timeout and not -1 because I did not want the program halt at the hr = WMIEXTENSIONLibISWbemEventSource_NextEvent(ppEnum, 10, BYVAL VARPTR(ppObject)) line until a print job is issued, so I can terminate the loop by changing the bFinish value.
Setting the timeout to -1 halts the application even when I am printing. Any timeout value always returns &H40004 that is not documented by Microsoft as possible error. ppEnum seems to have a valid value.

First time I tried this from VB it worked. I retried it now and it did not work either! Actually it did in about once from twenty attempts. Setting different timeouts in the query expression and in the timeout value does not show any affect.

The original code is from Microsoft at http://www.microsoft.com/technet/scr...5/hey1110.mspx

I figured out what was the problem why the event was not fired. In the SQL statement I had to put very small timeout (0.1 milliseconds). Than I got response from VB or from script, but still not from PowerBasic. I tried this both in synchronous and in asynchronous (creating a sink object and using IWbemServices_ExecNotificationQueryAsync) with success in VB and faliure in PB.



Thanks,

Peter Redei