NAME

DBD::WMI - interface to the Windows WMI

ABSTRACT

This module allows you to issue WQL queries through the DBI.

SYNOPSIS

use DBI;
my $dbh = DBI->connect('dbi:WMI:');

my $sth = $dbh->prepare(<<WQL);
  SELECT * FROM Win32_Process
WQL

$sth->execute();
while (my @row = $sth->fetchrow) {
  my $proc = $row[0];
  print join "\t", $proc->{Caption}, $proc->{ExecutablePath} || "<system>";
  # $proc->Terminate();
  print "\n";
}

The WMI allows you to query various tables ("namespaces"), like the filesystem, currently active processes and events:

SELECT * FROM Win32_Process

The driver/WMI implements two kinds of queries, finite queries like the query above and potentially infinite queries for events as they occur in the system:

my $query = q{

 SELECT * FROM __instanceoperationevent
 WITHIN 1
 WHERE TargetInstance ISA 'Win32_DiskDrive'
 
}

This query returns one row (via ->fetchrow_arrayref() ) whenever a disk drive gets added to or removed from the system (think of an USB stick).

There is currently no support for selecting specific columns instead of *. Support for selecting columns that then get returned as plain Perl scalars is planned.

DBD::WMI::db::parse_columns STATEMENT

This routine parses out the requested columns from the WQL statement and returns an array reference with the names of the columns.

Currently, this only works for SELECT statements. All other statements get an implicit column of *, meaning that the Win32::OLE objects will be returned.

HANDLING OF QUERY COLUMNS

The WMI and WQL return full objects instead of single columns. The specification of columns is merely a hint to the object what properties to preload. The DBD interface deviates from that approach in that it returns objects for queries of the form SELECT * and the values of the object properties when columns are specified. These columns are then case sensitive.

FUN QUERIES

List all printers

SELECT * FROM Win32_Printer

List all print jobs on a printer

SELECT * FROM Win32_PrintJob
  WHERE DriverName = 'HP Deskjet 6122'

Return a new row whenever a new print job is started

SELECT * FROM __InstanceCreationEvent
  WITHIN 10
  WHERE
    TargetInstance ISA 'Win32_PrintJob'

Finding the default printer

SELECT * FROM Win32_Printer
  WHERE Default = TRUE

Setting the default printer (untested, WinXP, Win2003)

use DBI;
my $dbh = DBI->connect('dbi:WMI:');
my $sth = $dbh->prepare(<<WQL);
    SELECT * FROM Win32_Printer
WQL

$sth->execute;
while (my @row = $sth->fetchrow) {
    # We get Win32::OLE objects back:
    my $printer = $row[0];
    printf "Making %s the default printer\n", $printer->{Name};
    $printer->SetDefaultPrinter;
};

Find all network adapters with IP enabled

SELECT * from Win32_NetworkAdapterConfiguration
  WHERE IPEnabled = True

Find files in a directory

ASSOCIATORS OF {Win32_Directory.Name='C:\WINNT'}
  WHERE ResultClass = CIM_DataFile

Find printers on a remote machine

use DBI;
my $machine = 'dawn';
my $dbh = DBI->connect('dbi:WMI:'.$machine);
my $sth = $dbh->prepare(<<WQL);
    SELECT * FROM Win32_Printer
WQL

$sth->execute;
while (my @row = $sth->fetchrow) {
    my $printer = $row[0];
    printf "Making %s the default printer on %s\n", $printer->{Name}, $machine;
    $printer->SetDefaultPrinter;
};

Get method names of objects

use Win32::OLE qw(in);
...

SELECT * FROM Win32_Process

$sth->execute;

while (my @row = $sth->fetchrow) {
    for my $method (in $row[0]->Methods_) {
        print "Can call $method() on the object\n"
    };
};

TODO

  • Implement placeholders and proper interpolation of values

  • Need to implement DSN parameters for remote computers, credentials

SEE ALSO

WMI is Microsofts implementation of the WBEM standard (http://www.dmtf.org/standards/wbem/) except that it uses DCOM and not CIM-XML as the transport medium.

The MS WMI main page at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmisdk/wmi/wmi_start_page.asp

The WQL documentation at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmisdk/wmi/wql_sql_for_wmi.asp

The "Hey Scripting Guy" column at http://www.microsoft.com/technet/scriptcenter/resources/qanda/default.mspx

Wikipedia on WMI at http://en.wikipedia.org/wiki/Windows_Management_Instrumentation

List of available Win32 WMI classes at http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmisdk/wmi/win32_classes.asp

REPOSITORY

The public repository of this module is https://github.com/Corion/dbd-wmi.

SUPPORT

The public support forum of this module is https://perlmonks.org/.

BUG TRACKER

Please report bugs in this module via the RT CPAN bug queue at https://rt.cpan.org/Public/Dist/Display.html?Name=DBD-WMI or via mail to dbd-wmi-Bugs@rt.cpan.org.

AUTHOR

Max Maischein corion@cpan.org

COPYRIGHT (c)

Copyright 2009-2018 by Max Maischein corion@cpan.org.

LICENSE

This module is released under the same terms as Perl itself.