Advanced Windows PowerShell Scripting Video Training

Advanced Windows PowerShell Scripting Video Training
Advanced Windows PowerShell Scripting Video Training

Wednesday, June 24, 2015

PowerShell Code That Write’s it’s Own Code

I know, sounds a bit out there, but it is possible.

My PowerShell Class this week took a question from PowerShell.com. I do this every once and a while so we can apply our newly acquired skill sets to real life situations. This time around we helped out an IT Pro who was importing a CSV file to modify user objects using the Set-ADUser cmdlet of the Active Directory Module for Windows PowerShell.

The problem that he was having is that the database that generated this CSV file would occasionally place a NULL value in one of the properties. If you hard code Set-ADUser with a parameter, but then feed it a NULL value, it errors. The same thing happens if you pipe in a NULL value. He needed help trying to fix this. So, we went into action. And generated the cmdlet below.

The cool part about this code is that we did not hard code anything with regards to sending data to Set-ADUser. We utilized Invoke-Expression to execute commands that the code generates live. We also did not know if the CSV file contained data that would not be valid for a user object. We handled this little issue the same way that we handled the NULL values in the CSV file. We captured the errors and did nothing with them. No harm, no foul. We used SamAccountName as our identity property. Just modify the code to fit the identity property that you are using. You must have access to the Active Directory module for Windows PoweerShell for this to work.

 

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103 

 

Function Set-ADUserFromCSV

{

[cmdletbinding()]

Param(

   

    [parameter(Mandatory=$true,

    ValueFromPipeline=$true)]

    $UserData,

 

    [Switch]

    $PassThru

)

Begin {} # END: Begin Block

Process

{

    # Import the data.

    $Data = Import-Csv -Path E:\data.csv

 

    # Extract the valid Property names from the object.

    $Props = $Data[0] | GM |

        Where-Object MemberType -eq NoteProperty |

        Select-Object -ExpandProperty Name

 

    $Data | ForEach-Object {

        ForEach ($P in $Props)

        {

            # This is the part that writes its own code.

            $String = "Set-ADUser -Identity $($_.SamAccountName) -$P $($_.$P)"

 

            # Add PassThru is requested.

            If ($PassThru) {$String += " -PassThru"}

 

            Try

            {

                # This makes the magic work.

                Write-Verbose "Executing: $String"

                Invoke-Expression -Command "$String" -ErrorAction Stop

            } # End: Try Block

            catch

            {

                <#

                Two items can cause errors here.

                1. Your CSV file have a property that is not a valid property for

                   a user object.

                2. You have a NULL field in your CSV.

                This will simply ignore the error and keep going.

                #>

 

            } # END: Catch Block

 

        } # END: ForEach ($P in $Props)

    } # END: ForEach-Object

} # END: Process Block

End {} #END: END: Block

<#

.SYNOPSIS

Modifies user accounts.

 

.DESCRIPTION

Takes an object containing SamAccountNames and other properties and

applies it to user accounts if the user account exists and the

property is a valid property for Set-ADUser.

 

.PARAMETER UserData

This is the object containing the data to be used to modify

the user object.

 

.PARAMETER PassThru

Places the modified user object into the pipeline.

 

.EXAMPLE

Import-Csv -Path E:\data.csv | Set-ADUserFromCSV

 

Modifies user objects based on the data imported from a CSV file.

 

.EXAMPLE

Import-Csv -Path E:\data.csv | Set-ADUserFromCSV -Verbose -PassThru

 

Modifies user objects based on the data imported from a CSV file.

This also places the user object into the pipeline and displays

verbose information.

 

.NOTES

Requires the Active Directory PowerShell Module.

 

===============================================================================

== Cmdlet: Set-ADUserFromCSV                                                 ==

== Author: Jason A. Yoder                                                    ==

== Company: MCTExpert of Arizona                                             ==

== Date:    2015JUN24                                                        ==

== Copyright: All rights reserved.                                           ==

== Version: 1.0.0.0                                                          ==

== Legal: The user assumes all responsibility and liability for the usage of ==

== this PowerShell code.  MCTExpert of Arizona, Its officers, shareholders,  ==

== owners, and their relatives are not liable for any damages.  As with all  ==

== code, review it and understand it prior to usage.  It is recommended that ==

== this code be fully tested and validated in a test environment prior to    ==

== usage in a production environment.                                        ==

==                                                                           ==

== Does this code make changes: Yes                                          ==

===============================================================================

#>

} # END: Function Set-ADUserFromCSV

 

 

 

 

No comments: