Summary<\/b>: Discover the power of the “double splat.”\nHonorary Scripting Guy, Sean Kearney, here filling in for our good friend, Ed. He’s keeping himself inside where it’s warm. I’m here in Canada typing really fast to keep even warmer! It’s 31 degrees below Celsius here in Ottawa, don’t cha know?\nI was developing a solution that needed to authenticate against two Active Directory domains, and the client threw in a twist during development (yes, these things happen). During this process, I discovered a cool trick called “double splatting.”\nIn my script, I first needed to authenticate against two possible Active Directory domains. “Well, that’s awfully easy,“ I thought to myself. “I’ll simply have two Windows PowerShell variables to hold the credentials and the domain controller, and use them as I create users. Too easy.”\nYes, that was the original thought. But as the script grew, feature creep from the client came forth. Additional parameters, such as target organizational units were be added to the mix. Multiple situations with more Active Directory cmdlets appeared. \nI found that I was adding the same information over and over and over…\nSo to resolve that issue, I decided to bite the bullet and use “splatting.” Splatting is a cool technique in Windows PowerShell where you can define parameters for a cmdlet and its values within an array, and pass that object directly to the cmdlet. The big advantage of splatting (other than avoiding some typing and a readability improvement) is that if there are common parameters that I need to change “en-masse” in a script, I can edit the array.\nIn my original script, I wrote something like this to query a user:<\/p>\n
#Domain Controller<\/p>\n
$DC=”192.168.1.5”\n <\/p>\n
#Domain Credentials<\/p>\n
$MyDomain=’Contoso.Dev’<\/p>\n
$MyClearTextUsername=’ServiceAdminAcct’<\/p>\n
$MyClearTextPassword=’S3cr3tP@ssw0rd!’\n <\/p>\n
$MyUsernameDomain=$MyDomain+’’+$MyClearTextUsername\n <\/p>\n
$SecurePassword=Convertto-SecureString –String<\/p>\n
$MyClearTextPassword –AsPlainText –force\n <\/p>\n
$Cred=New-object System.Management.Automation.PSCredential $MyUsernameDomain,$SecurePassword\nThen each time I would try to query a user, I would do this:<\/p>\n
REMOVE-ADUser JohnSmith –credential $Cred –server $DC\nTo use splatting, first create an array that contains the names of parameters for a cmdlet and their values:<\/p>\n
$ADparams=@{‘credential’=$Cred;’server’=$DC}\nThen pass it directly to the cmdlet:<\/p>\n
REMOVE-ADUser JohnSmith @ADparams\nThis now makes flipping the credentials and servers easier. I can also add additional parameters to the same array, and the cmdlets will use them. I was in my glory. Life was good…until…\nThe client decided, yes, feature creeeeep!\nThey needed to ensure that they could have a safety switch to test the script—not just a single cmdlet—without hurting data.\nWell, in Windows PowerShell, that’s easy. That’s the –whatif<\/b> parameter. I can flip cmdlets to automatically default to a whatif<\/b> mode by setting this variable:<\/p>\n
$WhatIfPreference=$TRUE\nThis worked like a charm, but every cmdlet (including those for creating logs) warned about what they were going to do without doing it. In my case, I only wanted it to happen for Active Directory cmdlets.\nSoooooo…scrap that idea. \nThen I stumbled across something really cool. When mucking about, I found that I can splat twice!\nYes, the parser doesn’t only work on one splat, you can have multiple in the same cmdlet. In my case, I created a tiny splat for the –whatif<\/b> parameter by defining one of two possible values.<\/p>\n
$Safety=@{‘whatif’=$NULL}<\/p>\n
Or<\/p>\n
$Safety=@{}\nTo work with those cmdlets, I can pass two splats to the Active Directory cmdlets that need a safety switch, and change the script globally from the top level as a parameter:<\/p>\n
REMOVE-ADuser JohnSmith @AdParams @Safety\nThe double splat! An available, built-in feature in Windows PowerShell. It’s been sitting there and ready to use the whole darn time!\nWe now return you to your regularly scheduled scripting!\nI invite you to follow the Scripting Guys on Twitter<\/a> and Facebook<\/a>. If you have any questions, send email to scripter@microsoft.com<\/a>, or post your questions on the Official Scripting Guys Forum<\/a>. See you tomorrow. Until then, peace.\nSean Kearney<\/b>, Honorary Scripting Guy and Windows PowerShell MVP <\/p>\n","protected":false},"excerpt":{"rendered":" Summary: Discover the power of the “double splat.” Honorary Scripting Guy, Sean Kearney, here filling in for our good friend, Ed. He’s keeping himself inside where it’s warm. I’m here in Canada typing really fast to keep even warmer! It’s 31 degrees below Celsius here in Ottawa, don’t cha know? I was developing a solution […]<\/p>\n","protected":false},"author":596,"featured_media":87096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[56,154,170,61,45],"class_list":["post-2250","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-guest-blogger","tag-sean-kearney","tag-splatting","tag-weekend-scripter","tag-windows-powershell"],"acf":[],"blog_post_summary":" Summary: Discover the power of the “double splat.” Honorary Scripting Guy, Sean Kearney, here filling in for our good friend, Ed. He’s keeping himself inside where it’s warm. I’m here in Canada typing really fast to keep even warmer! It’s 31 degrees below Celsius here in Ottawa, don’t cha know? I was developing a solution […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/2250","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/users\/596"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/comments?post=2250"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/2250\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media\/87096"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media?parent=2250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=2250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=2250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}