functions/New-DbaClientAlias.ps1

Function New-DbaClientAlias {
<#
    .SYNOPSIS
    Creates/updates a sql alias for the specified server - mimics cliconfg.exe
 
    .DESCRIPTION
    Creates/updates a SQL Server alias by altering HKLM:\SOFTWARE\Microsoft\MSSQLServer\Client
 
    .PARAMETER ComputerName
    The target computer where the alias will be created
 
    .PARAMETER Credential
    Allows you to login to remote computers using alternative credentials
 
    .PARAMETER ServerName
    The target SQL Server
         
    .PARAMETER Alias
    The alias to be created
         
    .PARAMETER Protocol
    The protocol for the connection, either TCPIP or NetBIOS. Defaults to TCPIP.
 
    .PARAMETER Silent
    Use this switch to disable any kind of verbose messages
 
    .NOTES
    Tags: Alias
 
    Website: https://dbatools.io
    Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
    License: GNU GPL v3 https://opensource.org/licenses/GPL-3.0
 
    .LINK
    https://dbatools.io/New-DbaClientAlias
 
    .EXAMPLE
    New-DbaClientAlias -ServerName sqlcluster\sharepoint -Alias sp
    Creates a new TCP alias on the local workstation called sp, which points sqlcluster\sharepoint
         
    .EXAMPLE
    New-DbaClientAlias -ServerName sqlcluster\sharepoint -Alias sp -Protocol NamedPipes
    Creates a new NamedPipes alias on the local workstation called sp, which points sqlcluster\sharepoint
         
#>

    [CmdletBinding()]
    Param (
        [DbaInstanceParameter[]]$ComputerName = $env:COMPUTERNAME,
        [PSCredential]$Credential,
        [parameter(Mandatory, ValueFromPipeline)]
        [DbaInstanceParameter[]]$ServerName,
        [parameter(Mandatory)]
        [string]$Alias,
        [ValidateSet("TCPIP", "NamedPipes")]
        [string]$Protocol = "TCPIP",
        [switch]$Silent
    )
    
    begin {
        # This is a script block so cannot use messaging system
        $scriptblock = {
            $basekeys = "HKLM:\SOFTWARE\WOW6432Node\Microsoft\MSSQLServer", "HKLM:\SOFTWARE\Microsoft\MSSQLServer"
            $ServerName = $args[0]
            $Alias = $args[1]
            $serverstring = $args[2]
            
            if ($env:PROCESSOR_ARCHITECTURE -like "*64*") { $64bit = $true }
            
            foreach ($basekey in $basekeys) {
                if ($64bit -ne $true -and $basekey -like "*WOW64*") { continue }
                
                if ((Test-Path $basekey) -eq $false) {
                    throw "Base key ($basekey) does not exist. Quitting."
                }
                
                $client = "$basekey\Client"
                
                if ((Test-Path $client) -eq $false) {
                    # "Creating $client key"
                    $null = New-Item -Path $client -Force
                }
                
                $connect = "$client\ConnectTo"
                
                if ((Test-Path $connect) -eq $false) {
                    # "Creating $connect key"
                    $null = New-Item -Path $connect -Force
                }
                
                if ($basekey -like "*WOW64*") {
                    $architecture = "32-bit"
                }
                else {
                    $architecture = "64-bit"
                }
                
                # Write-Verbose "Creating/updating alias for $ComputerName for $architecture"
                $null = New-ItemProperty -Path $connect -Name $Alias -Value $serverstring -PropertyType String -Force
            }
        }
    }
    
    process {
        if ($protocol -eq "TCPIP") {
            $serverstring = "DBMSSOCN,$ServerName"
        }
        else {
            $serverstring = "DBNMPNTW,\\$ServerName\pipe\sql\query"
        }
        
        foreach ($computer in $ComputerName.ComputerName) {
            
            $null = Test-ElevationRequirement -ComputerName $computer -Continue
            
            if ($PScmdlet.ShouldProcess($computer, "Adding $alias")) {
                try {
                    Invoke-Command2 -ComputerName $computer -Credential $Credential -ScriptBlock $scriptblock -ErrorAction Stop -ArgumentList $ServerName, $Alias, $serverstring
                }
                catch {
                    Stop-Function -Message "Failure" -ErrorRecord $_ -Target $computer -Continue
                }
            }
        }
        
        Get-DbaClientAlias -ComputerName $computer -Credential $Credential | Where-Object AliasName -eq $Alias
    }
}