Public/Connect-ExchangeOnPrem.ps1

<#
.SYNOPSIS
Connects to On-Premise Exchange.
 
.DESCRIPTION
Connect-ExchangeOnPrem uses information provided in the profile of the company specified
to connect to the specifiec company's on-premise exchange server.
 
.PARAMETER Company
The company profile to use for connecting.
This parameter supports Tab-Completion.
 
.EXAMPLE
Connect-ExchangeOnPrem -Company ExampleServices
 
 
.NOTES
 
 
#>


function Connect-ExchangeOnPrem {
    [cmdletbinding()]
    Param()
    DynamicParam {
        $ParameterName = 'Company'
        $RuntimeParameterDictionary = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary
        $ParameterAttribute = New-Object System.Management.Automation.ParameterAttribute

        $ParameterAttribute.Mandatory = $true
        $ParameterAttribute.Position = 1

        $AttributeCollection = New-Object System.Collections.ObjectModel.Collection[System.Attribute]
        $AttributeCollection.Add($ParameterAttribute)
        
        $ValidateSet = $Script:Config.Companies.Keys | Where-Object {
            $Script:Config.Companies.$_.OnPremServices.ExchangeUri
        }
        if($ValidateSet.length -gt 0) {
            $ValidateSetAttribute = New-Object System.Management.Automation.ValidateSetAttribute($ValidateSet)
            $AttributeCollection.Add($ValidateSetAttribute)
        }
 
        $RuntimeParameter = New-Object System.Management.Automation.RuntimeDefinedParameter($ParameterName, [string], $AttributeCollection)
        $RuntimeParameterDictionary.Add($ParameterName, $RuntimeParameter)
        return $RuntimeParameterDictionary
    }    
    Begin {
        $Company = $PSBoundParameters.Company

        #Validation Error handling
        if(
            !$Script:Config.Companies.ContainsKey($Company) -or
            !$Script:Config.Companies.$Company.OnPremServices.ExchangeUri
        ) {
            $message = "There is not a company profile available that supports this cmdlet. Please check your configuration and try again."
            $Param = @{
                ExceptionName = "System.ArgumentException"
                ExceptionMessage = $message
                ErrorId = "ExchangeOnPremNoCompaniesAvailable" 
                CallerPSCmdlet = $PSCmdlet
                ErrorCategory = 'InvalidArgument'
            }
            ThrowError @Param
        }

        #Clean conflicting sessions
        $OldSessions = Get-PSSession | Where-Object { $_.ConfigurationName -eq 'Microsoft.Exchange'}
        $OldSessions | Remove-PSSession

        $CompanyObj = $Script:Config.Companies.$Company

        #Make the connection
        $Param = @{
            ConfigurationName = "Microsoft.Exchange"
            ConnectionURI = $CompanyObj.OnPremServices.ExchangeUri
            Authentication = "Kerberos"
        }
        if($CompanyObj.OnPremServices.CredentialName) {
            $Credential = Get-StoredCredential -Target $CompanyObj.OnPremServices.CredentialName
            $Param.Add('Credential',$Credential)
        }

        $EXOSession = $false
        $EXOSession = New-PSSession @Param

        if($EXOSession) {
            $Param = @{
                Session = $EXOSession
                AllowClobber = $true
                DisableNameChecking = $true
            }
            $null = Import-Module (Import-PSSession @Param) -Scope Global -DisableNameChecking
        }
    }
}