Functions & powershell remoting - function

Question

I have a script that works fine but I want to improve my powershell knowledge and would like to know if there is an easier way to do this.....
Part of my script connects to a sever and pulls bak a list of files and sizes on it and exports it to a csv.
I have found a function (Exportcsv) that allows me to append to the csv with earlier versions of powershell.
At the moment I use the invoke-command to remote to each server and the run the script in the script block but this means adding the function each time. So I have the function in my script but then have to repeat it for each server I connect to so it will run remotely
Is there any way to pass the local function to the remote server so I don't have to add to each invoke command.
Invoke-Command –ComputerName server –ScriptBlock {
$wfile = "d:\folder\directorysize_H.csv"
$xfile = "d:\folder\directorysize_F.csv"
function ExportCSV {
[CmdletBinding(DefaultParameterSetName='Delimiter',
SupportsShouldProcess=$true, ConfirmImpact='Medium')]
param(
[Parameter(Mandatory=$true, ValueFromPipeline=$true,
ValueFromPipelineByPropertyName=$true)]
[System.Management.Automation.PSObject]
${InputObject},
[Parameter(Mandatory=$true, Position=0)]
[Alias('PSPath')]
[System.String]
${Path},
#region -Append
[Switch]
${Append},
#endregion
[Switch]
${Force},
[Switch]
${NoClobber},
[ValidateSet('Unicode','UTF7','UTF8','ASCII','UTF32',
'BigEndianUnicode','Default','OEM')]
[System.String]
${Encoding},
[Parameter(ParameterSetName='Delimiter', Position=1)]
[ValidateNotNull()]
[System.Char]
${Delimiter},
[Parameter(ParameterSetName='UseCulture')]
[Switch]
${UseCulture},
[Alias('NTI')]
[Switch]
${NoTypeInformation})
begin
{
# This variable will tell us whether we actually need to append
# to existing file
$AppendMode = $false
try {
$outBuffer = $null
if ($PSBoundParameters.TryGetValue('OutBuffer', [ref]$outBuffer))
{
$PSBoundParameters['OutBuffer'] = 1
}
$wrappedCmd = $ExecutionContext.InvokeCommand.GetCommand('Export-Csv',
[System.Management.Automation.CommandTypes]::Cmdlet)
#String variable to become the target command line
$scriptCmdPipeline = ''
# Add new parameter handling
#region Process and remove the Append parameter if it is present
if ($Append) {
$PSBoundParameters.Remove('Append') | Out-Null
if ($Path) {
if (Test-Path $Path) {
# Need to construct new command line
$AppendMode = $true
if ($Encoding.Length -eq 0) {
# ASCII is default encoding for Export-CSV
$Encoding = 'ASCII'
}
# For Append we use ConvertTo-CSV instead of Export
$scriptCmdPipeline += 'ConvertTo-Csv -NoTypeInformation '
# Inherit other CSV convertion parameters
if ( $UseCulture ) {
$scriptCmdPipeline += ' -UseCulture '
}
if ( $Delimiter ) {
$scriptCmdPipeline += " -Delimiter '$Delimiter' "
}
# Skip the first line (the one with the property names)
$scriptCmdPipeline += ' | Foreach-Object {$start=$true}'
$scriptCmdPipeline += '{if ($start) {$start=$false} else {$_}} '
# Add file output
$scriptCmdPipeline += " | Out-File -FilePath '$Path'"
$scriptCmdPipeline += " -Encoding '$Encoding' -Append "
if ($Force) {
$scriptCmdPipeline += ' -Force'
}
if ($NoClobber) {
$scriptCmdPipeline += ' -NoClobber'
}
}
}
}
$scriptCmd = {& $wrappedCmd #PSBoundParameters }
if ( $AppendMode ) {
# redefine command line
$scriptCmd = $ExecutionContext.InvokeCommand.NewScriptBlock(
$scriptCmdPipeline
)
} else {
# execute Export-CSV as we got it because
# either -Append is missing or file does not exist
$scriptCmd = $ExecutionContext.InvokeCommand.NewScriptBlock(
[string]$scriptCmd
)
}
# standard pipeline initialization
$steppablePipeline = $scriptCmd.GetSteppablePipeline(
$myInvocation.CommandOrigin)
$steppablePipeline.Begin($PSCmdlet)
} catch {
throw
}
}
process
{
try {
$steppablePipeline.Process($_)
} catch {
throw
}
}
end
{
try {
$steppablePipeline.End()
} catch {
throw
}
}
}
Write-Host "Removing old files from xxx"
If (Test-Path $wfile){
Remove-Item $wfile
}
If (Test-Path $xfile){
Remove-Item $xfile
}
write-host "Getting _f details"
get-childitem \\server\F$ -recurse |select directory, name, length|exportcsv $xfile -append -noclobber -notypeinformation
write-host "Getting _H details"
get-childitem \\server\H$ -recurse |select directory, name, length|exportcsv $wfile -append -noclobber -notypeinformation
}
TIA
Andy

Answer 1

No there isn't a straightforward way to pass the function to the remote computers, well other than what you are already doing. :-) However you can put all that script in a file (dirsize.ps1) and pass that to Invoke-Command using the FilePath parameter:
Invoke-Command –ComputerName server –FilePath .\dirsize.ps1
The file will be copied to the remote computers and executed.

Answer 2

try this:
#Local Function
function Get-Bits
{
Get-Service -Name BITS
}
Invoke-Command -ComputerName RemoteServer -ScriptBlock ${function:Get-Bits}
personally i put all my functions in a psm1 file in other words a module on a network share and import the module while in the remote session.