Including common code in header/footer with PowerShell - powershell

Question

I have common functions and formats to most of my scripts. Each script brings up a window for me to paste workstations and it performs basic tasks like checking connectivity before proceeding. Generally, I copy and paste this code and modify the body. What I would like to do is include a header and footer, but I get "Missing closing '}' in statement block." errors. Example:
<# Begin Header #>
if($canceled) {
write-host "Operation canceled."
}
else {
if($computers.length -gt 0) {
[array]$computers = $computers.split("`n").trim()
# Loop through computers entered
foreach($pc in $computers) {
# Skip zero length lines for computers
if(($pc.length -eq $null) -OR ($pc.length -lt 1)) {
continue
}
else {
# Try to connect to the computer, otherwise error and continue
write-host "Connecting to: $pc$hr"
if(test-connection -computername $pc -count 1 -ea 0) {
<# End Header #>
Body of script
<# Begin Footer #>
}
else {
utc # Unable to contact
}
}
write-host "`n"
}
}
}
<# End Footer #>
Rather than copying/pasting each time, I would prefer to do this...
."c:\scripts\header.ps1"
-- code --
."c:\scripts\footer.ps1"
Is that even possible when the header ends with an open bracket? I do this in PHP but I can't figure out a work-around in PowerShell.

Answer 1

Your approach could be changed into storing a function in one file and your custom script that runs for-each server in another. You can store a scriptblock to a variable in PowerShell and pass that as a parameter to a function. You can use Invoke-Command -scriptblock $Variable to execute that code.
Write your function like this:
function runAgainstServerList {
param ( [ScriptBlock]$ScriptBlock)
if($canceled) {
write-host "Operation canceled."
}
else {
if($computers.length -gt 0) {
[array]$computers = $computers.split("`n").trim()
# Loop through computers entered
foreach($pc in $computers) {
# Skip zero length lines for computers
if(($pc.length -eq $null) -OR ($pc.length -lt 1)) {
continue
}
else {
# Try to connect to the computer, otherwise error and continue
write-host "Connecting to: $pc$hr"
if(test-connection -computername $pc -count 1 -ea 0) {
Invoke-Command -ScriptBlock $ScriptBlock
}
else {
utc # Unable to contact
}
}
write-host "`n"
}
}
}
}
Now save that off to your include file like 'myFunctions.ps1'
Then create your custom script that you want to run per server like this:
. myFunctions.ps1
[ScriptBlock]$ScriptBlockToPass = {
## Insert custom code here
}
runAgainstServerList $ScriptBlockToPass
To get you a step closer to what might be your end goal, You may want to append the -ComputerName "ComputerNameHere" argument to your invoke-command statement inside your included function. This would cause your script to be executed on the remote system instead of locally.