Automated Windows to Windows SSH copy-id

win-to-win-ssh_copy_id.ps1

# UPDATE, VIEW: https://code.visualstudio.com/docs/remote/troubleshooting#_configuring-key-based-authentication

# SSH copy-id is not existent in win32 openssh (https://github.com/PowerShell/Win32-OpenSSH)
# So we need to do it ourselves.
# literally all I could find on Google was Windows to Unix:
# - https://www.chrisjhart.com/Windows-10-ssh-copy-id/
# - https://stackoverflow.com/a/9971617/10503012 ('cat source | ssh user@host "cat >> /path/to/target"' --> the 'cat >> ' part does not work on Windows, the variable is not properly piped through
#   I do not have enough experience on (Windows) piping to fix this in a proper way.
# Special shoutout to useless Stack answers:
# - https://stackoverflow.com/questions/65656813/copying-ssh-key-from-windows-machine-to-windows-server-2019
# - https://stackoverflow.com/a/67541732/10503012

# So here we go, it's disgusting, uses `Invoke-Expression` but it works:
function Copy-SSHKey {
    param(
        [Parameter(Position=0)]
        [string] $RemoteName,
        [Parameter(Position=1)]
        [string] $RemoteIp        
    )

    $address = -join($RemoteName, "@", $RemoteIp)
    $key = Get-Content $env:USERPROFILE\.ssh\id_ed25519.pub
    $dir = -join('C:\Users\', $RemoteName, '\.ssh\authorized_keys')
    $cmd1 = 'ssh.exe ' + $address
    $cmd2 = [string]::Format("'echo $key >> {0}'", $dir)
    $expr = -join($cmd1, " ", $cmd2)
    Invoke-Expression $expr
    
    # Results in following expression being executed:
    # ssh.exe {RemoteName}@{RemoteIp} 'echo {key} >> C:\Users\{Remotename}\.ssh\authorized_keys'
    # This solution also APPENDS to authorized_keys instead of overwriting, which I saw in some solutions
    # Obvious code cleanup appreciated...
}