Download modules from PSGallery

download-module.ps1

function Download-Module {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory,ValueFromPipelineByPropertyName)]
        [String[]]$Name,

        [Parameter(ValueFromPipelineByPropertyName)]
        [String]$Repository,
        [PSCredential]$Credential,

        [IO.DirectoryInfo]$OutDirectory
    )
    begin {
        $ModuleParams = @{}
        if ($Repository) {$ModuleParams.Repository = $Repository}
        if ($Credential) {$ModuleParams.Credential = $Credential}
        # TODO: This currently breaks on non-PSGallery repos. Fix that by not using Find-Module.
        $Name | %{
            $ModuleParams.Name = $PSItem
            [Array]$Modules += Find-Module @ModuleParams
        }

        if (Test-Path $OutFile -PathType Container) {
            $OutDirectory = $OutFile
            Remove-Variable OutFile
        } elseif ((Test-Path $OutFile -PathType Leaf) -and $Modules.Count -gt 1) {
            $OutDirectory = Split-Path $OutFile -Parent
            Remove-Variable OutFile
        } else {
            $OutDirectory = $PWD
        }
    }
    process {
        foreach ($Module in $Modules) {
            if (-not $OutFile -or $Modules.Count -gt 1) {$OutFile = Join-Path $OutDirectory "$($Module.Name).$($Module.Version).nupkg"}
            $DownloadParams = @{
                Uri = (Get-PSRepository -Name $Module.Repository).PublishLocation + "/" + $Module.Name + "/" + $Module.Version
                OutFile = $OutFile
            }
            if ($Credential) {$DownloadParams.Credential = $Credential}
            Invoke-WebRequest @DownloadParams

            [PSCustomObject]@{
                Name = $Module.Name
                Version = $Module.Version
                Path = $OutFile
            }
        }
    }
}