PSDepend

0.0.1

PSDependScripts/PSGalleryModule.ps1

<#
    .SYNOPSIS
        Installs a module from a PowerShell repository like the PowerShell Gallery.
 
    .DESCRIPTION
        Installs a module from a PowerShell repository like the PowerShell Gallery.
 
        Relevant Dependency metadata:
            Name: The name for this module
            Version: Used to identify existing installs meeting this criteria, and as RequiredVersion for installation. Defaults to 'latest'
            Target: Used as 'Scope' for Install-Module. If this is a path, we use Save-Module with this path. Defaults to 'AllUsers'
 
    .PARAMETER Repository
        PSRepository to download from. Defaults to PSGallery
#>
[cmdletbinding()]
param(
    [PSTypeName('PSDepend.Dependency')]
    [psobject[]]$Dependency,

    [string]$Repository = 'PSGallery' # From Parameters...
)

# Extract data from Dependency
    $DependencyName = $Dependency.DependencyName
    $Name = $Dependency.Name
    if(-not $Name)
    {
        $Name = $DependencyName
    }

    $Version = $Dependency.Version
    if(-not $Version)
    {
        $Version = 'latest'
    }

    # We use target as a proxy for Scope
    if(-not $Dependency.Target)
    {
        $Scope = 'AllUsers'
    }
    else
    {
        $Scope = $Dependency.Target
    }
    if('AllUsers', 'CurrentUser' -notcontains $Scope -and (Test-Path $Scope -PathType Container))
    {
        $command = 'save'
    }
    else
    {
        $command = 'install'
    }

Write-Verbose -Message "Getting dependency [$name] from PowerShell repository [$Repository]"

# Validate that $target has been setup as a valid PowerShell repository
$validRepo = Get-PSRepository -Name $Repository -Verbose:$false -ErrorAction SilentlyContinue
if (-not $validRepo) {
    Write-Error "[$Repository] has not been setup as a valid PowerShell repository."
    return
}

$params = @{
    Name = $Name
    Repository = $Repository
    Verbose = $VerbosePreference
    Force = $True
}

if( $Version -and $Version -ne 'latest')
{
    $Params.add('RequiredVersion',$Version)
}

# This code works for both install and save scenarios.
$Existing = $null
if($command -eq 'Save')
{
    $Existing = Get-Module -ListAvailable -Name (Join-Path $Scope $Name)
}
elseif ($Command -eq 'Install')
{
    $Existing = Get-Module -ListAvailable -Name $Name
}
if($Existing)
{
    Write-Verbose "Found existing module [$Name]"
    # Thanks to Brandon Padgett!
    $ExistingVersion = $Existing | Measure-Object -Property Version -Maximum | Select-Object -ExpandProperty Maximum
    $GalleryVersion = Find-Module -Name $Name -Repository PSGallery | Measure-Object -Property Version -Maximum | Select-Object -ExpandProperty Maximum
    
    # Version string, and equal to current
    if( $Version -and $Version -ne 'latest' -and $Version -eq $ExistingVersion)
    {
        Write-Verbose "You have the requested version [$Version] of [$Name]"
        return $null
    }
    
    # latest, and we have latest
    if( $Version -and
        ($Version -eq 'latest' -or $Version -like '') -and
        $GalleryVersion -le $ExistingVersion
    )
    {
        Write-Verbose "You have the latest version of [$Name], with installed version [$ExistingVersion] and PSGallery version [$GalleryVersion]"
        return $null
    }

    Write-Verbose "Continuing to install [$Name]: Requested version [$version], existing version [$ExistingVersion], PSGallery version [$GalleryVersion]"
}

if('AllUsers', 'CurrentUser' -contains $Scope)
{   
    Install-Module @params -Scope $Scope
}
elseif(Test-Path $Scope -PathType Container)
{
    Save-Module @params -Path $Scope
}