Public/Get-PlexPlaylist.ps1

function Get-PlexPlaylist
{
    <#
        .SYNOPSIS
            Gets playlists.
        .DESCRIPTION
            Gets playlists.
        .PARAMETER Id
            The id of the playlist to get.
        .PARAMETER IncludeItems
            If specified, the items in the playlist are returned.
        .PARAMETER AlternativeToken
            Alternative token to use for authentication. For example,
            when querying for playlists for a different user.
        .EXAMPLE
            Get-PlexPlaylist -Id 723 -IncludeItems
        .EXAMPLE
            $User = Get-PlexUser -Username "friendsusername"
            Get-PlexPlaylist -AlternativeToken $User.Token
    #>


    [CmdletBinding(SupportsShouldProcess)]
    param(
        [Parameter(Mandatory = $false)]
        [String]
        $Id,

        [Parameter(Mandatory = $false)]
        [Switch]
        $IncludeItems,

        [Parameter(Mandatory = $false)]
        [ValidateNotNullOrEmpty()]
        [String]
        $AlternativeToken
    )

    #############################################################################
    #Region Import Plex Configuration
    if(!$script:PlexConfigData)
    {
        try
        {
            Import-PlexConfiguration -WhatIf:$False
        }
        catch
        {
            throw $_
        }
    }
    #EndRegion

    #############################################################################
    #Region Get data
    Write-Verbose -Message "Function: $($MyInvocation.MyCommand): Getting playlist(s)"
    try
    {
        # Plex decided to automatically create Playlists with heart emojis in for music playlists.
        # When calling Invoke-RestMethod, PowerShell ends up converting these to squiggly a characters.
        # To work around this, we have to use Invoke-WebRequest and take the RawContentStream property
        # and use that.

        $DataUri = Get-PlexAPIUri -RestEndpoint "playlists/$Id" -Token $AlternativeToken
        $Data = Invoke-WebRequest -Uri $DataUri -ErrorAction Stop
        if($Data)
        {
            $UTF8String = [system.Text.Encoding]::UTF8.GetString($Data.RawContentStream.ToArray())
            [array]$Results = ($UTF8String | ConvertFrom-Json).MediaContainer.Metadata
        }
        else
        {
            return
        }
    }
    catch
    {
        throw $_
    }
    #EndRegion

    #############################################################################
    #Region Get items
    if($IncludeItems)
    {
        foreach($Playlist in $Results)
        {
            # If the playlist is smart skip it, as it doesn't have a static item list:
            if($Playlist.smart)
            {
                continue
            }

            # We don't need -AlternativeToken here as the playlists have unique IDs
            $ItemsUri = Get-PlexAPIUri -RestEndpoint "playlists/$($Playlist.ratingKey)/items"
            Write-Verbose -Message "Function: $($MyInvocation.MyCommand): Getting and appending playlist item(s)"
            try
            {
                [array]$Items = Invoke-RestMethod -Uri $ItemsUri -ErrorAction Stop
                $Playlist | Add-Member -NotePropertyName 'Items' -NotePropertyValue $Items.MediaContainer.Metadata
            }
            catch
            {
                throw $_
            }
        }
    }
    #EndRegion

    #############################################################################
    # Append type and return results
    $Results | ForEach-Object { $_.psobject.TypeNames.Insert(0, "PSPlex.Playlist") }
    return $Results
}