download files from vsts package feed - powershell

Question

We have certain Chocolatey packages stored in VSTS private package management feed. I'm trying to download a specific package from feed in VSTS in PowerShell. I'm using the below commands:
$user = "my-user-id"
$token = "my-pat-token"
$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $user,$token)))
$url = "vsts-package-url"
$webClient = New-Object System.Net.WebClient
$webClient.Headers.Add('HttpRequestHeader.Authorization',"Basic $base64AuthInfo")
After this, I should be able to download the package when using $webClient.DownloadFile($url, $fileName).
However file contains dummy text expecting me to sign-in and has 401 related details.
Its basically a PowerShell code. Can anyone please advise how should I go about this? I do not want to install the package from feed, only download it.
I was wondering if there is a better way to do this as this process still needs me to prepare package url first which would be different for each package iteration?

Answer 1

It looks like you're creating the auth header incorrectly. Basically, with a PAT, no user name is needed.
I use this snippet of code all the time:
$pat = 'yourPatHere'
$bytes = [System.Text.Encoding]::ASCII.GetBytes(":$($pat)")
$encodedText =[Convert]::ToBase64String($bytes)
$header = #{Authorization = "Basic $encodedText"}
You can then use Invoke-WebRequest to download the feed information:
Invoke-WebRequest -Uri 'https://uri' -Header $header -Method Get
That looks roughly the same as your code, but Invoke-WebRequest is idiomatic PowerShell vs creating a WebClient. Shouldn't matter in the end.
Actually downloading a file from a feed is a different matter. The packages are exposed via standard mechanisms for that specific type of feed. See the documentation. Basically, if you need a NuGet package, you download it from the NuGet feed, not from package management.