PowerShell DownloadFile() not working for Nexus artifact download

Question

I am trying to download the latest artifact from a Nexus repository. If I give the exact zip file name, it is working fine. When I try to download using a generic URL (REST URI) its giving me 401 Unauthorized. I have tried Invoke-WebRequest, WebClient and Invoke-RestMethod as well.

$wc = New-Object System.Net.WebClient
$URL = "http://nexusrepo/nexus/service/local/artifact/maven/redirect?r=my-snapshot&g=my.group.id&a=my.artifact.id&v=1.10.0-SNAPSHOT&c=win32.win32.x86_64&p=zip"
$username = "nexus"
$password = "nexus"
$auth = $username + ":" + $password
[System.Net.ServicePointManager]::ServerCertificateValidationCallback = {$true}
$Encoded = [System.Text.Encoding]::UTF8.GetBytes($auth)
$EncodedPassword = [System.Convert]::ToBase64String($Encoded)
$wc.Headers.Add("Accept-Encoding", "gzip,deflate")
$wc.Credentials = New-Object System.Net.NetworkCredential($username, $password)
$wc.Headers.Add("Authorization", "Basic " + $EncodedPassword)
$wc.UseDefaultCredentials = $false
$wc.DownloadFile($URL, "MyApp.zip")

Exception calling "DownloadString" with "1" argument(s): "The remote server
returned an error: (401) Unauthorized."
At C:\temp\NexusDownloadTest\Nexus-Download.ps1:39 char:1
+ $weburl = $wc.DownloadString($URL)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : WebException

Can someone please help me on this?

Answer 1

As an workaround, I went back to Invoke-WebRequest and first got the redirected URL by using MaximumRedirection 0 and then submitted that URL as a request. The below code works.

$URL = "http://nexusrepo/nexus/service/local/artifact/maven/redirect?r=my-snapshot&g=my.group.id&a=my.artifact.id&v=1.10.0-SNAPSHOT&c=win32.win32.x86_64&p=zip"
$username = "nexus"
$password = "nexus"
$auth=$username+":"+$password
$Encoded = [System.Text.Encoding]::UTF8.GetBytes($auth)
$EncodedPassword = [System.Convert]::ToBase64String($Encoded)
$latestArtifactURL = Invoke-WebRequest $url -Headers @{Authorization = "Basic $EncodedPassword"} -MaximumRedirection 0
$redirectedMessage = "$latestArtifactURL".IndexOf('http:')
$targetURL = "$latestArtifactURL".SubString("$redirectedMessage") 
Invoke-WebRequest $targetURL -Headers @{Authorization = "Basic $EncodedPassword"} -OutFile "MyApp.zip"