PowerShell Invoke-WebRequest, how to automatically use original file name?

Thanks to Ryan I have a semi-usable function:

Function Get-Url {
  param ( [parameter(position=0)]$uri )
  invoke-webrequest -uri "$uri" -outfile $(split-path -path "$uri" -leaf)
}

A graphic file and xml file I have been able to download. When I try to download this webpage and open it with Edge it will work at times.


Try this method (may not always work because the file name may not be in the response header)

  1. call Invoke-WebRequest to get the result. then you can inspect the result to look at what is in the headers.
  2. get the file name from the response header (this could be in Headers.Location, or some other place. When I run my query for a url that i was troubleshooting, I found it in the Headers["Content-Disposition"] and it looks like inline; filename="zzzz.docx"
  3. Create a new file based on the name and write the content to this file

Here is code sampe:

$result = Invoke-WebRequest -Method GET -Uri $url -Headers $headers

$contentDisposition = $result.Headers.'Content-Disposition'
$fileName = $contentDisposition.Split("=")[1].Replace("`"","")

$path = Join-Path $yourfoldername $fileName

$file = [System.IO.FileStream]::new($path, [System.IO.FileMode]::Create)
$file.write($result.Content, 0, $result.RawContentLength)
$file.close()

For the example given you're going to need to get the redirected URL, which includes the file name to be downloaded. You can use the following function to do so:

Function Get-RedirectedUrl {

    Param (
        [Parameter(Mandatory=$true)]
        [String]$URL
    )

    $request = [System.Net.WebRequest]::Create($url)
    $request.AllowAutoRedirect=$false
    $response=$request.GetResponse()

    If ($response.StatusCode -eq "Found")
    {
        $response.GetResponseHeader("Location")
    }
}

Then it's a matter of parsing the file name from the end of the responding URL (GetFileName from System.IO.Path will do that):

$FileName = [System.IO.Path]::GetFileName((Get-RedirectedUrl "http://go.microsoft.com/fwlink/?LinkId=393217"))

That will leave $FileName = rtools_setup_x64.exe and you should be able to download your file from there.


Essence of my code - this works.. using PS 5.1

I have commented out the normal -Outfile statement because that would imply I knew the filename in advance. I have put this together based upon a number of sources, there are lots of ways of parsing the Content-Disposition headers so use whatever works for you.

$outpath = "C:\\temp\\"

The call:

$result = Invoke-WebRequest -method GET -Uri $resourceUrl -Headers 
$resourceHeaders -Verbose #-OutFile $($outPath+"$nodeId.pdf")

parsing

$outFilename = $outpath+$result.Headers.'Content-Disposition'.Split("=")[1].Split('\\""')[1] #shaky parsing - might require improvement in time

Writing the file (this is mostly pdf's for me

[System.IO.File]::WriteAllBytes($outFilename, $result.content)

Tags:

Powershell

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