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

Question

How can I use Invoke-WebRequest to download a file but automatically make the file name the same as if I downloaded via browser? I haven't found a way to make -OutFile work without manually specifying the file name. I'm fine with this involving a few other lines of code.
A good solution will:
Work even if the file name isn't in the request URL. For example, the URL to download the Visual Studio x64 Remote Debugging Tools is http://go.microsoft.com/fwlink/?LinkId=393217 but it downloads the file rtools_setup_x64.exe.
Not save the whole file to memory before writing to disk, unless that's what Invoke-WebRequest already does even with the -OutFile parameter (?)
Thanks!

Answer 1

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.

Answer 2

Try this method (may not always work because the file name may not be in the response header)
call Invoke-WebRequest to get the result. then you can inspect the result to look at what is in the headers.
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"
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()

Answer 3

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.

Answer 4

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)

Answer 5

powershell.exe Invoke-WebRequest -Uri serverIP/file.exe -OutFile C:\Users\file.exe