Download a list of files from website using Powershell

## Download-files.ps1

## Downloads files from a website

<#

Requires:

inputfile - text file of files to download, 1 URL per line
outputpath - folder to store downloaded files in

EG:

Given a text file called listToDownload.txt containing the following:

http://www.filesgohere.com/wsus/WSUSMaintenance.zip
http://www.filesgohere.com/greenshot.exe
http://www.filesgohere.com/treesizefree.exe
http://www.filesgohere.com/WSUSMaintenance.zip

Running the command:
.\Download-files.ps1 -inputfile listToDownload.txt -outputpath "c:\temp"
will download the 4 files in the text file and save them in c:\temp.  The duplicate file, WSUSMaintenance.zip will have the 2nd copy renamed to "http___www.filesgohere.com__wsusmaintenance.zip"

EG: duplicates will be renamed to the full URL, excluding NTFS reserved characters (these will be replaced by underscores ("_").)


#>

param(
    [string]$inputfile=$(throw "-inputfile parameter is required"),
    [string]$outputpath=$(throw "-outputpath parameter is required")
)

$filestodownload=get-content $inputfile
$splitoption=[System.StringSplitOptions]::RemoveEmptyEntries
foreach ($webaddress in $filestodownload)
{
    $filenamearray=$webaddress.split("/",$splitoption)
    $filename=$filenamearray[-1]
    $destination = "$outputpath\$filename"
    if (test-path $destination)
    {
        $destination=$webaddress.replace("<","_")
        $destination=$destination.replace(">","_")
        $destination=$destination.replace(":","_")
        $destination=$destination.replace("`"","_")
        $destination=$destination.replace("/","_")
        $destination=$destination.replace("\","_")
        $destination=$destination.replace("|","_")
        $destination=$destination.replace("?","_")
        $destination=$destination.replace("*","_")
        $destination="$outputpath\$destination"
    }
    Invoke-WebRequest $webaddress -OutFile $destination
}