Powershell HTTP(S) redirector

Redirector.ps1

# This Powershell script can be used on a server to redirect HTTP/HTTPS
# traffic to different sources. Make sure your DNS routes the requests
# for the source URLs to this server. It automatically forwards the URL
# to the destination server without altering the rest of the URL.
#
# You can use multiple mappings. Of course the 'source' should be
# unique, but the destination can occur multiple times.
#
# Make sure PowerShell is allowed to run this script. You might need to
# change PowerShell's policy by running the following command as admin:
#
#   PS C:> Set-ExecutionPolicy RemoteSigned
#
# I would advise not to run this script as Administrator, but as a uwer
# with restricted permission (in production use). You might need to authorize
# the user to handle specific HTTP(S) URLs. Refer to http://bit.ly/1Crn0xz
# for more information how to do this.
#
# Script written by Nov 2014 by Ramon de Klein (mail@ramondeklein.nl).
# Use and alter as you please.

$map = @{
  # Source -> Destination
  "http://localhost:8888/" = "http://www.microsoft.com/"
  #"http://www.example.com/" = "https://example.com/"
  #"https://www.example.com/" = "https://example.com/"
  #"http://example.com/" = "https://example.com/"
  #"http://blog.example.com/" = "https://example.com/blog/"
  #"https://blog.example.com/" = "https://example.com/blog/"
}

# Setup the HTTP listener and start it
$listener = New-Object System.Net.HttpListener
$map.Keys | % { 
  # Listen on each source URL
  Write-Host "- Redirect $_ to" $map.Item($_)
  $listener.Prefixes.Add($_) 
}
$listener.Start()
 
while ($listener.IsListening)
{
  # Obtain HTTP context
  $context = $listener.GetContext()
  
  # Determine the request URL
  $url = $context.Request.Url.ToString()

  # Process the URL mappings
  $map.Keys | % { $url = $url.Replace($_, $map.Item($_)) }

  # Create a HTTP 301 (permanent redirect) response
  $response = $context.Response
  $response.StatusCode = 301
  $response.AddHeader("Location", $url)
  $response.Close()

  # Log the redirect  
  Write-Host "> Redirecting to $url"
}