Get Domain from URL in Powershell

问题:

I'm looking to strip out the domain in this scenario using PowerShell. What is the most effective method to get 'domain.com' out of the following variable?

$URL = "http://www.domain.com/folder/" 

(some sort of regex command here to convert/strip $URL into $DOMAIN using PowerShell)

$DOMAIN = "domain.com" #<-- taken from $URL 

I've searched and I've found results for finding the IP address from a domain but I need to establish what the domain is first using regex (or another method). Any suggestions are great.

回答1:

Try the Uri class:

PS> [System.Uri]"http://www.domain.com/folder/"   AbsolutePath   : /folder/ AbsoluteUri    : http://www.domain.com/folder/ LocalPath      : /folder/ Authority      : www.domain.com HostNameType   : Dns IsDefaultPort  : True IsFile         : False IsLoopback     : False PathAndQuery   : /folder/ Segments       : {/, folder/} IsUnc          : False Host           : www.domain.com Port           : 80 Query          : Fragment       : Scheme         : http OriginalString : http://www.domain.com/folder/ DnsSafeHost    : www.domain.com IsAbsoluteUri  : True UserEscaped    : False UserInfo       : 

And remove the www prefix:

PS> ([System.Uri]"http://www.domain.com/folder/").Host -replace '^www\.' domain.com 

回答2:

Like this:

PS C:\ps> [uri]$URL = "http://www.domain.com/folder/" PS C:\ps> $domain = $url.Authority -replace '^www\.' PS C:\ps> $domain domain.com 

回答3:

For properly calculating the sub-domain, the trick is you need to know the second to last period. Then you take a substring of that second to last period (or none if it is only one .) to the final position by subtracting the location of second period (or 0) from total length of domain. This will return the proper domain-only and will work regardless of how many sub-domains are nested under the TLD:

$domain.substring((($domain.substring(0,$domain.lastindexof("."))).lastindexof(".")+1),$domain.length-(($domain.substring(0,$domain.lastindexof("."))).lastindexof(".")+1))

Also note that System URI itself is valid 99% of the time but I'm parsing my IIS logs and finding that with VERY long (often invalid/malicious requests) URIs it does not properly parse and fails those.

I have this in function form as:

Function Get-DomainFromURL {     <#     .SYNOPSIS     Takes string URL and returns domain only     .DESCRIPTION     Takes string URL and returns domain only     .PARAMETER URL     URL to parse for domain     .NOTES     Author: Dane Kantner 9/16/2016      #>       [CmdletBinding()]         param(         [Alias("URI")][parameter(Mandatory=$True,ValueFromPipeline=$True)][string] $URL     )      try { $URL=([System.URI]$URL).host }     catch { write-error "Error parsing URL"}     return $URL.substring((($URL.substring(0,$URL.lastindexof("."))).lastindexof(".")+1),$URL.length-(($URL.substring(0,$URL.lastindexof("."))).lastindexof(".")+1)) } 

文章来源: Get Domain from URL in Powershell