CODEWITHSUNDEEP
regexpowershellsubstring
davetherave
davetherave

Reputation: 1167

regex, substring of a url from start till the 3rd one of a certain character

Ok so I have a series of urls ranging from something like 

http://www.test.com/sasa
http://www.test.com/sasdassasdssda
http://www.test.com/ewewewewsasa
http://www.test.com

What I want to do is just take a substring of each url which goes from the start to the third / and if there is no third / take the original string

basically I want to know how to get the position of the third /, as I assume if there is no third / then it will be -1 so I can just grab the position and if its not -1 do the substring bit. Anyway enough of me rambling. How do I find the position of the third slash?

Upvotes: 1

Views: 293

Answers (1)

Mathias R. Jessen
Mathias R. Jessen

Reputation: 174700

It sounds like you want the URI without the path (the segment after the third /) and the trailing / itself.

The easiest way to do that, is simply to convert the string to an actual URI object and then use the AbsoluteUri and PathAndQuery properties to calculate where to make to incision:

function Get-UriSchemeAndAuthority
{
    param(
        [string]$InputString
    )

    $Uri = $InputString -as [uri]
    if($Uri){
        $FullUri = $Uri.AbsoluteUri
        $Path = $Uri.PathAndQuery

        $SlashIndex = $FullUri.Length - $Path.Length

        return $FullUri.Substring(0,$SlashIndex)
    } else {
        throw "Malformed URI"
    }
}

Works with all of your test cases:

PS C:\> Get-UriSchemeAndAuthority http://www.test.com/sasa
http://www.test.com
PS C:\> Get-UriSchemeAndAuthority http://www.test.com/sasdassasdssda
http://www.test.com
PS C:\> Get-UriSchemeAndAuthority http://www.test.com/ewewewewsasa
http://www.test.com
PS C:\> Get-UriSchemeAndAuthority http://www.test.com
http://www.test.com

Alternatively, take the Scheme and Authority properties and create a new string from those (makes it much more concise) :

function Get-UriSchemeAndAuthority
{
    param(
        [string]$InputString
    )

    $Uri = $InputString -as [uri]
    if($Uri){
        return $("{0}://{1}" -f $Uri.Scheme,$Uri.Authority)
    } else {
        throw "Malformed URI"
    }
}

Upvotes: 2

Related Questions