URLs With PowerShell

URLs With PowerShell

by | Nov 11, 2022 | Information Technology, PowerShell

Regex… Even the PowerShell Masters struggle with it from time to time. I helped a friend of mine with some URL chaos. The URL he had was a software download and the token was inside the URL. Yeah, it was weird but totally worth it. There were many different ways to handle this one. But the Matches was the best way to go. What was interesting about this interaction was I could later in another script. Unlike my other posts, this one’s format is going to be a little different. Just following along.

The URL (Example)

"https://.download.software.net/windows/64/Company_Software_TKN_0w6xBqqzwvw3PWkY87Tg301LTa2zRuPo09iBxamALBfs512rSgomfRROaohiwgJx9YH7bl9k72YwJ_riGzzD3wEFfXQ7jFZyi5USZfLtje2H68w/MSI/installer"

Here is the string example we are working with. Inside the software installer, we have the name of the software, “Company_Software_” and the token, “0w6xBqqzwvw3PWkY87Tg301LTa2zRuPo09iBxamALBfs512rSgomfRROaohiwgJx9YH7bl9k72YwJ_riGzzD3wEFfXQ7jFZyi5USZfLtje2H68w” The question is how do you extract the token from this URL? Regex’s Matches we summon you!

Matches is one of the regex’s powerhouse tools. It’s a simple method that allows us to search a string for a match of our Regex. This will allow us to pull the token from URLs with PowerShell. First, it’s best to link to useful documentation. Here is the official Microsoft documentation. Sometimes it’s helpful. Another very useful tool can be found here.

PowerShell’s Regex can be expressed in many different ways. The clearest and most concise way is to use the -match flag. 

$String -match $Regex

This of course produces a true or false statement. Then if you call the $matches variable, you will see all of the matches. Another way of doing this is by using the type method. 

[regex]::Matches($String, $Regex)

This method is the same as above, but sometimes it makes more sense when dealing with complex items. The types method is the closest to the “.net” framework.

The Regex

Next, let’s take a look at the Regex itself. We are wanting to pull everything between TKN_ and the next /. This was a fun one. 

'_TKN_([^/]+)'

The first part is the token. We want our search to start at _TKN_. This clears out all of the following information automatically: https://.download.software.net/windows/64/Company_Software. A next part is a group. Notice the (). This creates a group for us to work with. Inside this group, we are searching for all the characters inside []. We are looking for Everything starting at where we are, the TKN_ to a matching /. We want all the information so we place a greedy little +. This selects our token. This regex produces two matches. One with the word _TKN_ and one without. Thus we will want to capture the second output, aka index of 1. 

$String -match '_TKN_([^/]+)'
$Matches[1]

Another way to go about this is the method-type model. 

$Token = [regex]::Matches($String, '_TKN_([^/]+)') | ForEach-Object { $_.Groups[1].Value }

It same concept, instead this time we are able to parse the output and grab from group one.

Replace Method

Another way to go about this is by using replace. This method is much easier to read for those without experience in regex. I always suggest making your scripts readable to yourself in 6 months. Breaking up the string using replace makes sense in this light. The first part of the string we want to pull out is everything before the _TKN_ and the TKN itself. The second part is everything after the /. Thus, we will be using two replaces for this process. 

$String -replace(".*TKN_",'')

Here we are removing everything before and the TKN_ itself. The .* ensures this. Then we wrap this code up and run another replace. 

$Token = ($String -replace(".*TKN_",'')) -replace('/.*','')

Now we have our token. This method is easier to follow.

Conclusion

In Conclusion, parsing URLs With PowerShell can be tough, but once you get a hang of it, life gets easier. Use the tools given to help understand what’s going on.

Additional Regex Posts

Image created with midjourney AI.

SHD Array To Line Of Text

SHD Array To Line Of Text

by | Sep 9, 2020 | Information Technology, PowerShell

Often times I need to put an array into a line of text. It can take a while. So I made a powershell to help me make powershells. This little guy takes a single array and turns it into a line of text that I can use in a parameter (“A”,”B”,”C”).

The Break Down

The first part of the code is the parameter block that Grabs the array. This is a simple input. We make sure the array is mandatory. 

    param (
        [parameter(HelpMessage = "Input of Array", Mandatory = $true)][array]$TheArray
    )

Next we create a blank line of text that we will be adding everything else to. 

$Line = ""

I’m a little anal when it comes down to my outputs. I like everything to be sorted. Its just cleaner and easier for me to understand after the fact. So I sort the Inputs and put the input back into the inputs. 

$TheArray = $TheArray | Sort-Object

Now we create the meat and potato of the script. The for loop. We will do a foreach loop in this case. Makes things easier to work with. We put each object into the $Line string with a +=.

foreach ($Info in $TheArray) {
    $Line += """$Info"","
}

Lets take a look at the three ” in front of the $Info variable. “””$Info””,” Inorder to have a qoute, you must have a qoute around it inside a string. “$Info” will just put the value info into the string. But placing a ““” adds “$info as part of the string. Doing the same with the end “” does the same. Then adding the , helps build the string.

After the loop is finished, we are left with a odd , mark. The best way to handle that is to remove it. I do this by pushing the value line into it self while removing the last character with substring. 

$Line = $Line.Substring(0, $Line.Length - 1)

Here the substring starts at character 0, and counts to the last character of the value line – 1. Basically, we don’t need that last one. So, everything else is pushed back into $Line.

Next we add the lazy man touch and push the string of text into the clip board to be used else where. Life is good. We do this by using the command clip

$Line | Clip

Finally, we display the information to the screen with a write-host command letting the end user know it’s inside their clipboard. 

Write-Host "Input is on in your clipboard: $Line"

It’s a simple little script that has saved me on hours worth of work. I use this little guy to create a “Create PDQ deployment script” script. A powershell script that builds powershell scripts.

The Script

I would be amissed if I didn’t post the script, so here you go. 

Function Convert-SHDArraytoLineofText {
    [cmdletbinding()]
    param (
        [parameter(HelpMessage = "Input of Array", Mandatory = $true)][array]$TheArray
    )
    $Line = ""
    $TheArray = $TheArray | Sort-Object
    foreach ($Info in $TheArray) {
        $Line += """$Info"","
    }
    $Line = $Line.Substring(0, $Line.Length - 1)
    $Line | Clip
    Write-Host "Input is on in your clipboard: $Line"
}

Roadmap

Like all things, this can be improved upon as well. Here are some ideas and possible future growth.

  • Validation that the input object is an array
  • validation that the input is a single object array instead of a multi object array.
  • A way to handle multiple layers of an array.

Thank you for reading, if you have any questions, feel free to contact me.