Powershell - Invoke-WebRequest - Issue with submit - powershell

Question

I'm working on a powershell script that will create a printer on my Company Print Server, which is all done and working.
But we have however a location where we list all used IP's, which is a webpage.
So I'm trying to use Invoke-WebRequest to do this. Login to the page works but then when it tries to use the form to add the IP it doesn't.
Login only has one submit button in the form and to add the IP there is three buttons. I will list them in the order they are on the page
Clear the form
Apply
Cancel
So I'm thinking when I Invoke-Webrequest it is using the "clear form" function.
Is there any way I could specify which function to use when sending a webrequest?
I cant remove the "Clear form" button since it is being used frequently, just to get that clear.
$R = Invoke-WebRequest -URI http://localhost -SessionVariable IP
$Form = $R.Forms[0]
$Form.fields["ctlUsername"]=User
$Form.fields["ctlPassword"]=Pass
$R=Invoke-WebRequest -Uri ("http://localhost/" + $Form.Action) -WebSession
$IP -Method POST -Body $Form.Fields
$D = Invoke-WebRequest -URI http://localhost/addIP.php -WebSession $Test
$Form2 = $D.Forms[0]
$Form2.fields["IP"]="172.10.0.1"
$Form2.fields["name"]="Printer300"
$Form2.fields["location"]="Room407"
$Form2.fields["MAC"]="000"
$Form2.fields["ID"]="000"
Invoke-WebRequest -Uri http://localhost/addIP.php -WebSession $IP -Method POST -Body $Form2.Fields

Answer 1

Don't think in terms of "filling in web pages" when it comes to sending those requests. Web pages for a human user. Filling in a form and clicking a button is the manual way of creating an HTTP message with data.
When you post this form:
IP: [172.10.0.1 ]
Name: [Printer300 ]
Location: [Room407 ]
[Apply] [Cancel]
the browser creates a text string like this:
IP=172.10.0.1&Name=Printer300&Location=Room407
and sends it to the target URL.
Invoke-WebRequest can create this format directly from your data. This means, you don't need to "fill in" anything. Just pass a hashtable with the proper keys and values:
Invoke-WebRequest "http://localhost/addIP.php" -WebSession $IP -Method POST -Body #{
IP = "172.10.0.1"
Name = "Printer300"
Location = "Room407"
MAC = "000"
ID = "000"
}
Of course the keys must correspond to the form field names.
That being said, I don't see much of a need for authentication with requests coming from the localhost. You can save yourself some busywork by disabling authentication for all local requests, and requiring it only for remote requests.
Anyway, making a website request a password and then storing that password in clear text in a script is not exactly secure to begin with.
Invoke-WebRequest supports Windows integrated authentication, so that you don't have to bother with usernames and passwords at all. This would be my preferred authentication solution for such tasks.

Answer 2

Found the issue, it needed a hidden value that was not being sent via the form but was added in php function later.
Thanks for all your help.