How to use GET method of Invoke-WebRequest to build a query string

Question

Is there a standard way to make use of Invoke-WebRequest or Invoke-RestMethod in PowerShell to get information from a web page using a query string?

For example, I know

Answer 1

It seems that the server running PHP is irrelevant here. I think you're asking how to send key/value pairs as query string parameters.

If that's the case, you're in luck. Both Invoke-RestMethod and Invoke-WebRequest will take a [hashtable] in the body and construct your query string for you:

$Parameters = @{
  Name = 'John'
  Children = 'Abe','Karen','Jo'
}
Invoke-WebRequest -Uri 'http://www.example.com/somepage.php' -Body $Parameters -Method Get # <-- optional, Get is the default

Edit

Now seeing that the issue is that you want a query string parameter to have multiple values, essentially an array, this rules out the data types you can pass to the body parameter.

So instead, let's build the URI piece by piece first by starting with a [UriBuilder] object and adding on a query string built using an [HttpValueCollection] object (which allows duplicate keys).

$Parameters = [System.Web.HttpUtility]::ParseQueryString([String]::Empty)
$Parameters['Name'] = 'John'
foreach($Child in @('Abe','Karen','Joe')) {
    $Parameters.Add('Children', $Child)
}

$Request = [System.UriBuilder]'http://www.example.com/somepage.php'

$Request.Query = $Parameters.ToString()

Invoke-WebRequest -Uri $Request.Uri -Method Get # <-- optional, Get is the default