Variable in Invoke-WebRequest -Uri path - powershell

Question

I am trying to pass a MAC Address and code (1,2,3,4) to Invoke-WebRequest.
Manually the command is working fine, but I am not able to do it via command.
The manual command that works is:
Invoke-WebRequest -Uri https://mywebsite.org/pcconfig/setstate.php?mac=F832E3A2503B"&"state=4
Now when I break this up into variable to use with the mac from the machine I do the following.
$LiveMAC = Get-NetAdapter -Physical |
where Status -eq "Up" |
Select-Object -ExpandProperty PermanentAddress
$Str1 = "https://mywebsite.org/pcconfig/setstate.php?mac=$LiveMAC"
$Str2 = $Str1 + '"&"' + 'state=4'
Invoke-WebRequest -Uri $Str2
When I run the above code I do not see errors in red, it seems to process but does not work.
Looking at $Str2 I see the below output, which seems correct, but when passing it as above it fails to work.
https://mywebsite.org/pcconfig/setstate.php?mac=F832E3A2503B"&"state=4

Answer 1

The double quotes in a statement like
Invoke-WebRequest -Uri https://example.org/some/sit.php?foo=x"&"bar=y
mask the ampersand for PowerShell, because otherwise otherwise PowerShell would throw an error that a bare & is reserved for future use. A more canonical way of avoiding this is to put the entire URI in quotes:
Invoke-WebRequest -Uri "https://example.org/some/sit.php?foo=x&bar=y"
Either way the actual URI that is passed to Invoke-WebRequest is
https://example.org/some/sit.php?foo=x&bar=y
without the quotes.
However, in a code snippet like this:
$Str1 = "https://example.org/some/site.php?foo=$foo"
$Str2 = $Str1 + '"&"' + 'state=4'
you're including literal double quotes as part of the URI, so the actual URI passed to the cmdlet would be
https://example.org/some/sit.php?foo=x"&"bar=y
which is invalid.
With that said, you don't need string concatenation for building your URI anyway. Simply put your variable in the double-quoted string:
$uri = "https://example.org/some/sit.php?foo=${foo}&bar=y"
If you need to insert the value of an object property or array element use either a subexpression
$uri = "https://example.org/some/sit.php?foo=$($foo[2])&bar=y"
or the format operator
$uri = 'https://example.org/some/sit.php?foo={0}&bar=y' -f $foo[2]