How to pass optional parameters in PowerShell? - powershell

Question

This is a wrapper function for Invoke-WebRequest (I have removed a lot of extra functionality to keep the noise down)
function Invoke-SERVERAPI($apiFolder, $adminCredentials, [ValidateSet("GET","POST","PUT","DELETE")] $HTTPmethod, $contentType, $body, $verbose)
{
$resp1HTTPCode= 'Not set'
try
{
if ( ($HTTPmethod -eq 'GET') -or ($HTTPmethod -eq 'DELETE'))
{
$resp1 = Invoke-WebRequest -Uri $apiFolder -Method $HTTPmethod -Credential $adminCredentials -ContentType $contentType -ErrorAction SilentlyContinue -Verbose:$verbose
}
else
{
$resp1 = Invoke-WebRequest -Uri $apiFolder -Body $body -Method $HTTPmethod -Credential $adminCredentials -ContentType $contentType -ErrorAction SilentlyContinue -Verbose:$verbose
}
$resp1HTTPCode = $resp1.StatusCode
}
catch [Exception]
{
$resp1HTTPCode = $_.Exception.Response.StatusCode.Value__
}
return $resp1HTTPCode
}
I need to pass -body parameter on verb POST and PUT but don't pass it in GET and DELETE. I managed to do it with an IF/ELSE.
Is there a better way to achieve this in PowerShell like I did in the switch parameter -Verbose?

Answer 1

Yes, it involves forming a hashtable with parameters and using that instead or in addition of parameter list, aka splatting. In your case, you do like this:
try
{
$ifbody=#{}
if ( ($HTTPmethod -eq 'PUT') -or ($HTTPmethod -eq 'POST'))
{
$ifbody."Body"=$body
}
$resp1 = Invoke-WebRequest -Uri $apiFolder #ifbody -Method $HTTPmethod -Credential $adminCredentials -ContentType $contentType -ErrorAction SilentlyContinue -Verbose:$verbose
$resp1HTTPCode = $resp1.StatusCode
}
The #ifbody reverts the hashtable into -key=value -key2=value2... sequence of parameters to a cmdlet or a function.

Answer 2

You should have a look at ParameterSetName in about_Functions_Advanced_Parameters. It can help you to differentiate different sets of parameters.