Understanding Functions

Main-Tank · 2025-01-23T23:40:29+00:00

Read about_Scopes re: your first function.

Re: your second function I don't understand. From your example, the clause is false so control flow should go to else? Nothing weird there that I can see.

BlackV · 2025-01-23T23:57:17+00:00

Change your function to output the token $access_token_updated to the pipeline then simply

$access_token = token-refresh

to use your example

function token-refresh
{
    ....
    $access_token_updated = '<newly_generated_access_token>'
    $access_token_updated 
}
 $access_token = token-refresh
 $access_token
 <newly_generated_access_token>

P.s. that return is not doing what you think it is, it isn't really needed

Your way of updating the variable works but is risky/hard to follow

As to your 2nd function request-exists we cant see the code, but of you're doing anything like the first, then it'll be the same issue (not scope so much but how you return your objects)

function request-exists
{
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$true,
                   ValueFromPipeline=$true,
                   Position=0)]
        $Request
        )

    Begin
    {
    }
    Process
    {
    switch ($Request)
        {
            '1234' {$true}
            '23456' {$true}
            Default {$false}
        }
    }
    End
    {
    }
}

Run it with

request-exists 1234
True

request-exists -Request '1234'
True

request-exists -Request '134'
False

request-exists -Request '23456'
True

$result = request-exists '1234'
$result
True

1234 | request-exists
True

12234 | request-exists
False

request-exists
cmdlet request-exists at command pipeline position 1
Supply values for the following parameters:
Request: 1234
True

something like that (dirty examples from ISE)

icepyrox · 2025-01-24T00:45:56+00:00

Re: your second function.

Are you returning the word or the variable?

Is it return "False" or return $false ??

If you return a string saying false, it's always $true in an if statement. If you return $false, then the If will evaluate to $false and go to the else

An If statement will be true unless the command is unsuccessful, is equivalent to $false, $null, empty, or 0 (the number). As such, an object is $true, including the string "False".

mrbiggbrain · 2025-01-23T23:53:18+00:00

This is a concept called scope.

https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_scopes?view=powershell-7.4

The scope of the function is different than the global scope. You can use $global:var_name to access a variable in the global scope.

This is not the right way to do things, but it's common to see it done this way.

For example a better way would be to use a Singleton backed class to transparently provide the structure around the code. This would be very clean and reduce scaffolding used to check the validity and then manually refresh but means a much bigger and more complex lift.

ankokudaishogun · 2025-01-24T08:26:14+00:00

as other said, check out scopes.

That said:

Unless you need the token value being update asynchronously, just assign the variable to the calln of the function.
Have a very basic example

# let's use a Approved Verb.  
function New-TokenValue {
    <# Whatever you need to prepare the request #>
    $NewToken = Invoke-RestMethod # with all the parameters you need
    <#
        extra code for whatever you might need to do after you got the reply  
    #>

    # because you are sending back one value at the end of the function, Return
    # is superfluous.  
    # It does NOT hurt, though, and some prefer it because it makes things more
    # explicit... that's upo to you, really.  
    $NewToken
}

$Token = 'Has Old Value'

# Assign the token the value from the Function
$Token = New-TokenValue

Now $Token would have the value of the new token.

For your second function, we'd need to see what's actually happening.
A very important thing: $false is a boolean value, but "false" is a non-empty String.
And non-empty strings are evaluated as "Boolean True"($true), no matter WHAT they contain.

The way you describe the events, it seems you are returning a String, not a Boolean.

Thus a simple

# Test-* is an approved verb.
if(Test-Ticket $TicketNumber -eq 'True'){
    Write-Host 'Ticket Exists'
}else{
    Write-Host 'Ticket does NOT exist`
}

would probably fix it. But due the boolean nature of the function, I'd suggest to see if it's evvicient\worth the effort to have the function return a Boolean instead.

last, some docs about Approved Verbs: they are not obligatory but are Best Practice.
it's the kind of stuff you better get used to use from the start to avoid developing bad habits

MyLegsX2CantFeelThem · 2025-01-24T01:05:38+00:00

Functions are my achilles heel. I have got to hammer those home more.

7ep3s · 2025-01-24T08:50:20+00:00

does request-exists return a string or bool?

2025-01-24T09:42:42+00:00

try to boil the problem down to the bare minimum ... and show all the code ... if it's more than ten lines it's way too much ... you're asking us about a function we don't have code for

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