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I am trying to get my head around exceptions, and implement exception handling that ultimately gets logged, since my code runs as a remote job and reviewing a txt log is the best means of reviewing results. Currently I have an issue where "unexpected" exceptions only show up in the console, so my focus right now is dealing with that.

So... here I have a first pass at trying to catch an unexpected exception and provide output that shows me script name and line, the exception message, and the exception type so I can potentially go back and add "expected" exception handling by specific type, and log those slightly differently.

class PxUnexpectedException : Exception {
    #PxUnexpectedException() {}
    PxUnexpectedException([string] $message) : base($message) {}
    #PxUnexpectedException([string] $message, [Exception] $inner) : base($message, $inner) {}

    static [array] ReviseTrace ([string]$path, [array]$trace) {
        $scriptPath = ", $(Split-Path $path -parent)\"
        $revisedTrace = $trace -replace [Regex]::Escape($scriptPath), ' in '
        return $revisedTrace
    }
}

function Test ($path) {
    try {
        Test-Path $path -errorAction:stop > $null
    } catch {
        # Standard Px error trap
        $trace = [PxUnexpectedException]::ReviseTrace($_.InvocationInfo.ScriptName, $_.ScriptStackTrace)
        throw [PxUnexpectedException] "[$($_.Exception.GetType().fullname)] $($_.Exception.Message)`n$trace"
    }
}

function ConvertException ([Exception]$exception) {
    foreach ($line in ($exception.Message -split "`n")) {
        Write-Host "$line" -ForegroundColor:red
    }
}

CLS
$path = '\\Server\InvalidFolder|'
try {
    Test $path
} catch [PxUnexpectedException] {
    ConvertException $_.Exception
}

My issue at this point is all the work needed to get a good message for throw [PxUnexpectedException]. I will have this same two lines (the $trace = and the throw) perhaps hundreds of times, and it feels like I SHOULD be able to instantiate my own exception but pass the entire error item to my constructor. Something like throw [PxUnexpectedException] $_ and handle creating the message within the constructor.

Am I really getting this all wrong? Or is duplication of code just the way this will have to be done? Also, in the .NET examples I have adapted my class from, all three constructors are there. But it seems to me that, assuming this IS the only way to build the message, the only constructor I will ever need is the one that takes the single $message argument, so simplification is best hear. Am I missing something and not having all three constructors is really going to come back to bite me?

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2
  • \$\begingroup\$ Unable to find type [PxExpectedException]. \$\endgroup\$
    – JosefZ
    Commented Mar 27, 2020 at 10:51
  • \$\begingroup\$ @JosefZ Typo. The type should be [PxUnexpectedException] in all cases. Revised the OP. \$\endgroup\$ Commented Mar 27, 2020 at 13:15

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