PowerShell Do Until script is not sending HTTP status code to console - output is Blank

Question

Experts, my PowerShell Do Until Script below is not Sending any HTTP Status Code to Console, even though I have told it do so. The output is blank. It does run without error. I can't figure out how to get the status code outputted to console. Note: The host notexist.nowhere.com below is intentionally wrong. It's there only for testing.

$url = "http://localhost"
$Header = @{Host = "notexist.nowhere.com"; "Pragma" = "no-cache"; "Cache-Control" = "no-cache, no-transform"}
$i = 1

Do{
    Try {
        $SC = (Invoke-RestMethod -Method POST -Uri $url -Headers $header -ErrorAction Stop ).StatusCode
    }
    catch {
        $SC = ( $_.Exception.Response.StatusCode.value__ )
    }
 
    Write-host($SC) -ForegroundColor Red -BackgroundColor Cyan
    $clipboard += $SC
 
    $i++
} Until( $SC -eq 200 -or $i -gt 2 )
# Until($i -gt 10)

I copied an executed the code exactly as you posted it and it works. I get an '405' error each time through the loop. — boxdog
– boxdog, Commented Apr 30, 2021 at 14:49
Just on general principles, I would write the condition as until (($SC -eq 200) -or ($i -gt 2)) — Jeff Zeitlin
– Jeff Zeitlin, Commented Apr 30, 2021 at 14:51
@boxdog - I get a 405 too, on IIS after I just tried it on that platform. But weirdly, on Apache web server, I do not get any status code. Quite odd. — John R Smith
– John R Smith, Commented May 3, 2021 at 12:06

Steven · Accepted Answer · 2021-04-30 15:05:02Z

2

I did something similar; knowing I likely don't have the REST API on my local system I ran the code anyhow.

The problem is there's no response code from a server that couldn't be communicated with. So, in your catch block you're assigning a null value, then you get to the Write-Host command and there's nothing to output, because $SC is NULL.

At a glance, and obviously not having the benefit of knowledge both of the environment and mission, I might address this using some logic inside the catch block:

$url = "http://localhost"
$Header = @{Host = "notexist.nowhere.com"; "Pragma" = "no-cache"; "Cache-Control" = "no-cache, no-transform"}
$i = 1

Do{
    Try {
        $SC = (Invoke-RestMethod -Method POST -Uri $url -Headers $header ).StatusCode
    }
    catch {
        If( $error[0].Exception.Message -eq "Unable to connect to the remote server" )
        {
            $SC = $error[0].Exception.Message
        }
        
        # $SC = ( $_.Exception.Response.StatusCode.value__ )
        
    }
 
    Write-host($SC) -ForegroundColor Red -BackgroundColor Cyan
    $clipboard += $SC
 
    $i++
} Until( $SC -eq 200 -or $i -gt 2 )

Note: I didn't use the approach of trying to catch specific exceptions. The exception thrown appears to be too generic for that.

Note: I used $Error[0] to get the last error record rather than $_. That's just a syntax preference because $_ is used so many other places...

You can add additional conditions as much as you need. You can put your own language in the $SC variable etc...

Obviously add more conditions

answered Apr 30, 2021 at 15:05

Steven

7,1271 gold badge17 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

John R Smith Over a year ago

I'm marking this as accepted, but I've come to the belief that the problem was not with my code, nor was it with Apache or IIS. Web servers may or may not respond at all to strange requests is my conclusion. A blank PowerShell output is indicative or the server not returning any status code.

Collectives™ on Stack Overflow

PowerShell Do Until script is not sending HTTP status code to console - output is Blank

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related