Test response times of public "what is my ip" services.

Test-PublicIpServicesResponseTimes.ps1

[CmdletBinding(SupportsShouldProcess)]
Param()

#
# Settings
#

# Services to test
$urls = 'https://1.1.1.1/cdn-cgi/trace',    # 13,86
        'https://myip.dnsomatic.com/',      # 17,45
        'https://icanhazip.com',            # 23,96
        'https://checkip.amazonaws.com/',   # 147,48
        'https://ipinfo.io/ip'              # 163,43

# Number of iterations
$MAX_STEPS = 5

# Number of values to discard from lower/higher results
$OUTLIERS = 1



#
# Functions
#
function Get-ResponseTimes {
    $urls | Foreach-Object {
        $m = Measure-Command { Invoke-RestMethod $_ -Verbose:$false }
        @{ $_ = $m.TotalMilliseconds }
    }
}



#
# Main
#

# Initialize allResponses with an empty array for each service
$allResponses = @{}
$urls | ForEach-Object {
    $allResponses[$_] = @() # empty array
}

# Cold run: Ignore
Write-Verbose 'Warming up...'
Get-ResponseTimes | Out-Null

# Warm run
$step = 1
while ($step -le $MAX_STEPS) {
    Write-Verbose "Running step $step of $MAX_STEPS..."
    $response = Get-ResponseTimes

    # For each service, append response time of this iteration to array
    $response.Keys | ForEach-Object {
        $service = $_
        $serviceResponseTime = $response.$_

        $allResponses[$service] += ,$serviceResponseTime
    }
    $step++
}

# Final output
$result = @{}
$allResponses.Keys | ForEach-Object { 
    $service = $_
    $serviceResponseTimes = $allResponses[$_]

    # Sort response times, discard outliers and get the average
    $serviceAverage = $serviceResponseTimes | 
        Sort-Object | 
            Select-Object -Skip $OUTLIERS | 
                Select-Object -SkipLast $OUTLIERS | 
                    Measure-Object -Average |
                        Select-Object -ExpandProperty 'Average'

    $result[$service] = $serviceAverage
}

# Final output
$result