Small notes on opening a webserver in PowerShell in the background and wait for a query parameter and also showing a progress bar

webserver_and_progress.ps1

$webserverProcess = [scriptblock]{

    param(
        [uri]$redirect
    )

    Add-Type -AssemblyName System.Web

    $http = [System.Net.HttpListener]::new() 

    # Hostname and port to listen on
    $http.Prefixes.Add($redirect)

    # Start the Http Server 
    $http.Start()

    # Log ready message to terminal 
    if ($http.IsListening) {
        Write-Information -MessageData " HTTP Server Ready on '$( $http.Prefixes )'" 
        #write-Log " HTTP Server Ready on '$( $http.Prefixes )'" #-f 'black' -b 'gre'
        #write-host "  now try going to $($http.Prefixes)" -f 'y'
        #write-host "  then try going to $($http.Prefixes)other/path" -f 'y'
    } else {
        throw "There was an error starting the HTTP server, pleasy retry or choose another port"
    }

    # Let the webserver listen, this loop gets only executed when a request takes place
    $r = $null
    $closeHttpListener = $false
    $code = ""
    do {

        # Get Request Url
        # When a request is made in a web browser the GetContext() method will return a request object
        $context = $http.GetContext()
    
        # Raw url
        if ($context.Request.HttpMethod -eq 'GET' -and $context.Request.RawUrl -eq '/') {

            # We can log the request to the terminal
            #write-host "$($context.Request.UserHostAddress)  =>  $($context.Request.Url)" -f 'mag'

            # the html/data you want to send to the browser
            # you could replace this with: [string]$html = Get-Content "C:\some\path\index.html" -Raw
            [string]$html = "Waiting for Code." 
        
            #resposed to the request
            $buffer = [System.Text.Encoding]::UTF8.GetBytes($html) # convert htmtl to bytes
            $context.Response.ContentLength64 = $buffer.Length
            $context.Response.OutputStream.Write($buffer, 0, $buffer.Length) #stream to broswer
            $context.Response.OutputStream.Close() # close the response
    
        }
    
        # If the url contains the code
        if ( $context.request.RawUrl -like "*code=*" ) {
        
            #Write-Verbose "Got a code" -verbose

            # Looking for code in query
            $callbackUri = [uri]$context.Request.Url
            $callbackUriSegments = [System.Web.HttpUtility]::ParseQueryString($callbackUri.Query)
            $code = $callbackUriSegments["code"]

            $r = $context
            $closeHttpListener = $true

            # We can log the request to the terminal
            #write-host "$($context.Request.UserHostAddress)  =>  $($context.Request.Url)" -f 'mag'

            # the html/data you want to send to the browser
            # you could replace this with: [string]$html = Get-Content "C:\some\path\index.html" -Raw
            [string]$html = "<h1>Received code: $( $code )</h1>"
                
            #resposed to the request
            $buffer = [System.Text.Encoding]::UTF8.GetBytes($html) # convert htmtl to bytes
            $context.Response.ContentLength64 = $buffer.Length
            $context.Response.OutputStream.Write($buffer, 0, $buffer.Length) #stream to broswer
            $context.Response.OutputStream.Close() # close the response
            
        } 

        <#
        a few examples
        $context.Request.HttpMethod gives you the method like GET
        $context.Request.RawUrl
        $context.Request.UserHostAddress
        $context.Request.Url
        #>
    
        # powershell will continue looping and listen for new requests...

    } until ( $closeHttpListener -eq $true ) #$http.IsListening

    $code

}

# Start the webserver in the background
$u = "http://localhost:$( Get-Random -Minimum 49152 -Maximum 65535 )/"
Write-Information -MessageData "Using $( $u )" -InformationAction Continue
$job = Start-Job -Name "ReceiveCodeViaHTTP" -ArgumentList $u -ScriptBlock $webserverProcess #| Wait-Job

# Show a progress bar and wait for a result
$maxSeconds = 360 # 5 minutes
$waitingStart = [datetime]::Now
Do {
    
    # Show the progress
    $ts = New-TimeSpan -Start $waitingStart -End ( [datetime]::now )
    $secondsRemaining = [math]::Ceiling($maxSeconds - $ts.TotalSeconds)
    Write-Progress -Activity "Waiting for callback/redirect" -Status "$( $secondsRemaining ) seconds left" -SecondsRemaining $secondsRemaining -PercentComplete ([math]::Round($secondsRemaining/$maxSeconds*100))

    # Wait
    Start-Sleep -Milliseconds 500

} While ( $ts.TotalSeconds -lt $maxSeconds -and $job.State -eq "Running")

# Kill the job, if it not completed yet
If ( $job.State -ne "Completed" ) {
    try {
        $job.StopJob()
    } catch {
    
    }
}

# Look for a result
$code = Receive-Job -Job $job

If ( $code.Length -gt 0 ) {
    Write-Host $code
} else {
    throw "No usable code received"
}