# iex (iwr "https://gist.github.com/anonhostpi/1cc0084b959a9ea9e97dca9dce414e1f/raw/webserver.ps1").Content

function Start-Webserver {
    param(
        [string] $Binding = "http://localhost:8080/",
        [string] $BaseDirectory = "$(Get-Location -PSProvider FileSystem)",
        [string] $ServerName = "PowerShell Webserver",
        [System.Collections.IDictionary] $Routes = @{
            Before = { param( $command, $listener, $context ) return $true }
            After = { param( $command, $listener, $context ) return $true }
            
            # "GET /" = { ... }
            # "GET /hello" = "./path/to/static/file.html"

            Default = {
                param( $command, $request, $response )
                $msg = "Hello, World!"
                # $response.OutputStream.Write( [System.Text.Encoding]::UTF8.GetBytes($msg), 0, $msg.Length )
                return $msg
            }
        }
    )

    $BaseDirectory = "$(Resolve-Path $BaseDirectory)"

    $serve_static = {
        param(
            [string] $path,
            $response
        )
            
        $file = "$BaseDirectory\$($path.TrimStart('/').Replace('/','\'))"
        $file = "$(Resolve-Path $file)"
        If( Test-Path $file ){

            # Prevent directory traversal attacks
            If( -not $file.StartsWith($BaseDirectory) ){
                $response.StatusCode = 403
                return "403 Forbidden"
            }

            return (Get-Content $file -Raw)
        } Else {
            $response.StatusCode = 404
            return "404 Not Found"
        }
    }

    If( [string]::IsNullOrWhitespace( $Routes.Default ) ) {
        If( [string]::IsNullOrWhitespace( $Routes["GET /"] ) ) {
            $Routes["GET /"] = { return "Hello, World!" }
        }

        # Simple static webfile server
        $Routes.Default = {
            param( $command, $request, $response )
            
            & $serve_static $request.Url.AbsolutePath $response
        }
    }
    
    $listener = New-Object System.Net.HttpListener
    $listener.Prefixes.Add($Binding)
    $listener.Start()

    $Error.Clear()

    Try {

        While ( $listener.IsListening ) {
            $task = $listener.GetContextAsync()
            $ready = $task.Wait(100) # 100 ms timeout
            if (-not $ready) { continue }

            $context = $task.Result

            $request = $context.Request
            $command = "{0} {1}" -f $request.HttpMethod, $request.Url.AbsolutePath
            
            If( $Routes.Before ) {
                $continue = & $Routes.Before $command $listener $context
                If( -not $continue ) {
                    continue
                }
            }
            $response = $context.Response
            $response.ContentType = "text/plain; charset=utf-8"

            $result = try {
                If( $Routes[$command] ) {
                    If ( $Routes[$command] -is [scriptblock] ) {
                        & $Routes[$command] $command $request $response
                    } Else {
                        & $serve_static $Routes[$command] $response
                    }
                } Else {
                    If( $Routes.Default -is [scriptblock] ) {
                        & $Routes.Default $command $request $response
                    } Else {
                        & $serve_static $Routes.Default $response
                    }
                }
            } catch {
                $response.StatusCode = 500
                "500 Internal Server Error`n`n$($_.Exception.Message)"
            }

            if( -not [string]::IsNullOrWhiteSpace($result) ) {
                $buffer = [System.Text.Encoding]::UTF8.GetBytes($result)
                $response.ContentLength64 = $buffer.Length

                If( [string]::IsNullOrWhiteSpace($response.Headers["Last-Modified"]) ){
                    $response.Headers.Add("Last-Modified", (Get-Date).ToString("r"))
                }
                If( [string]::IsNullOrWhiteSpace($response.Headers["Server"]) ){
                    $response.Headers.Add("Server", $ServerName)
                }

                $response.OutputStream.Write( $buffer, 0, $buffer.Length )
            }

            $response.Close()
            
            If( $Routes.After ) {
                $null = & $Routes.After $command $listener $context
            }
        }
    } finally {
        $listener.Stop()
        $listener.Close()
    }
}

Start "http://localhost:8080"
Start-WebServer