Send TCP Request to Remote Computer

##############################################################################
##
## Send-TcpRequest
##
## From Windows PowerShell Cookbook (O'Reilly)
## by Lee Holmes (http://www.leeholmes.com/guide)
##
##############################################################################

<#

.SYNOPSIS

Send a TCP request to a remote computer, and return the response.
If you do not supply input to this script (via either the pipeline, or the
-InputObject parameter,) the script operates in interactive mode.

.EXAMPLE

PS > $http = @"
  GET / HTTP/1.1
  Host:bing.com
  `n`n
"@

$http | Send-TcpRequest bing.com 80

#>

param(
    ## The computer to connect to
    [string] $ComputerName = "localhost",

    ## A switch to determine if you just want to test the connection
    [switch] $Test,

    ## The port to use
    [int] $Port = 80,

    ## A switch to determine if the connection should be made using SSL
    [switch] $UseSSL,

    ## The input string to send to the remote host
    [string] $InputObject,

    ## The delay, in milliseconds, to wait between commands
    [int] $Delay = 100
)

Set-StrictMode -Version 3

[string] $SCRIPT:output = ""

## Store the input into an array that we can scan over. If there was no input,
## then we will be in interactive mode.
$currentInput = $inputObject
if(-not $currentInput)
{
    $currentInput = @($input)
}
$scriptedMode = ([bool] $currentInput) -or $test

function Main
{
    ## Open the socket, and connect to the computer on the specified port
    if(-not $scriptedMode)
    {
        write-host "Connecting to $computerName on port $port"
    }

    try
    {
        $socket = New-Object Net.Sockets.TcpClient($computerName, $port)
    }
    catch
    {
        if($test) { $false }
        else { Write-Error "Could not connect to remote computer: $_" }

        return
    }

    ## If we're just testing the connection, we've made the connection
    ## successfully, so just return $true
    if($test) { $true; return }

    ## If this is interactive mode, supply the prompt
    if(-not $scriptedMode)
    {
        write-host "Connected.  Press ^D followed by [ENTER] to exit.`n"
    }

    $stream = $socket.GetStream()

    ## If we wanted to use SSL, set up that portion of the connection
    if($UseSSL)
    {
        $sslStream = New-Object System.Net.Security.SslStream $stream,$false
        $sslStream.AuthenticateAsClient($computerName)
        $stream = $sslStream
    }

    $writer = new-object System.IO.StreamWriter $stream

    while($true)
    {
        ## Receive the output that has buffered so far
        $SCRIPT:output += GetOutput

        ## If we're in scripted mode, send the commands,
        ## receive the output, and exit.
        if($scriptedMode)
        {
            foreach($line in $currentInput)
            {
                $writer.WriteLine($line)
                $writer.Flush()
                Start-Sleep -m $Delay
                $SCRIPT:output += GetOutput
            }

            break
        }
        ## If we're in interactive mode, write the buffered
        ## output, and respond to input.
        else
        {
            if($output)
            {
                foreach($line in $output.Split("`n"))
                {
                    write-host $line
                }
                $SCRIPT:output = ""
            }

            ## Read the user's command, quitting if they hit ^D
            $command = read-host
            if($command -eq ([char] 4)) { break; }

            ## Otherwise, Write their command to the remote host
            $writer.WriteLine($command)
            $writer.Flush()
        }
    }

    ## Close the streams
    $writer.Close()
    $stream.Close()

    ## If we're in scripted mode, return the output
    if($scriptedMode)
    {
        $output
    }
}

## Read output from a remote host
function GetOutput
{
    ## Create a buffer to receive the response
    $buffer = new-object System.Byte[] 1024
    $encoding = new-object System.Text.AsciiEncoding

    $outputBuffer = ""
    $foundMore = $false

    ## Read all the data available from the stream, writing it to the
    ## output buffer when done.
    do
    {
        ## Allow data to buffer for a bit
        start-sleep -m 1000

        ## Read what data is available
        $foundmore = $false
        $stream.ReadTimeout = 1000

        do
        {
            try
            {
                $read = $stream.Read($buffer, 0, 1024)

                if($read -gt 0)
                {
                    $foundmore = $true
                    $outputBuffer += ($encoding.GetString($buffer, 0, $read))
                }
            } catch { $foundMore = $false; $read = 0 }
        } while($read -gt 0)
    } while($foundmore)

    $outputBuffer
}

. Main