Exposes Zebra printer and scale connected via serial port to http port

ScaleServer.cs

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.IO.Ports;
using System.Net;
using System.Net.Sockets;
using System.Diagnostics;
using System.Windows.Forms;
using System.Text.RegularExpressions;
using System.Web;
using System.Collections.Specialized;
using ITDM;

using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Printing;
using Microsoft.Win32.SafeHandles;

using System.Globalization;

namespace HardwareIO
{
    class HardwareIO
    {
        [DllImport("kernel32.dll", SetLastError = true)]

        static extern SafeFileHandle CreateFile(string lpFileName, FileAccess dwDesiredAccess, uint dwShareMode, IntPtr lpSecurityAttributes, FileMode dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile);

        public static SerialPort p;
        public static SafeFileHandle label_printer;

        public static void ConfigureScalePort(String port){

            p = new SerialPort(port);
            p.ReadBufferSize = 14;
            try
            {
                p.Open();
            }
            catch (IOException e)
            {
                AlertAndWrite("Invalid COM port specified.  Please use device manager to determine correct COM port.  Should be between COM1 - COM4");
                return;
            }
            catch (UnauthorizedAccessException e){
                AlertAndWrite("COM PORT '" + port + "' is in use. Make sure that another instance of Scale Server is not running.");
                return;
            }
        }

        public static void TestPrinter() {
            String label = @"
N
A20,10,0,4,1,2,N,""248964-20130131-1923-ЗАЙЦЕ@S4-5-21""
A610,10,0,4,1,1,N,""2013-07-01""
A720,70,0,5,2,2,N,""P""
X710,60,2,790,180 
A20,70,0,2,2,2,N,""Uzlovaya""
A320,115,0,4,2,2,N,""10 of 10""
A600,70,0,4,3,3,N,""*""
A500,10,0,3,2,2,N,""""
A500,70,0,2,2,2,N,""RU""
A20,165,0,4,1,1,N,""170979297210""
B20,115,0,1,2,0,45,N,""669851:N""
A500,165,0,4,1,1,N,""669851:N""
A340,165,0,4,1,1,N,""q1""
P1,1";


            //RawPrinterHelper.SendStringToPrinter(@"EPL_2844", label);
             PrintLabel(label,  "1234", @"\\WIN-QU4U0SFT8SR\EPL_2844", true);
        }

        //First argument must be a communication port (COM3)
        static void Main(string[] args){
            //TestPrinter();
            if (args.Length == 0) {
                String instructions = @"
You ran HarwdareIO without command arguments, you probably don't know what you are doing.
0. Create Shortcut on Desktop to Hardware IO
----INSTRUCTIONS FOR LABLER----
1. Install printer (Ex. EPL2844)
2. Share printer (printer -> printer properties -> sharing)
3. Configure printer. (printer -> printer preferences) 
3.1 Item Labels: Width 3, Height: 2
3.2 Custom Commands tab -> Send command:
3.2.1 I8,C,001
3.2.2 q800
3.2.3 D15
5. Configure shortcut
5.1 -printer_port \\computer_name\printer_name
----Scale Server Instructions----
1. Configure scale into mode 1.0 (press AND hold 'm')
2. Figure out COM port (device manager -> com ports)
3. Configure shortcut
3.1 -scale_port COM_NUMBER
";
                AlertAndWrite(instructions);
                return;
                    
            }
            ConsoleCmdLine c = new ConsoleCmdLine();
            CmdLineString scale_port = new CmdLineString("scale_port", false, "Scale port name.");
            CmdLineString printer_port = new CmdLineString("printer_port", false, "Printer port.");
            c.RegisterParameter(scale_port);
            c.RegisterParameter(printer_port);
            c.Parse(args);              
            bool scale_setup = scale_port.Value.Length > 0;
            bool label_printer_setup = printer_port.Value.Length > 0;

            if(scale_setup)
                ConfigureScalePort(scale_port);
            
            TcpListener tcpListener = new TcpListener(IPAddress.Any, 3000);
            try{
                tcpListener.Start();
            }
            catch (SocketException e){
                AlertAndWrite("Port 3000 is already in use.  Make sure that another instance of Scale Server is not running.");
                return;
            }
            bool send_formatting_command_to_epl = true;
            //Listens for incoming connections
            while (true){
                TcpClient client = tcpListener.AcceptTcpClient();
                NetworkStream clientStream = client.GetStream();
                byte[] message = new byte[4096];
                int bytesRead;
                UTF8Encoding encoder = new UTF8Encoding();
                bytesRead = 0;
                //blocks until a client sends a message
                bytesRead = clientStream.Read(message, 0, 4096);
                String incoming_headers = encoder.GetString(message, 0, bytesRead);
                Console.WriteLine(incoming_headers);

                String incoming_url_string = ExtractUrlString(incoming_headers);
                Console.WriteLine("URL QUERY STRING: " + incoming_url_string);
                if (incoming_url_string.Length == 0)
                    continue;

                NameValueCollection parsedUrl = HttpUtility.ParseQueryString(incoming_url_string);

                String action = parsedUrl.Get("action");
                if (action == null)
                    continue;

                String result = "{}";

                Console.WriteLine("ACTION: " + action);
                
                if(action.Equals("read_weight")){
                    if (scale_setup)
                        result = ReadWeight();
                    else
                        AlertAndWrite("Scale not setup");
                }
                else if(action.Equals("print_item_label")){
                    if (label_printer_setup) {

                        String label = Uri.UnescapeDataString(Uri.UnescapeDataString(parsedUrl.Get("label"))).Replace("+", " ");
                        String order_item_id = parsedUrl.Get("order_item_id");
                        result = PrintLabel(label, order_item_id, printer_port, send_formatting_command_to_epl);
                        send_formatting_command_to_epl = false;
                    } else {
                        AlertAndWrite("Printer port not configured");
                    }
                }
                
                String headers = "HTTP/1.0 200 OK\r\n";
                headers += "Content-Type: text/javascript;charset=UTF-8\r\n\r\n";
                String callback = parsedUrl.Get("callback");
                result = headers + callback + "(" + result + ")";

                Console.WriteLine(result);

                byte[] buffer = encoder.GetBytes(result);
                clientStream.Write(buffer, 0, buffer.Length);

                clientStream.Flush();
                clientStream.Close();
                client.Close();
            }
        }
        
        //THINGS TO CONSIDER: I8,c,001 - Make Russian
        //q800 - fix margins
        //D15 - make dark
        public static String PrintLabel(String label, String order_item_id, String port, bool send_formatting_command){

            try{
              label_printer = CreateFile(port, FileAccess.Write, 0, IntPtr.Zero, FileMode.OpenOrCreate, 0, IntPtr.Zero);
                if (label_printer.IsInvalid) {
                    AlertAndWrite("Printer is Invalid");
                }
            } catch (Exception ex) {
                AlertAndWrite("Error happened configuring printer port: '" + ex.Message + "'");
                return "{\"STATUS\": \"FAILURE\"}";
            }
          try{
              if (send_formatting_command) {
                  label = "q800\nI8,C,001\nD15\n" + label;
              }
            Console.WriteLine("===========LABEL BEGIN===========");
            Console.WriteLine(label);
            Console.WriteLine("===========LABEL END===========");

            Encoding ANSI = Encoding.GetEncoding(1251);

            byte[] utf8Bytes = System.Text.Encoding.UTF8.GetBytes(label);
            byte[] ansiBytes = Encoding.Convert(Encoding.UTF8, ANSI, utf8Bytes);

            FileStream lpt1 = new FileStream(label_printer, FileAccess.ReadWrite);
            lpt1.Write(ansiBytes, 0, ansiBytes.Length);
            lpt1.Close();
            return "{\"STATUS\": \"SUCCESS\", \"ORDER_ITEM_ID\": \"" + order_item_id + "\"}";
          }
          catch(Exception ex){
            String err = "Error happened configuring printer port: '" + ex.Message + "'";
            Console.WriteLine(err);
            return "{\"STATUS\": \"FAILURE\"}";
          }
        }

        public static String ReadWeight()
        {
            p.WriteLine("\r\n");
            System.Threading.Thread.Sleep(200);
            String data = p.ReadExisting();

            if (data.Length != 14){
                Console.WriteLine("ERROR");
                return "{\"ERROR\": \"There is an error reading scale, please try again\"}";
            }
            String weight_seg = data.Substring(2, 7);
            weight_seg = System.Text.RegularExpressions.Regex.Replace(weight_seg, @"\s+", "");

            Console.WriteLine(weight_seg);
            float weight = float.Parse(weight_seg);
            char c = data[11];
            if (c == 'S'){
                return "{\"WEIGHT\":" + weight + "}";
            }
            else{
                return "{\"ERROR\": \"Scale is not stable\"}";
            }
        }

        public static void AlertAndWrite(String message){
            Console.WriteLine(message);
            MessageBox.Show(message);
        }

        public static String ExtractUrlString(String headers) {
            Match m = Regex.Match(headers, @"/(\S+)\s+HTTP");
            String val = "";
            if (m.Groups.Count == 2)
                val = m.Groups[1].Value;
            return val;
        }
    }
}