突破短板，传统桌面程序 使用webapi 扩展迎合web和移动端融合的需求

传统桌面程序不能完全被web和移动端替代，但是需要改造。这里要说的是巧用webapi把以前用dll和com组件,ocx等方式做接口，做分布式开发的方式，改成restful 风格api的方式实现跨平台，多客户端(类型).并分享几则案例.

1、智能储物柜

项目背景：某智慧城市项目需要用到有智能锁的储物柜，用app扫码控制存取，并和智慧城市后台交互。智能锁系统是工业的塔式控制器，使用modbus ascii协议控制，端口使用串口。储物柜配备了工控电脑32寸竖屏，工控电脑控制塔式控制器（单片机）,工控机上需要开发一套桌面程序，对外暴露储物柜的功能性（存取物品),对用户来说作为人机交互界面。话写的有点难懂还是上图吧：

 规格有几种，这是不是实物忘记了。总之也没去过现场。

柜机人机界面

说明：

工作区是底部的1024*1080像素的区域，关键设计是把二维码的内容设计成了JSON，app扫描后获取到设备和意图，智慧城市后台对云主机上的中间件发起控制请求，中间件转发给柜机程序，柜机程序和塔式控制器通信，塔式控制器控制锁动作。

中间件程序界面

说明：中间使用winform+owin宿主webapi，对外暴露api，对柜机程序提供套接字连接。中间件是socket server端，柜机程序作为client。

还是晕了吧，没看懂么。简单来说柜机程序是个上位机程序，设备需要把控制锁的需求封装成api给外部调用。这里的解决方案是使用中间件，中间件对外暴露api外部发起控制请求，中间件对内（设备端程序）执行控制指令。

为了实现"网页和移动客户端控制工控设备"这个核心需求，这也是挤破了脑袋吧.呵呵呵，总算不枉费你进来围观了一回...

不留下点代码，算什么分享呢！哼！

好的，上代码：

这就是传说中的asp.net mvc webapi啊

winform宿主：

IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
                EndPoint epSender = (EndPoint)ipeSender;
                serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                // 首次探测时间5 秒, 间隔侦测时间2 秒
                byte[] inValue = new byte[] { 1, 0, 0, 0, 0x88, 0x13, 0, 0, 0xd0, 0x07, 0, 0 };
                serverSocket.IOControl(IOControlCode.KeepAliveValues, inValue, null);
                IPEndPoint ipEndPoint = new IPEndPoint(IPAddress.Parse(SocketBindingIP), int.Parse(config.AppSettings.Settings["Middleware_PORT"].Value));
                try
                {
                    serverSocket.Bind(ipEndPoint);
                    serverSocket.Listen(1024);
                    backgroundWorker.WorkerSupportsCancellation = true;
                    backgroundWorker.RunWorkerAsync();
                    LogMessage(DateTime.Now + "->Socket启动成功，监听IP：" + ipEndPoint.Address.ToString() + ":" + config.AppSettings.Settings["Middleware_PORT"].Value);                    
                }
                catch (Exception ex)
                {
                    Com.DataCool.DotNetExpand.LogHelper.Error("服务启动失败,原因:" + ex.Message);                    
                }
                btnServiceControl.Tag = 1;
                btnServiceControl.Text = "停止监听";
                btnServiceControl.BackColor = Color.Green;
                pbxServiceStatus.BackgroundImage = Properties.Resources.online_status;
                lbWebApiBaseAddress.Text = SocketBindingIP;
                hostObject = WebApp.Start<RegisterRoutesStartup>("http://" + SocketBindingIP + ":5990");

 public class RegisterRoutesStartup
    {
        public void Configuration(IAppBuilder appBuilder)
        {
            HttpConfiguration config = new HttpConfiguration();
            //自定义路由
            config.Routes.MapHttpRoute(
              name: "CustomApi",
              routeTemplate: "api/{controller}/{action}/{id}",
              defaults: new { id = RouteParameter.Optional }
            );
            //只响应Json请求
            var jsonFormatter = new JsonMediaTypeFormatter();
            config.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(jsonFormatter));
            appBuilder.UseWebApi(config);
        }
    }

就是最后一句了。owin怎么宿主webapi去看看张善友等的文章吧。

 public ApiActionResult BufferBox_API_Request(string StationNo, string CellNo, string Action)
        {
            var result = new ApiActionResult()
            {
                Success = false,
                Result = null,
                Message = "操作失败。"
            };
            byte[] results = new byte[1024];
            Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            try
            {
                clientSocket.Connect(new IPEndPoint(IPAddress.Parse(conf.AppSettings.Settings["Middleware_IP"].Value), Convert.ToInt32(conf.AppSettings.Settings["Middleware_PORT"].Value)));
                using (var db = new BufferBoxDBEntities())
                {
                    var stationEntity = db.station_signin_session.Where(st => st.SessionDict == StationNo).FirstOrDefault();
                    if (stationEntity == null)
                    {
                        result.Message = "设备不存在或者设备编号有误！";
                        result.Result = "";
                        return result;
                    }
                    var requestEntity = new API_Request_session
                    {
                        API_Request_IP = Request.GetClientIpAddress(),
                        RequestID = Guid.NewGuid(),
                        RequestData = CellNo + "|" + Action,
                        RequestDataTime = DateTime.Now,
                        ResultData = "",
                        ExecuteFlag = false,
                        StationNo = StationNo
                    };
                    db.API_Request_session.AddObject(requestEntity);
                    db.SaveChanges();
                    clientSocket.Send(Encoding.UTF8.GetBytes("api_request:" + JsonConvert.SerializeObject(requestEntity)));
                    result.Success = true;
                    result.Message = "设备已经受理请求。";
                    result.Result = requestEntity.RequestID.ToString();
                }
            }
            catch (Exception ex)
            {
                result.Message = "中间件发生异常：" + ex.Message;
            }
            return result;
        }

　　这可是项目分析的关键之处啊。中间件是如何转发api请求并通知柜机客户端执行指令的呢。就是webapi里使用socket作为client去连接中间件的socket server的。

问题就是出在这里！webapi不能阻塞socket 直到柜机客户端响应之后回复了再返回给外部。

2、php页面js开POS触摸屏电脑外接的钱箱

　　这是昨天晚上接的一个小活。新年第一单，正是有了前面项目的经验，给提供了这个解决方案。

项目背景： php做的bs项目打包成桌面项目用内嵌浏览器访问php页面来代替POS触摸屏桌面程序。打印使用插件听说解决了，但是打开钱箱遇到麻烦了。由于发包方不知道网页如何控制本地设备，也不想用activex方式，所以提供了这个解决方案：

POS触摸屏上运行一windows服务程序对外提供api(控制钱箱)和php服务器端的中间件通信，中间件对外部暴露api。

这个项目图片不高大上，所以只有代码了：

using System;
using System.Net;
using System.Web.Http;
using System.Net.Sockets;
using System.Configuration;
using System.Text;

namespace MiddlewareServer
{
   /// <summary>
   /// POS触摸屏收银机钱箱控制API控制器
   /// </summary>
    public class MoneyBoxApiController : ApiController
    {
        public static readonly Configuration conf = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

        [HttpGet]
        /// <summary>
        /// 打开POS钱箱,IP取发起请求的客户端的IP，中间件以此IP为依据通知该POS机执行开钱箱动作
        /// 局域网环境IP最好是静态IP，不要使用DHIP，动态获取
        /// </summary>
        /// <returns>{Success,Result=请求发起机器的IP地址,Message}</returns>

        public ApiActionResult OpenMoneyBox()
        {
            var result = new ApiActionResult()
            {
                Success = false,
                Result = null,
                Message = "操作失败。"
            };
            byte[] results = new byte[1024];
            Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            try
            {
                clientSocket.Connect(new IPEndPoint(IPAddress.Parse(conf.AppSettings.Settings["Middleware_IP"].Value), Convert.ToInt32(conf.AppSettings.Settings["Middleware_PORT"].Value)));
                string ip = Request.GetClientIpAddress();
                clientSocket.Send(Encoding.UTF8.GetBytes("api_request:" + ip));
                result.Result = ip;
                result.Success = true;
                result.Message = "请求成功。";
            }
            catch (Exception ex)
            {
                result.Message = "中间件发生异常：" + ex.Message;
            }
            return result;
        }       
    }
}

　　

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.ServiceProcess;
using System.Text;
using System.Runtime.InteropServices;
using System.Configuration;
using Microsoft.Win32.SafeHandles;
using System.IO;
using System.Net.Sockets;
using System.Net;

namespace MoneyBoxSvr
{
    public partial class MoneyBoxService : ServiceBase
    {
        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern IntPtr CreateFile(string lpFileName, int dwDesiredAccess, int dwShareMode, int lpSecurityAttributes, int dwCreationDisposition, int dwFlagsAndAttributes, int hTemplateFile);

        private Configuration config;
        /// <summary>
        /// 打印机端口名称
        /// </summary>
        public string PrintPortName
        {
            get { return config.AppSettings.Settings["PortName"].Value; }
        }

        /// <summary>
        /// 中间件的IP地址
        /// </summary>
        public string RemoteServerIP
        {
            get
            {
                return config.AppSettings.Settings["MiddlewareIP"].Value;
            }
        }

        /// <summary>
        /// 中间件监听的端口
        /// </summary>
        public int MiddlewarePort
        {
            get
            {
                return Convert.ToInt32(config.AppSettings.Settings["MiddlewarePort"].Value);
            }
        }

        protected Socket clientSocket = null;
        /// <summary>
        /// 缓冲区
        /// </summary>        
        protected byte[] buffers = new byte[1024];

        protected System.Threading.Thread socketThread;

        public MoneyBoxService()
        {
            InitializeComponent();
            config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
        }      
       
        protected override void OnStart(string[] args)
        {
            StartSocketThread();
        }

        protected override void OnStop()
        {
            base.OnStop();
        }

        protected override void OnShutdown()
        {
            base.OnShutdown();
            socketThread.Abort();
            socketThread = null;
        }

        private void StartSocketThread()
        {          
            socketThread = new System.Threading.Thread(ThreadWork);
            socketThread.Start();
        }

        /// <summary>
        /// 异步接收到远程请求
        /// </summary>
        /// <param name="ar"></param>
        private void OnReceive(IAsyncResult ar)
        {
            try
            {
                IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
                EndPoint epSender = (EndPoint)ipeSender;
                //结束挂起的,从特定终结点进行异步读取
                if (clientSocket != null)
                {
                    int len = clientSocket.EndReceiveFrom(ar, ref epSender);
                    string requestCommand = System.Text.Encoding.UTF8.GetString(buffers);
                    if (requestCommand.StartsWith("api_request"))
                    {
                        OpenMoneyBox();
                    }
                }
            }
            catch
            { 
            
            }
            finally
            {
                try
                {
                    IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
                    EndPoint epSender = (EndPoint)ipeSender;
                    buffers = new byte[1024];
                    clientSocket.BeginReceiveFrom(buffers, 0, buffers.Length, SocketFlags.None, ref epSender, new AsyncCallback(OnReceive), epSender);
                }
                catch 
                {                    
                }
            }
        }

        private void ThreadWork()
        {
            while (true)
            {
                if (clientSocket == null)
                {
                    #region 建立socket连接
                    IPAddress ip = IPAddress.Parse(RemoteServerIP);
                    clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                    try
                    {
                        // 首次探测时间5 秒, 间隔侦测时间2 秒
                        byte[] inValue = new byte[] { 1, 0, 0, 0, 0x88, 0x13, 0, 0, 0xd0, 0x07, 0, 0 };
                        clientSocket.IOControl(IOControlCode.KeepAliveValues, inValue, null);
                        clientSocket.Connect(new IPEndPoint(IPAddress.Parse(RemoteServerIP), MiddlewarePort)); //配置服务器IP与端口  
                        #region 签到
                        string request = "pos_sign_in:";
                        clientSocket.Send(Encoding.UTF8.GetBytes(request));
                        IPEndPoint ipeSender = new IPEndPoint(IPAddress.Any, 0);
                        EndPoint epSender = (EndPoint)ipeSender;
                        buffers = new byte[1024];
                        clientSocket.BeginReceiveFrom(buffers, 0, buffers.Length, SocketFlags.None, ref epSender, new AsyncCallback(OnReceive), epSender);
                        #endregion
                    }
                    catch 
                    {
                        if (clientSocket != null)
                        {
                            clientSocket.Close();
                            clientSocket = null;
                        }
                    }
                    #endregion
                }
                if (clientSocket != null )
                {
                    #region 发0字节的包探测连接是否可用
                    bool blockingState = clientSocket.Blocking;
                    try
                    {
                        byte[] tmp = new byte[1];
                        clientSocket.Blocking = false;
                        clientSocket.Send(tmp, 0, 0);
                    }
                    catch 
                    {
                        if (clientSocket != null)
                        {
                            clientSocket.Close();
                            clientSocket = null;
                        }                        
                    }
                    finally
                    {
                        if (clientSocket != null)
                        {
                            clientSocket.Blocking = blockingState;
                        }
                    }
                    #endregion
                }
                System.Threading.Thread.Sleep(5000);
            }        
        }
        
        /// <summary>
        /// 开钱箱
        /// </summary>
        public void OpenMoneyBox()
        {
            IntPtr iHandle = CreateFile(PrintPortName, 0x40000000, 0, 0, 3, 0, 0);
            if (iHandle.ToInt32() != -1)
            {
                SafeFileHandle handle = new SafeFileHandle(iHandle, true);
                FileStream fs = new FileStream(handle, FileAccess.ReadWrite);
                StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);
                sw.Write(((char)27).ToString() + "p" + ((char)0).ToString() + ((char)60).ToString() + ((char)255).ToString());
                sw.Close();
                fs.Close();
            }
        }        
    }
}

　　好久没写博客了。就这样吧，目的就是分享和总结。还有不说你也知道的，这文章怎么看怎么“软”。希望大家体谅一下，技术把代码变成钱本身就是困难的事情。适度广告一下吧，项目和私活就是这样找上门的。