如何实现一个通用的IHttpHandler 万能的IHttpHandler HttpWebRequest文件上传

昨天遇到一个比较奇怪的需求，大致是需要在服务器上部署一个http服务，但是服务的具体功能不知道，以后在客服端实现。这里介绍一下系统背景，有一个系统运（部署在美国）行了很多年了，给系统产生了很多文件，现在需要把该系统的文件（依据数据库中的记录）来做相应的archive，做了后发现里面还有一些独立的文件（不与数据库记录相关），那么这时我们需要删除这些独立的文件，或者把它们remove到其他地方，需要得到这些文件的list。后来想了想以后会不会还有别的什么需求啊，所以就想做一个通用的HTTPhandler了。这里说明一下：production时在美国，Archive在香港；在我们大陆的系统权限放的都比较开，在美国那个权限管的非常紧，我们是没有权限直接操作Production上的文件，所以才需要用http 协议来做。这里的http server部署到US，而client 却部署到hk。

整个解决方案如图：

其中

WebApp项目部署到Production上（us）

ConsoleApp部署到archive上（hk）

HttpRequestLibrary 是一个对象序列化的通用类以及一个请求类的包装，WebApp和ConsoleApp都需要引用该dll

ProcessAction是在客户端实现的，但是在服务器端反序列化是必须有该文件，所以该dll将会从client 上传到Production上。

首先我们来看看服务器端的实现：

首先需要创建一个ProcessActionHandler.ashx来处理客户端的调用：

 public class ProcessActionHandler : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            try
            {
                string inputstring = ReadInputStream();
                if (!string.IsNullOrEmpty(inputstring))
                {
                    HttpRequestInfo requestinfo = inputstring;
                    if (requestinfo.Process != null)
                    {
                        requestinfo.Process(requestinfo);
                    }
                }
                else
                {
                    //context.Response.StatusCode = 404;
                    context.Response.Write("input error message");
                }
            }
            catch (Exception ex)
            {
                context.Response.Write(ex.Message);
            }
        }
        private string ReadInputStream()
        {
            StringBuilder inputString = new StringBuilder();
            using (Stream sr = HttpContext.Current.Request.InputStream)
            {
                byte[] data = new byte[ * ];
                int readCount = sr.Read(data, , data.Length);
                while (readCount > )
                {
                    string text = Encoding.UTF8.GetString(data, , readCount);
                    inputString.Append(text);
                    readCount = sr.Read(data, , data.Length);
                }
            }
            return inputString.ToString();
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

这里的HttpRequestInfo类是客户端创建的，这里调用HttpRequestInfo的Process方法也是客户端实现的。如何才能获得客户端的实现了，我们需要把客户端实现的dll文件上传到服务器上。

所以需要创建一个UploadActionHandler.ashx来上传客户端的处理：

 public class UploadActionHandler : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            string baseFilePath = context.Server.MapPath("Bin");
            if (context.Request.Files.Count > )
            {
                try
                {
                    HttpPostedFile file = context.Request.Files[];
                    FileInfo fileInfo = new FileInfo(file.FileName);
                    if (fileInfo.Extension.Equals(".dll"))
                    {
                        string tempPath = tempPath = Path.Combine(baseFilePath, fileInfo.Name);
                        file.SaveAs(tempPath);
                        context.Response.Write("Success");
                    }
                    else
                    {
                        context.Response.Write("Failed:\r\n There only upload dll file");
                    }
                }
                catch (Exception ex)
                {
                    context.Response.Write("Failed:\r\n" + ex.Message);
                }
            }
            else
            {
                context.Response.Write("Failed:\r\nThe  Request has not upload file");
            }
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

那么对象时如何序列化和反序列化，以及HttpRequestInfo的定义是什么样的了，这就要参考我们的HttpRequestLibrary项目了。

namespace HttpRequestLibrary
{

    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Net;
    using System.Runtime.Remoting.Messaging;
    using System.Runtime.Serialization.Formatters.Binary;
    using System.Runtime.Serialization.Formatters.Soap;
    using System.Text;
    using System.Web;

    public enum FormatterType
    {
        /// <summary>
        /// SOAP消息格式编码
        /// </summary>
        Soap,

        /// <summary>
        /// 二进制消息格式编码
        /// </summary>
        Binary
    }

    public static class SerializationHelper
    {
        private const FormatterType DefaultFormatterType = FormatterType.Binary;

        /// <summary>
        /// 按照串行化的编码要求，生成对应的编码器。
        /// </summary>
        /// <param name="formatterType"></param>
        /// <returns></returns>
        private static IRemotingFormatter GetFormatter(FormatterType formatterType)
        {
            switch (formatterType)
            {
                case FormatterType.Binary: return new BinaryFormatter();
                case FormatterType.Soap: return new SoapFormatter();
            }
            throw new NotSupportedException();
        }

        /// <summary>
        /// 把对象序列化转换为字符串
        /// </summary>
        /// <param name="graph">可串行化对象实例</param>
        /// <param name="formatterType">消息格式编码类型（Soap或Binary型）</param>
        /// <returns>串行化转化结果</returns>
        /// <remarks>调用BinaryFormatter或SoapFormatter的Serialize方法实现主要转换过程。
        /// </remarks>
        public static string SerializeObjectToString(object graph, FormatterType formatterType)
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                IRemotingFormatter formatter = GetFormatter(formatterType);
                formatter.Serialize(memoryStream, graph);
                Byte[] arrGraph = memoryStream.ToArray();
                return Convert.ToBase64String(arrGraph);
            }
        }
        public static string SerializeObjectToString(object graph)
        {
            return SerializeObjectToString(graph, DefaultFormatterType);
        }

        /// <summary>
        /// 把已序列化为字符串类型的对象反序列化为指定的类型
        /// </summary>
        /// <param name="serializedGraph">已序列化为字符串类型的对象</param>
        /// <param name="formatterType">消息格式编码类型（Soap或Binary型）</param>
        /// <typeparam name="T">对象转换后的类型</typeparam>
        /// <returns>串行化转化结果</returns>
        /// <remarks>调用BinaryFormatter或SoapFormatter的Deserialize方法实现主要转换过程。
        /// </remarks>
        public static T DeserializeStringToObject<T>(string graph, FormatterType formatterType)
        {
            Byte[] arrGraph = Convert.FromBase64String(graph);
            using (MemoryStream memoryStream = new MemoryStream(arrGraph))
            {
                IRemotingFormatter formatter = GetFormatter(formatterType);
                return (T)formatter.Deserialize(memoryStream);
            }
        }

        public static T DeserializeStringToObject<T>(string graph)
        {
            return DeserializeStringToObject<T>(graph, DefaultFormatterType);
        }
    }

    [Serializable]
    public class HttpRequestInfo
    {
        public HttpRequestInfo()
        {
            ContentData = new byte[0];
            CommData = new Dictionary<string, string>();
        }
        public byte[] ContentData { set; get; }
        public Action<HttpRequestInfo> Process { set; get; }
        public Dictionary<string, string> CommData { set; get; }

        public override string ToString()
        {
            string graph = SerializationHelper.SerializeObjectToString(this);
            return graph;
        }
        public static implicit operator HttpRequestInfo(string contentString)
        {
            return SerializationHelper.DeserializeStringToObject<HttpRequestInfo>(contentString);
        }
    }
}

那么客服端如何来操作服务器端了，需要查看ProcessAction项目的实现了：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
using HttpRequestLibrary;
using System.Web;

namespace ProcessAction
{
    public class HttpCommProcess
    {
        public static bool UploadFile(string address, string fileNamePath, out string error)
        {
            try
            {
                error = string.Empty;
                string strBoundary = "----------" + DateTime.Now.Ticks.ToString("x");
                byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + strBoundary + "\r\n");

                StringBuilder sb = new StringBuilder();
                sb.Append("--");
                sb.Append(strBoundary);
                sb.Append("\r\n");
                sb.Append("Content-Disposition: form-data; name=\"");
                sb.Append("file");
                sb.Append("\"; filename=\"");
                sb.Append(fileNamePath);
                sb.Append("\"");
                sb.Append("\r\n");
                sb.Append("Content-Type: ");
                sb.Append(@"application\octet-stream");
                sb.Append("\r\n");
                sb.Append("\r\n");
                string strPostHeader = sb.ToString();
                byte[] postHeaderBytes = Encoding.UTF8.GetBytes(strPostHeader);
                HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(new Uri(address));
                httpReq.Method = "POST";
                httpReq.AllowWriteStreamBuffering = false;

                httpReq.Timeout = 300000;
                httpReq.ContentType = "multipart/form-data; boundary=" + strBoundary;

                string responseText = string.Empty;
                using (FileStream fs = new FileStream(fileNamePath, FileMode.Open, FileAccess.Read))
                {
                    BinaryReader r = new BinaryReader(fs);
                    httpReq.ContentLength = fs.Length + postHeaderBytes.Length + boundaryBytes.Length; ;

                    byte[] buffer = new byte[fs.Length];
                    int size = r.Read(buffer, 0, buffer.Length);

                    using (Stream postStream = httpReq.GetRequestStream())
                    {
                        postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
                        postStream.Write(buffer, 0, size);
                        postStream.Write(boundaryBytes, 0, boundaryBytes.Length);
                    }
                }
                WebResponse webRespon = httpReq.GetResponse();
                using (StreamReader s = new StreamReader(webRespon.GetResponseStream()))
                {
                    responseText = s.ReadToEnd();
                }
                if (responseText.Contains("Success"))
                {
                    return true;
                }
                else
                {
                    error = "UploadFile :" + responseText;
                    return false;
                }
            }
            catch (Exception ex)
            {
                error = "UploadFile:" + ex.Message;
                return false;
            }

        }

        public static void SendHttpRequestData( string url,string reuestContent)
        {
            try
            {
                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
                request.Method = "POST";
                request.ContentType = "text/xml";
                request.KeepAlive = false;
                request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)";
                using (Stream sr = request.GetRequestStream())
                {
                    byte[] data = Encoding.UTF8.GetBytes(reuestContent);
                    sr.Write(data, 0, data.Length);
                }
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                if (response.StatusCode == HttpStatusCode.OK)
                {
                    StringBuilder responseMessage = new StringBuilder();
                    using (Stream sr = response.GetResponseStream())
                    {
                        byte[] data = new byte[1024 * 10];
                        int readcount = sr.Read(data, 0, data.Length);
                        while (readcount > 0)
                        {
                            string str = Encoding.UTF8.GetString(data, 0, readcount);
                            responseMessage.Append(str);
                            readcount = sr.Read(data, 0, data.Length);
                        }
                        Console.WriteLine(responseMessage);
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }

        public static string GetUploadFileContent(string filename)
        {
            HttpRequestInfo requestInfo = new HttpRequestInfo();
            FileInfo file = new FileInfo(filename);
            requestInfo.CommData.Add("FileName", file.Name);
            requestInfo.ContentData = new byte[file.Length];
            using (Stream sr = File.OpenRead(filename))
            {
                sr.Read(requestInfo.ContentData, 0, requestInfo.ContentData.Length);
            }
            requestInfo.Process = (x) =>
            {
                try
                {
                    string tempfile = Path.Combine(@"c:\test", x.CommData["FileName"]);
                    using (Stream wr = File.Open(tempfile, FileMode.OpenOrCreate, FileAccess.Write))
                    {
                        wr.Write(x.ContentData, 0, x.ContentData.Length);
                    }
                    HttpContext.Current.Response.Write("Success");
                }
                catch (Exception ex)
                {
                    HttpContext.Current.Response.Write(ex.Message);
                }

            };
            return requestInfo.ToString();
        }

        public static string GetFileNames(string folderpath)
        {
            HttpRequestInfo requestInfo = new HttpRequestInfo();
            requestInfo.CommData.Add("FolderPath", folderpath);
            requestInfo.Process = (x) =>
            {
                try
                {
                    DirectoryInfo dir=new DirectoryInfo( x.CommData["FolderPath"]);
                    foreach (FileInfo item in dir.GetFiles())
                    {
                        HttpContext.Current.Response.Write(item.FullName+Environment.NewLine);
                    }
                    HttpContext.Current.Response.Write("Success");
                }
                catch (Exception ex)
                {
                    HttpContext.Current.Response.Write(ex.Message);
                }

            };
            return requestInfo.ToString();
        }
    }
}

这里我们来看看GetFileNames方法的实现吧：

   public static string GetFileNames(string folderpath)
        {
            HttpRequestInfo requestInfo = new HttpRequestInfo();
            requestInfo.CommData.Add("FolderPath", folderpath);
            requestInfo.Process = (x) =>
            {
                try
                {
                    DirectoryInfo dir=new DirectoryInfo( x.CommData["FolderPath"]);
                    foreach (FileInfo item in dir.GetFiles())
                    {
                        HttpContext.Current.Response.Write(item.FullName+Environment.NewLine);
                    }
                    HttpContext.Current.Response.Write("Success");
                }
                catch (Exception ex)
                {
                    HttpContext.Current.Response.Write(ex.Message);
                }

            };
            return requestInfo.ToString();
        }
    }

很显然这里的Process就是服务器端将要call的回调函数。那么这个处理很显然是在客户端，服务器端如何才能识别了，就需要把该代码上传到服务器端。

那么最终客服端该如何调用该代码了：

 static void Main(string[] args)
        {
            string error = string.Empty;
            bool uploaded = HttpCommProcess.UploadFile("http://vihk2awwwdev01/webapp/UploadActionHandler.ashx", Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "ProcessAction.dll"), out error);
            if (!uploaded)
            {
                Console.WriteLine(error);
            }
            else
            {
                ///upload file
                string content = HttpCommProcess.GetUploadFileContent(@"C:\IPC.LOG");
                Console.WriteLine("Upload Fils");
                HttpCommProcess.SendHttpRequestData("http://vihk2awwwdev01/webapp/ProcessActionHandler.ashx", content);
                //get file List
                content = HttpCommProcess.GetFileNames(@"C:\ArchiveInfoCenter\ArchiveInfoCenter");
                Console.WriteLine("Get Fils List");
                HttpCommProcess.SendHttpRequestData("http://vihk2awwwdev01/webapp/ProcessActionHandler.ashx", content);
            }
            Console.ReadLine();
        }

首先上传dll文件，然后在发送http请求，运行结果如图：

客户端结果：

服务器文件上传结果（这里只能上传小文件，大文件序列化和反序列化会很慢很慢）

服务器上原文件目录：

在某种程度上我也不赞成这样做，会很危险的。这里只是纯粹从技术的角度来讲如何实现，有不好的地方还请大家拍砖。

源码下载地址：http://download.csdn.net/detail/dz45693/5856523