C# Post数据或文件到指定的服务器进行接收

应用场景

实现原理

实现代码

PostAnyWhere类

ashx文件部署

小结

应用场景

不同的接口服务器处理不同的应用，我们会在实际应用中将A服务器的数据提交给B服务器进行数据接收并处理业务。

比如我们想要处理一个OFFICE文件，由用户上传到A服务器，上传成功后，由B服务器负责进行数据处理和下载工作，这时我们就需要 POST A服务器的文件数据到B服务器进行处理。

实现原理

将用户上传的数据或A服务器已存在的数据，通过form-data的形式POST到B服务器，B服务由指定ashx文件进行数据接收，并转由指定的业务逻辑程序进行处理。如下图：

实现代码

PostAnyWhere类

创建一个 PostAnyWhere 类，

该类具有如下属性：

（1）public string PostUrl 要提交的服务器URL
（2）public List<PostFileItem> PostData 要准备的数据(PostFileItem类可包括数据和文件类型)

该类包含的关键方法如下：

（1）public void AddText(string key, string value)

该方法将指定的字典数据加入到PostData中

（2）public void AddFile(string name, string srcFileName, string desName, string contentType = "text/plain")

该方法将指定的文件添加到PostData中，其中 srcFileName 表示要添加的文件名，desName表示接收数据生成的文件名

（3）public string Send()

该方法将开始POST传送数据

代码如下：

    public class PostAnyWhere{public string PostUrl { get; set; }public List<PostFileItem> PostData { get; set; }public PostAnyWhere(){this.PostData = new List<PostFileItem>();}public void AddText(string key, string value){this.PostData.Add(new PostFileItem { Name = key, Value = value });}public void AddFile(string name, string srcFileName, string desName,string at, string contentType = "text/plain"){string[] srcName = Path.GetFileName(srcFileName).Split('.');string exName = "";if (srcName.Length > 1){exName = "."+srcName[srcName.Length-1];}this.PostUrl = "https://www.xxx.com/test.ashx?guid=" + desName;ReadyFile(name, GetBinaryData(srcFileName), exName,contentType);}void ReadyFile(string name, byte[] fileBytes, string fileExName = "", string contentType = "text/plain"){this.PostData.Add(new PostFileItem{Type = PostFileItemType.File,Name = name,FileBytes = fileBytes,FileName = fileExName,ContentType = contentType});}public string Send(){var boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");var request = (HttpWebRequest)WebRequest.Create(this.PostUrl);request.ContentType = "multipart/form-data; boundary=" + boundary;request.Method = "POST";request.KeepAlive = true;Stream memStream = new System.IO.MemoryStream();var boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");var endBoundaryBytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--");var formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";var formFields = this.PostData.Where(m => m.Type == PostFileItemType.Text).ToList();foreach (var d in formFields){var textBytes = System.Text.Encoding.UTF8.GetBytes(string.Format(formdataTemplate, d.Name, d.Value));memStream.Write(textBytes, 0, textBytes.Length);}const string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";var files = this.PostData.Where(m => m.Type == PostFileItemType.File).ToList();foreach (var fe in files){memStream.Write(boundarybytes, 0, boundarybytes.Length);var header = string.Format(headerTemplate, fe.Name, fe.FileName ?? "System.Byte[]", fe.ContentType ?? "text/plain");var headerbytes = System.Text.Encoding.UTF8.GetBytes(header);memStream.Write(headerbytes, 0, headerbytes.Length);memStream.Write(fe.FileBytes, 0, fe.FileBytes.Length);}memStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);request.ContentLength = memStream.Length;HttpWebResponse response;try{using (var requestStream = request.GetRequestStream()){memStream.Position = 0;var tempBuffer = new byte[memStream.Length];memStream.Read(tempBuffer, 0, tempBuffer.Length);memStream.Close();requestStream.Write(tempBuffer, 0, tempBuffer.Length);}response = (HttpWebResponse)request.GetResponse();}catch (WebException webException){response = (HttpWebResponse)webException.Response;}if (response == null){throw new Exception("HttpWebResponse is null");}var responseStream = response.GetResponseStream();if (responseStream == null){throw new Exception("ResponseStream is null");}using (var streamReader = new StreamReader(responseStream)){return streamReader.ReadToEnd();}}}public class PostFileItem{public PostFileItem(){this.Type = PostFileItemType.Text;}public PostFileItemType Type { get; set; }public string Value { get; set; }public byte[] FileBytes { get; set; }public string Name { get; set; }public string FileName { get; set; }public string ContentType { get; set; }}public enum PostFileItemType{Text = 0,File = 1}public byte[] GetBinaryData(string filename){if(!File.Exists(filename)){return null;}try{FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read);byte[] imageData = new Byte[fs.Length];fs.Read( imageData, 0,Convert.ToInt32(fs.Length));fs.Close();return imageData;}catch(Exception){return null;}finally{}}

ashx文件部署

在B服务器上部署ashx文件接收数据，ashx程序即，一般处理程序（HttpHandler），一个httpHandler接受并处理一个http请求，需要实现IHttpHandler接口，这个接口有一个IsReusable成员，一个待实现的方法ProcessRequest(HttpContextctx) 。.ashx程序适合产生供浏览器处理的、不需要回发处理的数据格式。

示例代码如下：

<%@ WebHandler Language="C#" Class="Handler" %>using System;
using System.Web;
using System.IO;public class Handler : IHttpHandler {public void ProcessRequest (HttpContext context) {if (context.Request.Files.Count > 0){string strPath = System.Web.HttpContext.Current.Server.MapPath("~/app_data/test/");string strName = context.Request.Files[0].FileName;string ext=Path.GetExtension(strName);string filename =HttpContext.Current.Request.QueryString["guid"].ToString()+Path.GetFileNameWithoutExtension(strName);if(ext!=""){filename = filename  + ext;}context.Request.Files[0].SaveAs(System.IO.Path.Combine(strPath, filename));}
}public bool IsReusable {get {return false;}
}}