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; } } }
小结
ashx处理接收的数据后,后续还需要配合实际的接口功能继续处理应用。另外,对于ashx页面,实际的应用则需要使用安全访问控制,只有正常登录或提供合法访问令牌的用户才可以进行访问。
以上代码仅供参考,欢迎大家指正,再次感谢您的阅读!