C# http系列之以form-data方式上传多个文件及键值对集合到远程服务器

<form id="form1" runat="server" action="UserManageHandler.ashx" method="post" enctype="multipart/form-data"> <div>  名称： <input type="text" name="uname" class="uname" /><br/>  邮件： <input type="text" name="email" class="email" /><p/>  附件1： <input type="file" name="file1" class="file" /><p/>  附件2： <input type="file" name="file2" class="file" /><p/>  附件3： <input type="file" name="file3" class="file" /><p/>    <input type="submit" name="submit" value="提交" /> </div></form>

HttpFileCollection files = HttpContext.Current.Request.Files; HttpPostedFile postedFile = files["fileUpload"]; postedFile.SaveAs(postedFile.FileName);

/// <summary>/// HTTP请求(包含多分部数据,multipart/form-data)。/// 将多个文件以及多个参数以多分部数据表单方式上传到指定url的服务器/// </summary>/// <param name="url">请求目标URL</param>/// <param name="fileFullNames">待上传的文件列表(包含全路径的完全限定名)。如果某个文件不存在，则忽略不上传</param>/// <param name="kVDatas">请求时表单键值对数据。</param>/// <param name="method">请求的方法。请使用 WebRequestMethods.Http 的枚举值</param>/// <param name="timeOut">获取或设置 <see cref="M:System.Net.HttpWebRequest.GetResponse" /> 和///      <see cref="M:System.Net.HttpWebRequest.GetRequestStream" /> 方法的超时值（以毫秒为单位）。///      -1 表示永不超时/// </param>/// <returns></returns>public HttpResult UploadFormByMultipart(string url, string[] fileFullNames, NameValueCollection kVDatas = null, string method = WebRequestMethods.Http.Post, int timeOut = -1){ #region 说明 /* 阿里云文档：https://www.alibabacloud.com/help/zh/doc-detail/42976.htm  C# 示例： https://github.com/aliyun/aliyun-oss-csharp-sdk/blob/master/samples/Samples/PostPolicySample.cs?spm=a2c63.p38356.879954.18.7f3f7c34W3bR9U&file=PostPolicySample.cs     (C#示例中仅仅是把文件中的文本内容当做 FormData 中的项，与文件流是不一样的。本方法展示的是文件流，更通用)  */ /* 说明：multipart/form-data 方式提交文件  *  (1) Header 一定要有 Content-Type: multipart/form-data; boundary={boundary}。  *  (2) Header 和bod y之间由 /r/n--{boundary} 分割。  *  (3) 表单域格式 ：Content-Disposition: form-data; name="{key}"/r/n/r/n  *     {value}/r/n  *     --{boundary}  *  (4)表单域名称大小写敏感，如policy、key、file、OSSAccessKeyId、OSSAccessKeyId、Content-Disposition。  *  (5)注意:表单域 file 必须为最后一个表单域。即必须放在最后写。  */ #endregion #region ContentType 说明 /* 该ContentType的属性包含请求的媒体类型。分配给ContentType属性的值在请求发送Content-typeHTTP标头时替换任何现有内容。    要清除Content-typeHTTP标头，请将ContentType属性设置为null。    * 注意：此属性的值存储在WebHeaderCollection中。如果设置了WebHeaderCollection，则属性值将丢失。  *  所以放置在Headers 属性之后设置  */ #endregion #region Method 说明 /* 如果 ContentLength 属性设置为-1以外的任何值，则必须将 Method 属性设置为上载数据的协议属性。 */ #endregion #region HttpWebRequest.CookieContainer 在 .NET3.5 与 .NET4.0 中的不同 /* 请参考：https://www.crifan.com/baidu_emulate_login_for_dotnet_4_0_error_the_fisrt_two_args_should_be_string_type_0_1/ */ #endregion HttpResult httpResult = new HttpResult(); #region 校验 if (fileFullNames == null || fileFullNames.Length == 0) {  httpResult.Status = HttpResult.STATUS_FAIL;  httpResult.RefCode = (int)HttpStatusCode2.USER_FILE_NOT_EXISTS;  httpResult.RefText = HttpStatusCode2.USER_FILE_NOT_EXISTS.GetCustomAttributeDescription();  return httpResult; } List<string> lstFiles = new List<string>(); foreach (string fileFullName in fileFullNames) {  if (File.Exists(fileFullName))  {   lstFiles.Add(fileFullName);  } } if (lstFiles.Count == 0) {  httpResult.Status = HttpResult.STATUS_FAIL;  httpResult.RefCode = (int)HttpStatusCode2.USER_FILE_NOT_EXISTS;  httpResult.RefText = HttpStatusCode2.USER_FILE_NOT_EXISTS.GetCustomAttributeDescription();  return httpResult; } #endregion string boundary = CreateFormDataBoundary();          // 边界符 byte[] beginBoundaryBytes = Encoding.UTF8.GetBytes("--" + boundary + "/r/n");  // 边界符开始。【☆】右侧必须要有 /r/n 。 byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("/r/n--" + boundary + "--/r/n"); // 边界符结束。【☆】两侧必须要有 --/r/n 。 byte[] newLineBytes = Encoding.UTF8.GetBytes("/r/n"); //换一行 MemoryStream memoryStream = new MemoryStream(); HttpWebRequest httpWebRequest = null; try {  httpWebRequest = WebRequest.Create(url) as HttpWebRequest; // 创建请求  httpWebRequest.ContentType = string.Format(HttpContentType.MULTIPART_FORM_DATA + "; boundary={0}", boundary);  //httpWebRequest.Referer = "http://bimface.com/user-console";  httpWebRequest.Method = method;  httpWebRequest.KeepAlive = true;  httpWebRequest.Timeout = timeOut;  httpWebRequest.UserAgent = GetUserAgent();  #region 步骤1：写入键值对  if (kVDatas != null)  {   string formDataTemplate = "Content-Disposition: form-data; name=/"{0}/"/r/n/r/n" +          "{1}/r/n";   foreach (string key in kVDatas.Keys)   {    string formItem = string.Format(formDataTemplate, key.Replace(StringUtils.Symbol.KEY_SUFFIX, String.Empty), kVDatas[key]);    byte[] formItemBytes = Encoding.UTF8.GetBytes(formItem);    memoryStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length); // 1.1 写入FormData项的开始边界符    memoryStream.Write(formItemBytes, 0, formItemBytes.Length);   // 1.2 将键值对写入FormData项中   }  }  #endregion  #region 步骤2：写入文件(表单域 file 必须为最后一个表单域)  const string filePartHeaderTemplate = "Content-Disposition: form-data; name=/"{0}/"; filename=/"{1}/"/r/n" +            "Content-Type: application/octet-stream/r/n/r/n";  int i = 0;  foreach (var fileFullName in lstFiles)  {   FileInfo fileInfo = new FileInfo(fileFullName);   string fileName = fileInfo.Name;   string fileHeaderItem = string.Format(filePartHeaderTemplate, "file", fileName);   byte[] fileHeaderItemBytes = Encoding.UTF8.GetBytes(fileHeaderItem);   if (i > 0)   {    // 第一笔及第一笔之后的数据项之间要增加一个换行     memoryStream.Write(newLineBytes, 0, newLineBytes.Length);   }   memoryStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length);  // 2.1 写入FormData项的开始边界符   memoryStream.Write(fileHeaderItemBytes, 0, fileHeaderItemBytes.Length); // 2.2 将文件头写入FormData项中   int bytesRead;   byte[] buffer = new byte[1024];   FileStream fileStream = new FileStream(fileFullName, FileMode.Open, FileAccess.Read);   while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)   {    memoryStream.Write(buffer, 0, bytesRead);        // 2.3 将文件流写入FormData项中   }   i++;  }  memoryStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);    // 2.4 写入FormData的结束边界符  #endregion  #region 步骤3：将表单域(内存流)写入 httpWebRequest 的请求流中，并发起请求  httpWebRequest.ContentLength = memoryStream.Length;  Stream requestStream = httpWebRequest.GetRequestStream();  memoryStream.Position = 0;  byte[] tempBuffer = new byte[memoryStream.Length];  memoryStream.Read(tempBuffer, 0, tempBuffer.Length);  memoryStream.Close();  requestStream.Write(tempBuffer, 0, tempBuffer.Length);  // 将内存流中的字节写入 httpWebRequest 的请求流中  requestStream.Close();  #endregion  HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse; // 获取响应  if (httpWebResponse != null)  {   //GetHeaders(ref httpResult, httpWebResponse);   GetResponse(ref httpResult, httpWebResponse);   httpWebResponse.Close();  } } catch (WebException webException) {  GetWebExceptionResponse(ref httpResult, webException); } catch (Exception ex) {  GetExceptionResponse(ref httpResult, ex, method, HttpContentType.MULTIPART_FORM_DATA); } finally {  if (httpWebRequest != null)  {   httpWebRequest.Abort();  } } return httpResult;}

/// <summary>/// HTTP请求(包含多分部数据,multipart/form-data)。/// 将文件以及多个参数以多分部数据表单方式上传到指定url的服务器/// </summary>/// <param name="url">请求目标URL</param>/// <param name="fileFullName">待上传的文件(包含全路径的完全限定名)</param>/// <param name="kVDatas">请求时表单键值对数据。</param>/// <param name="method">请求的方法。请使用 WebRequestMethods.Http 的枚举值</param>/// <param name="timeOut">获取或设置 <see cref="M:System.Net.HttpWebRequest.GetResponse" /> 和///      <see cref="M:System.Net.HttpWebRequest.GetRequestStream" /> 方法的超时值（以毫秒为单位）。///      -1 表示永不超时/// </param>/// <returns></returns>public HttpResult UploadFormByMultipart(string url, string fileFullName, NameValueCollection kVDatas = null, string method = WebRequestMethods.Http.Post, int timeOut = -1){ string[] fileFullNames = { fileFullName }; return UploadFormByMultipart(url, fileFullNames, kVDatas, method, timeOut);}

/// <summary>/// HTTP请求(包含多分部数据,multipart/form-data)。/// 将文件以多分部数据表单方式上传到指定url的服务器/// </summary>/// <param name="url">请求目标URL</param>/// <param name="fileFullName">待上传的文件(包含全路径的完全限定名)</param>/// <param name="kVDatas">请求时表单键值对数据。</param>/// <param name="method">请求的方法。请使用 WebRequestMethods.Http 的枚举值</param>/// <param name="timeOut">获取或设置 <see cref="M:System.Net.HttpWebRequest.GetResponse" /> 和///      <see cref="M:System.Net.HttpWebRequest.GetRequestStream" /> 方法的超时值（以毫秒为单位）。///      -1 表示永不超时/// </param>/// <returns></returns>public HttpResult UploadFormByMultipart(string url, string fileFullName, Dictionary<string, string> kVDatas = null, string method = WebRequestMethods.Http.Post, int timeOut = -1){ var nvc = kVDatas.ToNameValueCollection(); return UploadFormByMultipart(url, fileFullName, nvc, method, timeOut);}