C# HTTP系列13 以form-data方式上传多个文件以及键值对集合到远程服务器

  1 /// <summary>
  2 /// HTTP请求(包含多分部数据,multipart/form-data)。
  3 /// 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
  4 /// </summary>
  5 /// <param name="url">请求目标URL</param>
  6 /// <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>
  7 /// <param name="kVDatas">请求时表单键值对数据。</param>
  8 /// <param name="method">请求的方法。请使用 WebRequestMethods.Http 的枚举值</param>
  9 /// <param name="timeOut">获取或设置 <see cref="M:System.Net.HttpWebRequest.GetResponse" /> 和
 10 ///                       <see cref="M:System.Net.HttpWebRequest.GetRequestStream" /> 方法的超时值（以毫秒为单位）。
 11 ///                       -1 表示永不超时
 12 /// </param>
 13 /// <returns></returns>
 14 public HttpResult UploadFormByMultipart(string url, string[] fileFullNames, NameValueCollection kVDatas = null, string method = WebRequestMethods.Http.Post, int timeOut = -1)
 15 {
 16     #region 说明
 17     /* 阿里云文档：https://www.alibabacloud.com/help/zh/doc-detail/42976.htm
 18        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
 19                    (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)
 20       */
 21 
 22     /* 说明：multipart/form-data 方式提交文件
 23      *     (1) Header 一定要有 Content-Type: multipart/form-data; boundary={boundary}。
 24      *     (2) Header 和bod y之间由 rn--{boundary} 分割。
 25      *     (3) 表单域格式 ：Content-Disposition: form-data; name="{key}"rnrn
 26      *                   {value}rn
 27      *                   --{boundary}
 28      *     (4)表单域名称大小写敏感，如policy、key、file、OSSAccessKeyId、OSSAccessKeyId、Content-Disposition。
 29      *     (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。
 30      */
 31     #endregion
 32 
 33     #region ContentType 说明
 34     /* 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。
 35        
 36        要清除Content-typeHTTP标头，请将ContentType属性设置为null。
 37        
 38      * 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。
 39      *      所以放置在Headers 属性之后设置
 40      */
 41     #endregion
 42 
 43     #region Method 说明
 44     /* 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。 */
 45     #endregion
 46 
 47     #region HttpWebRequest.CookieContainer 在 .NET3.5 与 .NET4.0 中的不同
 48     /* 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/ */
 49     #endregion
 50 
 51     HttpResult httpResult = new HttpResult();
 52 
 53     #region 校验
 54 
 55     if (fileFullNames == null || fileFullNames.Length == 0)
 56     {
 57         httpResult.Status = HttpResult.STATUS_FAIL;
 58 
 59         httpResult.RefCode = (int)HttpStatusCode2.USER_FILE_NOT_EXISTS;
 60         httpResult.RefText = HttpStatusCode2.USER_FILE_NOT_EXISTS.GetCustomAttributeDescription();
 61 
 62         return httpResult;
 63     }
 64 
 65     List<string> lstFiles = new List<string>();
 66     foreach (string fileFullName in fileFullNames)
 67     {
 68         if (File.Exists(fileFullName))
 69         {
 70             lstFiles.Add(fileFullName);
 71         }
 72     }
 73 
 74     if (lstFiles.Count == 0)
 75     {
 76         httpResult.Status = HttpResult.STATUS_FAIL;
 77 
 78         httpResult.RefCode = (int)HttpStatusCode2.USER_FILE_NOT_EXISTS;
 79         httpResult.RefText = HttpStatusCode2.USER_FILE_NOT_EXISTS.GetCustomAttributeDescription();
 80 
 81         return httpResult;
 82     }
 83 
 84     #endregion
 85 
 86     string boundary = CreateFormDataBoundary();                                       // 边界符
 87     byte[] beginBoundaryBytes = Encoding.UTF8.GetBytes("--" + boundary + "rn");     // 边界符开始。【☆】右侧必须要有 rn 。
 88     byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("rn--" + boundary + "--rn"); // 边界符结束。【☆】两侧必须要有 --rn 。
 89     byte[] newLineBytes = Encoding.UTF8.GetBytes("rn"); //换一行
 90     MemoryStream memoryStream = new MemoryStream();
 91 
 92     HttpWebRequest httpWebRequest = null;
 93     try
 94     {
 95         httpWebRequest = WebRequest.Create(url) as HttpWebRequest; // 创建请求
 96         httpWebRequest.ContentType = string.Format(HttpContentType.MULTIPART_FORM_DATA + "; boundary={0}", boundary);
 97         //httpWebRequest.Referer = "http://bimface.com/user-console";
 98         httpWebRequest.Method = method;
 99         httpWebRequest.KeepAlive = true;
100         httpWebRequest.Timeout = timeOut;
101         httpWebRequest.UserAgent = GetUserAgent();
102 
103         #region 步骤1：写入键值对
104         if (kVDatas != null)
105         {
106             string formDataTemplate = "Content-Disposition: form-data; name="{0}"rnrn" +
107                                       "{1}rn";
108 
109             foreach (string key in kVDatas.Keys)
110             {
111                 string formItem = string.Format(formDataTemplate, key.Replace(StringUtils.Symbol.KEY_SUFFIX, String.Empty), kVDatas[key]);
112                 byte[] formItemBytes = Encoding.UTF8.GetBytes(formItem);
113 
114                 memoryStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length); // 1.1 写入FormData项的开始边界符
115                 memoryStream.Write(formItemBytes, 0, formItemBytes.Length);           // 1.2 将键值对写入FormData项中
116             }
117         }
118         #endregion
119 
120         #region 步骤2：写入文件(表单域 file 必须为最后一个表单域)
121 
122         const string filePartHeaderTemplate = "Content-Disposition: form-data; name="{0}"; filename="{1}"rn" +
123                                               "Content-Type: application/octet-streamrnrn";
124 
125         int i = 0;
126         foreach (var fileFullName in lstFiles)
127         {
128             FileInfo fileInfo = new FileInfo(fileFullName);
129             string fileName = fileInfo.Name;
130 
131             string fileHeaderItem = string.Format(filePartHeaderTemplate, "file", fileName);
132             byte[] fileHeaderItemBytes = Encoding.UTF8.GetBytes(fileHeaderItem);
133 
134             if (i > 0)
135             {
136                 // 第一笔及第一笔之后的数据项之间要增加一个换行 
137                 memoryStream.Write(newLineBytes, 0, newLineBytes.Length);
138             }
139             memoryStream.Write(beginBoundaryBytes, 0, beginBoundaryBytes.Length);      // 2.1 写入FormData项的开始边界符
140             memoryStream.Write(fileHeaderItemBytes, 0, fileHeaderItemBytes.Length);    // 2.2 将文件头写入FormData项中
141 
142             int bytesRead;
143             byte[] buffer = new byte[1024];
144 
145             FileStream fileStream = new FileStream(fileFullName, FileMode.Open, FileAccess.Read);
146             while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
147             {
148                 memoryStream.Write(buffer, 0, bytesRead);                              // 2.3 将文件流写入FormData项中
149             }
150 
151             i++;
152         }
153 
154         memoryStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);             // 2.4 写入FormData的结束边界符
155 
156         #endregion
157 
158         #region 步骤3：将表单域(内存流)写入 httpWebRequest 的请求流中，并发起请求
159         httpWebRequest.ContentLength = memoryStream.Length;
160 
161         Stream requestStream = httpWebRequest.GetRequestStream();
162 
163         memoryStream.Position = 0;
164         byte[] tempBuffer = new byte[memoryStream.Length];
165         memoryStream.Read(tempBuffer, 0, tempBuffer.Length);
166         memoryStream.Close();
167 
168         requestStream.Write(tempBuffer, 0, tempBuffer.Length);        // 将内存流中的字节写入 httpWebRequest 的请求流中
169         requestStream.Close();
170         #endregion
171 
172         HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse; // 获取响应
173         if (httpWebResponse != null)
174         {
175             //GetHeaders(ref httpResult, httpWebResponse);
176             GetResponse(ref httpResult, httpWebResponse);
177             httpWebResponse.Close();
178         }
179     }
180     catch (WebException webException)
181     {
182         GetWebExceptionResponse(ref httpResult, webException);
183     }
184     catch (Exception ex)
185     {
186         GetExceptionResponse(ref httpResult, ex, method, HttpContentType.MULTIPART_FORM_DATA);
187     }
188     finally
189     {
190         if (httpWebRequest != null)
191         {
192             httpWebRequest.Abort();
193         }
194     }
195 
196     return httpResult;
197 }