c#模拟formdata_c# 模拟表单提交，post form 上传文件、数据内容

转自：https://www.cnblogs.com/DoNetCShap/p/10696277.html

表单提交协议规定：

要先将 HTTP 要求的 Content-Type 设为 multipart/form-data，而且要设定一个 boundary 参数，

这个参数是由应用程序自行产生，它会用来识别每一份资料的边界 (boundary)，

用以产生多重信息部份 (message part)。

而 HTTP 服务器可以抓取 HTTP POST 的信息，

基本内容：

1. 每个信息部份都要用 –[BOUNDARY_NAME] 来包装，以分隔出信息的每个部份，而最后要再加上一个 –[BOUNDARY_NAME] 来表示结束。

2. 每个信息部份都要有一个 Content-Disposition: form-data; name=””，而 name 设定的就是 HTTP POST 的键值 (key)。

3. 声明区和值区中间要隔两个新行符号(\r\n)。

4. 中间可以夹入二进制资料，但二进制资料必须要格式化为二进制字符串。

5. 若要设定不同信息段的资料型别 (Content-Type)，则要在信息段内的声明区设定。

两个form内容模板

boundary = “—-” + DateTime.Now.Ticks.ToString(“x”);//程序生成

1.文本内容

“\r\n–” + boundary +

“\r\nContent-Disposition: form-data; name=\”键\”; filename=\”文件名\”” +

“\r\nContent-Type: application/octet-stream” +

“\r\n\r\n”;

2.文件内容

“\r\n–” + boundary +

“\r\nContent-Disposition: form-data; name=\”键\”” +

“\r\n\r\n内容”;

1 ///

2 ///表单数据项3 ///

4 public classFormItemModel5 {6 ///

7 ///表单键，request[“key”]8 ///

9 public string Key { set; get; }10 ///

11 ///表单值,上传文件时忽略，request[“key”].value12 ///

13 public string Value { set; get; }14 ///

15 ///是否是文件16 ///

17 public boolIsFile18 {19 get

20 {21 if (FileContent==null || FileContent.Length == 0)22 return false;23

24 if (FileContent != null && FileContent.Length > 0 && string.IsNullOrWhiteSpace(FileName))25 throw new Exception(“上传文件时 FileName 属性值不能为空”);26 return true;27 }28 }29 ///

30 ///上传的文件名31 ///

32 public string FileName { set; get; }33 ///

34 ///上传的文件内容35 ///

36 public Stream FileContent { set; get; }37 }

1 ///

2 ///使用Post方法获取字符串结果3 ///

4 ///

5 /// Post表单内容

6 ///

7 /// 默认20秒

8 /// 响应内容的编码类型(默认utf-8)

9 ///

10 public static string PostForm(string url, List formItems, CookieContainer cookieContainer = null, string refererUrl = null, Encoding encoding = null,int timeOut = 20000)11 {12 HttpWebRequest request =(HttpWebRequest)WebRequest.Create(url);13 #region 初始化请求对象

14 request.Method = “POST”;15 request.Timeout =timeOut;16 request.Accept = “text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8”;17 request.KeepAlive = true;18 request.UserAgent = “Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36”;19 if (!string.IsNullOrEmpty(refererUrl))20 request.Referer =refererUrl;21 if (cookieContainer != null)22 request.CookieContainer =cookieContainer;23 #endregion

24

25 string boundary = “—-” + DateTime.Now.Ticks.ToString(“x”);//分隔符

26 request.ContentType = string.Format(“multipart/form-data; boundary={0}”, boundary);27 //请求流

28 var postStream = newMemoryStream();29 #region 处理Form表单请求内容

30 //是否用Form上传文件

31 var formUploadFile = formItems != null && formItems.Count > 0;32 if(formUploadFile)33 {34 //文件数据模板

35 string fileFormdataTemplate =

36 “\r\n–” + boundary +

37 “\r\nContent-Disposition: form-data; name=\”{0}\”; filename=\”{1}\”” +

38 “\r\nContent-Type: application/octet-stream” +

39 “\r\n\r\n”;40 //文本数据模板

41 string dataFormdataTemplate =

42 “\r\n–” + boundary +

43 “\r\nContent-Disposition: form-data; name=\”{0}\”” +

44 “\r\n\r\n{1}”;45 foreach (var item informItems)46 {47 string formdata = null;48 if(item.IsFile)49 {50 //上传文件

51 formdata = string.Format(52 fileFormdataTemplate,53 item.Key, //表单键

54 item.FileName);55 }56 else

57 {58 //上传文本

59 formdata = string.Format(60 dataFormdataTemplate,61 item.Key,62 item.Value);63 }64

65 //统一处理

66 byte[] formdataBytes = null;67 //第一行不需要换行

68 if (postStream.Length == 0)69 formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length – 2));70 else

71 formdataBytes =Encoding.UTF8.GetBytes(formdata);72 postStream.Write(formdataBytes, 0, formdataBytes.Length);73

74 //写入文件内容

75 if (item.FileContent != null && item.FileContent.Length>0)76 {77 using (var stream =item.FileContent)78 {79 byte[] buffer = new byte[1024];80 int bytesRead = 0;81 while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)82 {83 postStream.Write(buffer, 0, bytesRead);84 }85 }86 }87 }88 //结尾

89 var footer = Encoding.UTF8.GetBytes(“\r\n–” + boundary + “–\r\n”);90 postStream.Write(footer, 0, footer.Length);91

92 }93 else

94 {95 request.ContentType = “application/x-www-form-urlencoded”;96 }97 #endregion

98

99 request.ContentLength =postStream.Length;100

101 #region 输入二进制流

102 if (postStream != null)103 {104 postStream.Position = 0;105 //直接写入流

106 Stream requestStream =request.GetRequestStream();107

108 byte[] buffer = new byte[1024];109 int bytesRead = 0;110 while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0)111 {112 requestStream.Write(buffer, 0, bytesRead);113 }114

115 debug

116 //postStream.Seek(0, SeekOrigin.Begin);117 //StreamReader sr = new StreamReader(postStream);118 //var postStr = sr.ReadToEnd();

119 postStream.Close();//关闭文件访问

120 }121 #endregion

122

123 HttpWebResponse response =(HttpWebResponse)request.GetResponse();124 if (cookieContainer != null)125 {126 response.Cookies =cookieContainer.GetCookies(response.ResponseUri);127 }128

129 using (Stream responseStream =response.GetResponseStream())130 {131 using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ??Encoding.UTF8))132 {133 string retString =myStreamReader.ReadToEnd();134 returnretString;135 }136 }137 }

运行方式：

1 var url = “http://127.0.0.1/testformdata.aspx?aa=1&bb=2&ccc=3″;2 var log1=@”D:\temp\log1.txt”;3 var log2 = @”D:\temp\log2.txt”;4 var formDatas = new List();5 //添加文件

6 formDatas.Add(newGrass.Net.FormItemModel()7 {8 Key=”log1″,9 Value=””,10 FileName = “log1.txt”,11 FileContent=File.OpenRead(log1)12 });13 formDatas.Add(newGrass.Net.FormItemModel()14 {15 Key = “log2”,16 Value = “”,17 FileName = “log2.txt”,18 FileContent =File.OpenRead(log2)19 });20 //添加文本

21 formDatas.Add(newGrass.Net.FormItemModel()22 {23 Key = “id”,24 Value = “id-test-id-test-id-test-id-test-id-test-“

25 });26 formDatas.Add(newGrass.Net.FormItemModel()27 {28 Key = “name”,29 Value = “name-test-name-test-name-test-name-test-name-test-“

30 });31 //提交表单

32 var result = PostForm(url, formDatas);

以下内容做了一些优化修改：

1 if(formUploadFile)2 {3 //文件数据模板

4 string fileFormdataTemplate =

5 “\r\n–” + boundary +

6 “\r\nContent-Disposition: form-data; name=\”{0}\”; filename=\”{1}\”” +

7 “\r\nContent-Type: application/octet-stream” +

8 “\r\n\r\n”;9 //文本数据模板

10 string dataFormdataTemplate =

11 “\r\n–” + boundary +

12 “\r\nContent-Disposition: form-data; name=\”{0}\”” +

13 “\r\n\r\n{1}”;14 //头部

15 var header = Encoding.UTF8.GetBytes(“–” +boundary);16 postStream.Write(header, 0, header.Length);17 var index = 0;18 foreach (var item informItems)19 {20 index++;21 string formdata = null;22 if(item.IsFile)23 {24 if (index == 1)25 {26 formdata = string.Format(“\r\nContent-Disposition: form-data; name=\”{0}\”; filename=\”{1}\”\r\nContent-Type: application/octet-stream\r\n\r\n”, item.Key, item.FileName);27

28 }29 else

30 {31 //上传文件

32 formdata = string.Format(fileFormdataTemplate,item.Key,item.FileName);33

34 }35

36 }37 else

38 {39 if (index==1)40 {41 formdata = string.Format(“\r\nContent-Disposition: form-data; name=\”{0}\”\r\n\r\n{1}”, item.Key, item.FileName);42 }43 else

44 {45 //上传文本

46 formdata = string.Format(dataFormdataTemplate, item.Key, item.Value);47 }48

49 }50

51 //统一处理

52 byte[] formdataBytes =Encoding.UTF8.GetBytes(formdata);53

54 postStream.Write(formdataBytes, 0, formdataBytes.Length);55

56 //写入文件内容57 //if (item.FileContent != null && item.FileContent.Length > 0)

58 if(item.IsFile)59 {60

61 FileStream fs = new FileStream(item.FilePath, FileMode.Open, FileAccess.Read);//可以是其他重载方法

62 byte[] byData = new byte[fs.Length];63 fs.Read(byData, 0, byData.Length);64 fs.Close();65 postStream.Write(byData, 0, byData.Length);66 }67 }68 //结尾

69 var footer = Encoding.UTF8.GetBytes(“\r\n–” + boundary + “–“);70 postStream.Write(footer, 0, footer.Length);71

72 }