c# 模擬表單提交，post form 上傳檔案、大資料內容
阿新 • • 發佈：2019-01-11
表單提交協議規定：
要先將 HTTP 要求的 Content-Type 設為 multipart/form-data，而且要設定一個 boundary 引數，
這個引數是由應用程式自行產生，它會用來識別每一份資料的邊界 (boundary)，
用以產生多重資訊部份 (message part)。
而 HTTP 伺服器可以抓取 HTTP POST 的資訊，
基本內容：
1. 每個資訊部份都要用 --[BOUNDARY_NAME] 來包裝，以分隔出資訊的每個部份，而最後要再加上一個 --[BOUNDARY_NAME] 來表示結束。
2. 每個資訊部份都要有一個 Content-Disposition: form-data; name=""，而 name 設定的就是 HTTP POST 的鍵值 (key)。
3. 宣告區和值區中間要隔兩個新行符號（\r\n）。
4. 中間可以夾入二進位制資料，但二進位制資料必須要格式化為二進位制字串。
5. 若要設定不同資訊段的資料型別 (Content-Type)，則要在資訊段內的宣告區設定。
兩個form內容模板
boundary = "----" + DateTime.Now.Ticks.ToString("x");//程式生成
1.文字內容
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"鍵\"; filename=\"檔名\"" +
"\r\nContent-Type: application/octet-stream" +
"\r\n\r\n";
2.檔案內容
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"鍵\"" +
"\r\n\r\n內容";
程式碼
1.表示一個表單項的物件
/// <summary> /// 表單資料項 /// </summary> public class FormItemModel { /// <summary> /// 表單鍵，request["key"] /// </summary> public string Key { set; get; } /// <summary> /// 表單值,上傳檔案時忽略，request["key"].value /// </summary> public string Value { set; get; } /// <summary> /// 是否是檔案 /// </summary> public bool IsFile { get { if (FileContent==null || FileContent.Length == 0) return false; if (FileContent != null && FileContent.Length > 0 && string.IsNullOrWhiteSpace(FileName)) throw new Exception("上傳檔案時 FileName 屬性值不能為空"); return true; } } /// <summary> /// 上傳的檔名 /// </summary> public string FileName { set; get; } /// <summary> /// 上傳的檔案內容 /// </summary> public Stream FileContent { set; get; } }
2.提交表單主邏輯實現
/// <summary> /// 使用Post方法獲取字串結果 /// </summary> /// <param name="url"></param> /// <param name="formItems">Post表單內容</param> /// <param name="cookieContainer"></param> /// <param name="timeOut">預設20秒</param> /// <param name="encoding">響應內容的編碼型別（預設utf-8）</param> /// <returns></returns> public static string PostForm(string url, List<FormItemModel> formItems, CookieContainer cookieContainer = null, string refererUrl = null, Encoding encoding = null,int timeOut = 20000) { HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); #region 初始化請求物件 request.Method = "POST"; request.Timeout = timeOut; request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"; request.KeepAlive = true; request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36"; if (!string.IsNullOrEmpty(refererUrl)) request.Referer = refererUrl; if (cookieContainer != null) request.CookieContainer = cookieContainer; #endregion string boundary = "----" + DateTime.Now.Ticks.ToString("x");//分隔符 request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary); //請求流 var postStream = new MemoryStream(); #region 處理Form表單請求內容 //是否用Form上傳檔案 var formUploadFile = formItems != null && formItems.Count > 0; if (formUploadFile) { //檔案資料模板 string fileFormdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" + "\r\nContent-Type: application/octet-stream" + "\r\n\r\n"; //文字資料模板 string dataFormdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"" + "\r\n\r\n{1}"; foreach (var item in formItems) { string formdata = null; if (item.IsFile) { //上傳檔案 formdata = string.Format( fileFormdataTemplate, item.Key, //表單鍵 item.FileName); } else { //上傳文字 formdata = string.Format( dataFormdataTemplate, item.Key, item.Value); } //統一處理 byte[] formdataBytes = null; //第一行不需要換行 if (postStream.Length == 0) formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length - 2)); else formdataBytes = Encoding.UTF8.GetBytes(formdata); postStream.Write(formdataBytes, 0, formdataBytes.Length); //寫入檔案內容 if (item.FileContent != null && item.FileContent.Length>0) { using (var stream = item.FileContent) { byte[] buffer = new byte[1024]; int bytesRead = 0; while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0) { postStream.Write(buffer, 0, bytesRead); } } } } //結尾 var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n"); postStream.Write(footer, 0, footer.Length); } else { request.ContentType = "application/x-www-form-urlencoded"; } #endregion request.ContentLength = postStream.Length; #region 輸入二進位制流 if (postStream != null) { postStream.Position = 0; //直接寫入流 Stream requestStream = request.GetRequestStream(); byte[] buffer = new byte[1024]; int bytesRead = 0; while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0) { requestStream.Write(buffer, 0, bytesRead); } ////debug //postStream.Seek(0, SeekOrigin.Begin); //StreamReader sr = new StreamReader(postStream); //var postStr = sr.ReadToEnd(); postStream.Close();//關閉檔案訪問 } #endregion HttpWebResponse response = (HttpWebResponse)request.GetResponse(); if (cookieContainer != null) { response.Cookies = cookieContainer.GetCookies(response.ResponseUri); } using (Stream responseStream = response.GetResponseStream()) { using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ?? Encoding.UTF8)) { string retString = myStreamReader.ReadToEnd(); return retString; } } }
3.呼叫模擬post表單
var url = "http://127.0.0.1/testformdata.aspx?aa=1&bb=2&ccc=3";
var [email protected]"D:\temp\log1.txt";
var log2 = @"D:\temp\log2.txt";
var formDatas = new List<Grass.Net.FormItemModel>();
//新增檔案
formDatas.Add(new Grass.Net.FormItemModel()
{
Key="log1",
Value="",
FileName = "log1.txt",
FileContent=File.OpenRead(log1)
});
formDatas.Add(new Grass.Net.FormItemModel()
{
Key = "log2",
Value = "",
FileName = "log2.txt",
FileContent = File.OpenRead(log2)
});
//新增文字
formDatas.Add(new Grass.Net.FormItemModel()
{
Key = "id",
Value = "id-test-id-test-id-test-id-test-id-test-"
});
formDatas.Add(new Grass.Net.FormItemModel()
{
Key = "name",
Value = "name-test-name-test-name-test-name-test-name-test-"
});
//提交表單
var result = PostForm(url, formDatas);