[C#][ASP.net] 透過 HttpWebRequest 模擬Client上傳檔案
2012-11-22
事情是這樣子的(抖哥如是說)，因為常常會跟其他開發技術合作像是 JSP or PHP ..
他們會跟你說我們上傳檔案是這樣子的..然後給你一個Sample Code :
Client :
<form action = "http://192.168.1.100/uploadFile.jsp"
method="post" enctype="multipart/form-data">
Desc : <input type="text" name="iptDesc">
<br>
<input type="file" name="uploadFileName" />
<input type="submit" value="上傳" />
</form>
實際上，他可能是在Server這邊的內網，那我該如何這邊透過Server 端 把使用者傳給我的圖片上傳給他呢?!
這時候要透過 HttpWebRerequest 來做
/// <summary>/// 上傳檔案至 Server 透過HttpWebRequest/// </summary>/// <param name="url">上傳網址</param>/// <param name="file">檔案位置</param>/// <param name="paramName">該control name</param>/// <param name="contentType">image type </param>/// <param name="nvc">其他參數</param>/// <returns></returns>public string UploadFileByHttpWebRequest(string url, string file, string paramName, string contentType, NameValueCollection nvc)
{ // Debug.WriteLine(string.Format("上傳至 {0} to {1}", file, url));string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
wr.ContentType = "multipart/form-data; boundary=" + boundary; wr.Method = "POST"; wr.KeepAlive = true;wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
Stream rs = wr.GetRequestStream();
string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
foreach (string key in nvc.Keys)
{rs.Write(boundarybytes, 0, boundarybytes.Length);
string formitem = string.Format(formdataTemplate, key, nvc[key]);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);rs.Write(formitembytes, 0, formitembytes.Length);
}
rs.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
string header = string.Format(headerTemplate, paramName, file, contentType);
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);rs.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);byte[] buffer = new byte[4096];
int bytesRead = 0; while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) {rs.Write(buffer, 0, bytesRead);
}
fileStream.Close();
byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
rs.Write(trailer, 0, trailer.Length);
rs.Close();
WebResponse wresp = null; var result = ""; try {wresp = wr.GetResponse();
Stream stream2 = wresp.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2); //成功回傳結果result = reader2.ReadToEnd();
//File.WriteAllText(Server.MapPath("log.txt"), string.Format("Server 回應{0}", reader2.ReadToEnd()));}
catch (Exception ex) { // File.WriteAllText(Server.MapPath("log.txt"), string.Format("上傳失敗，錯誤訊息: {0}", ex.Message));if (wresp != null)
{wresp.Close();
}
}
wr = null; return result; }
呼叫端:
///增加其他參數NameValueCollection nvc = new NameValueCollection();nvc.Add("iptDesc", "我是敘述");
//上傳檔案var result = UploadFileByHttpWebRequest("http://192.168.1.100/uploadFile.jsp",Server.MapPath("sample3.jpg"), "uploadFileName", "image/jpeg", nvc);
//回傳結果Response.Write(result);
給有需要的人，因為反覆測試花很多時間，順帶一提跟Facebook 很多上傳相片的方法也是透過一樣的方式..
參考文件: http://0rz.tw/5oNBw