HttpWebRequest post "multipart/form-data"类型的web数据

最新推荐文章于 2022-01-13 16:12:20 发布

原创最新推荐文章于 2022-01-13 16:12:20 发布 · 1.8k 阅读

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文章标签：

#web #stream #string #cookies #file #byte

本文介绍如何使用C#手动构造multipart/form-data格式的数据包来上传文件，包括设置请求头、构造请求体及发送POST请求的具体步骤。

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webRqst.ContentType = "multipart/form-data; boundary=xyz";
所以数据提交部份实际上是从你的boundary也就是
-----------------------------7d42bf2030536开始到结束。
以下是一个例子：

System.Uri uri = new Uri(msp_url);
string dataBoundary = "--xyz";
System.Net.HttpWebRequest webRqst = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(uri);

//add existing cookies to the webrequest.
webRqst.CookieContainer = new CookieContainer();
webRqst.CookieContainer.Add(mspCookies);

//create the WebRequest Content-Body manually for file upload.
webRqst.ContentType = "multipart/form-data; boundary=xyz";
webRqst.Method = "POST";
webRqst.KeepAlive = true;

//get the file content that will be uploaded.
StreamReader sr = new StreamReader(filepath);
string FileData = sr.ReadToEnd(); // test data to send.
sr.Close();

//make a string to store the content.
StringBuilder DataString = new StringBuilder();

DataString.Append(dataBoundary + "/r/n");
DataString.Append("Content-Disposition: form-data; name=/"filename/"/r/n/r/n" + "test.txt/r/n");

DataString.Append(dataBoundary + "/r/n");
DataString.Append("Content-Disposition: form-data; name=" + "/"submitFile/"" +
"; filename=" + "/"" + filename + "/"" + "/r/n");
DataString.Append("Content-Type: text/plain/r/n/r/n");
DataString.Append(FileData);
DataString.Append(dataBoundary + "--/r/n");

byte []Postdata = System.Text.Encoding.Default.GetBytes(DataString.ToString());

//change the requests content length to the size of data being posted in request.
webRqst.ContentLength = Postdata.Length;

//get the response stream from the webrequest and write the data to be posted to the
//Request Stream

Stream tempStream = webRqst.GetRequestStream();
tempStream.Write(Postdata,0,Postdata.Length);
tempStream.Flush();
tempStream.Close();

//change certificate policy to always allow.
System.Net.ServicePointManager.CertificatePolicy = new MyPolicy();
System.Net.HttpWebResponse webRsp = (System.Net.HttpWebResponse)webRqst.GetResponse();