使用HttpWebRequest POST上传文件

2019/10/27, .Net c#代码片段

摘要：使用HttpWebRequest向Api接口发送文件，multipart-form数据格式，POST方式

参考地址

/// <summary>

/// HttpWebRequest发送文件

/// </summary>

/// <param name="url">url</param>

/// <param name="filePath">文件路径</param>

/// <param name="paramName">文件参数名</param>

/// <param name="contentType">contentType</param>

/// <param name="nameValueCollection">其余要附带的参数键值对</param>

public static void HttpUploadFile(string url, string filePath, string paramName, string contentType, NameValueCollection nameValueCollection)

{

    string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");

    byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

    request.ContentType = "multipart/form-data; boundary=" + boundary;

    request.Method = "POST";

    request.KeepAlive = true;

    request.Credentials = CredentialCache.DefaultCredentials;

    Stream requestStream = request.GetRequestStream();

    string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";

    foreach (string key in nameValueCollection.Keys)

    {

        requestStream.Write(boundarybytes, 0, boundarybytes.Length);

        string formitem = string.Format(formdataTemplate, key, nameValueCollection[key]);

        byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);

        requestStream.Write(formitembytes, 0, formitembytes.Length);

    }

    requestStream.Write(boundarybytes, 0, boundarybytes.Length);

    string header = string.Format("Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n", paramName, filePath, contentType);

    byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);

    requestStream.Write(headerbytes, 0, headerbytes.Length);

    FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);

    byte[] buffer = new byte[4096];

    int bytesRead = 0;

    while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)

    {

        requestStream.Write(buffer, 0, bytesRead);

    }

    fileStream.Close();

    byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

    requestStream.Write(trailer, 0, trailer.Length);

    requestStream.Close();

    WebResponse webResponse = null;

    try

    {

        webResponse = request.GetResponse();

        Stream responseStream = webResponse.GetResponseStream();

        StreamReader streamReader = new StreamReader(responseStream);

        string result = streamReader.ReadToEnd();

    }

    catch (Exception ex)

    {

        if (webResponse != null)

        {

            webResponse.Close();

            webResponse = null;

        }

    }

    finally

    {

        request = null;

    }

}

使用

NameValueCollection nvc = new NameValueCollection();

nvc.Add("id", "1000");

nvc.Add("name", "user1");

HttpUploadFile("http://your.server.com/upload",@"C:\test\test.jpg", "file", "image/jpeg", nvc);

巴特西

使用HttpWebRequest POST上传文件

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