使用C#通过HTTP POST发送文件
使用C#通过HTTP POST发送文件
提问于 2009-07-15 13:31:24
我一直在搜索和阅读，但找不到任何真正有用的东西。
我正在写一个小的C# win应用程序，允许用户发送文件到网络服务器，而不是通过FTP，而是通过超文本传输协议使用POST。可以把它想象成一个运行在windows应用程序上的web表单。
我使用如下代码创建了我的HttpWebRequest对象
HttpWebRequest req = WebRequest.Create(uri) as HttpWebRequest 并设置Method、ContentType和ContentLength属性。但这就是我所能做的了。
这是我的代码片段：
HttpWebRequest req = WebRequest.Create(uri) as HttpWebRequest;
req.KeepAlive = false;
req.Method = "POST";
req.Credentials = new NetworkCredential(user.UserName, user.UserPassword);
req.PreAuthenticate = true;
req.ContentType = file.ContentType;
req.ContentLength = file.Length;
HttpWebResponse response = null;
try
{
response = req.GetResponse() as HttpWebResponse;
}
catch (Exception e)
{
}所以我的问题基本上是如何通过HTTP POST使用C#发送fie (文本文件、图像、音频等)。
谢谢!
回答 8
Stack Overflow用户
回答已采纳
发布于 2013-10-30 01:15:20
使用.NET 4.5 (或通过添加来自.NET的Microsoft.Net.Http包的NuGet 4.0 )有一种更简单的方法来模拟表单请求。下面是一个示例：
private async Task<System.IO.Stream> Upload(string actionUrl, string paramString, Stream paramFileStream, byte [] paramFileBytes)
{
HttpContent stringContent = new StringContent(paramString);
HttpContent fileStreamContent = new StreamContent(paramFileStream);
HttpContent bytesContent = new ByteArrayContent(paramFileBytes);
using (var client = new HttpClient())
using (var formData = new MultipartFormDataContent())
{
formData.Add(stringContent, "param1", "param1");
formData.Add(fileStreamContent, "file1", "file1");
formData.Add(bytesContent, "file2", "file2");
var response = await client.PostAsync(actionUrl, formData);
if (!response.IsSuccessStatusCode)
{
return null;
}
return await response.Content.ReadAsStreamAsync();
}
}Stack Overflow用户
发布于 2015-07-21 17:31:40
对我来说，client.UploadFile仍然将内容包装在一个多部分的请求中，所以我不得不这样做：
using (WebClient client = new WebClient())
{
client.Headers.Add("Content-Type", "application/octet-stream");
using (Stream fileStream = File.OpenRead(filePath))
using (Stream requestStream = client.OpenWrite(new Uri(fileUploadUrl), "POST"))
{
fileStream.CopyTo(requestStream);
}
}Stack Overflow用户
发布于 2013-06-11 23:01:51
我也遇到了同样的问题，下面的代码完美地回答了这个问题：
//Identificate separator
string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
//Encoding
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
//Creation and specification of the request
HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url); //sVal is id for the webService
wr.ContentType = "multipart/form-data; boundary=" + boundary;
wr.Method = "POST";
wr.KeepAlive = true;
wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
string sAuthorization = "login:password";//AUTHENTIFICATION BEGIN
byte[] toEncodeAsBytes = System.Text.ASCIIEncoding.ASCII.GetBytes(sAuthorization);
string returnValue = System.Convert.ToBase64String(toEncodeAsBytes);
wr.Headers.Add("Authorization: Basic " + returnValue); //AUTHENTIFICATION END
Stream rs = wr.GetRequestStream();
string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}"; //For the POST's format
//Writting of the file
rs.Write(boundarybytes, 0, boundarybytes.Length);
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(Server.MapPath("questions.pdf"));
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, "file", "questions.pdf", contentType);
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
rs.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream(Server.MapPath("questions.pdf"), 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();
rs = null;
WebResponse wresp = null;
try
{
//Get the response
wresp = wr.GetResponse();
Stream stream2 = wresp.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2);
string responseData = reader2.ReadToEnd();
}
catch (Exception ex)
{
string s = ex.Message;
}
finally
{
if (wresp != null)
{
wresp.Close();
wresp = null;
}
wr = null;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/1131425
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