我有以下的代码,从FTP服务器上下载文件:如果我从一个流读取WebRequest.GetResponseStream我会从内存或网络阅读
var req = (FtpWebRequest)WebRequest.Create(ftp_addr + file_path);
req.Credentials = new NetworkCredential(...);
req.Method = WebRequestMethods.Ftp.DownloadFile;
using (var resp = req.GetResponse())
using (var strm = resp.GetResponseStream())
using (var mem_strm = new MemoryStream())
{
//The Web Response stream doesn't support seek, so we have to do a buffered read into a memory stream
byte[] buffer = new byte[2048];
int red_byts = 0;
do
{
red_byts = strm.Read(buffer, 0, 2048);
mem_strm.Write(buffer, 0, red_byts);
}
while (strm.CanRead && red_byts > 0);
//Reset the stream to position 0 for reading
mem_strm.Position = 0;
//Now I've got a mem stream that I can use
}
由于原料流从“的GetResponseStream返回“不能被读取或寻找(不能在其上查找)。在我看来,这段代码实际上正在向FTP服务器发出一个请求,请求下一个文件块并将其复制到内存中。我是否正确,或者当您可以GetResponseStream时下载整个响应?
我只是想知道,所以我可以在使用FTP下载的异步方法中正确应用等待与ReadAsync调用。我的直觉告诉我,更改行:
red_byts = strm.Read(...);
到
red_byts = await strm.ReadAsync(...);
WebRequest.GetResponseStream的文件似乎并没有规定,也没有对FtpWebRequest.GetResponseStream的文档。