我需要流式传输文件,这将导致在浏览器中保存为提示。问题是,该文件所在的目录已虚拟映射,因此我无法使用Server.MapPath确定其实际位置。该目录与网站不在同一位置(甚至不在实时服务器上)。
我想要类似以下的内容,但这将允许我传递Web URL,而不是服务器文件路径。
我可能最终不得不从配置基本路径构建我的文件路径,然后追加到路径的其余部分,但是希望我可以用这种方式来代替。
var filePath = Server.MapPath(DOCUMENT_PATH); if (!File.Exists(filePath)) return; var fileInfo = new System.IO.FileInfo(filePath); Response.ContentType = "application/octet-stream"; Response.AddHeader("Content-Disposition", String.Format("attachment;filename=\"{0}\"", filePath)); Response.AddHeader("Content-Length", fileInfo.Length.ToString()); Response.WriteFile(filePath); Response.End();
您可以使用HttpWebRequest获取文件并将其流回客户端。这使您可以获取带有URL的文件。我发现的一个示例(但不记得该在哪里归功)是
//Create a stream for the file Stream stream = null; //This controls how many bytes to read at a time and send to the client int bytesToRead = 10000; // Buffer to read bytes in chunk size specified above byte[] buffer = new Byte[bytesToRead]; // The number of bytes read try { //Create a WebRequest to get the file HttpWebRequest fileReq = (HttpWebRequest) HttpWebRequest.Create(url); //Create a response for this request HttpWebResponse fileResp = (HttpWebResponse) fileReq.GetResponse(); if (fileReq.ContentLength > 0) fileResp.ContentLength = fileReq.ContentLength; //Get the Stream returned from the response stream = fileResp.GetResponseStream(); // prepare the response to the client. resp is the client Response var resp = HttpContext.Current.Response; //Indicate the type of data being sent resp.ContentType = "application/octet-stream"; //Name the file resp.AddHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); resp.AddHeader("Content-Length", fileResp.ContentLength.ToString()); int length; do { // Verify that the client is connected. if (resp.IsClientConnected) { // Read data into the buffer. length = stream.Read(buffer, 0, bytesToRead); // and write it out to the response's output stream resp.OutputStream.Write(buffer, 0, length); // Flush the data resp.Flush(); //Clear the buffer buffer = new Byte[bytesToRead]; } else { // cancel the download if client has disconnected length = -1; } } while (length > 0); //Repeat until no data is read } finally { if (stream != null) { //Close the input stream stream.Close(); } }