Strim atau Muat Turun Fail daripada URL Jauh dalam ASP.NET
Isu:
Anda perlu menstrim atau memuat turun fail daripada URL jauh dan memaparkannya sebagai dialog simpan sebagai dalam penyemak imbas. Walau bagaimanapun, direktori fail adalah maya, menjadikannya tidak boleh diakses melalui kaedah tradisional seperti Server.MapPath.
Penyelesaian:
Gunakan HttpWebRequest untuk mendapatkan semula fail daripada URL dan strim ia kembali kepada pelanggan. Pendekatan ini membolehkan anda bekerja dengan fail yang boleh diakses hanya melalui URL.
Berikut ialah contoh kod:
//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 = MediaTypeNames.Application.Octet; //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(); } }
Atas ialah kandungan terperinci Bagaimana untuk Strim atau Muat Turun Fail dari URL Jauh di ASP.NET?. Untuk maklumat lanjut, sila ikut artikel berkaitan lain di laman web China PHP!