web檔案下載實現

標籤：timeout   stream   ring   position   .text   false   int   request   ret   

 

服務端實現

 public HttpResponseMessage GetFile(string fileName,string folder,long expires=0)        {            try            {                string filePath = UpdateController.BaseDir + folder + "\\" + fileName;                if (File.Exists(filePath) == false)                {                    ServerLogger.Error("get file failed,cannot find file:"+ filePath);                    HttpResponseMessage message = new HttpResponseMessage(HttpStatusCode.InternalServerError)                    {                        Content = new StringContent("get file failed,cannot find file:"+ filePath, System.Text.Encoding.UTF8, "text/plain")                    };                    return message;                }                var fs =  File.OpenRead(filePath);                MemoryStream stream = new MemoryStream();                fs.CopyTo(stream);                HttpResponseMessage response = new HttpResponseMessage();                response.Content = new ByteArrayContent(stream.GetBuffer(), 0, (int)stream.Length);                response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");                response.Content.Headers.ContentDisposition.FileName = fileName;                stream.Dispose();                return response;            }            catch(Exception ex)            {                ServerLogger.Error("Get update file exception,fileName:"+ fileName + ",folder:"+ folder, ex);                HttpResponseMessage message = new HttpResponseMessage(HttpStatusCode.InternalServerError)                {                    Content = new StringContent("GetFile failed,exception occured,fileName:"+fileName, System.Text.Encoding.UTF8, "text/plain")                };                return message;            }        }

 

前端實現

                    var webRequest = (HttpWebRequest)WebRequest.Create(fileUrl);                    webRequest.Timeout = 1000 * 120;                     webRequest.Method = HttpMethod.Get.ToString().ToUpperInvariant();                    var response = webRequest.GetResponse() as HttpWebResponse;                    if (response != null && response.StatusCode == HttpStatusCode.OK)//如果成功                    {                        string fileinfo = response.Headers["Content-Disposition"];                        string fileName = fileinfo.Substring(fileinfo.LastIndexOf("filename="));                        fileName = fileName.Replace("filename=", "");                        string filePath = folder+ fileName;                                           var fs = new FileStream(filePath, FileMode.CreateNew);                        //var ms = new MemoryStream();//輸出的stream                        WriteTo(response.GetResponseStream(), fs);//寫到ms中                        fs.Seek(0, SeekOrigin.Begin);                        fs.Close();                    }

其中WriteTo為：

        void WriteTo(Stream src, Stream dest)        {            int bufferSize = 4 * 1024;            var buffer = new byte[bufferSize];            int bytesRead;            while ((bytesRead = src.Read(buffer, 0, buffer.Length)) > 0)            {                dest.Write(buffer, 0, bytesRead);            }            dest.Flush();            src.Close();        }

 

web檔案下載實現