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c# download multi part
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| using System; | |
| using System.Collections.Generic; | |
| using System.IO; | |
| using System.Net.Http; | |
| using System.Threading.Tasks; | |
| namespace TestApp | |
| { | |
| internal class Program | |
| { | |
| private static void Main(string[] args) | |
| { | |
| Task.Run(() => new Downloader().Download( | |
| "url_file_download", | |
| "url_save_to" | |
| )).Wait(); | |
| } | |
| } | |
| public class Downloader | |
| { | |
| public async Task Download(string url, string saveAs) | |
| { | |
| var httpClient = new HttpClient(); | |
| var response = await httpClient.SendAsync(new HttpRequestMessage(HttpMethod.Head, url)); | |
| var parallelDownloadSuported = response.Headers.AcceptRanges.Contains("bytes"); | |
| var contentLength = response.Content.Headers.ContentLength ?? 0; | |
| if (parallelDownloadSuported) | |
| { | |
| const double numberOfParts = 5.0; | |
| var tasks = new List<Task>(); | |
| var partSize = (long)Math.Ceiling(contentLength / numberOfParts); | |
| File.Create(saveAs).Dispose(); | |
| for (var i = 0; i < numberOfParts; i++) | |
| { | |
| var start = i*partSize + Math.Min(1, i); | |
| var end = Math.Min((i + 1)*partSize, contentLength); | |
| tasks.Add( | |
| Task.Run(() => DownloadPart(url, saveAs, start, end)) | |
| ); | |
| } | |
| await Task.WhenAll(tasks); | |
| } | |
| } | |
| private async Task DownloadPartAsync(string url, string saveAs, long start, long end) | |
| { | |
| using (var httpClient = new HttpClient()) | |
| using (var fileStream = new FileStream(saveAs, FileMode.Open, FileAccess.Write, FileShare.Write)) | |
| { | |
| var message = new HttpRequestMessage(HttpMethod.Get, url); | |
| message.Headers.Add("Range", string.Format("bytes={0}-{1}", start, end)); | |
| fileStream.Position = start; | |
| var response = await httpClient.SendAsync(message); | |
| await response.Content.CopyToAsync(fileStream); | |
| } | |
| } | |
| } | |
| } |
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