/// <summary>
/// 断点续传下载
/// </summary>
/// <param name="uri"></param>
/// <returns></returns>
public async void ResumeDownload(string partPath)
{
bool success = false;
using (FileStream fileStream = System.IO.File.Open(partPath, FileMode.Open))
using (HttpClient httpClient = new HttpClient()
{
Timeout = TimeSpan.FromSeconds(30)
})
{
DownloadFile downloadFile = DownloadFile.FromFileStream(fileStream);
if (downloadFile == null) //为空说明已经完成
{
success = true;
}
else
{
try
{
httpClient.DefaultRequestHeaders.Range = new RangeHeaderValue(downloadFile.RangeBegin, null);
HttpResponseMessage httpResponseMessage = await httpClient.GetAsync(downloadFile.URL, HttpCompletionOption.ResponseHeadersRead);
long?contentLength = httpResponseMessage.Content.Headers.ContentLength;
if (httpResponseMessage.Content.Headers.ContentRange != null) //如果为空，则说明服务器不支持断点续传
{
contentLength = httpResponseMessage.Content.Headers.ContentRange.Length; //服务器上的文件大小
}
string md5 = httpResponseMessage.Content.Headers.ContentMD5 == null ? null : Convert.ToBase64String(httpResponseMessage.Content.Headers.ContentMD5);
if (md5 != downloadFile.MD5)
{
throw new Exception("服务器的上的版本已经变化");
}
Stream stream = await httpResponseMessage.Content.ReadAsStreamAsync();
stream.ReadTimeout = 10 * 1000;
await Download(stream, fileStream, downloadFile);
if (fileStream.Length == downloadFile.Length)
{
if (md5 == null || md5 == MD5Tools.GetFileMd5(partPath))
{
success = true;
}
}
else
{
success = false;
}
}
catch (Exception ex)
{
//请求错误
this.OnDownloadError(new ErrorArgs(ex.Message));
}
}
}
if (success)
{
try
{
System.IO.File.Move(partPath, partPath.Replace(".downloadPart", ""));
}
catch (Exception ex)
{
this.OnDownloadError(new ErrorArgs(ex.Message));
}
}
this.OnDownloadCompleted(new CompletedArgs(success));
}
