/// <summary>
/// 下载分片
/// </summary>
/// <param name="segment"></param>
/// <param name="progressAction"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
protected virtual DownloadTask DownloadSegmentFileAsync(DownloadSegmentInfo segment, Action <long, float> progressAction, CancellationToken cancellationToken = default)
{
Stream localFile;
if (string.IsNullOrEmpty(segment.TempFile))
{
localFile = new FileStream(LocalFileFullPath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite);
localFile.Position = segment.Start + segment.TotalReadBytes;
}
else
{
localFile = new FileStream(segment.TempFile, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite);
}
segment.DstStream = localFile;
var task = segment.DownloadAsync(progressAction, cancellationToken);
return(task);
}
/// <summary>
/// 加载M3U8分片内容
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
private Task <IList <DownloadSegmentInfo> > LoadM3U8FileSegmentsAsync(Stream stream)
{
int Count = 0;
Uri uri = new Uri(Url);
IList <DownloadSegmentInfo> list = new List <DownloadSegmentInfo>();
using (var reader = new StreamReader(stream))
{
string line;
while ((line = reader.ReadLine()) != null)
{
string newUrl = string.Empty;
if (line.StartsWith("http:"))
{
newUrl = line;
}
else if (!line.StartsWith("#EXT"))
{
var schema = uri.AbsoluteUri.Substring(0, uri.AbsoluteUri.LastIndexOf("/"));
newUrl = $"{schema}/{line}";
}
if (!string.IsNullOrEmpty(newUrl))
{
var downloadSegmentInfo = new DownloadSegmentInfo()
{
ID = Count++,
Url = newUrl,
TotalReadBytes = 0,
TempFile = Path.GetTempFileName()
};
list.Add(downloadSegmentInfo);
}
}
}
return(Task.FromResult(list));
}
public DownloadTask(DownloadSegmentInfo downloadSegmentInfo)
{
_downloadSegmentInfo = downloadSegmentInfo;
}
public static DownloadTask DownloadAsync(this DownloadSegmentInfo downloadInfo,
Action <long, float> progressAction, CancellationToken cancellationToken = default)
{
Pipe pipeline = new Pipe();
bool isCompleted = false;
var downloadTask = new DownloadTask(downloadInfo);
Func <List <Task> > func = new Func <List <Task> >(() =>
{
var readTask = Task.Run(async() =>
{
int bytesRead;
try
{
if (downloadInfo.Percentage >= 100)
{
return;
}
if (downloadInfo.Size != 0 && downloadInfo.TotalReadBytes == downloadInfo.Size)
{
return;
}
if (downloadInfo.SrcStream == null)
{
var httpClient = HttpClientFactory.Instance.GetHttpClient(downloadInfo.Url);
if (downloadInfo.Size != 0)
{
httpClient.DefaultRequestHeaders.Range = new RangeHeaderValue(downloadInfo.TotalReadBytes, downloadInfo.Size);
}
var response = await httpClient.GetAsync(downloadInfo.Url);
downloadInfo.SrcStream = await response.Content.ReadAsStreamAsync();
var size = response.Content.Headers.ContentLength.GetValueOrDefault();
if (size > 0 && downloadInfo.Size == 0)
{
downloadInfo.Size = size;
if (downloadInfo.End == 0)
{
downloadInfo.End = downloadInfo.Start + size;
}
}
if (downloadInfo.TotalReadBytes > 0)
{
///设置文件流写入位置
downloadInfo.DstStream.Position = downloadInfo.Start + downloadInfo.TotalReadBytes;
}
}
while (true) // Where the downloading part is happening
{
bytesRead = await downloadInfo.SrcStream.ReadAsync(pipeline.Writer.GetMemory(), cancellationToken);
if (bytesRead <= 0)
{
break;
}
pipeline.Writer.Advance(bytesRead);
var flushResult = await pipeline.Writer.FlushAsync(cancellationToken);
if (flushResult.IsCanceled)
{
break;
}
if (flushResult.IsCompleted)
{
break;
}
}
pipeline.Writer.Complete();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
isCompleted = true;
}
}, cancellationToken);
var writeTask = Task.Run(async() =>
{
float percentage = 0;
long bytesRead = 0;
try
{
while (true)
{
var readResult = await pipeline.Reader.ReadAsync(cancellationToken);
foreach (var segment in readResult.Buffer)
{
bytesRead += segment.Length;
await downloadInfo.DstStream.WriteAsync(segment, cancellationToken);
}
downloadInfo.TotalReadBytes += bytesRead;
if (bytesRead > 0)//有进度才会提示
{
percentage = downloadInfo.Percentage;
progressAction.Invoke(bytesRead, percentage); // To Get the current percentage.
bytesRead = 0;
}
pipeline.Reader.AdvanceTo(readResult.Buffer.End);
if (readResult.IsCompleted || readResult.IsCanceled)
{
break;
}
if (isCompleted)
{
break;
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
isCompleted = true;
downloadTask.Close();
}
pipeline.Reader.Complete();
}, cancellationToken);
return(new List <Task>()
{
readTask, writeTask
});
});
downloadTask.Create(func);
return(downloadTask);
}
