/// <summary>
/// 立即开始录播任务
/// </summary>
public static async void LaunchRecording(RecordSchedule schedule)
{
// 获取视频片段长度
HttpClient client = new HttpClient();
var m3u = await client.GetStringAsync(schedule.PlaylistUri);
client.Dispose();
const string tag = "#EXT-X-TARGETDURATION";
var tag_index = m3u.IndexOf(tag) + tag.Length + 1;
string interval = m3u.Substring(tag_index, m3u.IndexOf('\n', tag_index) - tag_index);
schedule.SegmentLength = TimeSpan.FromSeconds(double.Parse(interval));
// 创建下载任务
await schedule.GenerateDownloadTask();
schedule.Status = ScheduleStatus.Downloading;
}
/// <summary>
/// 开始录播计划任务，定时开始下载
/// </summary>
/// <param name="schedule">任务对象</param>
public static async void LaunchSchedule(RecordSchedule schedule)
{
// 获取后台运行权限，这个感觉不是必要的？
var status = await BackgroundExecutionManager.RequestAccessAsync();
if (status == BackgroundAccessStatus.Unspecified || status == BackgroundAccessStatus.Denied)
{
// TODO: 权限被拒绝，需要提示用户
return;
}
var key = schedule.Key;
Guid taskId;
var builder = ScheduleTask.CreateBackgroundTaskBuilder(
out taskId, schedule.StartTime.Subtract(DateTimeOffset.Now));
Container.Values[key] = taskId;
}
// TODO: 后台定时器有15分钟的误差，因此若需准确开始需要提前15分钟
public async void Run(IBackgroundTaskInstance taskInstance)
{
// 寻找对应的下载计划
RecordSchedule schedule = null;
foreach (var item in RecordScheduleManager.Container.Values)
{
if ((Guid)item.Value == taskInstance.Task.TaskId)
{
schedule = new RecordSchedule(item.Key);
}
}
if (schedule == null)
{
System.Diagnostics.Debug.WriteLine("未找到对应的下载计划", "Error");
return;
}
if (schedule.Status == ScheduleStatus.Terminated)
{
System.Diagnostics.Debug.WriteLine("下载计划被终止");
return;
}
var _defer = taskInstance.GetDeferral();
// 生成下一个下载，若下载完毕则直接处理文件
schedule.Status = ScheduleStatus.Downloading;
var operation = await schedule.GenerateDownloadTask();
if (operation == null)
{
// TODO: 什么情况下会发生？
System.Diagnostics.Debugger.Break();
schedule.Status = ScheduleStatus.Completed;
}
_defer.Complete();
}
/// <summary>
/// 创建新的录播计划
/// </summary>
/// <param name="identifier">标识名，每一个下载任务不应相同</param>
/// <param name="playlistUri">直播文件的地址</param>
/// <param name="startTime">开始录播的时间</param>
/// <param name="recordSpan">录播时长</param>
public static RecordSchedule CreateSchedule(
string identifier, string playlistUri, DateTimeOffset startTime, TimeSpan recordSpan)
{
var key = EncodeIndentifier(identifier);
// 这里直接同步运行以避免async传染
var video = Async.InvokeAndWait(async() => await StorageLibrary.GetLibraryAsync(KnownLibraryId.Videos));
object path = null;
ApplicationData.Current.LocalSettings.Values.TryGetValue("RecordingPath", out path);
var pathstr = path?.ToString();
var filepath = (string.IsNullOrWhiteSpace(pathstr) ? video.SaveFolder.Path : pathstr) + '\\' + identifier + ".ts";
var schedule = new RecordSchedule(key)
{
PlaylistUri = playlistUri,
StartTime = startTime,
ScheduleSpan = recordSpan,
Status = ScheduleStatus.Scheduled,
SavePath = filepath
};
RecordScheduleMessager.Instance.Trigger(key, RecordScheduleMessageType.Created);
return(schedule);
}
/// <summary>
/// 删除下载计划的记录
/// </summary>
/// <param name="schedule">下载计划对象</param>
public static void DeleteSchedule(RecordSchedule schedule)
{
Container.DeleteContainer(schedule.Key);
Container.Values.Remove(schedule.Key);
RecordScheduleMessager.Instance.Trigger(schedule.Key, RecordScheduleMessageType.Deleted);
}
/// <summary> /// 终止下载计划 /// </summary> public static void TerminateSchedule(RecordSchedule schedule) => schedule.Status = ScheduleStatus.Terminated;
public async void Run(IBackgroundTaskInstance taskInstance)
{
var details = taskInstance.TriggerDetails as BackgroundTransferCompletionGroupTriggerDetails;
if (details == null)
{
System.Diagnostics.Debug.WriteLine("下载任务非下载完成后触发", "Error");
return;
}
// 寻找对应的下载计划
RecordSchedule schedule = null;
foreach (var item in RecordScheduleManager.Container.Values)
{
if ((Guid)item.Value == taskInstance.Task.TaskId)
{
schedule = new RecordSchedule(item.Key);
}
}
if (schedule == null)
{
System.Diagnostics.Debug.WriteLine("未找到对应的下载计划", "Error");
return;
}
if (details.Downloads.Any(op => IsFailed(op)))
{
// 下载失败
schedule.Status = ScheduleStatus.Failed;
// 生成下载失败的消息提醒
XmlDocument failedToastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastText01);
failedToastXml.GetElementsByTagName("text").Item(0).InnerText = "一项录播任务失败";
ToastNotification failedToast = new ToastNotification(failedToastXml);
ToastNotificationManager.CreateToastNotifier().Show(failedToast);
return;
}
RecordScheduleMessager.Instance.Trigger(schedule.Key, RecordScheduleMessageType.DownloadedOne);
var _defer = taskInstance.GetDeferral();
if (schedule.Status == ScheduleStatus.Terminated)
{
System.Diagnostics.Debug.WriteLine("下载计划被终止");
// 将已下载的缓存合并成文件保存下来
schedule.Status = ScheduleStatus.Decoding;
var continuous = await schedule.ConcatenateSegments(schedule.SavePath);
schedule.Status = ScheduleStatus.Terminated;
return;
}
// 生成下一个下载，若下载完毕则直接处理文件
var operation = await schedule.GenerateDownloadTask();
if (operation == null)
{
schedule.Status = ScheduleStatus.Decoding;
var continuous = await schedule.ConcatenateSegments(schedule.SavePath);
// 生成下载成功的消息提醒
XmlDocument successToastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastText01);
successToastXml.GetElementsByTagName("text").Item(0).InnerText =
"一项录播任务已经成功结束" + (continuous ? string.Empty : "，但可能录播不完整。");
ToastNotification successToast = new ToastNotification(successToastXml);
ToastNotificationManager.CreateToastNotifier().Show(successToast);
}
_defer.Complete();
}
