private Uri DetermineRealUri()
{
// The VideoXpert system does some non-standard RTSP redirecting so that it can determine the intent of
// the client (intent being live or playback). It stats off by creating a spoofed SDP and then will
// redirect on play. What we will do it write a wrapper that does some of the RTSP calls to first
// determine what the actual live RTSP uri is.
using (RtspClient client = new RtspClient(_uri))
{
try
{
var method = RtspRequest.RtspMethod.OPTIONS;
CheckResponse(client.Send(RtspRequest.CreateBuilder()
.Method(method)
.Uri(_uri)
.Build()), method);
method = RtspRequest.RtspMethod.DESCRIBE;
var res = CheckResponse(client.Send(RtspRequest.CreateBuilder()
.Method(method)
.Uri(_uri)
.Build()), method);
var sdp = res.GetBodyAsSdp();
if (!sdp.SessionName.Contains("Spoofed session"))
{
// We are not working with a spoofed session just return
// the current uri.
return(_uri);
}
Uri controlUri = null;
var tracks = MediaTracks.FromSdp(sdp, _uri);
foreach (var track in tracks)
{
if (track.Type.Is(MimeType.ANY_VIDEO))
{
if (GetRedirectUri(client, track, out controlUri))
{
return(controlUri);
}
}
}
throw new RtspClientException($"Unable to retrieve usable uri from server at endpoint '{_uri}'");
}
catch (Exception e)
{
LOG.Error(e, $"Failed while communicating with RTSP server at '{_uri}'");
throw e;
}
}
}
private bool GetRedirectUri(RtspClient client, MediaTrack track, out Uri uri)
{
var transport = TransportHeader.CreateBuilder()
.Type(TransportType.RtspInterleaved)
.InterleavedChannels(0, 1)
.Build();
var method = RtspRequest.RtspMethod.SETUP;
var res = CheckResponse(client.Send(RtspRequest.CreateBuilder()
.Method(method)
.Uri(track.ControlUri)
.AddHeader(RtspHeaders.Names.TRANSPORT, transport.ToString())
.Build()), method);
if (!res.Headers.ContainsKey(RtspHeaders.Names.SESSION))
{
uri = null;
return(false);
}
var rtspSession = Session.Parse(res.Headers[RtspHeaders.Names.SESSION]);
method = RtspRequest.RtspMethod.PLAY;
res = CheckResponse(client.Send(RtspRequest.CreateBuilder()
.Method(method)
.Uri(track.ControlUri)
.AddHeader(RtspHeaders.Names.SESSION, rtspSession.ID)
.Build()), method);
var status = res.ResponseStatus;
if (status.Is(RtspResponse.Status.MovedPermanently) || status.Is(RtspResponse.Status.MovedTemporarily))
{
// We received a redirect lets get the uri and return it.
if (res.Headers.ContainsKey(RtspHeaders.Names.LOCATION))
{
var value = res.Headers[RtspHeaders.Names.LOCATION];
return(Uri.TryCreate(value, UriKind.RelativeOrAbsolute, out uri));
}
}
uri = null;
return(false);
}