mgth/LittleBigMouse · error · HttpRequestException

No VIDAA descriptor answered at

Error message

No VIDAA descriptor answered at {ipAddress} on ports {string.Join('/', HisenseVidaaProtocol.DescriptorPorts)}.

What it means

HisenseVidaaDiscovery.ProbeAsync fetches the device descriptor XML from the projector at a given IP across the known VIDAA descriptor ports. If every port attempt fails with an HttpRequestException, it rethrows an HttpRequestException describing the IP and ports tried, meaning no VIDAA-capable device responded at that address.

Solutions

Ping the projector IP and confirm it is powered on and connected to the same network
Check that the projector's network remote/VIDAA control setting is enabled
Verify no firewall or AP isolation blocks HTTP on the descriptor ports
Re-run discovery on the /24 subnet (FindAsync with a seed address) to locate the device

Example fix

// before
var device = await discovery.ProbeAsync(ip);
// after
try
{
    var device = await discovery.ProbeAsync(ip);
}
catch (HttpRequestException)
{
    // device unreachable: check power/network, then rescan subnet
}

Defensive patterns

Strategy: try-catch

Validate before calling

// ping first
using var ping = new Ping();
var reply = await ping.SendPingAsync(ip, 1500);
if (reply.Status != IPStatus.Success) throw new InvalidOperationException("Projector unreachable");

Try / catch

try { return await discovery.ProbeAsync(ip, token); }
catch (HttpRequestException ex) { throw new DeviceUnreachableException($"{ip}: {ex.Message}", ex); }

Prevention

Ping the device before probing
Store the projector IP in settings only after a successful probe
Check AP isolation/firewall when discovery fails network-wide
Treat timeouts and refused connections as 'device asleep' and prompt user

When it happens

Trigger: Calling ProbeAsync (directly or via FindAsync or subnet scan) with an IP where nothing answers on HisenseVidaaProtocol.DescriptorPorts: connection refused, timeout, or HTTP errors on all descriptor ports.

Common situations: Typo in the projector IP; TV/projector asleep or powered off; device on a different VLAN/subnet; firewall or AP isolation blocking the ports; TV's network settings restricting remote control.

Understand the failure class

Background: ECONNREFUSED and "connection refused" / "could not connect to server" errors: what they mean and how to fix them — this error's family across 44 libraries.

Related errors

AI-assisted analysis of mgth/LittleBigMouse@7a42f01d47 (2026-09-16). Data as JSON: /api/errors/6b4a9a96a524e358. Report an issue: GitHub.

Appendix: source

Thrown at LittleBigMouse.Plugins/LittleBigMouse.Plugin.Vcp.Avalonia/HisenseVidaa/HisenseVidaaDiscovery.cs:43

            {
                using var attempt = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
                attempt.CancelAfter(TimeSpan.FromSeconds(2));
                var xml = await httpClient.GetStringAsync(
                    $"http://{ipAddress}:{port}/MediaServer/rendererdevicedesc.xml", attempt.Token)
                    .ConfigureAwait(false);
                return HisenseVidaaProtocol.ParseDescriptor(ipAddress, xml);
            }
            catch (OperationCanceledException e) when (!cancellationToken.IsCancellationRequested)
            {
                lastError = e;
            }
            catch (HttpRequestException e)
            {
                lastError = e;
            }
        }

        throw new HttpRequestException(
            $"No VIDAA descriptor answered at {ipAddress} on ports {string.Join('/', HisenseVidaaProtocol.DescriptorPorts)}.",
            lastError);
    }

    public async Task<HisenseVidaaDevice> FindAsync(
        string lastKnownAddress,
        CancellationToken cancellationToken = default)
    {
        if (!Ipv4Address.TryParse(lastKnownAddress, out var seed))
            throw new ArgumentException("Enter a valid projector IPv4 address.", nameof(lastKnownAddress));

        try
        {
            return await ProbeAsync(lastKnownAddress, cancellationToken).ConfigureAwait(false);
        }
        catch (HttpRequestException)
        {
            // SSDP multicast does not cross routers. Search only the /24 of the

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