Fixed database price history caching issue.

Controller/MarketDataController.cs

@@ -15,6 +15,20 @@ namespace Backend.Controller
 			_marketDataService = marketDataService;
 		}
 
+		[HttpGet("symbol-check/{symbol}")]
+		public IActionResult CheckSymbol(string symbol)
+		{
+			try
+			{
+				var (found, message) = _marketDataService.CheckSymbol(symbol.ToUpperInvariant());
+				return Ok(new { found, message });
+			}
+			catch (Exception ex)
+			{
+				return StatusCode(500, new { error = ex.ToString() });
+			}
+		}
+
 		[HttpGet("live/{symbol}")]
 		public IActionResult GetLive(string symbol)
 		{

MarketDataRequest/IBGatewayControl.cs

@@ -29,6 +29,9 @@ namespace Backend.MarketDataRequest
 		private readonly ConcurrentDictionary<int, FundamentalsEquitySnapshot> _fundamentalsSnapshotsByRequest = new();
 		private readonly ConcurrentDictionary<int, TaskCompletionSource<FundamentalsEquitySnapshot>> _fundamentalsRequests = new();
 
+		// Symbol lookup data
+		private readonly ConcurrentDictionary<int, TaskCompletionSource<ContractDescription[]>> _symbolLookupRequests = new();
+
 		public IBGatewayControl()
 		{
 			Client = new EClientSocket(this, _signal);
@@ -160,6 +163,14 @@ namespace Backend.MarketDataRequest
 
 				fundamentalsTcs.TrySetException(
 					new InvalidOperationException($"IB error for fundamentals reqId={id}: {errorCode} - {errorMsg}"));
+				return;
+			}
+
+			// Symbol lookup
+			if (id > 0 && _symbolLookupRequests.TryRemove(id, out var symbolLookupTcs))
+			{
+				symbolLookupTcs.TrySetException(
+					new InvalidOperationException($"IB error for symbol lookup reqId={id}: {errorCode} - {errorMsg}"));
 			}
 		}
 
@@ -272,6 +283,51 @@ namespace Backend.MarketDataRequest
 			}
 		}
 
+		public ContractDescription[] RequestMatchingSymbolsBlocking(SymbolLookupRequest request, TimeSpan timeout)
+		{
+			ThrowIfDisposed();
+			request.Validate();
+
+			if (!Client.IsConnected())
+				throw new InvalidOperationException("IB Gateway is not connected.");
+
+			if (!_apiReady)
+				throw new InvalidOperationException("IB API is not ready yet.");
+
+			if (_symbolLookupRequests.ContainsKey(request.RequestId))
+				throw new InvalidOperationException($"Symbol lookup RequestId {request.RequestId} is already in use.");
+
+			var tcs = new TaskCompletionSource<ContractDescription[]>(TaskCreationOptions.RunContinuationsAsynchronously);
+
+			if (!_symbolLookupRequests.TryAdd(request.RequestId, tcs))
+				throw new InvalidOperationException($"Unable to register symbol lookup request {request.RequestId}.");
+
+			try
+			{
+				Console.WriteLine($"Requesting matching symbols: Pattern={request.Pattern}");
+				Client.reqMatchingSymbols(request.RequestId, request.Pattern);
+
+				if (tcs.Task.Wait(timeout))
+					return tcs.Task.GetAwaiter().GetResult();
+
+				_symbolLookupRequests.TryRemove(request.RequestId, out _);
+				throw new TimeoutException($"Timed out waiting for symbol lookup reqId={request.RequestId}.");
+			}
+			catch
+			{
+				_symbolLookupRequests.TryRemove(request.RequestId, out _);
+				throw;
+			}
+		}
+
+		public override void symbolSamples(int reqId, ContractDescription[] contractDescriptions)
+		{
+			Console.WriteLine($"[symbolSamples] reqId={reqId}, count={contractDescriptions.Length}");
+
+			if (_symbolLookupRequests.TryRemove(reqId, out var tcs))
+				tcs.TrySetResult(contractDescriptions);
+		}
+
 		public void Dispose()
 		{
 			if (_disposed)

MarketDataRequest/SymbolLookupRequest.cs

@@ -0,0 +1,17 @@
+namespace Backend.MarketDataRequest
+{
+	public sealed class SymbolLookupRequest
+	{
+		public int RequestId { get; init; }
+		public string Pattern { get; init; } = string.Empty;
+
+		public void Validate()
+		{
+			if (RequestId <= 0)
+				throw new ArgumentException("RequestId must be greater than 0.");
+
+			if (string.IsNullOrWhiteSpace(Pattern))
+				throw new ArgumentException("Pattern is required.");
+		}
+	}
+}

ServiceHandler/MarketDataHander.cs

@@ -166,6 +166,39 @@ namespace Backend.ServiceHander
 				.ToList();
 		}
 
+		public (bool Found, string Message) CheckSymbol(string symbol)
+	{
+		var request = new SymbolLookupRequest
+		{
+			RequestId = GetNextRequestId(),
+			Pattern = symbol
+		};
+
+		ContractDescription[] results = Gateway.RequestMatchingSymbolsBlocking(request, TimeSpan.FromSeconds(10));
+
+		// Find exact symbol matches (IBKR pattern search may return partial matches)
+		var exactMatches = results
+			.Where(c => string.Equals(c.Contract.Symbol, symbol, StringComparison.OrdinalIgnoreCase))
+			.ToList();
+
+		bool isStockOrEtf = exactMatches.Any(c =>
+			string.Equals(c.Contract.SecType, "STK", StringComparison.OrdinalIgnoreCase) ||
+			string.Equals(c.Contract.SecType, "ETF", StringComparison.OrdinalIgnoreCase));
+
+		if (!isStockOrEtf)
+			return (false, "This symbol does not belong to any stock or ETF, please try again.");
+
+		bool isNasdaq = exactMatches.Any(c =>
+			(string.Equals(c.Contract.SecType, "STK", StringComparison.OrdinalIgnoreCase) ||
+			 string.Equals(c.Contract.SecType, "ETF", StringComparison.OrdinalIgnoreCase)) &&
+			c.Contract.PrimaryExch.Contains("NASDAQ", StringComparison.OrdinalIgnoreCase));
+
+		if (!isNasdaq)
+			return (false, "Unfortunately, this symbol is currently unsupported. We only support NASDAQ listed stocks.");
+
+		return (true, "Symbol found.");
+	}
+
 	private static string NormalizeDuration(string duration)
 		{
 			return duration.Trim().Replace("+", " ");