time series download fixes

Author: tikig21

Numerics/Data/Time Series/Support/TimeSeriesDownload.cs

@@ -173,11 +173,7 @@ public enum HeightUnit
         /// <returns>A downloaded time series.</returns>
         public static async Task<TimeSeries> FromGHCN(string siteNumber, TimeSeriesType timeSeriesType = TimeSeriesType.DailyPrecipitation, DepthUnit unit = DepthUnit.Inches)
         {
-            // Check internet connection
-            if (!await IsConnectedToInternet())
-            {
-                throw new InvalidOperationException("No internet connection.");
-            }
+            
 
             // Check site number
             if (siteNumber.Length != 11)
@@ -195,6 +191,12 @@ public static async Task<TimeSeries> FromGHCN(string siteNumber, TimeSeriesType
             DateTime? previousDate = null;
             string tempFilePath = Path.Combine(Path.GetTempPath(), $"{siteNumber}.dly");
 
+            // Check internet connection
+            if (!await IsConnectedToInternet())
+            {
+                throw new InvalidOperationException("No internet connection.");
+            }
+
             try
             {
 
@@ -353,11 +355,7 @@ private static string CreateURLForUSGSDownload(string siteNumber, TimeSeriesType
         /// <param name="timeSeriesType">The time series type.</param>
         public static async Task<(TimeSeries TimeSeries, string RawText)> FromUSGS(string siteNumber, TimeSeriesType timeSeriesType = TimeSeriesType.DailyDischarge)
         {
-            // Check internet connection
-            if (!await IsConnectedToInternet())
-            {
-                throw new InvalidOperationException("No internet connection.");
-            }
+            
 
             // Check site number
             if (siteNumber.Length != 8)
@@ -371,6 +369,12 @@ private static string CreateURLForUSGSDownload(string siteNumber, TimeSeriesType
                 throw new ArgumentException("The time series type cannot be daily precipitation or daily snow.", nameof(timeSeriesType));
             }
 
+            // Check internet connection
+            if (!await IsConnectedToInternet())
+            {
+                throw new InvalidOperationException("No internet connection.");
+            }
+
             var timeSeries = new TimeSeries();
             string textDownload = "";
 
@@ -742,9 +746,7 @@ public static async Task<TimeSeries> FromABOM(
             DateTime? startDate = null,
             DateTime? endDate = null)
         {
-            // Check connectivity
-            if (!await IsConnectedToInternet())
-                throw new InvalidOperationException("No internet connection.");
+            
 
             // Validate station number (BOM station numbers are typically 6 digits)
             if (string.IsNullOrWhiteSpace(stationNumber) || stationNumber.Length < 6)
@@ -754,6 +756,10 @@ public static async Task<TimeSeries> FromABOM(
             if (timeSeriesType != TimeSeriesType.DailyDischarge && timeSeriesType != TimeSeriesType.DailyStage)
                 throw new ArgumentException("BOM API supports DailyDischarge or DailyStage only.", nameof(timeSeriesType));
 
+            // Check connectivity
+            if (!await IsConnectedToInternet())
+                throw new InvalidOperationException("No internet connection.");
+
             // Set default dates
             DateTime sd = startDate ?? new DateTime(1800, 1, 1);
             DateTime ed = endDate ?? DateTime.Today;