Prevent duplicate filters on structured logs page

src/Aspire.Dashboard/Components/Pages/StructuredLogs.razor.cs

@@ -434,7 +434,10 @@ public void UpdateViewModelFromQuery(StructuredLogsPageViewModel viewModel)
             if (filters.Count > 0)
             {
                 ViewModel.ClearFilters();
-                ViewModel.AddFilters(filters);
+                foreach (var filter in filters)
+                {
+                    ViewModel.AddFilter(filter);
+                }
             }
         }
 

src/Aspire.Dashboard/Model/Otlp/LogFilter.cs

@@ -10,7 +10,7 @@
 namespace Aspire.Dashboard.Model.Otlp;
 
 [DebuggerDisplay("{FilterText,nq}")]
-public class LogFilter
+public class LogFilter : IEquatable<LogFilter>
 {
     public const string KnownMessageField = "log.message";
     public const string KnownCategoryField = "log.category";
@@ -142,4 +142,29 @@ public IEnumerable<OtlpLogEntry> Apply(IEnumerable<OtlpLogEntry> input)
                 }
         }
     }
+
+    public bool Equals(LogFilter? other)
+    {
+        if (other == null)
+        {
+            return false;
+        }
+
+        if (Field != other.Field)
+        {
+            return false;
+        }
+
+        if (Condition != other.Condition)
+        {
+            return false;
+        }
+
+        if (!string.Equals(Value, other.Value, StringComparison.OrdinalIgnoreCase))
+        {
+            return false;
+        }
+
+        return true;
+    }
 }

src/Aspire.Dashboard/Model/StructuredLogsViewModel.cs

@@ -34,17 +34,21 @@ public void ClearFilters()
         _logs = null;
     }
 
-    public void AddFilters(IEnumerable<LogFilter> filters)
-    {
-        _filters.AddRange(filters);
-        _logs = null;
-    }
-
     public void AddFilter(LogFilter filter)
     {
+        // Don't add duplicate filters.
+        foreach (var existingFilter in _filters)
+        {
+            if (existingFilter.Equals(filter))
+            {
+                return;
+            }
+        }
+
         _filters.Add(filter);
         _logs = null;
     }
+
     public bool RemoveFilter(LogFilter filter)
     {
         if (_filters.Remove(filter))
@@ -54,6 +58,7 @@ public bool RemoveFilter(LogFilter filter)
         }
         return false;
     }
+
     public int StartIndex { get => _logsStartIndex; set => SetValue(ref _logsStartIndex, value); }
     public int? Count { get => _logsCount; set => SetValue(ref _logsCount, value); }
     public LogLevel? LogLevel { get => _logLevel; set => SetValue(ref _logLevel, value); }

tests/Aspire.Dashboard.Components.Tests/Pages/StructuredLogsTests.cs

@@ -5,6 +5,7 @@
 using Aspire.Dashboard.Components.Resize;
 using Aspire.Dashboard.Components.Tests.Shared;
 using Aspire.Dashboard.Configuration;
+using Aspire.Dashboard.Extensions;
 using Aspire.Dashboard.Model;
 using Aspire.Dashboard.Model.BrowserStorage;
 using Aspire.Dashboard.Model.Otlp;
@@ -64,6 +65,45 @@ public void Render_TraceIdAndSpanId_FilterAdded()
             });
     }
 
+    [Fact]
+    public void Render_DuplicateFilters_SingleFilterAdded()
+    {
+        // Arrange
+        SetupStructureLogsServices();
+
+        var logFilter = new LogFilter { Field = "TestField", Condition = FilterCondition.Contains, Value = "TestValue" };
+        var serializedFilter = LogFilterFormatter.SerializeLogFiltersToString([logFilter]);
+
+        var navigationManager = Services.GetRequiredService<NavigationManager>();
+        var uri = navigationManager.GetUriWithQueryParameters(new Dictionary<string, object?>
+        {
+            ["filters"] = serializedFilter + "+" + serializedFilter,
+        });
+        navigationManager.NavigateTo(uri);
+
+        var viewport = new ViewportInformation(IsDesktop: true, IsUltraLowHeight: false, IsUltraLowWidth: false);
+
+        var dimensionManager = Services.GetRequiredService<DimensionManager>();
+        dimensionManager.InvokeOnBrowserDimensionsChanged(viewport);
+
+        // Act
+        var cut = RenderComponent<StructuredLogs>(builder =>
+        {
+            builder.Add(p => p.ViewportInformation, viewport);
+        });
+
+        // Assert
+        var viewModel = Services.GetRequiredService<StructuredLogsViewModel>();
+
+        Assert.Collection(viewModel.Filters,
+            f =>
+            {
+                Assert.Equal(logFilter.Field, f.Field);
+                Assert.Equal(logFilter.Condition, f.Condition);
+                Assert.Equal(logFilter.Value, f.Value);
+            });
+    }
+
     private void SetupStructureLogsServices()
     {
         var version = typeof(FluentMain).Assembly.GetName().Version!;