From e1e3796192c3e98dbd4d0154013f2f8666b30313 Mon Sep 17 00:00:00 2001
From: Thomas Ardal <thomasardal@gmail.com>
Date: Wed, 3 Jul 2024 10:19:37 +0200
Subject: [PATCH] Migrate OnFilter to use OnMessageFilter event on
 Elmah.Io.Client

---
 .../Sinks/ElmahIo/ElmahIOSink.cs              | 14 +++++++----
 .../Sinks/ElmahIo/ElmahIOSinkTest.cs          | 23 +++++++++++++++++++
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/src/Serilog.Sinks.ElmahIo/Sinks/ElmahIo/ElmahIOSink.cs b/src/Serilog.Sinks.ElmahIo/Sinks/ElmahIo/ElmahIOSink.cs
index 7968b05..f60bc42 100644
--- a/src/Serilog.Sinks.ElmahIo/Sinks/ElmahIo/ElmahIOSink.cs
+++ b/src/Serilog.Sinks.ElmahIo/Sinks/ElmahIo/ElmahIOSink.cs
@@ -69,6 +69,15 @@ public async Task EmitBatchAsync(IEnumerable<LogEvent> batch)
                     Timeout = new TimeSpan(0, 0, 30),
                     UserAgent = UserAgent(),
                 });
+
+                api.Messages.OnMessageFilter += (sender, args) =>
+                {
+                    var filter = _options.OnFilter?.Invoke(args.Message);
+                    if (filter.HasValue && filter.Value)
+                    {
+                        args.Filter = true;
+                    }
+                };
                 api.Messages.OnMessage += (sender, args) =>
                 {
                     _options.OnMessage?.Invoke(args.Message);
@@ -109,11 +118,6 @@ public async Task EmitBatchAsync(IEnumerable<LogEvent> batch)
                     QueryString = QueryString(logEvent),
                 };
 
-                if (_options.OnFilter != null && _options.OnFilter(message))
-                {
-                    continue;
-                }
-
                 messages.Add(message);
             }
 
diff --git a/test/Serilog.Sinks.ElmahIo.Tests/Sinks/ElmahIo/ElmahIOSinkTest.cs b/test/Serilog.Sinks.ElmahIo.Tests/Sinks/ElmahIo/ElmahIOSinkTest.cs
index 9e9001c..d44188f 100644
--- a/test/Serilog.Sinks.ElmahIo.Tests/Sinks/ElmahIo/ElmahIOSinkTest.cs
+++ b/test/Serilog.Sinks.ElmahIo.Tests/Sinks/ElmahIo/ElmahIOSinkTest.cs
@@ -192,6 +192,29 @@ await sink.EmitBatchAsync(new List<LogEvent>
             Assert.That(loggedMessage.Category, Is.EqualTo("category"));
         }
 
+        [Test]
+        public async Task CanFilterBatchFromOptions()
+        {
+            // Arrange
+            var messages = 0;
+            var options = new ElmahIoSinkOptions("API_KEY", Guid.NewGuid())
+            {
+                OnFilter = msg => true,
+                OnMessage = msg => messages++
+            };
+            var sink = new ElmahIoSink(options);
+
+            // Act
+            await sink.EmitBatchAsync(new List<LogEvent>
+            {
+                new(Now, LogEventLevel.Error, null, new MessageTemplate("Test1", new List<MessageTemplateToken>()), new List<LogEventProperty>())
+            });
+
+            // Assert
+            Assert.That(messages, Is.EqualTo(0));
+
+        }
+
         private static Exception Exception()
         {
             return new Exception("error", new DivideByZeroException());