fix: don't post empty HTTP messages

Prevent posting HTTP messages without any log events.

CHANGELOG.md

@@ -10,6 +10,10 @@ This project adheres to [Semantic Versioning](http://semver.org/) and is followi
 
 - [#22](https://github.com/FantasticFiasco/serilog-sinks-http/issues/22) Batch formatter `ArrayBatchFormatter` which is compatible with the Logstash HTTP input plugin configured to use the JSON codec
 
+### Fixed
+
+- Prevent posting HTTP messages without any log events
+
 ## [4.0.0] - 2017-06-17
 
 ### Added

src/Serilog.Sinks.Http/Sinks/Http/BatchFormatters/ArrayBatchFormatter.cs

@@ -15,6 +15,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 
 namespace Serilog.Sinks.Http.BatchFormatters
 {
@@ -58,6 +59,12 @@ public override void Format(IEnumerable<string> logEvents, TextWriter output)
             if (output == null)
                 throw new ArgumentNullException(nameof(output));
 
+            // Abort if sequence of log events is empty
+            if (!logEvents.Any())
+            {
+                return;
+            }
+
             output.Write("[");
 
             var delimStart = string.Empty;

src/Serilog.Sinks.Http/Sinks/Http/BatchFormatters/DefaultBatchFormatter.cs

@@ -15,6 +15,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 
 namespace Serilog.Sinks.Http.BatchFormatters
 {
@@ -60,6 +61,12 @@ public override void Format(IEnumerable<string> logEvents, TextWriter output)
             if (output == null)
                 throw new ArgumentNullException(nameof(output));
 
+            // Abort if sequence of log events is empty
+            if (!logEvents.Any())
+            {
+                return;
+            }
+
             output.Write("{\"events\":[");
 
             var delimStart = string.Empty;