Add pretty-print JSON support to RichTextBox sink

Introduces pretty-printing for JSON output in the RichTextBox sink, controlled via new options.

Author: vonhoff

CODE_OF_CONDUCT.md

@@ -55,7 +55,7 @@ a project may be further defined and clarified by project maintainers.
 ## Enforcement
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported by contacting the project team at `simon.vonhoff[at]outlook.com`. All
+reported by contacting the project team at `simon.vonhoff@outlook.com`. All
 complaints will be reviewed and investigated and will result in a response that
 is deemed necessary and appropriate to the circumstances. The project team is
 obligated to maintain confidentiality with regard to the reporter of an incident.

Demo/Form1.Designer.cs

@@ -35,6 +35,7 @@ public partial class Form1 : Form
         private RichTextBoxSinkOptions? _options;
         private RichTextBoxSink? _sink;
         private bool _toolbarsVisible = true;
+        private bool _prettyPrintJson = false;
 
         public Form1()
         {
@@ -47,7 +48,8 @@ private void Initialize()
             _options = new RichTextBoxSinkOptions(
                 theme: ThemePresets.Literate,
                 outputTemplate: "[{Timestamp:HH:mm:ss} {Level:u3}] {Message:l}{NewLine}{Exception}",
-                formatProvider: new CultureInfo("en-US"));
+                formatProvider: new CultureInfo("en-US"),
+                prettyPrintJson: _prettyPrintJson);
 
             _sink = new RichTextBoxSink(richTextBox1, _options);
             Log.Logger = new LoggerConfiguration()
@@ -77,6 +79,7 @@ private void Initialize()
 
             Log.Debug("Started logger.");
             btnDispose.Enabled = true;
+            btnPrettyPrint.Text = _prettyPrintJson ? "Disable Pretty Print" : "Enable Pretty Print";
         }
 
         private void Form1_Load(object sender, EventArgs e)
@@ -350,6 +353,18 @@ private void btnAutoScroll_Click(object sender, EventArgs e)
             btnAutoScroll.Text = _options.AutoScroll ? "Disable Auto Scroll" : "Enable Auto Scroll";
         }
 
+        private void btnPrettyPrint_Click(object sender, EventArgs e)
+        {
+            _prettyPrintJson = !_prettyPrintJson;
+            btnPrettyPrint.Text = _prettyPrintJson ? "Disable Pretty Print" : "Enable Pretty Print";
+            
+            // Recreate the sink and logger with new pretty print setting
+            CloseAndFlush();
+            Initialize();
+            
+            Log.Information("Pretty print JSON: {PrettyPrint}", _prettyPrintJson);
+        }
+
         private void Form1_KeyDown(object sender, KeyEventArgs e)
         {
             if (e.Control && e.KeyCode == Keys.T)

Demo/Form1.cs

@@ -15,9 +15,16 @@ A [Serilog](https://github.com/serilog/serilog) sink that writes log events to a
 - Multiple theme presets with customization options
 - High-performance asynchronous processing
 - Line limit to control memory usage
+- Pretty printing of JSON objects
 - WCAG compliant color schemes based on the [Serilog WPF RichTextBox](https://github.com/serilog-contrib/serilog-sinks-richtextbox) sink.
 
-## Get Started
+> **Consider supporting the development of this project on Ko-fi!**
+>
+> Your support keeps this project alive. Even a small gesture means a lot.
+>
+> [![ko-fi](https://ko-fi.com/img/githubbutton_sm.svg)](https://ko-fi.com/vonhoff)
+
+## Getting Started
 
 Install the package from NuGet:
 

README.md

@@ -2,7 +2,7 @@
 
 ## Reporting a Vulnerability
 
-If you find a security issue, please email `simon.vonhoff[at]outlook.com` with a description. Include a suggested fix if you have one.
+If you find a security issue, please email `simon.vonhoff@outlook.com` with a description. Include a suggested fix if you have one.
 
 We will review the report, release a fix or mitigation if needed, and credit you. Do **not** disclose the issue publicly until a fix is released. Once addressed, public disclosure is allowed.
 

SECURITY.md

@@ -1,4 +1,7 @@
+using System;
 using Serilog.Events;
+using Serilog.Sinks.RichTextBoxForms;
+using Serilog.Sinks.RichTextBoxForms.Themes;
 using Xunit;
 
 namespace Serilog.Tests.Integration
@@ -92,5 +95,163 @@ public void ControlCharacters_AreEscapedAsUnicode()
                 Assert.Equal(expected, RenderAndGetText(strEvent, "{Message:j}"));
             }
         }
+
+        [Fact]
+        public void PrettyPrintJson_FormatsNestedObjectsWithIndentation()
+        {
+            var nestedProp = new LogEventProperty("Nested", new StructureValue(new[]
+            {
+                new LogEventProperty("Id", new ScalarValue(123)),
+                new LogEventProperty("Name", new ScalarValue("test"))
+            }, "MyObj"));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{Nested:j}"), new[] { nestedProp });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "{\n    \"Id\": 123,\n    \"Name\": \"test\",\n    \"$type\": \"MyObj\"\n}";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_FormatsArraysWithIndentation()
+        {
+            var arrayProp = new LogEventProperty("Array", new SequenceValue(new[]
+            {
+                new ScalarValue(1),
+                new ScalarValue(2),
+                new ScalarValue(3)
+            }));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{Array:j}"), new[] { arrayProp });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "[\n    1,\n    2,\n    3\n]";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_FormatsDictionariesWithIndentation()
+        {
+            var dict = new Dictionary<ScalarValue, LogEventPropertyValue>
+            {
+                { new ScalarValue("a"), new ScalarValue(1) },
+                { new ScalarValue("b"), new ScalarValue("hello") }
+            };
+            var dictProp = new LogEventProperty("DictProp", new DictionaryValue(dict));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{DictProp:j}"), new[] { dictProp });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "{\n    \"a\": 1,\n    \"b\": \"hello\"\n}";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_FormatsNestedStructures()
+        {
+            var inner = new StructureValue(new[]
+            {
+                new LogEventProperty("Value", new ScalarValue(42))
+            }, "Inner");
+            var outer = new LogEventProperty("Outer", new StructureValue(new[]
+            {
+                new LogEventProperty("Inner", inner),
+                new LogEventProperty("Name", new ScalarValue("test"))
+            }, "Outer"));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{Outer:j}"), new[] { outer });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "{\n    \"Inner\": {\n        \"Value\": 42,\n        \"$type\": \"Inner\"\n    },\n    \"Name\": \"test\",\n    \"$type\": \"Outer\"\n}";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_EmptyCollectionsFormatCorrectly()
+        {
+            var emptyArray = new LogEventProperty("EmptyArray", new SequenceValue(Array.Empty<LogEventPropertyValue>()));
+            var emptyObject = new LogEventProperty("EmptyObject", new StructureValue(Array.Empty<LogEventProperty>(), null));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("Array: {EmptyArray:j}, Object: {EmptyObject:j}"), new[] { emptyArray, emptyObject });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            Assert.Contains("Array: []", result);
+            Assert.Contains("Object: {}", result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_UsesTabsWhenConfigured()
+        {
+            var prop = new LogEventProperty("Test", new StructureValue(new[]
+            {
+                new LogEventProperty("Id", new ScalarValue(123))
+            }, "MyObj"));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{Test:j}"), new[] { prop });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 4,
+                useSpacesForIndent: false);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "{\n\t\"Id\": 123,\n\t\"$type\": \"MyObj\"\n}";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void PrettyPrintJson_RespectsIndentSize()
+        {
+            var prop = new LogEventProperty("Test", new StructureValue(new[]
+            {
+                new LogEventProperty("Id", new ScalarValue(123))
+            }, "MyObj"));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("{Test:j}"), new[] { prop });
+
+            var options = new RichTextBoxSinkOptions(
+                theme: _defaultTheme,
+                prettyPrintJson: true,
+                indentSize: 2,
+                useSpacesForIndent: true);
+
+            var result = RenderAndGetText(logEvent, "{Message:l}", options);
+            var expected = "{\n  \"Id\": 123,\n  \"$type\": \"MyObj\"\n}";
+            Assert.Equal(expected, result);
+        }
+
+        [Fact]
+        public void CompactJson_StillWorksByDefault()
+        {
+            var complexProp = new LogEventProperty("ComplexProp", new StructureValue(new[] { new LogEventProperty("Id", new ScalarValue(123)) }, "MyObj"));
+            var logEvent = new LogEvent(DateTimeOffset.Now, LogEventLevel.Information, null, _parser.Parse("Value: {ComplexProp}"), new[] { complexProp });
+            
+            // Default behavior (compact)
+            Assert.Equal("Value: {\"Id\": 123, \"$type\": \"MyObj\"}", RenderAndGetText(logEvent, "{Message:j}"));
+        }
     }
 }

Serilog.Sinks.RichTextBox.WinForms.Colored.Test/Integration/JsonFormattingTests.cs

@@ -45,6 +45,14 @@ protected string RenderAndGetText(LogEvent logEvent, string outputTemplate, IFor
             return _richTextBox.Text.TrimEnd('\n', '\r');
         }
 
+        protected string RenderAndGetText(LogEvent logEvent, string outputTemplate, RichTextBoxSinkOptions options)
+        {
+            _richTextBox.Clear();
+            var renderer = new TemplateRenderer(options.Theme, outputTemplate, options.FormatProvider, options);
+            renderer.Render(logEvent, _canvas);
+            return _richTextBox.Text.TrimEnd('\n', '\r');
+        }
+
         public virtual void Dispose()
         {
             GC.SuppressFinalize(this);

Serilog.Sinks.RichTextBox.WinForms.Colored.Test/RichTextBoxSinkTestBase.cs

@@ -45,6 +45,9 @@ public static class RichTextBoxSinkLoggerConfigurationExtensions
         /// <param name="formatProvider">Format provider, or <c>null</c> for invariant culture.</param>
         /// <param name="minimumLogEventLevel">Minimum log level for events to be written.</param>
         /// <param name="levelSwitch">Optional switch to change the minimum log level at runtime.</param>
+        /// <param name="prettyPrintJson">If <c>true</c>, formats JSON values with indentation and line breaks. Defaults to <c>false</c>.</param>
+        /// <param name="indentSize">Number of spaces per indentation level when pretty printing JSON. Defaults to 4.</param>
+        /// <param name="useSpacesForIndent">If <c>true</c> (default), uses spaces for indentation; otherwise uses tabs.</param>
         /// <returns>The logger configuration, for chaining.</returns>
         public static LoggerConfiguration RichTextBox(
             this LoggerSinkConfiguration sinkConfiguration,
@@ -56,12 +59,15 @@ public static LoggerConfiguration RichTextBox(
             string outputTemplate = OutputTemplate,
             IFormatProvider? formatProvider = null,
             LogEventLevel minimumLogEventLevel = LogEventLevel.Verbose,
-            LoggingLevelSwitch? levelSwitch = null)
+            LoggingLevelSwitch? levelSwitch = null,
+            bool prettyPrintJson = false,
+            int indentSize = 4,
+            bool useSpacesForIndent = true)
         {
             var appliedTheme = theme ?? ThemePresets.Literate;
             var appliedFormatProvider = formatProvider ?? CultureInfo.InvariantCulture;
-            var renderer = new TemplateRenderer(appliedTheme, outputTemplate, appliedFormatProvider);
-            var options = new RichTextBoxSinkOptions(appliedTheme, autoScroll, maxLogLines, outputTemplate, appliedFormatProvider);
+            var options = new RichTextBoxSinkOptions(appliedTheme, autoScroll, maxLogLines, outputTemplate, appliedFormatProvider, prettyPrintJson, indentSize, useSpacesForIndent);
+            var renderer = new TemplateRenderer(appliedTheme, outputTemplate, appliedFormatProvider, options);
             richTextBoxSink = new RichTextBoxSink(richTextBoxControl, options, renderer);
             return sinkConfiguration.Sink(richTextBoxSink, minimumLogEventLevel, levelSwitch);
         }
@@ -78,6 +84,9 @@ public static LoggerConfiguration RichTextBox(
         /// <param name="formatProvider">Format provider, or <c>null</c> for invariant culture.</param>
         /// <param name="minimumLogEventLevel">Minimum log level for events to be written.</param>
         /// <param name="levelSwitch">Optional switch to change the minimum log level at runtime.</param>
+        /// <param name="prettyPrintJson">If <c>true</c>, formats JSON values with indentation and line breaks. Defaults to <c>false</c>.</param>
+        /// <param name="indentSize">Number of spaces per indentation level when pretty printing JSON. Defaults to 4.</param>
+        /// <param name="useSpacesForIndent">If <c>true</c> (default), uses spaces for indentation; otherwise uses tabs.</param>
         /// <returns>The logger configuration, for chaining.</returns>
         public static LoggerConfiguration RichTextBox(
             this LoggerSinkConfiguration sinkConfiguration,
@@ -88,7 +97,10 @@ public static LoggerConfiguration RichTextBox(
             string outputTemplate = OutputTemplate,
             IFormatProvider? formatProvider = null,
             LogEventLevel minimumLogEventLevel = LogEventLevel.Verbose,
-            LoggingLevelSwitch? levelSwitch = null)
+            LoggingLevelSwitch? levelSwitch = null,
+            bool prettyPrintJson = false,
+            int indentSize = 4,
+            bool useSpacesForIndent = true)
         {
             return RichTextBox(
                 sinkConfiguration,
@@ -100,7 +112,10 @@ public static LoggerConfiguration RichTextBox(
                 outputTemplate,
                 formatProvider,
                 minimumLogEventLevel,
-                levelSwitch);
+                levelSwitch,
+                prettyPrintJson,
+                indentSize,
+                useSpacesForIndent);
         }
     }
 }