Optional values in rule formatter.

backend/src/Squidex.Domain.Apps.Core.Operations/HandleRules/RuleEventFormatter.cs

@@ -29,7 +29,7 @@ namespace Squidex.Domain.Apps.Core.HandleRules
     {
         private const string Fallback = "null";
         private static readonly Regex RegexPatternOld = new Regex(@"^(?<FullPath>(?<Type>[^_]*)_(?<Path>[^\s]*))", RegexOptions.Compiled);
-        private static readonly Regex RegexPatternNew = new Regex(@"^\{(?<FullPath>(?<Type>[\w]*)_(?<Path>[\w\.\-]*))[\s]*(\|[\s]*(?<Transform>[^\}]*)){0,1}\}", RegexOptions.Compiled);
+        private static readonly Regex RegexPatternNew = new Regex(@"^\{(?<FullPath>(?<Type>[\w]+)_(?<Path>[\w\.\-]+))[\s]*(\|[\s]*(?<Transform>[^\?}]+))?(\?[\s]*(?<Fallback>[^\}\s]+))?[\s]*\}", RegexOptions.Compiled);
         private readonly List<(string Pattern, Func<EnrichedEvent, string?> Replacer)> patterns = new List<(string Pattern, Func<EnrichedEvent, string?> Replacer)>();
         private readonly IJsonSerializer jsonSerializer;
         private readonly IUrlGenerator urlGenerator;
@@ -153,7 +153,19 @@ namespace Squidex.Domain.Apps.Core.HandleRules
                     (length, text) = ResolveFromPath(match, @event);
                 }
 
-                return (TransformText(text, match.Groups["Transform"]?.Value), length);
+                var result = TransformText(text, match.Groups["Transform"]?.Value);
+
+                if (result == null)
+                {
+                    result = match.Groups["Fallback"]?.Value;
+                }
+
+                if (string.IsNullOrEmpty(result))
+                {
+                    result = Fallback;
+                }
+
+                return (result, length);
             }
 
             return (Fallback, 0);
@@ -327,7 +339,7 @@ namespace Squidex.Domain.Apps.Core.HandleRules
             return null;
         }
 
-        private static string TransformText(string? text, string? transform)
+        private static string? TransformText(string? text, string? transform)
         {
             if (text != null && !string.IsNullOrWhiteSpace(transform))
             {
@@ -357,7 +369,7 @@ namespace Squidex.Domain.Apps.Core.HandleRules
                 }
             }
 
-            return text ?? Fallback;
+            return text;
         }
 
         private (int Length, string? Result) ResolveFromPath(Match match, EnrichedEvent @event)

backend/tests/Squidex.Domain.Apps.Core.Tests/Operations/HandleRules/RuleEventFormatterTests.cs

@@ -489,44 +489,26 @@ namespace Squidex.Domain.Apps.Core.Operations.HandleRules
             Assert.Equal("From client:android", result);
         }
 
-        [Fact]
-        public void Should_format_json()
-        {
-            var @event = new EnrichedContentEvent { Actor = new RefToken(RefTokenType.Client, "android") };
-
-            var result = sut.Format("Script(JSON.stringify({ actor: event.actor.toString() }))", @event);
-
-            Assert.Equal("{\"actor\":\"client:android\"}", result);
-        }
-
-        [Fact]
-        public void Should_format_json_with_special_characters()
-        {
-            var @event = new EnrichedContentEvent { Actor = new RefToken(RefTokenType.Client, "mobile\"android") };
-
-            var result = sut.Format("Script(JSON.stringify({ actor: event.actor.toString() }))", @event);
-
-            Assert.Equal("{\"actor\":\"client:mobile\\\"android\"}", result);
-        }
-
-        [Fact]
-        public void Should_evaluate_script_if_starting_with_whitespace()
+        [Theory]
+        [InlineData("${EVENT_INVALID ? file}", "file")]
+        public void Should_provide_fallback_if_path_is_invalid(string script, string expect)
         {
-            var @event = new EnrichedContentEvent { Type = EnrichedContentEventType.Created };
+            var @event = new EnrichedAssetEvent { FileName = null! };
 
-            var result = sut.Format(" Script(`${event.type}`)", @event);
+            var result = sut.Format(script, @event);
 
-            Assert.Equal("Created", result);
+            Assert.Equal(expect, result);
         }
 
-        [Fact]
-        public void Should_evaluate_script_if_ends_with_whitespace()
+        [Theory]
+        [InlineData("${ASSET_FILENAME ? file}", "file")]
+        public void Should_provide_fallback_if_value_is_null(string script, string expect)
         {
-            var @event = new EnrichedContentEvent { Type = EnrichedContentEventType.Created };
+            var @event = new EnrichedAssetEvent { FileName = null! };
 
-            var result = sut.Format("Script(`${event.type}`) ", @event);
+            var result = sut.Format(script, @event);
 
-            Assert.Equal("Created", result);
+            Assert.Equal(expect, result);
         }
 
         [Theory]
@@ -588,5 +570,45 @@ namespace Squidex.Domain.Apps.Core.Operations.HandleRules
 
             Assert.Equal(expect, result);
         }
+
+        [Fact]
+        public void Should_format_json()
+        {
+            var @event = new EnrichedContentEvent { Actor = new RefToken(RefTokenType.Client, "android") };
+
+            var result = sut.Format("Script(JSON.stringify({ actor: event.actor.toString() }))", @event);
+
+            Assert.Equal("{\"actor\":\"client:android\"}", result);
+        }
+
+        [Fact]
+        public void Should_format_json_with_special_characters()
+        {
+            var @event = new EnrichedContentEvent { Actor = new RefToken(RefTokenType.Client, "mobile\"android") };
+
+            var result = sut.Format("Script(JSON.stringify({ actor: event.actor.toString() }))", @event);
+
+            Assert.Equal("{\"actor\":\"client:mobile\\\"android\"}", result);
+        }
+
+        [Fact]
+        public void Should_evaluate_script_if_starting_with_whitespace()
+        {
+            var @event = new EnrichedContentEvent { Type = EnrichedContentEventType.Created };
+
+            var result = sut.Format(" Script(`${event.type}`)", @event);
+
+            Assert.Equal("Created", result);
+        }
+
+        [Fact]
+        public void Should_evaluate_script_if_ends_with_whitespace()
+        {
+            var @event = new EnrichedContentEvent { Type = EnrichedContentEventType.Created };
+
+            var result = sut.Format("Script(`${event.type}`) ", @event);
+
+            Assert.Equal("Created", result);
+        }
     }
 }