Fix MappingMatcher in case of an exception in LinqMatcher. (#322)

* Fix MappingMatcher in case of an exception in LinqMatcher.

* update unit-tests

src/WireMock.Net/Matchers/LinqMatcher.cs

@@ -56,18 +56,32 @@ public LinqMatcher(MatchBehaviour matchBehaviour, [NotNull] string[] patterns)
         /// <inheritdoc cref="IStringMatcher.IsMatch"/>
         public double IsMatch(string input)
         {
+            double match = MatchScores.Mismatch;
+
             // Convert a single input string to a Queryable string-list with 1 entry.
             IQueryable queryable = new[] { input }.AsQueryable();
 
-            // Use the Any(...) method to check if the result matches
-            double match = MatchScores.ToScore(_patterns.Select(pattern => queryable.Any(pattern)));
+            try
+            {
+                // Use the Any(...) method to check if the result matches
+                match = MatchScores.ToScore(_patterns.Select(pattern => queryable.Any(pattern)));
+
+                return MatchBehaviourHelper.Convert(MatchBehaviour, match);
+            }
+            catch
+            {
+                // just ignore exception
+                // TODO add logging?
+            }
 
             return MatchBehaviourHelper.Convert(MatchBehaviour, match);
         }
 
         /// <inheritdoc cref="IObjectMatcher.IsMatch"/>
         public double IsMatch(object input)
         {
+            double match = MatchScores.Mismatch;
+
             JObject value;
             switch (input)
             {
@@ -83,16 +97,27 @@ public double IsMatch(object input)
             // Convert a single object to a Queryable JObject-list with 1 entry.
             var queryable1 = new[] { value }.AsQueryable();
 
-            // Generate the DynamicLinq select statement.
-            string dynamicSelect = JsonUtils.GenerateDynamicLinqStatement(value);
+            try
+            {
+                // Generate the DynamicLinq select statement.
+                string dynamicSelect = JsonUtils.GenerateDynamicLinqStatement(value);
+
+                // Execute DynamicLinq Select statement.
+                var queryable2 = queryable1.Select(dynamicSelect);
 
-            // Execute DynamicLinq Select statement.
-            var queryable2 = queryable1.Select(dynamicSelect);
+                // Use the Any(...) method to check if the result matches.
+                match = MatchScores.ToScore(_patterns.Select(pattern => queryable2.Any(pattern)));
 
-            // Use the Any(...) method to check if the result matches.
-            double match = MatchScores.ToScore(_patterns.Select(pattern => queryable2.Any(pattern)));
+                return MatchBehaviourHelper.Convert(MatchBehaviour, match);
+            }
+            catch
+            {
+                // just ignore exception
+                // TODO add logging?
+            }
 
             return MatchBehaviourHelper.Convert(MatchBehaviour, match);
+
         }
 
         /// <inheritdoc cref="IStringMatcher.GetPatterns"/>

src/WireMock.Net/Matchers/XPathMatcher.cs

@@ -59,6 +59,7 @@ public double IsMatch(string input)
                 catch (Exception)
                 {
                     // just ignore exception
+                    // TODO add logging?
                 }
             }
 

src/WireMock.Net/Owin/IMappingMatcher.cs

@@ -1,9 +1,7 @@
-using WireMock.Matchers.Request;
-
-namespace WireMock.Owin
+namespace WireMock.Owin
 {
     internal interface IMappingMatcher
     {
-        (IMapping Mapping, RequestMatchResult RequestMatchResult) Match(RequestMessage request);
+        MappingMatcherResult FindBestMatch(RequestMessage request);
     }
 }

src/WireMock.Net/Owin/MappingMatcher.cs

@@ -1,5 +1,6 @@
-using System.Linq;
-using WireMock.Matchers.Request;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using WireMock.Validation;
 
 namespace WireMock.Owin
@@ -15,34 +16,41 @@ public MappingMatcher(IWireMockMiddlewareOptions options)
             _options = options;
         }
 
-        public (IMapping Mapping, RequestMatchResult RequestMatchResult) Match(RequestMessage request)
+        public MappingMatcherResult FindBestMatch(RequestMessage request)
         {
-            var mappings = _options.Mappings.Values
-                .Select(m => new
+            var mappings = new List<MappingMatcherResult>();
+            foreach (var mapping in _options.Mappings.Values)
+            {
+                try
+                {
+                    string scenario = mapping.Scenario != null && _options.Scenarios.ContainsKey(mapping.Scenario) ? _options.Scenarios[mapping.Scenario].NextState : null;
+
+                    mappings.Add(new MappingMatcherResult
+                    {
+                        Mapping = mapping,
+                        RequestMatchResult = mapping.GetRequestMatchResult(request, scenario)
+                    });
+                }
+                catch (Exception ex)
                 {
-                    Mapping = m,
-                    MatchResult = m.GetRequestMatchResult(request, m.Scenario != null && _options.Scenarios.ContainsKey(m.Scenario) ? _options.Scenarios[m.Scenario].NextState : null)
-                })
-                .ToList();
+                    _options.Logger.Error($"Getting a Request MatchResult for Mapping '{mapping.Guid}' failed. This mapping will not be evaluated. Exception: {ex}");
+                }
+            }
 
             if (_options.AllowPartialMapping)
             {
                 var partialMappings = mappings
-                    .Where(pm => (pm.Mapping.IsAdminInterface && pm.MatchResult.IsPerfectMatch) || !pm.Mapping.IsAdminInterface)
-                    .OrderBy(m => m.MatchResult)
+                    .Where(pm => (pm.Mapping.IsAdminInterface && pm.RequestMatchResult.IsPerfectMatch) || !pm.Mapping.IsAdminInterface)
+                    .OrderBy(m => m.RequestMatchResult)
                     .ThenBy(m => m.Mapping.Priority)
                     .ToList();
 
-                var bestPartialMatch = partialMappings.FirstOrDefault(pm => pm.MatchResult.AverageTotalScore > 0.0);
-
-                return (bestPartialMatch?.Mapping, bestPartialMatch?.MatchResult);
+                return partialMappings.FirstOrDefault(pm => pm.RequestMatchResult.AverageTotalScore > 0.0);
             }
 
-            var perfectMatch = mappings
+            return mappings
                 .OrderBy(m => m.Mapping.Priority)
-                .FirstOrDefault(m => m.MatchResult.IsPerfectMatch);
-
-            return (perfectMatch?.Mapping, perfectMatch?.MatchResult);
+                .FirstOrDefault(m => m.RequestMatchResult.IsPerfectMatch);
         }
     }
-}
+}

src/WireMock.Net/Owin/MappingMatcherResult.cs

@@ -0,0 +1,11 @@
+using WireMock.Matchers.Request;
+
+namespace WireMock.Owin
+{
+    internal class MappingMatcherResult
+    {
+        public IMapping Mapping { get; set; }
+
+        public RequestMatchResult RequestMatchResult { get; set; }
+    }
+}

src/WireMock.Net/Owin/WireMockMiddleware.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Threading.Tasks;
 using WireMock.Logging;
-using WireMock.Matchers.Request;
 using System.Linq;
 using WireMock.Matchers;
 using WireMock.Util;
@@ -74,7 +73,7 @@ private async Task InvokeInternal(IContext ctx)
 
             bool logRequest = false;
             ResponseMessage response = null;
-            (IMapping TargetMapping, RequestMatchResult RequestMatchResult) result = (null, null);
+            MappingMatcherResult result = null;
             try
             {
                 foreach (var mapping in _options.Mappings.Values.Where(m => m?.Scenario != null))
@@ -89,9 +88,9 @@ private async Task InvokeInternal(IContext ctx)
                     }
                 }
 
-                result = _mappingMatcher.Match(request);
-                var targetMapping = result.TargetMapping;
+                result = _mappingMatcher.FindBestMatch(request);
 
+                var targetMapping = result?.Mapping;
                 if (targetMapping == null)
                 {
                     logRequest = true;
@@ -129,7 +128,7 @@ private async Task InvokeInternal(IContext ctx)
             }
             catch (Exception ex)
             {
-                _options.Logger.Error($"Providing a Response for Mapping '{result.TargetMapping.Guid}' failed. HttpStatusCode set to 500. Exception: {ex}");
+                _options.Logger.Error($"Providing a Response for Mapping '{result?.Mapping?.Guid}' failed. HttpStatusCode set to 500. Exception: {ex}");
                 response = ResponseMessageBuilder.Create(JsonConvert.SerializeObject(ex), 500);
             }
             finally
@@ -139,9 +138,9 @@ private async Task InvokeInternal(IContext ctx)
                     Guid = Guid.NewGuid(),
                     RequestMessage = request,
                     ResponseMessage = response,
-                    MappingGuid = result.TargetMapping?.Guid,
-                    MappingTitle = result.TargetMapping?.Title,
-                    RequestMatchResult = result.RequestMatchResult
+                    MappingGuid = result?.Mapping?.Guid,
+                    MappingTitle = result?.Mapping?.Title,
+                    RequestMatchResult = result?.RequestMatchResult
                 };
 
                 LogRequest(log, logRequest);

test/WireMock.Net.Tests/Owin/MappingMatcherTests.cs

@@ -14,7 +14,7 @@ namespace WireMock.Net.Tests.Owin
     public class MappingMatcherTests
     {
         private readonly Mock<IWireMockMiddlewareOptions> _optionsMock;
-        private readonly IMappingMatcher _sut;
+        private readonly MappingMatcher _sut;
 
         public MappingMatcherTests()
         {
@@ -24,25 +24,50 @@ public MappingMatcherTests()
             _optionsMock.Setup(o => o.LogEntries).Returns(new ConcurrentObservableCollection<LogEntry>());
             _optionsMock.Setup(o => o.Scenarios).Returns(new ConcurrentDictionary<string, ScenarioState>());
 
+            var loggerMock = new Mock<IWireMockLogger>();
+            loggerMock.SetupAllProperties();
+            loggerMock.Setup(l => l.Error(It.IsAny<string>()));
+            _optionsMock.Setup(o => o.Logger).Returns(loggerMock.Object);
+
             _sut = new MappingMatcher(_optionsMock.Object);
         }
 
         [Fact]
-        public void MappingMatcher_Match_NoMappingsDefined()
+        public void MappingMatcher_FindBestMatch_WhenNoMappingsDefined_ShouldReturnNull()
+        {
+            // Assign
+            var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "GET", "::1");
+
+            // Act
+            var result = _sut.FindBestMatch(request);
+
+            // Assert and Verify
+            Check.That(result).IsNull();
+        }
+
+        [Fact]
+        public void MappingMatcher_FindBestMatch_WhenMappingThrowsException_ShouldReturnNull()
         {
             // Assign
+            var mappingMock = new Mock<IMapping>();
+            mappingMock.Setup(m => m.GetRequestMatchResult(It.IsAny<RequestMessage>(), It.IsAny<string>())).Throws<Exception>();
+
+            var mappings = new ConcurrentDictionary<Guid, IMapping>();
+            mappings.TryAdd(Guid.NewGuid(), mappingMock.Object);
+
+            _optionsMock.Setup(o => o.Mappings).Returns(mappings);
+
             var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "GET", "::1");
 
             // Act
-            var result = _sut.Match(request);
+            var result = _sut.FindBestMatch(request);
 
             // Assert and Verify
-            Check.That(result.Mapping).IsNull();
-            Check.That(result.RequestMatchResult).IsNull();
+            Check.That(result).IsNull();
         }
 
         [Fact]
-        public void MappingMatcher_Match_GetBestMapping_Exact()
+        public void MappingMatcher_FindBestMatch_WhenAllowPartialMappingIsFalse_ShouldReturnExactMatch()
         {
             // Assign
             var mappings = InitMappings(new[] { (Guid.Parse("00000000-0000-0000-0000-000000000001"), 0.1), (Guid.Parse("00000000-0000-0000-0000-000000000002"), 1.0) });
@@ -51,15 +76,15 @@ public void MappingMatcher_Match_GetBestMapping_Exact()
             var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "GET", "::1");
 
             // Act
-            var result = _sut.Match(request);
+            var result = _sut.FindBestMatch(request);
 
             // Assert and Verify
             Check.That(result.Mapping.Guid).IsEqualTo(Guid.Parse("00000000-0000-0000-0000-000000000002"));
             Check.That(result.RequestMatchResult.AverageTotalScore).IsEqualTo(1.0);
         }
 
         [Fact]
-        public void MappingMatcher_Match_GetBestMapping_AllowPartialMapping()
+        public void MappingMatcher_FindBestMatch_WhenAllowPartialMappingIsTrue_ShouldReturnAnyMatch()
         {
             // Assign
             _optionsMock.SetupGet(o => o.AllowPartialMapping).Returns(true);
@@ -69,7 +94,7 @@ public void MappingMatcher_Match_GetBestMapping_AllowPartialMapping()
             var request = new RequestMessage(new UrlDetails("http://localhost/foo"), "GET", "::1");
 
             // Act
-            var result = _sut.Match(request);
+            var result = _sut.FindBestMatch(request);
 
             // Assert and Verify
             Check.That(result.Mapping.Guid).IsEqualTo(Guid.Parse("00000000-0000-0000-0000-000000000002"));

test/WireMock.Net.Tests/Owin/WireMockMiddlewareTests.cs

@@ -11,7 +11,6 @@
 using WireMock.Util;
 using WireMock.Admin.Requests;
 using WireMock.Logging;
-using WireMock.Matchers.Request;
 using WireMock.Matchers;
 using System.Collections.Generic;
 #if NET452
@@ -61,7 +60,7 @@ public WireMockMiddlewareTests()
 
             _matcherMock = new Mock<IMappingMatcher>();
             _matcherMock.SetupAllProperties();
-            _matcherMock.Setup(m => m.Match(It.IsAny<RequestMessage>())).Returns(((IMapping)null, (RequestMatchResult)null));
+            _matcherMock.Setup(m => m.FindBestMatch(It.IsAny<RequestMessage>())).Returns(new MappingMatcherResult());
 
             _contextMock = new Mock<IContext>();
 
@@ -92,7 +91,7 @@ public async void WireMockMiddleware_Invoke_IsAdminInterface_EmptyHeaders_401()
 
             _optionsMock.SetupGet(o => o.AuthorizationMatcher).Returns(new ExactMatcher());
             _mappingMock.SetupGet(m => m.IsAdminInterface).Returns(true);
-            _matcherMock.Setup(m => m.Match(It.IsAny<RequestMessage>())).Returns((_mappingMock.Object, (RequestMatchResult)null));
+            _matcherMock.Setup(m => m.FindBestMatch(It.IsAny<RequestMessage>())).Returns(new MappingMatcherResult { Mapping = _mappingMock.Object });
 
             // Act
             await _sut.Invoke(_contextMock.Object);
@@ -113,7 +112,7 @@ public async void WireMockMiddleware_Invoke_IsAdminInterface_MissingHeader_401()
 
             _optionsMock.SetupGet(o => o.AuthorizationMatcher).Returns(new ExactMatcher());
             _mappingMock.SetupGet(m => m.IsAdminInterface).Returns(true);
-            _matcherMock.Setup(m => m.Match(It.IsAny<RequestMessage>())).Returns((_mappingMock.Object, (RequestMatchResult)null));
+            _matcherMock.Setup(m => m.FindBestMatch(It.IsAny<RequestMessage>())).Returns(new MappingMatcherResult { Mapping = _mappingMock.Object });
 
             // Act
             await _sut.Invoke(_contextMock.Object);