Support multiple template paths and matching

src/OpenApiValidate/Helpers/OpenApiExtensions.cs

@@ -67,6 +67,7 @@ out IOpenApiPathItem path
     {
         var requestPathString = new PathString(requestPath);
 
+        TemplateMatchScore bestMatchScore = TemplateMatchScore.Min;
         IOpenApiPathItem? matchingTemplatePathItem = null;
 
         foreach (var kvp in paths)
@@ -80,7 +81,12 @@ out IOpenApiPathItem path
 
             if (isTemplatePath)
             {
-                matchingTemplatePathItem = kvp.Value;
+                var matchScore = GetTemplateMatchScore(specPath);
+                if (matchScore.BetterThan(bestMatchScore))
+                {
+                    bestMatchScore = matchScore;
+                    matchingTemplatePathItem = kvp.Value;
+                }
                 continue;
             }
 
@@ -98,6 +104,29 @@ out IOpenApiPathItem path
         return false;
     }
 
+    private static TemplateMatchScore GetTemplateMatchScore(PathString specPath)
+    {
+        var literalSegmentCount = 0;
+        var literalPrefixCount = 0;
+
+        for (var i = 0; i < specPath.Segments.Length; i++)
+        {
+            if (IsTemplateSegment(specPath.Segments[i]))
+            {
+                continue;
+            }
+
+            literalSegmentCount++;
+
+            if (literalPrefixCount == i)
+            {
+                literalPrefixCount++;
+            }
+        }
+
+        return new TemplateMatchScore(literalSegmentCount, literalPrefixCount);
+    }
+
     private static bool IsPathMatch(
         PathString specPath,
         PathString requestPath,
@@ -115,19 +144,14 @@ out bool isTemplatePath
         {
             var segment = specPath.Segments[i];
 
-            if (segment.StartsWith('{') && segment.EndsWith('}'))
+            if (IsTemplateSegment(segment))
             {
                 // Is template parameter, so skip checking
                 isTemplatePath = true;
                 continue;
             }
 
-            if (
-                !segment.Equals(
-                    requestPath.Segments[i],
-                    StringComparison.InvariantCultureIgnoreCase
-                )
-            )
+            if (!segment.Equals(requestPath.Segments[i], StringComparison.OrdinalIgnoreCase))
             {
                 isTemplatePath = false;
                 return false;
@@ -136,4 +160,26 @@ out bool isTemplatePath
 
         return true;
     }
+
+    private static bool IsTemplateSegment(string segment)
+    {
+        return segment.StartsWith('{') && segment.EndsWith('}');
+    }
+
+    private class TemplateMatchScore(int literalSegmentCount, int literalPrefixCount)
+    {
+        public static readonly TemplateMatchScore Min = new(int.MinValue, int.MinValue);
+
+        public int LiteralSegmentCount { get; } = literalSegmentCount;
+        public int LiteralPrefixCount { get; } = literalPrefixCount;
+
+        public bool BetterThan(TemplateMatchScore other)
+        {
+            return LiteralSegmentCount > other.LiteralSegmentCount
+                || (
+                    LiteralSegmentCount == other.LiteralSegmentCount
+                    && LiteralPrefixCount > other.LiteralPrefixCount
+                );
+        }
+    }
 }

test/OpenApiValidate.Tests/ResponseValidatorTests.cs

@@ -265,6 +265,48 @@ public async Task LiteralAndTemplatedPath_DeleteMeUser()
         validateAction.ShouldNotThrow();
     }
 
+    [Fact]
+    public async Task LiteralAndTemplatedPath_DeleteMeUserRole()
+    {
+        var openApiDocument = await GetDocument("TestData/LiteralAndTemplatedPath.yaml");
+
+        var validator = new OpenApiValidator(openApiDocument);
+
+        var request = new Request(
+            "DELETE",
+            new Uri("http://api.example.com/v1/user/me/role/admin")
+        );
+        var response = new Response(204);
+
+        var validateAction = () =>
+        {
+            validator.Validate(request, response);
+        };
+
+        validateAction.ShouldNotThrow();
+    }
+
+    [Fact]
+    public async Task LiteralAndTemplatedPath_DeleteMeUserRole_ReversedDefinitionOrder()
+    {
+        var openApiDocument = await GetDocument("TestData/LiteralAndTemplatedPathReversed.yaml");
+
+        var validator = new OpenApiValidator(openApiDocument);
+
+        var request = new Request(
+            "DELETE",
+            new Uri("http://api.example.com/v1/user/me/role/admin")
+        );
+        var response = new Response(204);
+
+        var validateAction = () =>
+        {
+            validator.Validate(request, response);
+        };
+
+        validateAction.ShouldNotThrow();
+    }
+
     private static async Task<OpenApiDocument> GetDocument(string filename)
     {
         var settings = new OpenApiReaderSettings();

test/OpenApiValidate.Tests/TestData/LiteralAndTemplatedPath.yaml

@@ -49,4 +49,37 @@ paths:
       summary: Deletes my user.
       responses:
         "204":
-          description: User deleted successfully
+          description: User deleted successfully
+
+  /user/me/role/{roleId}:
+    get:
+      summary: Returns a single role
+      responses:
+        "200":
+          description: A role object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+    delete:
+      summary: Deletes a role
+      responses:
+        "204":
+          description: Role deleted successfully
+
+  /user/{userId}/role/{roleId}:
+    get:
+      summary: Returns a single role
+      responses:
+        "200":
+          description: A role object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string

test/OpenApiValidate.Tests/TestData/LiteralAndTemplatedPathReversed.yaml

@@ -0,0 +1,85 @@
+openapi: 3.0.0
+
+info:
+  title: Sample API
+  description: Optional multiline or single-line description in [CommonMark](http://commonmark.org/help/) or HTML.
+  version: 0.1.9
+
+servers:
+  - url: http://api.example.com/v1
+    description: Optional server description, e.g. Main (production) server
+  - url: http://staging-api.example.com
+    description: Optional server description, e.g. Internal staging server for testing
+
+paths:
+  /user/{UserId}:
+    get:
+      summary: Returns a single user
+      parameters:
+        - name: UserId
+          in: path
+          required: true
+          schema:
+            type: string
+      responses:
+        "200":
+          description: A user object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+
+  /user/me:
+    get:
+      summary: Returns my user.
+      responses:
+        "200":
+          description: A user object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+    delete:
+      summary: Deletes my user.
+      responses:
+        "204":
+          description: User deleted successfully
+
+  /user/{userId}/role/{roleId}:
+    get:
+      summary: Returns a single role
+      responses:
+        "200":
+          description: A role object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+
+  /user/me/role/{roleId}:
+    get:
+      summary: Returns a single role
+      responses:
+        "200":
+          description: A role object
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  id:
+                    type: string
+    delete:
+      summary: Deletes a role
+      responses:
+        "204":
+          description: Role deleted successfully