Merge pull request #1563 from microsoft/mk/add-pattern-properties

Adds PatternProperties to the OpenAPI Schema

Author: MaggieKimani1

src/Microsoft.OpenApi.Readers/V31/JsonSchemaDeserializer.cs

@@ -167,6 +167,12 @@ internal static partial class OpenApiV31Deserializer
                     o.Properties(n.CreateMap(LoadSchema));
                 }
             },
+            {
+                "patternProperties", (o, n) =>
+                {
+                    o.PatternProperties(n.CreateMap(LoadSchema));
+                }
+            },
             {
                 "additionalProperties", (o, n) =>
                 {

src/Microsoft.OpenApi/Models/OpenApiConstants.cs

@@ -400,6 +400,11 @@ public static class OpenApiConstants
         /// </summary>
         public const string Properties = "properties";
 
+        /// <summary>
+        /// Field: Pattern Properties
+        /// </summary>
+        public const string PatternProperties = "patternProperties";
+
         /// <summary>
         /// Field: AdditionalProperties
         /// </summary>

src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs

@@ -1,10 +1,12 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text.Json;
+using System.Text.RegularExpressions;
 using Json.Schema;
 using Json.Schema.OpenApi;
 using Microsoft.OpenApi.Any;
@@ -536,6 +538,16 @@ public void WriteJsonSchemaWithoutReference(IOpenApiWriter writer, JsonSchema sc
             writer.WriteOptionalMap(OpenApiConstants.Properties, (IDictionary<string, JsonSchema>)schema.GetProperties(),
                 (w, key, s) => w.WriteJsonSchema(s, version));
 
+            // pattern properties
+            var patternProperties = schema?.GetPatternProperties();
+            var stringPatternProperties = patternProperties?.ToDictionary(
+                kvp => kvp.Key.ToString(),  // Convert Regex key to string
+                kvp => kvp.Value
+            );
+
+            writer.WriteOptionalMap(OpenApiConstants.PatternProperties, stringPatternProperties,
+                (w, key, s) => w.WriteJsonSchema(s, version));
+
             // additionalProperties
             if (schema.GetAdditionalPropertiesAllowed() ?? false)
             {

test/Microsoft.OpenApi.Readers.Tests/Microsoft.OpenApi.Readers.Tests.csproj

@@ -30,6 +30,7 @@
     <ItemGroup>
         <ProjectReference Include="..\..\src\Microsoft.OpenApi\Microsoft.OpenApi.csproj" />
         <ProjectReference Include="..\..\src\Microsoft.OpenApi.Readers\Microsoft.OpenApi.Readers.csproj" />
+        <ProjectReference Include="..\Microsoft.OpenApi.Tests\Microsoft.OpenApi.Tests.csproj" />
     </ItemGroup>
 
 </Project>

test/Microsoft.OpenApi.Readers.Tests/V31Tests/OpenApiDocumentTests.cs

@@ -3,8 +3,10 @@
 using System.IO;
 using FluentAssertions;
 using Json.Schema;
+using Microsoft.OpenApi.Extensions;
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.Tests;
 using Microsoft.OpenApi.Writers;
 using Xunit;
 
@@ -352,5 +354,49 @@ public void ParseDocumentWithExampleInSchemaShouldSucceed()
             // Assert
             Assert.NotNull(actual);
         }
+
+        [Fact]
+        public void ParseDocumentWithPatternPropertiesInSchemaWorks()
+        {
+            // Arrange
+            using var stream = Resources.GetStream(Path.Combine(SampleFolderPath, "docWithPatternPropertiesInSchema.yaml"));
+
+            // Act
+            var doc = new OpenApiStreamReader().Read(stream, out var diagnostic);
+
+            var actualSchema = doc.Paths["/example"].Operations[OperationType.Get].Responses["200"].Content["application/json"].Schema;
+
+            var expectedSchema = new JsonSchemaBuilder()
+                .Type(SchemaValueType.Object)
+                .Properties(
+                    ("prop1", new JsonSchemaBuilder().Type(SchemaValueType.String)),
+                    ("prop2", new JsonSchemaBuilder().Type(SchemaValueType.String)),
+                    ("prop3", new JsonSchemaBuilder().Type(SchemaValueType.String)))
+                .PatternProperties(
+                    ("^x-.*$", new JsonSchemaBuilder().Type(SchemaValueType.String)))
+                .Build();
+            
+            // Serialization
+            var mediaType = doc.Paths["/example"].Operations[OperationType.Get].Responses["200"].Content["application/json"];
+
+            var expectedMediaType = @"schema:
+  type: object
+  properties:
+    prop1:
+      type: string
+    prop2:
+      type: string
+    prop3:
+      type: string
+  patternProperties:
+    ^x-.*$:
+      type: string";
+            
+            var actualMediaType = mediaType.SerializeAsYaml(OpenApiSpecVersion.OpenApi3_1);
+
+            // Assert
+            actualSchema.Should().BeEquivalentTo(expectedSchema);
+            actualMediaType.MakeLineBreaksEnvironmentNeutral().Should().BeEquivalentTo(expectedMediaType.MakeLineBreaksEnvironmentNeutral());
+        }
     }
 }

test/Microsoft.OpenApi.Readers.Tests/V31Tests/Samples/OpenApiDocument/docWithPatternPropertiesInSchema.yaml

@@ -0,0 +1,25 @@
+openapi: 3.1.0
+info:
+  title: Example API
+  version: 1.0.0
+paths:
+  /example:
+    get:
+      summary: Get example object
+      responses:
+        '200':
+          description: Successful operation
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  prop1:
+                    type: string
+                  prop2:
+                    type: string
+                  prop3:
+                    type: string
+                patternProperties:
+                  "^x-.*$":
+                    type: string