Support custom data type for DataTypeAttribute (#3868)

Adds support for the `DataTypeAttribute` when a custom data type string is provided (e.g., `[DataType("uuid")]`). This will set the format property on the corresponding OpenAPI schema.

Author: tayfunyuksel

src/Swashbuckle.AspNetCore.SwaggerGen/SchemaGenerator/OpenApiSchemaExtensions.cs

@@ -173,6 +173,10 @@ private static void ApplyDataTypeAttribute(OpenApiSchema schema, DataTypeAttribu
         {
             schema.Format = format;
         }
+        else if (dataTypeAttribute.DataType == AnnotationsDataType.Custom)
+        {
+            schema.Format = dataTypeAttribute.CustomDataType;
+        }
     }
 
     private static void ApplyMinLengthAttribute(OpenApiSchema schema, MinLengthAttribute minLengthAttribute)

test/Swashbuckle.AspNetCore.SwaggerGen.Test/Fixtures/FakeController.cs

@@ -34,6 +34,9 @@ public void ActionWithParameterWithBindNeverAttribute([BindNever] string param)
     public void ActionWithParameterWithRequiredAttribute([Required] string param)
     { }
 
+    public void ActionWithParameterWithCustomDataTypeAttribute([DataType("uuid")] string param)
+    { }
+
     public void ActionWithParameterWithBindRequiredAttribute([BindRequired] string param)
     { }
 

test/Swashbuckle.AspNetCore.SwaggerGen.Test/SwaggerGenerator/OpenApiSchemaExtensionsTests.cs

@@ -134,6 +134,21 @@ public static void ApplyValidationAttributes_Handles_Invalid_RangeAttribute_Valu
         Assert.Null(schema.Maximum);
     }
 
+    [Fact]
+    public static void ApplyValidationAttributes_Handles_DataTypeAttribute_CustomDataType_Correctly()
+    {
+        // Arrange
+        string customDataType = "uuid";
+        var dataTypeAttribute = new DataTypeAttribute(customDataType);
+        var schema = new OpenApiSchema();
+
+        // Act
+        schema.ApplyValidationAttributes([dataTypeAttribute]);
+
+        // Assert
+        Assert.Equal(customDataType, schema.Format);
+    }
+
     private sealed class CultureSwitcher : IDisposable
     {
         private readonly CultureInfo _previous;

test/Swashbuckle.AspNetCore.SwaggerGen.Test/VerifyTests.cs

@@ -622,6 +622,33 @@ public async Task ApiParameterIsBoundToPath()
         await Verify(document);
     }
 
+    [Fact]
+    public async Task ActionWithCustomDataTypeQueryParameter()
+    {
+        var subject = Subject(
+            apiDescriptions:
+            [
+                ApiDescriptionFactory.Create(
+                    methodInfo: typeof(FakeController).GetMethod(nameof(FakeController.ActionWithParameterWithCustomDataTypeAttribute)),
+                    groupName: "v1",
+                    httpMethod: "POST",
+                    relativePath: "resource",
+                    parameterDescriptions:
+                    [
+                        new ApiParameterDescription
+                        {
+                            Name = "param",
+                            Source = BindingSource.Query
+                        }
+                    ])
+            ]
+        );
+
+        var document = subject.GetSwagger("v1");
+
+        await Verify(document);
+    }
+
     [Theory]
     [InlineData(nameof(FakeController.ActionWithParameterWithRequiredAttribute))]
     [InlineData(nameof(FakeController.ActionWithParameterWithBindRequiredAttribute))]

test/Swashbuckle.AspNetCore.SwaggerGen.Test/snapshots/10_0/VerifyTests.ActionWithCustomDataTypeQueryParameter.verified.txt

@@ -0,0 +1,37 @@
+{
+  "openapi": "3.0.4",
+  "info": {
+    "title": "Test API",
+    "version": "V1"
+  },
+  "paths": {
+    "/resource": {
+      "post": {
+        "tags": [
+          "Fake"
+        ],
+        "parameters": [
+          {
+            "name": "param",
+            "in": "query",
+            "schema": {
+              "type": "string",
+              "format": "uuid"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    }
+  },
+  "components": { },
+  "tags": [
+    {
+      "name": "Fake"
+    }
+  ]
+}

test/Swashbuckle.AspNetCore.SwaggerGen.Test/snapshots/8_0/VerifyTests.ActionWithCustomDataTypeQueryParameter.verified.txt

@@ -0,0 +1,37 @@
+{
+  "openapi": "3.0.4",
+  "info": {
+    "title": "Test API",
+    "version": "V1"
+  },
+  "paths": {
+    "/resource": {
+      "post": {
+        "tags": [
+          "Fake"
+        ],
+        "parameters": [
+          {
+            "name": "param",
+            "in": "query",
+            "schema": {
+              "type": "string",
+              "format": "uuid"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    }
+  },
+  "components": { },
+  "tags": [
+    {
+      "name": "Fake"
+    }
+  ]
+}

test/Swashbuckle.AspNetCore.SwaggerGen.Test/snapshots/9_0/VerifyTests.ActionWithCustomDataTypeQueryParameter.verified.txt

@@ -0,0 +1,37 @@
+{
+  "openapi": "3.0.4",
+  "info": {
+    "title": "Test API",
+    "version": "V1"
+  },
+  "paths": {
+    "/resource": {
+      "post": {
+        "tags": [
+          "Fake"
+        ],
+        "parameters": [
+          {
+            "name": "param",
+            "in": "query",
+            "schema": {
+              "type": "string",
+              "format": "uuid"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    }
+  },
+  "components": { },
+  "tags": [
+    {
+      "name": "Fake"
+    }
+  ]
+}