Add PATCH endpoint documentation to minimal API tutorial

aspnetcore/tutorials/min-web-api.md

@@ -1,10 +1,11 @@
 ---
 title: "Tutorial: Create a Minimal API with ASP.NET Core"
 author: wadepickett
-description: Learn how to build a Minimal API with ASP.NET Core.
+description: Learn how to build a minimal API with ASP.NET Core.
+ai-usage: ai-assisted
 ms.author: wpickett
-ms.date: 07/29/2024
 ms.custom: engagement-fy24
+ms.date: 02/12/2026
 monikerRange: '>= aspnetcore-6.0'
 uid: tutorials/min-web-api
 ---
@@ -33,6 +34,7 @@ This tutorial creates the following API:
 | `GET /todoitems/{id}`                  | Get an item by ID              | None         | To-do item           |
 | `POST /todoitems`                      | Add a new item                 | To-do item   | To-do item           |
 | `PUT /todoitems/{id}`                  | Update an existing item   | To-do item   | None                 |
+| `PATCH /todoitems/{id}`                | Partially update an item  | Partial to-do item | None           |
 | `DELETE /todoitems/{id}`     | Delete an item       | None         | None                 |
 
 ## Prerequisites
@@ -513,6 +515,81 @@ Use Swagger to send a PUT request:
 
 ---
 
+## Examine the PATCH endpoint
+
+Create a file named `TodoPatchDto.cs` with the following code:
+
+:::code language="csharp" source="~/tutorials/min-web-api/samples/9.x/todo/TodoPatchDto.cs":::
+
+The `TodoPatchDto` class uses nullable properties (`string?` and `bool?`) to distinguish between a field that wasn't provided in the request versus a field explicitly set to a value.
+
+The sample app implements a single PATCH endpoint using `MapPatch`:
+
+[!code-csharp[](~/tutorials/min-web-api/samples/9.x/todo/Program.cs?name=snippet_patch)]
+
+This method is similar to the `MapPut` method, except it uses HTTP PATCH and only updates the fields provided in the request. A successful response returns [204 (No Content)](https://www.rfc-editor.org/rfc/rfc9110#status.204). According to the HTTP specification, a PATCH request enables partial updates, allowing clients to send only the fields that need to be changed.
+
+The PATCH endpoint uses a `TodoPatchDto` class with nullable properties to properly handle partial updates. Using nullable properties allows the endpoint to distinguish between a field that wasn't provided (null) versus a field explicitly set to a value (including false for boolean fields). Without nullable properties, a non-nullable bool would default to false, potentially overwriting an existing true value when that field wasn't included in the request.
+
+> [!NOTE]
+> PATCH operations allow partial updates to resources. For more advanced partial updates using JSON Patch documents, see <xref:web-api/jsonpatch>.
+
+## Test the PATCH endpoint
+
+This sample uses an in-memory database that must be initialized each time the app is started. There must be an item in the database before you make a PATCH call. Call GET to ensure there's an item in the database before making a PATCH call.
+
+Update only the `name` property of the to-do item that has `Id = 1` and set its name to `"run errands"`.
+
+# [Visual Studio](#tab/visual-studio)
+
+* In **Endpoints Explorer**, right-click the **PATCH** endpoint, and select **Generate request**.
+
+  The following content is added to the `TodoApi.http` file:
+
+  ```http
+  PATCH {{TodoApi_HostAddress}}/todoitems/{id}
+
+  ###
+  ```
+
+* In the PATCH request line, replace `{id}` with `1`.
+
+* Add the following lines immediately after the PATCH request line:
+
+  ```http
+  Content-Type: application/json
+
+  {
+    "name": "run errands"
+  }
+  ```
+
+  The preceding code adds a Content-Type header and a JSON request body with only the field to update.
+
+* Select the **Send request** link that is above the new PATCH request line.
+
+  The PATCH request is sent to the app and the response is displayed in the **Response** pane. The response body is empty, and the status code is 204.
+
+# [Visual Studio Code](#tab/visual-studio-code)
+
+Use Swagger to send a PATCH request:
+
+* Select **Patch /todoitems/{id}** > **Try it out**.
+
+* Set the **id** field to `1`.
+
+* Set the request body to the following JSON:
+
+  ```json
+  {
+    "name": "run errands"
+  }
+  ```
+
+* Select **Execute**.
+
+---
+
 ## Examine and test the DELETE endpoint
 
 The sample app implements a single DELETE endpoint using `MapDelete`:

aspnetcore/tutorials/min-web-api/includes/min-web-api6-7.md

@@ -15,6 +15,7 @@ This tutorial creates the following API:
 | `GET /todoitems/{id}`                  | Get an item by ID              | None         | To-do item           |
 | `POST /todoitems`                      | Add a new item                 | To-do item   | To-do item           |
 | `PUT /todoitems/{id}`                  | Update an existing item   | To-do item   | None                 |
+| `PATCH /todoitems/{id}`                | Partially update an item  | Partial to-do item | None           |
 | `DELETE /todoitems/{id}`     | Delete an item       | None         | None                 |
 
 ## Prerequisites
@@ -320,6 +321,47 @@ Use Swagger to send a PUT request:
 
 * Select **Execute**.
 
+## Examine the PATCH endpoint
+
+Create a file named `TodoPatchDto.cs` with the following code:
+
+:::code language="csharp" source="~/tutorials/min-web-api/samples/7.x/todo/TodoPatchDto.cs":::
+
+The `TodoPatchDto` class uses nullable properties (`string?` and `bool?`) to distinguish between a field that wasn't provided in the request versus a field explicitly set to a value.
+
+The sample app implements a single PATCH endpoint using `MapPatch`:
+
+[!code-csharp[](~/tutorials/min-web-api/samples/7.x/todo/Program.cs?name=snippet_patch)]
+
+This method is similar to the `MapPut` method, except it uses HTTP PATCH and only updates the fields provided in the request. A successful response returns [204 (No Content)](https://www.rfc-editor.org/rfc/rfc9110#status.204). According to the HTTP specification, a PATCH request enables partial updates, allowing clients to send only the fields that need to be changed.
+
+The PATCH endpoint uses a `TodoPatchDto` class with nullable properties to properly handle partial updates. Using nullable properties allows the endpoint to distinguish between a field that wasn't provided (null) versus a field explicitly set to a value (including false for boolean fields). Without nullable properties, a non-nullable bool would default to false, potentially overwriting an existing true value when that field wasn't included in the request.
+
+> [!NOTE]
+> PATCH operations allow partial updates to resources. For more advanced partial updates using JSON Patch documents, see <xref:web-api/jsonpatch>.
+
+## Test the PATCH endpoint
+
+This sample uses an in-memory database that must be initialized each time the app is started. There must be an item in the database before you make a PATCH call. Call GET to ensure there's an item in the database before making a PATCH call.
+
+Update only the `name` property of the to-do item that has `Id = 1` and set its name to `"run errands"`.
+
+Use Swagger to send a PATCH request:
+
+* Select **Patch /todoitems/{id}** > **Try it out**.
+
+* Set the **id** field to `1`.
+
+* Set the request body to the following JSON:
+
+  ```json
+  {
+    "name": "run errands"
+  }
+  ```
+
+* Select **Execute**.
+
 ## Examine and test the DELETE endpoint
 
 The sample app implements a single DELETE endpoint using `MapDelete`:

aspnetcore/tutorials/min-web-api/includes/min-web-api8.md

@@ -15,6 +15,7 @@ This tutorial creates the following API:
 | `GET /todoitems/{id}`                  | Get an item by ID              | None         | To-do item           |
 | `POST /todoitems`                      | Add a new item                 | To-do item   | To-do item           |
 | `PUT /todoitems/{id}`                  | Update an existing item   | To-do item   | None                 |
+| `PATCH /todoitems/{id}`                | Partially update an item  | Partial to-do item | None           |
 | `DELETE /todoitems/{id}`     | Delete an item       | None         | None                 |
 
 ## Prerequisites
@@ -491,6 +492,81 @@ Use Swagger to send a PUT request:
 
 ---
 
+## Examine the PATCH endpoint
+
+Create a file named `TodoPatchDto.cs` with the following code:
+
+:::code language="csharp" source="~/tutorials/min-web-api/samples/8.x/todo/TodoPatchDto.cs":::
+
+The `TodoPatchDto` class uses nullable properties (`string?` and `bool?`) to distinguish between a field that wasn't provided in the request versus a field explicitly set to a value.
+
+The sample app implements a single PATCH endpoint using `MapPatch`:
+
+[!code-csharp[](~/tutorials/min-web-api/samples/8.x/todo/Program.cs?name=snippet_patch)]
+
+This method is similar to the `MapPut` method, except it uses HTTP PATCH and only updates the fields provided in the request. A successful response returns [204 (No Content)](https://www.rfc-editor.org/rfc/rfc9110#status.204). According to the HTTP specification, a PATCH request enables partial updates, allowing clients to send only the fields that need to be changed.
+
+The PATCH endpoint uses a `TodoPatchDto` class with nullable properties to properly handle partial updates. Using nullable properties allows the endpoint to distinguish between a field that wasn't provided (null) versus a field explicitly set to a value (including false for boolean fields). Without nullable properties, a non-nullable bool would default to false, potentially overwriting an existing true value when that field wasn't included in the request.
+
+> [!NOTE]
+> PATCH operations allow partial updates to resources. For more advanced partial updates using JSON Patch documents, see <xref:web-api/jsonpatch>.
+
+## Test the PATCH endpoint
+
+This sample uses an in-memory database that must be initialized each time the app is started. There must be an item in the database before you make a PATCH call. Call GET to ensure there's an item in the database before making a PATCH call.
+
+Update only the `name` property of the to-do item that has `Id = 1` and set its name to `"run errands"`.
+
+# [Visual Studio](#tab/visual-studio)
+
+* In **Endpoints Explorer**, right-click the **PATCH** endpoint, and select **Generate request**.
+
+  The following content is added to the `TodoApi.http` file:
+
+  ```http
+  PATCH {{TodoApi_HostAddress}}/todoitems/{id}
+
+  ###
+  ```
+
+* In the PATCH request line, replace `{id}` with `1`.
+
+* Add the following lines immediately after the PATCH request line:
+
+  ```http
+  Content-Type: application/json
+
+  {
+    "name": "run errands"
+  }
+  ```
+
+  The preceding code adds a Content-Type header and a JSON request body with only the field to update.
+
+* Select the **Send request** link that is above the new PATCH request line.
+
+  The PATCH request is sent to the app and the response is displayed in the **Response** pane. The response body is empty, and the status code is 204.
+
+# [Visual Studio Code](#tab/visual-studio-code)
+
+Use Swagger to send a PATCH request:
+
+* Select **Patch /todoitems/{id}** > **Try it out**.
+
+* Set the **id** field to `1`.
+
+* Set the request body to the following JSON:
+
+  ```json
+  {
+    "name": "run errands"
+  }
+  ```
+
+* Select **Execute**.
+
+---
+
 ## Examine and test the DELETE endpoint
 
 The sample app implements a single DELETE endpoint using `MapDelete`:

aspnetcore/tutorials/min-web-api/samples/7.x/todo/Program.cs

@@ -1,4 +1,4 @@
-#define FINAL // MINIMAL FINAL TYPEDR
+#define FINAL // MINIMAL FINAL WITHPATCH TYPEDR
 #if MINIMAL
 // <snippet_min>
 var builder = WebApplication.CreateBuilder(args);
@@ -77,6 +77,77 @@ is Todo todo
 
 app.Run();
 // </snippet_all>
+#elif WITHPATCH
+using Microsoft.EntityFrameworkCore;
+
+var builder = WebApplication.CreateBuilder(args);
+builder.Services.AddDbContext<TodoDb>(opt => opt.UseInMemoryDatabase("TodoList"));
+builder.Services.AddDatabaseDeveloperPageExceptionFilter();
+var app = builder.Build();
+
+app.MapGet("/todoitems", async (TodoDb db) =>
+    await db.Todos.ToListAsync());
+
+app.MapGet("/todoitems/complete", async (TodoDb db) =>
+    await db.Todos.Where(t => t.IsComplete).ToListAsync());
+
+app.MapGet("/todoitems/{id}", async (int id, TodoDb db) =>
+    await db.Todos.FindAsync(id)
+        is Todo todo
+            ? Results.Ok(todo)
+            : Results.NotFound());
+
+app.MapPost("/todoitems", async (Todo todo, TodoDb db) =>
+{
+    db.Todos.Add(todo);
+    await db.SaveChangesAsync();
+
+    return Results.Created($"/todoitems/{todo.Id}", todo);
+});
+
+app.MapPut("/todoitems/{id}", async (int id, Todo inputTodo, TodoDb db) =>
+{
+    var todo = await db.Todos.FindAsync(id);
+
+    if (todo is null) return Results.NotFound();
+
+    todo.Name = inputTodo.Name;
+    todo.IsComplete = inputTodo.IsComplete;
+
+    await db.SaveChangesAsync();
+
+    return Results.NoContent();
+});
+
+// <snippet_patch>
+app.MapPatch("/todoitems/{id}", async (int id, TodoPatchDto inputTodo, TodoDb db) =>
+{
+    var todo = await db.Todos.FindAsync(id);
+
+    if (todo is null) return Results.NotFound();
+
+    if (inputTodo.Name is not null) todo.Name = inputTodo.Name;
+    if (inputTodo.IsComplete is not null) todo.IsComplete = inputTodo.IsComplete.Value;
+
+    await db.SaveChangesAsync();
+
+    return Results.NoContent();
+});
+// </snippet_patch>
+
+app.MapDelete("/todoitems/{id}", async (int id, TodoDb db) =>
+{
+    if (await db.Todos.FindAsync(id) is Todo todo)
+    {
+        db.Todos.Remove(todo);
+        await db.SaveChangesAsync();
+        return Results.NoContent();
+    }
+
+    return Results.NotFound();
+});
+
+app.Run();
 #elif TYPEDR
 using Microsoft.AspNetCore.Http.HttpResults;
 using Microsoft.EntityFrameworkCore;

aspnetcore/tutorials/min-web-api/samples/7.x/todo/TodoPatchDto.cs

@@ -0,0 +1,5 @@
+public class TodoPatchDto
+{
+    public string? Name { get; set; }
+    public bool? IsComplete { get; set; }
+}