• .NET
  • C#
  • ASP.NET Core

Related code examples

.NET 6 Minimal APIs sample using ASP.NET Core
.NET 6 Minimal APIs sample using ASP.NET Core

Minimal API code example for ASP.NET Core

We have a number of minimal API tutorials which include creating routes, adding parameters, how to return a result, filters, authentication and unit testing.

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The code example will be in a zip file and will include all the minimal API tutorials separated by a numeric folder name.

Software

This is the software that will need to be installed onto your machine.

Tutorials

Here are the different minimal API tutorials available:

How to use routing in Minimal APIs with one line of code

You can read more about how you create a route with one line of code or watch the video:

In Visual Studio, open up 01/RoundTheCode.MinimalApi._01.sln from the code example zip file that you downloaded.

You can test out the different ways of registering minimal API routes by changing the toDoRoutes variable in Program.cs. You can change it to:

  • Program_cs - This adds the routes in Program.cs
  • ToDoEndpoints - This adds the routes in the ToDoEndpoints class. This is the default.

Run the application and it will load up the Scalar OpenAPI document on https://localhost:8402/scalar/v1.

For mapping multiple methods in the same routes and the different ways to return a response, here is what you can test:

  • Hello world - https://localhost:8402/hello-world
  • Hello world with GET and HEAD HTTP requests in the same route - https://localhost:8402/hello-world/get-head
  • Hello world using a local function - https://localhost:8402/hello-world/local
  • Hello world using a class instance - https://localhost:8402/hello-world/class-instance
  • Hello world using a static method - https://localhost:8402/hello-world/static

For the different ToDo routes, here is what you can test:

  • Gets a ToDo item - https://localhost:8402/todo/{id} - GET
  • Creates a ToDo item - https://localhost:8402/todo - POST
    • Body: { "text": "{Text}" }
  • Updates a ToDo item - https://localhost:8402/todo/{id} - PUT
    • Body: { "text": "{Text}" }
  • Deletes a ToDo item - https://localhost:8402/todo/{id} - DELETE

To test out the different ToDo routes in a group, here is what you can test:

  • Gets a ToDo item - https://localhost:8402/todo-group/{id} - GET
  • Creates a ToDo item - https://localhost:8402/todo-group - POST
    • Body: { "text": "{Text}" }
  • Updates a ToDo item - https://localhost:8402/todo-group/{id} - PUT
    • Body: { "text": "{Text}" }
  • Deletes a ToDo item - https://localhost:8402/todo-group/{id} - DELETE

How to use parameter binding for routes in Minimal APIs

You can read more about parameter binding with minimal API routes or watch the video:

In Visual Studio, open up 02/RoundTheCode.MinimalApi._02.sln from the code example zip file that you downloaded.

Run the application and it will load up the Scalar OpenAPI document on https://localhost:8402/scalar/v1.

Here is what you can test:

  • Route parameter binding - https://localhost:8402/todo/{id} - GET
  • Query string parameter binding - https://localhost:8402/todo?id={id} - GET
  • Route and query string parameter binding - https://localhost:8402/todo/from/{id}?id={id} - GET
  • AsParameters attribute - https://localhost:8402/todo/params/{id} - GET
    • Optional page query string
    • Optional type query string
    • Optional api-key request header
  • Wildcard route parameter - https://localhost:8402/todo/wildcard/{*slug} - GET
  • Regex route constraint - https://localhost:8402/todo/regex-wildcard/{*slug:regex(^[a-z0-9_-]+$)} - GET
  • Use HttpContext in a minimal api - https://localhost:8402/hello-world - GET
  • Route with a name - https://localhost:8402/my-link - GET
  • Get the link with a name - https://localhost:8402/get-my-link - GET
  • Form values - https://localhost:8402/form-values - POST
    • multipart/form-data
    • Supply keys and values and see them outputted as part of the response
  •  Upload a singular file - https://localhost:8402/upload-file - POST
    • multipart/form-data
    • Supply the file key with the file to upload. Use the Scalar document to do this and it will upload it to the uploads folder in your application.
  • Upload multiple files - https://localhost:8402/upload-files - POST
    • multipart/form-data
    • Supply files[*] with the files to upload. Replace * with the index number e.g. files[0]. Use the Scalar document to do this and it will upload each file to the uploads folder in your application.

TypedResults or Results for Minimal API responses?

You can read more about whether to use TypedResults or Results for minimal API responses or watch the video:

In Visual Studio, open up 03/RoundTheCode.MinimalApi._03.sln from the code example zip file that you downloaded.

Run the application and it will load up the Scalar OpenAPI document on https://localhost:8402/scalar/v1.

Here is what you can test. All of these endpoints use the GET request:

  • Using the Results type with no expected Body response in the OpenAPI documentation - https://localhost:8402/product/results
  • Using the TypedResults type with an expected ProductDto response in the OpenAPI documentation - https://localhost:8402/product/typed-results
  • A JSON response - https://localhost:8402/json
  • A JSON response changing the naming policy to snake case upper - https://localhost:8402/json-snakecaseupper
  • A status code response returning a 418 I'm a Teapot response - https://localhost:8402/status-code
  • An internal server error response - https://localhost:8402/internal-server-error
  • A problem response - https://localhost:8402/problem
  • A validation problem response - https://localhost:8402/validation-problem
  • A text response - https://localhost:8402/robots.txt
  • A 301 permanent redirect to /robots.txt - https://localhost:8402/permanent-redirect
  • A 302 temporary redirect to /robots.txt - https://localhost:8402/temporary-redirect
  • Returns a file using Results.File - https://localhost:8402/file
  • Returns a file using TypedResults.File - https://localhost:8402/file-from-stream
  • Returns either an Ok or NotFound response type - https://localhost:8402/different-responses/{id}
    • Will return an Ok response if the Id is 1 or less.
    • Will return a NotFound response if the Id is greater than 1.

Minimal API filters: Run code before the endpoint handler

You can read more about minimal API filters or watch the video:

In Visual Studio, open up 04/RoundTheCode.MinimalApi._04.sln from the code example zip file that you downloaded.

Run the application and it will load up the Scalar OpenAPI document on https://localhost:8402/scalar/v1.

Here is what you can test. All of these endpoints use the GET request:

  • Using filters in controllers - https://localhost:8402/api/Product/{id}
    • Will return an Ok response if the Id is 9 or less.
    • Will return a NotFound response if the Id is greater than 9.
  • Add an endpoint filter in a minimal API - https://localhost:8402/api/product-minimal/{id}
    • Will return an Ok response if the Id is 9 or less.
    • Will return a NotFound response if the Id is greater than 9.
  • Multiple endpoint filters in a minimal API - https://localhost:8402/api/product-minimal/multiple-filters/{id}?name={name}
    • Will return an Ok response if the Id is 9 or less and Name equals My product.
    • Will return a NotFound response if the Id is greater than 9 or Name does not equal My product.
  • Run code after the endpoint handler has been executed - https://localhost:8402/api/product-minimal/multiple-filters-executed/{id}?name={name}
    • Will return an Ok response if the Id is 9 or less and Name equals My product.
    • Will return a NotFound response if the Id is greater than 9 or Name does not equal My product.
    • Timestamps will appear in the console application for both filters
  • Move filter to its own class - https://localhost:8402/api/product-minimal/standalone-filters/{id}
    • Will return an Ok response if the Id is 9 or less.
    • Will return a NotFound response if the Id is greater than 9.

Add API key authentication to an Minimal API endpoint

You can read more about how to add API key authentication to a minimal API endpoint or watch the video:

In Visual Studio, open up 05/RoundTheCode.MinimalApi._05.sln from the code example zip file that you downloaded.

Run the application and it will load up the Scalar OpenAPI document on https://localhost:8402/scalar/v1.

Here is what you can test. All of these endpoints use the GET request:

  • Specific route with authentication - https://localhost:8402/hello-world
    • The api-key request header must match what's in Api -> Key in appsettings.Development.json to return a 200 response. Otherwise it will return a 401 response.
  • Fallback policy - https://localhost:8402/hello-world-no-authorization
    • The api-key request header must match what's in Api -> Key in appsettings.Development.json to return a 200 response. Otherwise it will return a 401 response.

How to add unit testing to Minimal APIs routes using xUnit

You can read more about unit testing minimal API routes, or watch the video:

In Visual Studio, open up 06/RoundTheCode.MinimalApi._06.sln from the code example zip file that you downloaded.

There are two projects contained within the solution.

  • RoundTheCode.MinimalApi - ASP.NET Core Web API
  • RoundTheCode.MinimalApi.XUnit - xUnit test project that unit test classes that are in RoundTheCode.MinimalApi

In the top menu, you can go to Test and Test Explorer. This allows you to run all five tests that are in the xUnit test project. They should all pass.