Documenting ASP.NET Core 2.0 Web API

Problem

How to add documentation and help pages for ASP.NET Core Web API.

Solution

Add NuGet package - Swashbuckle.AspNetCore

Update the Startup class to add services and middleware for Swagger.

public void ConfigureServices(
     IServiceCollection services)
 {
     services.AddSwaggerGen(options =>
     {
         options.SwaggerDoc("help", new Info
         {
             Title = "Fiver.Api Help",
             Version = "v1"
         });
     });

     // other services
 }

 public void Configure(
     IApplicationBuilder app,
     IHostingEnvironment env)
 {
     app.UseSwagger();
     app.UseSwaggerUI(options =>
     {
         options.SwaggerEndpoint(
           "/swagger/help/swagger.json", "Fiver.Api Help Endpoint");
     });

     // other middleware
 }

The help page can be accessed via: [host]/swagger

Discussion

Swagger is a format to describe RESTful APIs and Swashbuckle generates these swagger documents.

Note

The name specified when configuring services via SwaggerDoc method (e.g. “help” our sample code) must be the same as specified in the SwaggerEndpoint method.

XML Documentation

Documents generated by Swagger can include XML documentation. This can be turned on from project Properties > Build tab and configuring swagger services.

var xmlDocPath = PlatformServices.Default.Application.ApplicationBasePath;
options.IncludeXmlComments(Path.Combine(xmlDocPath, "Fiver.Api.Help.xml"));

Using XML comments, data annotations on model and action attributes we can produce detailed documentation that would be useful for the client developers, e.g.:

/// <summary>
  /// Adds a new movie
  /// </summary>
  /// <remarks>
  /// A sample request body
  ///
  ///     POST /movies
  ///     {
  ///         "title": "Thunderball",
  ///         "releaseYear": 1965,
  ///         "summary": "James Bond heads to The Bahamas to recover two nuclear
  ///                        warheads stolen by SPECTRE"
  ///     }
  /// </remarks>
  /// <returns>Newly added movie</returns>
  /// <response code="201">if movie created</response>
  /// <response code="400">if input null or invalid</response>
  [HttpPost]
  [ProducesResponseType(typeof(MovieOutputModel), 201)]
  [Produces("application/json", Type = typeof(MovieOutputModel))]

Source Code

GitHub