How to use Swagger in ASP.Net WebAPI 2.0 with token based authentication

alaa_sayegh picture alaa_sayegh · Jun 30, 2018 · Viewed 8.9k times · Source

I have a ASP.Net WebApi with token based authentication and I want to use swagger to create documentation for this RestApi.

The Api has for now only 2 methods, one for requesting a token i.e. http://localhost:4040/token and the other one is for creating a notification. The returned bearer token is sent like follows:

using (var client = new HttpClient())
{
    // setup client
    client.BaseAddress = new Uri("http://localhost:4040");
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    client.DefaultRequestHeaders.Add("Authorization", "Bearer " + token);

    var serializedNotification = new JavaScriptSerializer().Serialize(notification);
    var stringContent = new StringContent(serializedNotification, Encoding.UTF8, "application/json");

    var response = await client.PostAsync("api/Notification", stringContent);
    response.EnsureSuccessStatusCode();

    // return URI of the created resource.
    return response.Headers.Location;
 }

With swagger I can see the post Notification method, however I can't do a request because I don't have a token and I don't know how to do it in swagger.

Answer

alaa_sayegh picture alaa_sayegh · Jul 7, 2018

I found the solution myself. I would like to share it in case anybody is facing the same problem. The solution is of 2 steps, first one is to request a token and the next step, is to add the token into the header request.

So the first step:

Customize the frontend to enable post request for requesting a token:

enter image description here

Add a AuthTokenOperation class to enable which inherits the IDcoumentFilter interface and implements the Apply method:

public class AuthTokenOperation : IDocumentFilter
    {
        /// <summary>
        /// Apply custom operation.
        /// </summary>
        /// <param name="swaggerDoc">The swagger document.</param>
        /// <param name="schemaRegistry">The schema registry.</param>
        /// <param name="apiExplorer">The api explorer.</param>
        public void Apply(SwaggerDocument swaggerDoc, SchemaRegistry schemaRegistry, IApiExplorer apiExplorer)
        {
            swaggerDoc.paths.Add("/token", new PathItem
            {
                post = new Operation
                {
                    tags = new List<string> { "Auth"},
                    consumes = new List<string>
                    {
                        "application/x-www-form-urlencoded"
                    },
                    parameters = new List<Parameter>
                    {
                        new Parameter
                        {
                            type = "string",
                            name = "grant_type",
                            required = true,
                            @in = "formData"
                        },
                        new Parameter
                        {
                            type = "string",
                            name = "username",
                            required = false,
                            @in = "formData"
                        },
                        new Parameter
                        {
                            type = "string",
                            name = "password",
                            required = false,
                            @in = "formData"
                        },
                    }
                }
            });
        }
    }

And in the SwaggerConfig class in the register method, add this action

c.DocumentFilter<AuthTokenOperation>();

to the extension method:

GlobalConfiguration.Configuration.EnableSwagger

To add the authorization token in the request header:

enter image description here

Add this operation class:

/// <summary>
    /// The class to add the authorization header.
    /// </summary>
    public class AddAuthorizationHeaderParameterOperationFilter : IOperationFilter
    {
        /// <summary>
        /// Applies the operation filter.
        /// </summary>
        /// <param name="operation"></param>
        /// <param name="schemaRegistry"></param>
        /// <param name="apiDescription"></param>
        public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
        {
            if (operation.parameters != null)
            {
                operation.parameters.Add(new Parameter
                {
                    name = "Authorization",
                    @in = "header",
                    description = "access token",
                    required = false,
                    type = "string"
                });
            }
        }
    }

And in the SwaggerConfig class in the register method, add this action

c.OperationFilter<AddAuthorizationHeaderParameterOperationFilter>();

to the extension method:

GlobalConfiguration.Configuration.EnableSwagger

Of course in the Authoization field, you need to add: Bearer token_string