3 min read
This is the 6th tutorial of the Auth Series. Previously in the 5th tutorial - # Auth Series #5 - Call Microsoft Entra ID/Azure AD Protected Web API via ASP.NET Core MVC using Authorization Code Flow we created a sample protected Todo Api and Todo Web App (ASP.NET Core MVC) and make the web calls to the api via Authorization Code Flow to access the protected api.
Now, we want to improve our Todo Api to have an open api a.k.a Swagger integrated into the project. So, we can test our api without having to setup any client application like we did in 5th tutorial series.
Enabling Swagger only is not enough. We need to make sure that our Swagger can authenticate against the api itself. So, the Swagger will act like the client app to get the token to access the api.
That’s why we need to register our Swagger to app registration in azure. For those that have not followed our 1st and 2nd tutorials, I encourage you to read those first to make sure you have better understanding on how to setup the app registrations.
If you follow along our 2nd tutorial, we have created two new app registrations:
To register our Swagger, make sure you go to the uptec-auth-api-caller. In the Overview page, click the Endpoints button and take a note of both values of “OAuth 2.0 authorization endpoint (v2)” and “OAuth 2.0 token endpoint (v2)”. We will need those urls in our Swagger to do authentication.
Next, you should go to the Authentication page/menu. On that page, click Add a platform button (you can follow this only if you haven’t created one) and select the “Single-page application”.
Enter this value in the redirect uris: https://localhost:8181/swagger/oaut2-redirect.html. Why do we use port 8181 ? In our sample project Todo Api, we used port 8181 in our previous tutorial (5th tutorial). This is optional, if you used different port previously, you can adjust based on your setup.
After that, scroll down the page until you find checkbox with label “ID tokens (used for implicit and hybrid flows)”. Make sure you tick that to enable implicit flow/hybrid flow in our swagger to get the token for authentication. Don’t forget to hit save after changes we made.
The last step is to take a note of the scopes we created earlier for the API (in the uptec-auth-api’s app registration). Because in the previous tutorials we have requested the permission inside the uptec-auth-api-caller, you don’t need to switch to uptec-auth-api. Just go to the API permissions, click the Access.Read & Access. Write permissions and copy the full permission names like in the screenshots below.
NB: Make sure you follow the previous tutorials to understand how to expose scopes and use them in your api and client apps
Because in our Todo Api project we haven’t configured the Swagger yet, we need to setup the Swagger first.
Install the Swashbuckle.AspNetcore nuget package in our UptecTodoApi project.
Go to appsettings.json, and add this additional config for swagger.
"Swagger": {
//client id of the caller
"ClientId": "CALLER_CLIENT_ID",
//auth endpoint of the caller
"AuthorizationEndpoint": "https://login.microsoftonline.com/API_TENANT_ID/oauth2/v2.0/authorize",
//token endpoint of the caller
"TokenEndpoint": "https://login.microsoftonline.com/API_TENANT_ID/oauth2/v2.0/token",
//scopes of the api (Access.Read & Access.Write) in full pattern separated by space
"Scopes": "api://3a9b9211-6791-4992-b779-bb05935f708b/Access.Read api://3a9b9211-6791-4992-b779-bb05935f708b/Access.Write"
}
Last step, we need to register the swagger in the Program.cs and configure its auth as well.
Add these blocks to the service collection part.
-> Configure the SwaggerGen
string[] scopes =
config["Swagger:Scopes"]?.Split(' ') ?? new string[0];
services.AddSwaggerGen(c =>
{
c.SwaggerDoc("v1", new OpenApiInfo
{
Title = "UptecTodoApi",
Version = "v1",
});
c.AddSecurityDefinition("OAuth2", new OpenApiSecurityScheme
{
Name = "OAuth2",
Type = SecuritySchemeType.OAuth2,
Flows = new OpenApiOAuthFlows
{
AuthorizationCode = new OpenApiOAuthFlow
{
AuthorizationUrl = new Uri(config["Swagger:AuthorizationEndpoint"] ?? string.Empty),
TokenUrl = new Uri(config["Swagger:TokenEndpoint"] ?? string.Empty),
Scopes = scopes?.ToDictionary(c => c)
}
}
});
c.AddSecurityRequirement(new OpenApiSecurityRequirement
{
{
new OpenApiSecurityScheme
{
Reference = new OpenApiReference
{
Type = ReferenceType.SecurityScheme, Id = "OAuth2"
}
},
scopes
}
});
});
The code above will tell the Swagger that we’re going to use Authorization Code Flow with the authorization endpoint and token endpoint we got from the previous step. And Swagger will use Scopes we got from API registration (Access.Read & Access.Write) that listed in the appsettings.json config.
Add these blocks in the app builder blocks to enable the Swagger UI.
app.UseSwagger();
app.UseSwaggerUI(c =>
{
c.SwaggerEndpoint("/swagger/v1/swagger.json", "Todo Api v1");
c.OAuthClientId(config["Swagger:ClientId"]);
c.OAuthUsePkce();
c.OAuthScopes(scopes);
});
NB: Details can be seen in the source code in the GitHub
Ok, now we are going to test our Swagger. When you run the project, go to /swagger url to open the Swagger UI.
Do you notice Authorize button above? That button used to authenticate our calls. If you don’t hit that for authentication, when you test the api, you’ll get 401 like in the screenshot below.
Hit, the authorize button, and select all scopes and then login to your MS Account registered with the Azure.
Once completed, let’s try to create a post request (create Todo) and then try to get all todos.
Awesome. Now we can access/test our endpoints without using Postman or other client applications.
Ok, i think that’s all for this tutorial. You can check the source code here:
Todo Api: https://github.com/mirzaevolution/UptecTodoApi
Regards,
Mirza Ghulam Rasyid
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