DarkLoop.Azure.Functions.Authorization.InProcess 4.1.0-preview-240521-1

functions-authorize

Bringing AuthorizeAttribute Behavior to Azure Functions v3 and v4 (In-Process)

It hooks into .NET Core dependency injection container to enable authentication and authorization in the same way ASP.NET Core does.

Using the package

Installing the package

dotnet add package DarkLoop.Azure.Functions.Authorize

Setting up authentication

The goal is to utilize the same authentication framework provided for ASP.NET Core

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using MyFunctionAppNamespace;

[assembly: FunctionsStartup(typeof(Startup))]
namespace MyFunctionAppNamespace
{
  class Startup : FunctionsStartup
  {
    public void Configure(IFunctionsHostBuilder builder)
    {
      builder
        .AddAuthentication(options =>
        {
          options.DefaultAuthenticationScheme = JwtBearerDefaults.AuthenticationScheme;
          options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
        })
        .AddOpenIdConnect(options =>
        {
          options.ClientId = "<my-client-id>";
          // ... more options here
        })
        // This is important as Bearer scheme is used by the platform
        .AddJwtFunctionsBearer(options =>
        {
          options.Audience = "<my-audience>";
          // ... more options here
        });

      builder
        .AddAuthorization(options =>
        {
          options.AddPolicy("OnlyAdmins", policyBuilder =>
          {
            // configure my policy requirements
          });
        });
    }
  }
}

Starting with version 4.1.0, the default Bearer scheme is not supported by this framework. You can use a custom scheme or make use of AddJwtFunctionsBearer(Action<JwtBearerOptions>) as shown above. This one adds the "FunctionsBearer" scheme. Clients still submit token for Authorization header in the format: Bearer <token>.

No need to register the middleware the way we do for ASP.NET Core applications.

Using the attribute

And now lets use FunctionAuthorizeAttribute the same way we use AuthorizeAttribute in our ASP.NET Core applications.

public class Functions
{
  [FunctionAuthorize]
  [FunctionName("get-record")]
  public async Task<IActionResult> GetRecord(
    [HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequest req,
    ILogger log)
  {
    var user = req.HttpContext.User;
    var record = GetUserData(user.Identity.Name);
    return new OkObjectResult(record);
  }

  [FunctionAuthorize(Policy = "OnlyAdmins")]
  [FunctionName("get-all-records")]
  public async Task<IActionResult> GetAllRecords(
    [HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequest req,
    ILogger log)
  {
    var records = GetAllData();
    return new OkObjectResult(records);
  }
}