Mocking the Graph API - Groups/Members/Graph.User

[Irubataru]

Hi! I am trying to mock parts of the Graph API to have a local entra mock for local testing. I am only implementing the endpoints that my application uses when talking to Entra, but I am struggling a bit with getting the correct behaviour from OData.

Specifically I need to mock groups/{groupId}/members/graph.user. This endpoint should return a collection of entra User objects.

I have tried making a Group object that looks like this

public class Group
{
    public required string Id { get; set; }

    [AutoExpand]
    public IEnumerable<User> Members { get; set; } = [];
}

And then have the following GroupsController

public class GroupsController(IUserRepository userRepository) : ODataController
{
    private readonly IUserRepository _userRepository = userRepository;

    [EnableQuery]
    public ActionResult<IQueryable<Group>> Get()
    {
        var group = new Group
        {
            Id = "12345",
            Members = _userRepository.GetUsers()
        };

        var groups = new List<Group> { group };
        
        return Ok(groups);
    }
    
    
    [HttpGet("groups/{key}/members")]
    [EnableQuery]
    public ActionResult<IEnumerable<User>> GetMembers([FromRoute] string key)
    {
        if (key != "12345")
            return NotFound();
    
        var users = _userRepository.GetUsers();
        return Ok(users);
    }
    
    [HttpGet("groups/{key}/members/graph.user")]
    [EnableQuery]
    public ActionResult<IEnumerable<User>> GetMembersGraphUsers([FromRoute] string key)
    {
        if (key != "12345")
            return NotFound();
    
        var users = _userRepository.GetUsers();
        return Ok(users);
    }
}

This makes e.g. groups/12345/members work, but the final part, the Graph.User does not. I tried making it a function, but it does not seem that you can have function routing on top of properties. I am a bit unsure how to proceed, or how to build a correct model and controller to get the endpoint to work.

Edit:

I have gotten it working by making the Members property be of type DirectoryObject, and then have User inherit from this object. Then the final part of the URL is a derived type mapping.

One follow-up question: Why can't I use explicit routing to specify the endpoint in this case?

This works, but only if I move my User class to the Graph namespace.

    [HttpGet("groups/{key}/members/Graph.User")]
    [EnableQuery]
    public ActionResult<IEnumerable<User>> GetMembersOfUser([FromRoute] string key)
    {
        if (key != "12345")
            return NotFound();
    
        var users = _userRepository.GetUsers();
        return Ok(users);
    }

If I try to keep it in a different namespace, but with explicit routing, it does not work.

[habbes]

Hello @Irubataru

The routing is based on OData conventions and specifications. If you use the template groups/{key}/members/graph.user, how this gets interpreted depends on the schema (IEdmModel).

I supposed that members is a navigation property of the group entity. The members navigation property, can be followed by different types of segments depending on its type. For example, if you had a function in your schema called graph.user (i.e. function name is user, in the graph namespace), then for it be used next to members, it would need to defined as a bound function whose binding parameter type correspond to the type of the members navigation property. In this case I assume it would be a collection of directory objects.

But it doesn't seem like graph.user is meant to be a user, but rather a cast segment. If graph.user is a type cast segment, then you need to have in your schema a type called user in the namespace graph which inherits from the type assigned to the members navigation property.

So creating a type user that inherits from directoryObject which is the "element type" of the members navigation property is the correct implementation.

To learn more about OData routing and the various conventions, check out the docs: https://learn.microsoft.com/en-us/odata/webapi-8/fundamentals/routing-overview?tabs=net60

[Irubataru]

Thank you! I got it working 😊

I am quite new to OData, basically just needed it for simplifying writing one mock, so it's a bit much to dive into just for that 😅

So, if I were to keep the User class inside another namespace, but still map the Graph.User endpoint, it is possible by manually editing the EDM model to that the EDM model refers to it as Graph.User and not MyNameSpace.User?