PostgrestException: ReferenceAttribute must be used with Postgrest BaseModels (supabase-csharp)

[will11600]

Hi All,

I'm currently building a C# WebAssembly application using the supabase-csharp library. I have been getting this error every time I try to get data from a table. I have been debugging for a while now and I'm still scratching my head, was wondering if anyone might be able to point me in the right direction. I'm not sure what I'm doing wrong.

System.Reflection.CustomAttribute.GetCustomAttributesBase(ICustomAttributeProvider obj, Type attributeType, Boolean inheritedOnly) at System.Reflection.CustomAttribute.GetCustomAttributes(ICustomAttributeProvider obj, Type attributeType, Boolean inherit) at System.Reflection.RuntimePropertyInfo.GetCustomAttributes(Type attributeType, Boolean inherit) at Postgrest.Table`1[[SimonApp.Data.Report, SimonApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]..ctor(String baseUrl, JsonSerializerSettings serializerSettings, ClientOptions options) at Postgrest.Client.Table[Report]() at SimonApp.Pages.Reports.GetReportsAsync() in C:\Users\mrnic\source\repos\SimonApp\Client\Pages\Reports.razor:line 46

The method that is throwing the error:

private async Task<Report[]> GetReportsAsync()
{
    IsLoading = true;

    try
    {
        var reports = await supabase.Postgrest.Table<Report>().Get();
        return reports.Models.ToArray();
    }
    catch (Exception ex) { exceptionHandler.Handle(ex); }
    finally { IsLoading = false; }

    return Array.Empty<Report>();
}

This is the class I am trying to retrieve, I have followed these examples. However, mine does not seem to work.

using Postgrest.Attributes;
using Postgrest.Models;
using Supabase.Gotrue;

namespace SimonApp.Data
{
    [Table("reports")]
    public class Report : BaseModel
    {
        [PrimaryKey("id")]
        public int Id { get; set; }

        [Column("created_at")]
        public DateTime CreatedAt { get; set; }

        [Reference(typeof(Room), propertyName: "room_id")]
        public Room Room { get; set; } = default!;

        [Column("description")]
        public string Description { get; set; } = default!;

        [Reference(typeof(ServiceCategory), propertyName: "service_category_id")]
        public ServiceCategory ServiceCategory { get; set; } = default!;

        [Column("resolve_by_date")]
        public DateTime ResolveBy { get; set; }

        [Reference(typeof(User), propertyName: "user_uuid")]
        public User? User { get; set; }

        [Reference(typeof(ReportSeries), propertyName: "series_id")]
        public ReportSeries Series { get; set; } = default!;

        [Reference(typeof(ReportEvent))]
        public List<ReportEvent> Events { get; set; } = default!;
    }
}

Any help would be greatly appreciated! :)

[acupofjose]

Does the ServiceCategory class derive from BaseModel?

[will11600]

Thank you for getting in touch!

Yes, I can confirm all of the classes, including ServiceCategory derive from BaseModel.

[acupofjose]

Hm... a few other things to check:

• ServiceCategory (or another Reference-ed) class may also contain Reference attributes and one of those models may not be derived from BaseModel
• Reference could be referencing an attribute from another library, be sure that it's actually using Postgrest.Attributes (it looks like you are, but might as well confirm).

[will11600]

Ok, so I found the source of the issue! I had created a reference to Supabase.Gotrue.User, which does not derive from the BaseModel class.

What would be the best practice method of storing a reference to a user inside a table?

[acupofjose]

Ah! Interesting, yes. Store a foreign key on your desired table that references the Auth.User table. (i.e. Report has a user_id field that has a foreign key relationship to Auth.User.Id. Then create a reference model for User that derives from BaseModel with the columns you want selected.

[acupofjose]

Actually, I’m wrong there. You’d need a trigger that would move “public” data from Auth.User data into a Public.User table. I don’t believe postgrest allows you to query the Auth.User table from the client!

[will11600]

Ah ok, fair enough! Thanks for your help! :)

I thought about it, and actually, I don't think it's critical that I have access to that data from my client anyway.
The main purpose was so that I could display who had submitted each report in my application. While I was setting everything up, it didn't actually occur to me that, understandably so, there aren't columns for first name, last name, etc. in the user table out of the box.

On the online portal, the auth schema is listed under the protected category. So, I'm assuming that I'm not supposed to touch it? My plan is to set up an RLS-protected table under the public schema for this information. Unless there's a better way to do it?

[acupofjose]

Happy to! Yeah the suggested way would be to have a trigger for user registration that writes public data over to a different table. Say, for instance, a profile table.

You can see more here! https://supabase.com/docs/guides/auth/managing-user-data

[will11600]

Thanks again!

I haven't fully implemented a user sign-up yet. However, I've taken your suggestion and setup a profile table!