C#•2y ago

❔ I apparently have an infinite loop, but I can't fix it to work

I've tried a lot of stuff, even a "NewtonJson" fix I saw, but it wouldn't solve the problem because whenever I would get all my movies, it would not include the MoviesParticipantsSeasons part With the Newtonjson, it would let me get MoviesParticipantsSeason with the includes though What am I doing wrong? Do I really need NewtonJson? Please help, been on this for days now :/

16 Replies

Jimmacle•2y ago

the problem is you have bidirectional navigation properties in your EF model which creates infinite cycles when you try to serialize it to JSON i would have separate models, one for your database and one for json serialization or for a quick and dirty solution, annotate the redundant properties so they're ignored by the json serializer

Marcoelho97OP•2y ago

How would that work, exactly? I would use this model I already have for database creation And then another for _context.xyz?

Jimmacle•2y ago

you would define a new set of classes specifically to represent the data you want to serialize, then write a mapping function to convert your DB representation to that assuming you're returning this data as part of a web request you should really separate your database models and DTOs anyway for example, in one of my current projects i do things like this

    public async Task<Result<ShippingOrderDetailsDto>> Handle(GetShippingOrderDetailsQuery request,
        CancellationToken cancellationToken)
    {
        await using var db = await _db.CreateDbContextAsync(cancellationToken);
        var order = await db.ShippingOrders.AsNoTracking()
            .Include(o => o.RequestedBy)
            .Where(o => o.Number == request.Number)
            .Select(o => new ShippingOrderDetailsDto(
                o.Number, o.RequestedBy.FullName, o.Description, o.Address, o.Method, o.CostCenter.Id + " " + o.CostCenter.Name, o.Packages,
                o.CreatedOn, o.ShippedOn, o.TrackingNumber, o.CostUsd, o.Attn, o.ShipTo,
                o.BillTo, o.Status, o.Project, o.Carrier, o.AccountNumber,
                o.Packages.Sum(p => p.UnitValueUsd * p.Quantity)))
            .FirstOrDefaultAsync(cancellationToken);
        return order ?? Result<ShippingOrderDetailsDto>.Fail("Order not found.");
    }

    public async Task<Result<ShippingOrderDetailsDto>> Handle(GetShippingOrderDetailsQuery request,
        CancellationToken cancellationToken)
    {
        await using var db = await _db.CreateDbContextAsync(cancellationToken);
        var order = await db.ShippingOrders.AsNoTracking()
            .Include(o => o.RequestedBy)
            .Where(o => o.Number == request.Number)
            .Select(o => new ShippingOrderDetailsDto(
                o.Number, o.RequestedBy.FullName, o.Description, o.Address, o.Method, o.CostCenter.Id + " " + o.CostCenter.Name, o.Packages,
                o.CreatedOn, o.ShippedOn, o.TrackingNumber, o.CostUsd, o.Attn, o.ShipTo,
                o.BillTo, o.Status, o.Project, o.Carrier, o.AccountNumber,
                o.Packages.Sum(p => p.UnitValueUsd * p.Quantity)))
            .FirstOrDefaultAsync(cancellationToken);
        return order ?? Result<ShippingOrderDetailsDto>.Fail("Order not found.");
    }

ignore the ridiculous amount of properties

Marcoelho97OP•2y ago

So Your model is ShippingOrders Your return is the ShippingOrderDetailsDto, in which you select every property you wanna return? So that you can "remove" the unwanted ones?

Jimmacle•2y ago

essentially correct

Marcoelho97OP•2y ago

That is genius

Jimmacle•2y ago

i map the data in the database to an object that has the data the frontend needs it also means that if you ever need to change your database or API they aren't tightly coupled and you don't necessarily have to change them together

Jimmacle•2y ago

the DTO is a very simple object that's easy to serialize and only has the exact data needed by the endpoint

Marcoelho97OP•2y ago

I'll give that a go :D Thank you so much!

Jimmacle•2y ago

(i don't actually serialize to JSON because this is a blazor server app, but the concepts apply either way)

Marcoelho97OP•2y ago

But I still have a question, what about a create? How would I use a DTO and not the model? For example I create a movie Save I then create a relationship And when I go to save, it goes into loop too

Jimmacle•2y ago

you'd do the same thing but backwards your client sends JSON that you deserialize into a DTO, then translate that into your DB model

Marcoelho97OP•2y ago

But the problem happens because of the DB Model, no? Because of that "Movie" and "MovieParticipantSeason" properties

Jimmacle•2y ago

the exception you got is related to reading/writing JSON, not your DB model EF core will handle navigation properties automatically

Marcoelho97OP•2y ago

So, is it happening because I'm returning the object at its full? That makes sense 🤔 I will give this a try and give feedback :D Thank you so much! It worked! Thank you so much! ♥

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity. Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

Gaming

Programming

❔ I apparently have an infinite loop, but I can't fix it to work