C#•3y 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 :/

MMarcoelho97 I've tried a lot of stuff, even a "NewtonJson" fix I saw, but it wouldn't solve ...

Jimmacle•4/10/23, 3:24 PM

the problem is you have bidirectional navigation properties in your EF model which creates infinite cycles when you try to serialize it to JSON

Jimmacle•4/10/23, 3:24 PM

i would have separate models, one for your database and one for json serialization

Jimmacle•4/10/23, 3:25 PM

or for a quick and dirty solution, annotate the redundant properties so they're ignored by the json serializer

JJimmacle i would have separate models, one for your database and one for json serializati...

Marcoelho97OP•4/10/23, 3:26 PM

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

Jimmacle•4/10/23, 3:27 PM

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

Jimmacle•4/10/23, 3:28 PM

assuming you're returning this data as part of a web request you should really separate your database models and DTOs anyway

Jimmacle•4/10/23, 3:32 PM

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.");
    }

Jimmacle•4/10/23, 3:32 PM

ignore the ridiculous amount of properties

Marcoelho97OP•4/10/23, 3:33 PM

So
Your model is ShippingOrders
Your return is the ShippingOrderDetailsDto, in which you select every property you wanna return?

Marcoelho97OP•4/10/23, 3:33 PM

So that you can "remove" the unwanted ones?

Jimmacle•4/10/23, 3:33 PM

essentially correct

Marcoelho97OP•4/10/23, 3:34 PM

That is genius

Jimmacle•4/10/23, 3:34 PM

i map the data in the database to an object that has the data the frontend needs

Jimmacle•4/10/23, 3:34 PM

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•4/10/23, 3:36 PM

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

Marcoelho97OP•4/10/23, 3:36 PM

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

Jimmacle•4/10/23, 3:37 PM

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

Marcoelho97OP•4/10/23, 3:41 PM

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•4/10/23, 3:42 PM

you'd do the same thing but backwards

Jimmacle•4/10/23, 3:42 PM

your client sends JSON that you deserialize into a DTO, then translate that into your DB model

Marcoelho97OP•4/10/23, 3:44 PM

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

Jimmacle•4/10/23, 3:44 PM

the exception you got is related to reading/writing JSON, not your DB model

Jimmacle•4/10/23, 3:45 PM

EF core will handle navigation properties automatically

Marcoelho97OP•4/10/23, 3:45 PM

So, is it happening because I'm returning the object at its full?

Marcoelho97OP•4/10/23, 3:45 PM

That makes sense

Marcoelho97OP•4/10/23, 3:46 PM

I will give this a try and give feedback :D Thank you so much!

Marcoelho97OP•4/10/23, 5:02 PM

It worked! Thank you so much!

Accord•4/11/23, 5:03 PM

Was this issue resolved? If so, run

/close

/close

otherwise I will mark this as stale and this post will be archived until there is new activity.

Accord•6/19/23, 7:07 PM

Was this issue resolved? If so, run

/close

/close

otherwise I will mark this as stale and this post will be archived until there is new activity.

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."); }

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

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