C#•3y ago

Converting id's to entities

I have this kind of request: BookRequest( string name, string description, ICollection<long> authorIds) I want to map it to an entity. I consider there approaches: 1) Map it partially (name, description), then in a handler find the authors associated with passed authorIds and populate the entity Authors collection with them 2) Inject DB context into Mapper profile instance (Is it SOLID? Somebody said that it is not, but I feel like it is pretty ok) 3) Implement id->entity converter class to retrieve Authors by Ids and use it in the mapper. Which do you consider the best? What are the other options?

17 Replies

Tvde1•3y ago

in what piece of code do you want to get the entities associated with the authorIds? somewhere it should do

var authors = await _context.Authors
    .Where(a => authorIds.Contains(a))
    .ToListAsync();

var authors = await _context.Authors
    .Where(a => authorIds.Contains(a))
    .ToListAsync();

bookuhaOP•3y ago

In a mapping method Preferably But not sure if it is ok to do

Tvde1•3y ago

like in an extension method?

bookuhaOP•3y ago

yes

Tvde1•3y ago

ToDto() something?

bookuhaOP•3y ago

yes!

Tvde1•3y ago

I would never do any database calls in such a method

bookuhaOP•3y ago

yeah. so another approach is to make a class that would do it? or idk

Tvde1•3y ago

usually for me a controller calls a Service (e..g AuthorService) class which would do everything needed for the functionality

bookuhaOP•3y ago

I think of calling ToDto() that doesnt maps ids, and then map them manually in a service

Tvde1•3y ago

class BookService
{
    public void AddBook(BookRequest request)
    {
        // get authors
        // validate stuff
        // create book
    }
}

class BookService
{
    public void AddBook(BookRequest request)
    {
        // get authors
        // validate stuff
        // create book
    }
}

a BookRequest already feels like a DTO

bookuhaOP•3y ago

yes, it is is it appropriate naming?

Tvde1•3y ago

well is it to create a book, retrieve a book, update a book? I'd put a verb in front of it

bookuhaOP•3y ago

create

Tvde1•3y ago

CreateBookRequest then :D

bookuhaOP•3y ago

ty! the problem is I may get confused because I already have CreateBookCommand from mediatR 😄 but i guess it is a bad practice to use mediatr objects there thank you!

Tvde1•3y ago

wait with doing db calls until your class actually needs them, then you're sending less data through events

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Converting id's to entities

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