How to implement a social media "following feed" query using Prisma 2?

Question

I have a question related to writing a "social media" style feed query, but in this case I'm using Prisma 2. I have a music application where I'd like to display a feed of all Albums from Artists that a User follows.

In my schema.prisma, I have the following models:

User

model User {
  id         Int      @id @default(autoincrement())
  email      String   @unique
  following  Artist[]
}

Artist

model Artist {
  id        Int     @id @default(autoincrement())
  name      String
  followers User[]
  albums    Album[]
}

Prisma creates an implicit join table called UserToArtist to track when a User follows an Artist

Album

model Album {
  id          Int      @id @default(autoincrement())
  title       String
  date        DateTime <-- this is an ISO date string
  artists     Artist[] <-- an album can have several artists
}

Prisma creates an implicit join table called ArtistToAlbum to track which Artists are associated to certain Albums.

So how can I create a Prisma query to find all albums of artists that a user follows ordered by Album date? Here was my first attempt, but this doesn't seem to be correct and the albums aren't sorted by date:

const results = await ctx.db.album.findMany({
  where: {
    date: {
      gt: moment().startOf('day').toISOString()
    },
    artists: {
      some: {
        followers: {
          some: {
            id: args.userId, <-- the userId for the feed
          },
        },
      },
    },
  },
  orderBy: {
    date: 'asc',
  },
})

Notice how I have to filter down through two some statements? Just doesn't feel right... What recommendations do you have for a query like this? Thanks!

score 0 · Answer 1 · answered Jul 18 '20 at 03:54

You can use the fluent API to grab all the artists that a user follows, and it should look something like this:

const followedArtists = await ctx.db.user.findOne({ where: { id: args.userId, } }).following()

From here you can grab the albums from all of those artists and then sort them in your server code to then be sent back as the query result

How to implement a social media "following feed" query using Prisma 2?

1 Answers1