Populate 2 levels deep

[luke-robertson]

Hello, wandering if this is possible ?

&$populate=attachments
&$populate=attachments.creator

creator is a ID REF inside the attachment table to a user

Currently its only populating attachments which is good, but also need to populate creator inside the attachments if possible,

Thanks !

Luke

[luke-robertson]

IV tired this :

    '&$populate=attachments' + '&$populate[]=attachments.creator'

But no luck

[luke-robertson]

@daffl any idea how to do this please?

[luke-robertson]

@ekryski you got any ideas ?

[daffl]

Set $populate to the nested array populating syntax in a before hook.

[luke-robertson]

@daffl So this is not possible with the query string ? im going to have to create a custom hook to populate 2 levels ?

[daffl]

You could try the querystring representation of the query (require('qs').stringify(nestedSyntax)) but it may not work.

[luke-robertson]

@daffl
Not sure how id do that, but thanks for the responce i appreciate it

[daffl]

The code sample I showed should show how it looks:

const qs = require('qs');
const query = qs.stringify({
  $populate: { 
     path: 'pages',
     populate: {
       path: 'components',
       model: 'Component'
     } 
  }
});

console.log(query);

This will print something like $populate[path]=pages&$populate[populate][path]=components&$populate[populate][model]=Component which would be the query string you'd pass. More information can be found in the NodeJS querystring and qs module documentation.

[luke-robertson]

Oh right i see !

Sorry i misunderstood, thanks a lot ill give it a test

[luke-robertson]

@daffl

const attachAssets = () => context => {
  const stringList = context.params.query['$populate'] || []

  context.params.query['$populate'] = {
    path: `assets ${stringList.join(' ')}`,
    populate: {
      path: 'creator',
    },
  }

  return context
}

😬

[johnnyx3m]

The code sample I showed should show how it looks:

const qs = require('qs');
const query = qs.stringify({
  $populate: { 
     path: 'pages',
     populate: {
       path: 'components',
       model: 'Component'
     } 
  }
});

console.log(query);

This will print something like $populate[path]=pages&$populate[populate][path]=components&$populate[populate][model]=Component which would be the query string you'd pass. More information can be found in the NodeJS querystring and qs module documentation.

Thanks @daffl This one works magically. Just a question, from this, can we also do a condition 2 levels down?

[DaddyWarbucks]

I am a bit confused here. The Feathers app should be using qs under the hood to parse queries already. This is typically handled with

app.use(express.urlencoded({ extended: true }));

in app.js. So if you are using the proper "nested query syntax", then the query should be parsed correctly.

Try these solutions out. Mongoose should support a couple of different syntax for populate.

// Mongoose supports space delimited string
&populate=attachments attachments.creator
// will become
q.populate('attachments attachments.creator')

// Mongoose supports array of strings
&populate[0]=attachments&populate[1]=attachments.creator
// will become
q.populate(['attachments', 'attachments.creator'])