Strapi multi-level population with field selection - rest

Question

I want to populate a multilevel relational field on strapi with REST API with specific field selection, but only the id comes up at the response.
When I populate the field without field selections with a GET request at: localhost:1337/api/home?populate[0]=Reasons&populate[1]=Reasons.IconsList&populate[2]=Reasons.IconsList.Icon, I
get this JSON response:
{
"data": {
"id": 1,
"attributes": {
"createdAt": "2022-10-31T11:24:55.202Z",
"updatedAt": "2022-11-09T13:50:40.445Z",
"publishedAt": "2022-10-31T11:26:30.944Z",
"PageInfo": "Homepage",
"Reasons": {
"id": 1,
"IconsList": [
{
"id": 1,
"Content": "Free cancellation on most bookings",
"Icon": {
"data": {
"id": 3,
"attributes": {
"name": "cancellation.svg",
"alternativeText": "Free cancellation on most bookings",
"caption": "cancellation.svg",
"width": 21,
"height": 21,
"formats": null,
"hash": "cancellation_b2308d4b63",
"ext": ".svg",
"mime": "image/svg+xml",
"size": 1.57,
"url": "/uploads/cancellation_b2308d4b63.svg",
"previewUrl": null,
"provider": "local",
"provider_metadata": null,
"createdAt": "2022-10-20T12:02:37.735Z",
"updatedAt": "2022-10-31T11:23:48.326Z"
}
}
}
},
{
"id": 2,
"Content": "No credit card fees",
"Icon": {
"data": {
"id": 5,
"attributes": {
"name": "credit-card.svg",
"alternativeText": "credit-card.svg",
"caption": "credit-card.svg",
"width": 22,
"height": 16,
"formats": null,
"hash": "credit_card_06b9eca40f",
"ext": ".svg",
"mime": "image/svg+xml",
"size": 0.89,
"url": "/uploads/credit_card_06b9eca40f.svg",
"previewUrl": null,
"provider": "local",
"provider_metadata": null,
"createdAt": "2022-10-20T12:21:46.342Z",
"updatedAt": "2022-10-20T12:21:46.342Z"
}
}
}
},
{
"id": 3,
"Content": "24/7 Customer care",
"Icon": {
"data": {
"id": 2,
"attributes": {
"name": "customer-care.svg",
"alternativeText": "24/7 Customer care",
"caption": "customer-care.svg",
"width": 20,
"height": 22,
"formats": null,
"hash": "customer_care_6aa8ac8eea",
"ext": ".svg",
"mime": "image/svg+xml",
"size": 1.48,
"url": "/uploads/customer_care_6aa8ac8eea.svg",
"previewUrl": null,
"provider": "local",
"provider_metadata": null,
"createdAt": "2022-10-20T12:02:37.734Z",
"updatedAt": "2022-10-20T12:04:39.792Z"
}
}
}
}
]
}
}
},
"meta": {}
}
Following this guide: https://docs.strapi.io/developer-docs/latest/developer-resources/database-apis-reference/rest/populating-fields.html#combining-population-with-other-operators, when I try to define the fields I want from the response: localhost:1337/api/home?fields[0]=PageInfo&populate[Reasons][IconsList]fields]=Content, I only get this JSON:
{
"data": {
"id": 1,
"attributes": {
"PageInfo": "Homepage",
"Reasons": {
"id": 1
}
}
},
"meta": {}
}
I want to get IconsList's Content and Icon.alternativeText and Icon.url but I cannot find how to build my query parameters.

Answer 1

For future reference to this problem, my question was answered on Strapi forum: https://forum.strapi.io/t/strapi-multi-level-population-with-field-selection/23473
This tutorial explains the reasoning behind deep populating and filtering and it's really interesting.
The problem was that you need to pupulate the relational field again like that: localhost:1337/api/home?fields[0]=PageInfo&populate[Reasons][populate][IconsList][fields][0]=Content to be able to access its data.