I am setting up a system where one Drupal site serves as a Canonical source for specific content for a group of other Drupal sites to import from. I wanted to use the built-in Drupal JSON:API and Drupal Migration system to do this, but have had trouble figuring out how to properly import entity reference fields.
The Drupal JSON:API returns entity reference field data from a node as a relationship data set. It does not include the data for the entity referenced, just a separate API URL to request the data. For example an image reference returns this:
"relationships": {
"news_banner": {
"data": null,
"links": {
"related": {
"href": "SITEURL/jsonapi/node/news/69f1dfc0-5f83-4bfc-9520-1688782cfb12/news_banner?resourceVersion=id%3A40756"
},
"self": {
"href": "SITEURL/jsonapi/node/news/69f1dfc0-5f83-4bfc-9520-1688782cfb12/relationships/news_banner?resourceVersion=id%3A40756"
}
}
},
From what I have found, the Drupal Migration System nor the migrate_plus module have an out of the box method to make sub-requests as part of the original migration. Additionally, the JSON:API nor the jsonapi_extras module have an out of the box method to return the data for referenced entities/relationships as part of the larger request.
The method I've seen documented for the Migration System is
to chain multiple migrations together →
. This method uses a separate migration to pull the entities referenced later and then link them back to the parent entity using a migration_lookup plugin. However, this method does not have a means to pull only the referenced entities you need to pull from the previous migration. It does not seem intended to run sub-requests from a previous migration to "fill in the blanks", but to migrate ALL data from a source and link the data together.
Is there a way to do a sub-request as part of a Drupal Migration or to expose referenced entity data as part of a single JSON:API request without writing custom code?
I am tempted to create a View that returns the JSON data required with Contextual Filters to allow filtering of the response. But I was hoping to avoid creating yet another View and that Drupal Core would have an out of the box solution for this type of data transfer between multiple Drupal instances.
