Flexible Association Managers in Rails 7 APIs

Adding association management methods to Rails models

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If you’re a Rails developer, you’re probably familiar with updating associated records through the association_name_ids= setter method. That strategy works well, but often leads to cluttered controller methods for managing record associations.

In a current project, I found myself wanting a more convenient interface for add, removing, and resetting record associations. So here is my implementation, where I added connect_*, disconnect_*, reconnect_* to relevant models. With them implemented, the following API calls do exactly what you’d expect 🙃

// Add a new record to a has_many collection (without removing existing ones)
api.put('/authors/1', {
  "item": {
    "connect_posts": [1, 8]
  }
})

// Remove a record from a has_many collection (leaving all others be)
api.put('/authors/1', {
  "item": {
    "disconnect_posts": [9]
  }
})

// Remove all records from a has_many collection and replace with new ones.
api.put('/authors/1', {
  "item": {
    "reconnect_posts": [2,3]
  }
})

// Perform multiple operations in one call.
api.put('/authors/1', {
  "item": {
    "manage": {
      "connect": [1, 8],
      "disconnect": [9],
      "reconnect": [2,3]
    }
  }
})

Creating an ActiveSupport::Concern