outside_controller_use.md

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Using ActiveModelSerializers Outside Of A Controller

Serializing a resource

In ActiveModelSerializers versions 0.10 or later, serializing resources outside of the controller context is fairly simple:

# Create our resource
post = Post.create(title: "Sample post", body: "I love Active Model Serializers!")

# Optional options parameters for both the serializer and instance
options = {serializer: PostDetailedSerializer, username: 'sample user'}

# Create a serializable resource instance
serializable_resource = ActiveModelSerializers::SerializableResource.new(post, options)

# Convert your resource into json
model_json = serializable_resource.as_json

The object that is passed to ActiveModelSerializers::SerializableResource.new can be a single resource or a collection. The additional options are the same options that are passed through controllers.

Looking up the Serializer for a Resource

If you want to retrieve the serializer class for a specific resource, you can do the following:

# Create our resource
post = Post.create(title: "Another Example", body: "So much fun.")

# Optional options parameters
options = {}

# Retrieve the default serializer for posts
serializer = ActiveModel::Serializer.serializer_for(post, options)

You could also retrieve the serializer via:

ActiveModelSerializers::SerializableResource.new(post, options).serializer

Both approaches will return the serializer class that will be used for the resource.

Additionally, you could retrieve the serializer instance for the resource via:

ActiveModelSerializers::SerializableResource.new(post, options).serializer_instance

Serializing before controller render

At times, you might want to use a serializer without rendering it to the view. For those cases, you can create an instance of ActiveModelSerializers::SerializableResource with the resource you want to be serialized and call .as_json.

def create
  message = current_user.messages.create!(message_params)
  message_json = ActiveModelSerializers::SerializableResource.new(message).as_json
  MessageCreationWorker.perform(message_json)
  head 204
end