GraphQL ActiveRecord AutoSelect

Automatic ActiveRecord column selection for GraphQL (Ruby) fields.

This library was developed for- and extracted from HireFire.

The documentation can be found on RubyDoc.

Compatibility

• Ruby 2.5+
• ActiveRecord 5.0+
• GraphQL (Ruby) 1.9+

Installation

Add the gem to your Gemfile and run bundle.

gem "graphql_activerecord_autoselect", "~> 1"

Example

class Types::Actor < Types::Base::Object
  using GraphQLActiveRecordAutoSelect

  field :organizations, Types::Organization, null: false, extras: [:lookahead]

  def organizations(lookahead:)
    object.organizations.autoselect(lookahead)
  end

  field :organization, Types::Organization, null: false, extras: [:lookahead] do
    argument :id, ID, required: true
  end

  def organization(id:, lookahead:)
    object.organizations.autoselect(lookahead).find(id)
  end
end

In this example an actor has many organizations. We allow the client to query all of the actor's organizations, or a specific one by id. We acquire the lookahead functionality provided by GraphQL Ruby and pass it to autoselect.

The autoselect method is made available to ActiveRecord::Base at the class level, as well as to all instances of ActiveRecord::Relations, in classes where the GraphQLActiveRecordAutoSelect refinement is used (using GraphQLActiveRecordAutoSelect).

If you submit the following query to the server:

query {
  actor {
    organizations {
      name
      time_zone
    }
  }
}

It'll translate this:

object.organizations.autoselect(lookahead)

Into this:

object.organizations.select(:id, :actor_id, :name, :time_zone)

Notice that it didn't only select the :name and :time_zone fields, but :id and :actor_id as well. These kinds of identifiers are always selected in order to avoid potential lookup issues on other relations where they're mandatory.

The following fields are always selected:

• The primary key field (typically id)
• The type field
• Fields that end in _id
• Fields that end in _type

The example above builds a select on a has many relation, but the same works for belongs to.

class Types::Organization < Types::Base::Object
  using GraphQLActiveRecordAutoSelect

  field :actor, Types::Actor, null: false, extras: [:lookahead]

  def actor(lookahead:)
    Actor.autoselect(lookahead).find(object.actor_id)
  end
end

And with this query:

query {
  organization {
    actor {
      email
    }
  }
}

It'll translate this:

Actor.autoselect(lookahead).find(object.actor_id)

Into this:

Actor.select(:id, :email).find(object.actor_id)

Dependents

You might have fields or methods that depend on the presence of one or more fields. You can specify dependents to ensure that the requested field or method will be able to successfully compute:

class Actor < ActiveRecord::Base
  def secret
    decrypt(secret_digest)
  end

  private

  def decrypt(column)
    # ...
  end
end

class Types::Actor < Types::Base::Object
  # ...

  field :email, String, null: false
  field :full_name, String, null: false
  field :secret, String, null: false

  def self.dependents
    {
      :full_name => [:first_name, :last_name],
      :secret    => [:secret_digest],
    }
  end

  def full_name
    "#{object.first_name} #{object.last_name}"
  end

  # ...
end

class Types::Organization < Types::Base::Object
  using GraphQLActiveRecordAutoSelect

  field :actor, Types::Actor, null: false, extras: [:lookahead]

  def actor(lookahead:)
    Actor.autoselect(lookahead, Types::Actor.dependents).find(object.actor_id)
  end
end

There's a few things to note here.

1. We've defined the secret method in the Actor model which decrypts and returns the encrypted data stored in the secret_digest column.
2. We've defined self.dependents on the Types::Actor class which describes which fields depend on what columns.
3. We've passed in that dependent configuration to the second argument of autoselect.

We're essentially telling autoselect that if the client selects the full_name field, that it has to select the first_name and last_name columns on the model. Likewise, when selecting the secret field, it'll select the secret_digest column on the model so that it has the encrypted data it needs to decrypt and return.

query {
  organization {
    actor {
      email
      full_name
      secret
    }
  }
}

It'll translates this:

Actor.autoselect(lookahead, Actor.dependents).find(object.actor_id)

Into this:

Actor.select(:id, :email, :first_name, :last_name, :secret_digest).find(object.actor_id)

Since we've selected the full_name and secret fields, autoselect selects the first_name, last_name, and secret_digest columns, as these are necessary in order to compute full_name and secret.

Contributing

Bug reports and pull requests are welcome on GitHub at:

https://github.com/mrrooijen/graphql_activerecord_autoselect

To install the dependencies:

$ bundle

To open an interactive console:

$ bundle console

To run the tests:

$ bundle exec rake

To view the code coverage (generated after each test run):

$ open coverage/index.html

To run the local documentation server:

$ bundle exec rake doc

To build a gem:

$ bundle exec rake build

To build and install a gem on your local machine:

$ bundle exec rake install

For a list of available tasks:

$ bundle exec rake --tasks

Author / License

Released under the MIT License by Michael van Rooijen.