LaForge

By Combinaut.

LaForge is a gem that makes it easy to build records using data from several data sources. It aims to facilitate management of which data sources a record is assembled from, and to perform the actual data assembly in order to output a record.

Key features:

• Allows published content to be edited without those changes immediately being seen by visitors
• Can selectively update content without needing to sync the entire database with production

Setup

1. Add Laforge to your Gemfile:

gem 'laforge', github: 'combinaut/laforge'

2. Add laforge to your model.

  # In your model
  class MyModel < ApplicationModel
    laforged
  end

Usage

1. Create some sources and prioritize them, giving higher priority to sources whose attributes should override those same attributes from lower priority sources.

  source1 = LaForge::DataSource.create(name: 'Encyclopedia Britannica', priority: 2)
  source2 = LaForge::DataSource.create(name: 'Wikipedia', priority: 1)

2. Build a new model, or update an existing one with data from any of your sources.

  foo = MyModel.new
  foo.record_data_entries({ height: 20, width: 5 }, source1)
  foo.record_data_entries({ height: 19, name: 'El Capitan' }, source2)
  foo.forge! # => Saves the model with the attributes { height: 20, width: 5, name: 'El Capitan' }

Note: Calling record_data_entries builds the Data Entries, but they are not persisted and and the record's attributes not updated until forge! is called.

3. Remove data for an existing model from any of your sources.

  foo.remove_data_entries(source1)
  foo.forge! # => Saves the model with the attributes { height: 19, width: nil, name: 'El Capitan' }

Note: calling remove_data_entries marks the Data Entries for destruction, but they are not destroyed and the removed attributes not nullified until forge! is called.

Overriding Priority

The priority of a data entry can be customized to override the priority inherited from the data source.

  foo = MyModel.new
  foo.record_data_entries({ height: 20, width: 5 }, source1)
  foo.record_data_entries({ height: 19 }, source2, priority: 3) # Override the priority inherited from the data source
  foo.forge! # => Saves the model with the attributes { height: 19, width: 5 }

Querying

  MyModel.with_source(source1) # => All records from source1
  MyModel.without_source(source1) # => All records not from source1

  MyModel.with_attribute(:height) # => All records with a recorded height attribute from any source
  MyModel.without_attribute(:height) # => All records without a recorded height attribute from any source

  MyModel.with_attribute_with_source(:height, source1) # => All records with a recorded height attribute from source1
  MyModel.with_attribute_with_source([:height, :width], source1) # => All records with a recorded height or width attribute from source1

  MyModel.with_attribute_without_source(:height, source1) # => All records with a recorded height not from source1
  MyModel.with_attribute_without_source([:height, :width], source1) # => All records with a recorded height or width attribute not from source1
  MyModel.with_attribute_with_source(:height, source1).with_attribute_with_source(:width, source1) # => All records with both a recorded height and width attribute from source1

  MyModel.without_attribute_with_source(:height, source1) # => All records without a recorded height attribute from source1
  MyModel.without_attribute_with_source([:height, :width], source1) # => All records missing a recorded height or missing a recorded width from source1
  MyModel.without_attribute_with_source(:height, source1).without_attribute_with_source(:width, source1) # => All records without both a recorded height and width attribute from source1