Mappable

Lightweight string mappings engine for Rails

Synopsis

Provides models and a UI for creating and maintaining string pairs. A tiny DSL is included so developers to easily make use of the generated data. The UI allows system administrators to create groups of string pairs that can be maintained by non-technical people.

We use this tool to map account names in a legacy system, where we don't control the names, to their corresponding names in our in-house system.

Installation

Add it to your Gemfile

gem 'mappable'

Bundle it up

bundle install

Install the migrations and apply them

rake mappable:install:migrations
rake db:migrate

The migrations will add tables similar to this

create_table "mappable_mappings", :force => true do |t|
  t.integer  "map_id"
  t.string   "from"
  t.string   "to"
end

create_table "mappable_maps", :force => true do |t|
  t.string   "subject"
  t.string   "attr"
  t.string   "from"
  t.string   "to"
end

Mount the engine

mount Mappable::Engine => '/map'

You can use the included generator to copy the views if you'd like to customize them

rails generate mappable:views

If you want to override the views for mappings that belong to a specific map puts them in app/views/mappable/[MAP_NAME]/mappings. This is most useful for overriding the mappings/_form partial. Often one side of the mapping is a controlled value that can be selected from a select box element, etc. You can generate these scoped views with:

rails generate mappable:views account_names

Definitions

• Mappings: String pairs that map to each other

  • http://localhost:3000/map/account/name

• Maps: A group of mappings and relevant metadata.

  • http://localhost:3000/map

Example usage

Given the following records

Map

id = 1
subject = 'account'
attr = 'name'
from = 'legacy'
to = 'current'

Mapping

id = 1
map_id = 1
from = 'Old Account Name'
to = 'New Account Name'

Now you can map strings in either direction using the following grammar

LegacyAccountName("Old Account Name").to_current #=> "New Account Name"
CurrentAccountName("New Account Name").to_legacy #=> "Old Account Name"

TODO

Move rebuilding of maps to an initializer and/or add notes to readme about why Map.all gets called on every request in development Better indexing in migrations Add security features Deal with going from/to when there's more than one to with the same name