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@grncdr
Created November 5, 2021 20:41
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The lowest-overhead way to get all tables & columns out of an ActiveRecord db/schema.rb
#!/usr/bin/env ruby
# frozen_string_literal: true
module Nop
def nop(*methods)
methods.each do |method|
define_method(method) { |*_args| nil }
end
end
end
# A simple stub that collects the information in a Rails db/schema.rb file
class FakeSchemaDSL
extend Nop
def initialize(info)
@info = info
@tables = {}
end
def create_table(name, **opts)
raise 'block is required' unless block_given?
t = @tables[name] = TableHelper.new(opts)
yield t
end
attr_reader :tables
nop :enable_extension, :add_foreign_key
class TableHelper
extend Nop
nop :index
def initialize(opts)
@table_opts = opts
@columns = {}
end
attr_reader :columns
def respond_to_missing?(_name, _include_private = true)
true
end
def method_missing(type, column_name, **opts)
@columns[column_name] = { type: type, opts: opts }
end
end
end
module ActiveRecord
class Schema
def self.define(info, &block)
raise '#define called twice' if @dsl
@dsl = FakeSchemaDSL.new(info)
@dsl.instance_eval(&block)
end
def self.tables
@dsl.tables
end
end
end
require_relative '../db/schema' or abort 'noooo'
require 'pp'
pp ActiveRecord::Schema.tables.transform_values(&:columns)
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