Module: Automodel::Helpers

Defined in:
lib/automodel/helpers.rb

Overview

Houses some helper methods used directly by #automodel.

Class Method Summary collapse

Class Method Details

.map_tables(connection_handler, subschema: '') ⇒ Array<Hash>

Takes a connection handler (an object that implements ActiveRecord::ConnectionHandling), scrapes the target database, and returns a list of the tables' metadata.

Parameters:

  • connection_handler (ActiveRecord::ConnectionHandling) —

    The connection pool/handler to inspect and map out.

  • subschema (String) —

    The name of an additional namespace with which tables in the target database are prefixed, as eplained in #automodel.

Returns:

  • (Array<Hash>) —

    An Array where each value is a Hash representing a table in the target database. Each such Hash will define the following keys:

    • :name (String) – The table name, prefixed with the subschema name (if one is given).

    • :columns (Array<ActiveRecord::ConnectionAdapters::Column>)

    • :primary_key (String, Array<String>)

    • :foreign_keys (Array<ActiveRecord::ConnectionAdapters::ForeignKeyDefinition>)

    • :base_name (String) – The table name, with no subschema.

    • :model_name (String) – A Railsy class name for the corresponding model.

    • :composite_primary_key (true, false)

    • :column_aliases (Hash<String, ActiveRecord::ConnectionAdapters::Column>)



34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
 
# File 'lib/automodel/helpers.rb', line 34

def map_tables(connection_handler, subschema: '')
  ## Normalize the "subschema" name.
  ##
  subschema = "#{subschema}.".sub(%r{\.+$}, '.').sub(%r{^\.}, '')

  ## Prep the Automodel::SchemaInspector we'll be using.
  ##
  schema_inspector = Automodel::SchemaInspector.new(connection_handler)

  ## Get as much metadata as possible out of the Automodel::SchemaInspector.
  ##
  schema_inspector.tables.map do |table_name|
    table = {}

    table[:name] = "#{subschema}#{table_name}"
    table[:columns] = schema_inspector.columns(table[:name])
    table[:primary_key] = schema_inspector.primary_key(table[:name])
    table[:foreign_keys] = schema_inspector.foreign_keys(table[:name])

    table[:base_name] = table[:name].split('.').last
    table[:model_name] = table[:base_name].underscore.classify
    table[:composite_primary_key] = table[:primary_key].is_a? Array
    table[:column_aliases] = table[:columns].map { |column| [column.name, column] }.to_h

    table
  end
end

.railsy_column_name(column) ⇒ String

Returns a Railsy name for the given column.

Parameters:

  • column (ActiveRecord::ConnectionAdapters::Column) —

    The column for which we want to generate a Railsy name.

Returns:

  • (String) —

    The given column's name, in Railsy form.

    Note Date/Datetime columns are not suffixed with “on” or “at” per Rails norm, as this can work against you sometimes (“BirthDate” turns into “birth_on”). A future release will address this by building out a comprehensive list of such names and their correct Railsy representation, but that is not currently the case.



77
78
79
80
81
82
 
# File 'lib/automodel/helpers.rb', line 77

def railsy_column_name(column)
  name = railsy_name(column.name)
  name = name.sub(%r{^is_}, '') if column.type == :boolean

  name
end

.railsy_name(name) ⇒ String

Returns the given name in Railsy form.

Parameters:

  • name (String, Symbol) —

    The column name for which we want to generate a Railsy name.

Returns:

  • (String) —

    The given name, in Railsy form.



94
95
96
 
# File 'lib/automodel/helpers.rb', line 94

def railsy_name(name)
  name.to_s.gsub(%r{[^a-z0-9]+}i, '_').underscore
end

.register_class(class_object, as:, within: nil) ⇒ Class

Registers the given class as the given name and within the given namespace (if any).

Parameters:

  • class_object (Class) —

    The class to register.

  • as (String) —

    The name with which to register the class. Note this should be a base name (no “::”).

  • within (String, Symbol, Module, Class) —

    The module/class under which the given class should be registered. If the named module or class does not exist, as many nested modules as needed are declared so the class can be registered as requested.

    e.g. Calling this method with an “as” value of "Sample" and a “within” value of "Many::Levels::Deep" will: check for module/class “Many” and create one as a Module if it doesn't already exist; then check for a module/class “Many::Levels” and create a “Levels” Module within Many if it doesn't already exist; then check for a module/class “Many::Levels::Deep” and create a “Deep” Module within Many::Levels if it doesn't already exist; and finally register the given class as “Sample” within Many::Levels::Deep.

Returns:

  • (Class) —

    The newly-registered class (the same value as the originally-submitted “class_object”).



124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
 
# File 'lib/automodel/helpers.rb', line 124

def register_class(class_object, as:, within: nil)
  components = within.to_s.split('::').compact.map(&:to_sym)
  components.unshift(:Kernel) unless components.first.to_s.safe_constantize.present?

  namespace = components.shift.to_s.constantize
  components.each do |component|
    namespace = if component.in? namespace.constants
                  namespace.const_get(component)
                else
                  namespace.const_set(component, Module.new)
                end
  end

  namespace.const_set(as, class_object)
end