Class: ActiveFacts::Generate::Rails::Models

Inherits:
Object
  • Object
show all
Defined in:
lib/activefacts/generate/rails/models.rb

Overview

Generate Rails models for the vocabulary Invoke as

afgen --rails/schema[=options] <file>.cql

Constant Summary collapse

HEADER = 
"# Auto-generated from CQL, edits will be lost"

Instance Method Summary collapse

Instance Method Details

#column_constraints(table) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 175

def column_constraints table
  return [] unless @validations
  ccs =
    table.columns.map do |column|
      name = column.rails_name
      column.is_mandatory &&
	!column.is_auto_assigned && !column.is_auto_timestamp ? [
	"    validates :#{name}, :presence => true"
      ] : []
    end.flatten
  ccs.unshift("") unless ccs.empty?
  ccs
end

#create_if_ok(filename) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 104

def create_if_ok filename
  # Create a file in the output directory, being careful not to overwrite carelessly
  if @output
    pathname = (@output+'/'+filename).gsub(%r{//+}, '/')
    @preexisting_files.reject!{|f| f == pathname }    # Don't clean up this file
    if generated_file_exists(pathname) == false
      $stderr.puts "not overwriting non-generated file #{pathname}"
      @individual_file = nil
      return
    end
    @individual_file = @out = File.open(pathname, 'w')
    puts "#{HEADER}"
  end
  true
end

#delete_old_generated_files ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 77

def delete_old_generated_files
  remaining = []
  cleaned = 0
  @preexisting_files.each do |pathname|
    if generated_file_exists(pathname) == true
      File.unlink(pathname) 
      cleaned += 1
    else
      remaining << pathname
    end
  end
  $stderr.puts "Cleaned up #{cleaned} old generated files" if @preexisting_files.size > 0
  $stderr.puts "Remaining non-generated files:\n\t#{remaining*"\n\t"}" if remaining.size > 0
end

#from_associations(table) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 139

def from_associations table
  # has_one/has_many Associations
  table.foreign_keys_to.sort_by{|fk| fk.describe}.map do |fk|
    # Get the jump reference

    if fk.from_columns.size > 1
      raise "Can't emit Rails associations for multi-part foreign key with #{fk.references.inspect}. Did you mean to use --transform/surrogate"
    end

    association_type, association_name = *fk.rails_to_association

    ref = fk.jump_reference
    [
      "\n    \# #{fk.verbalised_path}" +
      "\n" +
	%Q{    #{association_type} :#{association_name}} +
	%Q{, :class_name => '#{fk.from.rails_class_name}'} +
	%Q{, :foreign_key => :#{fk.from_columns[0].rails_name}} +
	%Q{, :dependent => :destroy}
    ] +
      # If ref.from is a join table, we can emit a has_many :through for each other key
      # REVISIT Could alternately do this for all belongs_to's in ref.from
      if ref.from.identifier_columns.length > 1
	ref.from.identifier_columns.map do |ic|
	  next nil if ic.references[0] == ref or	# Skip the back-reference
	    ic.references[0].is_unary		# or use rails_plural_name(ic.references[0].to_names) ?
	  # This far association name needs to be augmented for its role name
	  far_association_name = ic.references[0].to.rails_name
	  %Q{    has_many :#{far_association_name}, :through => :#{association_name}} # \# via #{ic.name}}
	end
      else
	[]
      end
  end.flatten.compact
end

#generate(out = $>) ⇒ Object

:nodoc:



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# File 'lib/activefacts/generate/rails/models.rb', line 57

def generate(out = $>)      #:nodoc:
  return if @helping
  @out = out
  list_extant_files if @output

  # Populate all foreignkeys first:
  @vocabulary.tables.each { |table| table.foreign_keys }
  ok = true
  @vocabulary.tables.each do |table|
    ok &= generate_table(table)
  end
  $stderr.puts "\# #{@vocabulary.name} generated with errors" unless ok
  delete_old_generated_files if @output
  ok
end

#generate_table(table) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 209

def generate_table table
  old_out = @out
  filename = table.rails_singular_name+'.rb'

  return unless create_if_ok filename

  puts "\n"
  puts "module #{@concern}" if @concern
  puts model_body(table).gsub(/^./, @concern ? '  \0' : '\0')
  puts 'end' if @concern

  true	  # We succeeded
ensure
  @out = old_out
  @individual_file.close if @individual_file
end

#generated_file_exists(pathname) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 92

def generated_file_exists pathname
  File.open(pathname, 'r') do |existing|
    first_lines = existing.read(1024)	  # Make it possible to pass over a magic charset comment
    if first_lines.length == 0 or first_lines =~ %r{^#{HEADER}}
      return true
    end
  end
  return false	  # File exists, but is not generated
rescue Errno::ENOENT
  return nil	  # File does not exist
end

#list_extant_files ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 73

def list_extant_files
  @preexisting_files = Dir[@output+'/*.rb']
end

#model_body(table) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 189

def model_body table
  %Q{module #{table.rails_class_name}
 extend ActiveSupport::Concern
 included do} +
    (table.identifier_columns.length == 1 ? %Q{
   self.primary_key = '#{table.identifier_columns[0].rails_name}'
} : ''
    ) +

    (
      to_associations(table) +
      from_associations(table) +
      column_constraints(table)
    ) * "\n" +
    %Q{
 end
end
}
end

#to_associations(table) ⇒ Object 



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# File 'lib/activefacts/generate/rails/models.rb', line 120

def to_associations table
  # belongs_to Associations
  table.foreign_keys.map do |fk|
    association_name = fk.rails_from_association_name

    foreign_key = ""
    if association_name != fk.to.rails_singular_name
      # A different class_name is implied, emit an explicit one:
      class_name = ", :class_name => '#{fk.to.rails_class_name}'"
      from_column = fk.from_columns
      foreign_key = ", :foreign_key => :#{fk.from_columns[0].rails_name}"
    end

    %Q{
   \# #{fk.verbalised_path}
   belongs_to :#{association_name}#{class_name}#{foreign_key}}
  end
end