Class: Rails::Generator::Commands::Create

Inherits:
Base show all
Defined in:
lib/rails_generator/commands.rb

Overview

Create is the premier generator command. It copies files, creates directories, renders templates, and more.

Direct Known Subclasses

Update

Instance Attribute Summary

Attributes inherited from Base

#args, #destination_root, #source_root

Attributes included from Options

#options

Instance Method Summary collapse

Methods inherited from Base

#dependency, #invoke!

Methods inherited from Base

#destination_path, #initialize, #manifest, #source_path

Methods included from Options

append_features

Constructor Details

This class inherits a constructor from Rails::Generator::Base

Instance Method Details

#class_collisions(*class_names) ⇒ Object

Check whether the given class names are already taken by Ruby or Rails. In the future, expand to check other namespaces such as the rest of the user’s app.



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# File 'lib/rails_generator/commands.rb', line 138

def class_collisions(*class_names)
  class_names.flatten.each do |class_name|
    # Convert to string to allow symbol arguments.
    class_name = class_name.to_s

    # Skip empty strings.
    next if class_name.strip.empty?

    # Split the class from its module nesting.
    nesting = class_name.split('::')
    name = nesting.pop

    # Extract the last Module in the nesting.
    last = nesting.inject(Object) { |last, nest|
      break unless last.const_defined?(nest)
      last.const_get(nest)
    }

    # If the last Module exists, check whether the given
    # class exists and raise a collision if so.
    if last and last.const_defined?(name.camelize)
      raise_class_collision(class_name)
    end
  end
end

#complex_template(relative_source, relative_destination, template_options = {}) ⇒ Object 



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# File 'lib/rails_generator/commands.rb', line 281

def complex_template(relative_source, relative_destination, template_options = {})
  options = template_options.dup
  options[:assigns] ||= {}
  options[:assigns]['template_for_inclusion'] = render_template_part(template_options)
  template(relative_source, relative_destination, options)
end

#directory(relative_path) ⇒ Object

Create a directory including any missing parent directories. Always directories which exist.



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# File 'lib/rails_generator/commands.rb', line 290

def directory(relative_path)
  path = destination_path(relative_path)
  if File.exists?(path)
    logger.exists relative_path
  else
    logger.create relative_path
    FileUtils.mkdir_p(path) unless options[:pretend]
    
    # Optionally add file to subversion
    system("svn add #{path}") if options[:svn]
  end
end

#file(relative_source, relative_destination, file_options = {}, &block) ⇒ Object

Copy a file from source to destination with collision checking.

The file_options hash accepts :chmod and :shebang and :collision options. :chmod sets the permissions of the destination file:

file 'config/empty.log', 'log/test.log', :chmod => 0664

:shebang sets the #!/usr/bin/ruby line for scripts

file 'bin/generate.rb', 'script/generate', :chmod => 0755, :shebang => '/usr/bin/env ruby'

:collision sets the collision option only for the destination file: 

file 'settings/server.yml', 'config/server.yml', :collision => :skip

Collisions are handled by checking whether the destination file exists and either skipping the file, forcing overwrite, or asking the user what to do.



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# File 'lib/rails_generator/commands.rb', line 177

def file(relative_source, relative_destination, file_options = {}, &block)
  # Determine full paths for source and destination files.
  source              = source_path(relative_source)
  destination         = destination_path(relative_destination)
  destination_exists  = File.exists?(destination)

  # If source and destination are identical then we're done.
  if destination_exists and identical?(source, destination, &block)
    return logger.identical(relative_destination) 
  end

  # Check for and resolve file collisions.
  if destination_exists

    # Make a choice whether to overwrite the file.  :force and
    # :skip already have their mind made up, but give :ask a shot.
    choice = case (file_options[:collision] || options[:collision]).to_sym #|| :ask
      when :ask   then force_file_collision?(relative_destination)
      when :force then :force
      when :skip  then :skip
      else raise "Invalid collision option: #{options[:collision].inspect}"
    end

    # Take action based on our choice.  Bail out if we chose to
    # skip the file; otherwise, log our transgression and continue.
    case choice
      when :force then logger.force(relative_destination)
      when :skip  then return(logger.skip(relative_destination))
      else raise "Invalid collision choice: #{choice}.inspect"
    end

  # File doesn't exist so log its unbesmirched creation.
  else
    logger.create relative_destination
  end

  # If we're pretending, back off now.
  return if options[:pretend]

  # Write destination file with optional shebang.  Yield for content
  # if block given so templaters may render the source file.  If a
  # shebang is requested, replace the existing shebang or insert a
  # new one.
  File.open(destination, 'wb') do |df|
    File.open(source, 'rb') do |sf|
      if block_given?
        df.write(yield(sf))
      else
        if file_options[:shebang]
          df.puts("#!#{file_options[:shebang]}")
          if line = sf.gets
            df.puts(line) if line !~ /^#!/
          end
        end
        df.write(sf.read)
      end
    end
  end

  # Optionally change permissions.
  if file_options[:chmod]
    FileUtils.chmod(file_options[:chmod], destination)
  end
  
  # Optionally add file to subversion
  system("svn add #{destination}") if options[:svn]
end

#identical?(source, destination, &block) ⇒ Boolean

Checks if the source and the destination file are identical. If passed a block then the source file is a template that needs to first be evaluated before being compared to the destination.

Returns:

  • (Boolean) 


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# File 'lib/rails_generator/commands.rb', line 248

def identical?(source, destination, &block)
  return false if File.directory? destination
  source      = block_given? ? File.open(source) {|sf| yield(sf)} : IO.read(source)
  destination = IO.read(destination)
  source == destination
end

#migration_template(relative_source, relative_destination, template_options = {}) ⇒ Object

When creating a migration, it knows to find the first available file in db/migrate and use the migration.rb template.



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# File 'lib/rails_generator/commands.rb', line 312

def migration_template(relative_source, relative_destination, template_options = {})
  migration_directory relative_destination
  migration_file_name = template_options[:migration_file_name] || file_name
  raise "Another migration is already named #{migration_file_name}: #{existing_migrations(migration_file_name).first}" if migration_exists?(migration_file_name)
  template(relative_source, "#{relative_destination}/#{next_migration_string}_#{migration_file_name}.rb", template_options)
end

#readme(*relative_sources) ⇒ Object

Display a README.



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# File 'lib/rails_generator/commands.rb', line 304

def readme(*relative_sources)
  relative_sources.flatten.each do |relative_source|
    logger.readme relative_source
    puts File.read(source_path(relative_source)) unless options[:pretend]
  end
end

#template(relative_source, relative_destination, template_options = {}) ⇒ Object

Generate a file for a Rails application using an ERuby template. Looks up and evalutes a template by name and writes the result.

The ERB template uses explicit trim mode to best control the proliferation of whitespace in generated code. <%- trims leading whitespace; -%> trims trailing whitespace including one newline.

A hash of template options may be passed as the last argument. The options accepted by the file are accepted as well as :assigns, a hash of variable bindings. Example:

template 'foo', 'bar', :assigns => { :action => 'view' }

Template is implemented in terms of file. It calls file with a block which takes a file handle and returns its rendered contents.



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# File 'lib/rails_generator/commands.rb', line 269

def template(relative_source, relative_destination, template_options = {})
  file(relative_source, relative_destination, template_options) do |file|
    # Evaluate any assignments in a temporary, throwaway binding.
    vars = template_options[:assigns] || {}
    b = binding
    vars.each { |k,v| eval "#{k} = vars[:#{k}] || vars['#{k}']", b }

    # Render the source file with the temporary binding.
    ERB.new(file.read, nil, '-').result(b)
  end
end