Rails - The Menu Problem - Handling Large Scale Applications moving to Rails

It was interesting. I'm doing a large progject, and there are 500+ tables to deal with. This is my first "legacy" as it is project. And of course the "same" old tricks dont always work.

One of the problems, to check my models, of course I generate activescaffold controllers.

If your've read my previous post, my converts/imports usually do the following:

1. Move the table.
a. grab the schema
b. add missing fields
c. fix field names and table names for destination database
d. create the sequence number
e. create the table in the new schema
2. Create a model
3. Create a controller
4. Update the menu

This strategy has worked great. You get a reasobly native rails app,
and cleanup some of the database/schmema issues in the process.

New project is a bit different. Its all in oracle all ready. And its a "off-the-shelf" application.

So now I need to not "touch" the database schema, but man, I need a extra table, and
how to do menus etc when the functionality is so "rich".

So I decided to create a separate sqlite3 database just to do menus and functions.
(and maybe some other things along the way).

So first, need a do a migration (001_system_menu.rb). This will create our new
sqlite3 database, not touching our oracle database that is already working.
I did a trick to get this to work, I created a "empty" sqlite3 database file,
so the schema_version table would already exist, otherwise you get a "nice" error message saying you "cannot" create it.

Next wanted to get some data "into" the tables, so I created a second migration
(002_add_base_menus.rb) that creates some data so the menu system can be tweaked further.

So now how to "fill" up the tables in the operating "application"?
So in the models, I added the ability to "walk" the "controller" directory,
and any associated namespaces, and create entries. This will allow you then
to "play" them into the "menu" tree and "treak" the names, and the roles.

The "update_functions" method does a few things:
1. Verify "functions(controllers)" actually exist,
then enable or disable as appropriate
(If we delete we loose the custimization)
2. Find any new controllers and "add" them into the system

For now thats what we got, next will be to automatically generation of
menu (tabnav) partials for each level of the menu, and arrange for "hooks" in
the application to "know" what his menu is.

The system_function model has a very good example of "walking" directories.


#-----------------------001_system_menu.rb ------------------------
class SystemMenu < ActiveRecord::Migration

class SystemMenu < ActiveRecord::Base
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "db/system.sqlite3"
)
acts_as_tree
has_many :SystemFunction
end

class SystemFunction < ActiveRecord::Base
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "db/system.sqlite3"
)
belongs_to :SystemMenu
end

def self.up
create_table :system_functions do |t|
t.column :system_menu_id, :number
t.column :present, :boolean
t.column :enable, :boolean
t.column :name, :string, :limit =>32, :null => false
t.column :title, :string, :limit =>64, :null => false
t.column :controller, :string, :limit =>128
t.column :role, :string
t.column :created_at, :datetime
t.column :updated_at, :datetime
end
create_table :system_menus do |t|
t.column :name, :string, :limit =>32, :null => false
t.column :title, :string, :limit =>64, :null => false
t.column :role, :string, :limit =>32
t.column :enable, :boolean
t.column :parent_id, :number
t.column :created_at, :datetime
t.column :updated_at, :datetime
end

end

def self.down
drop_table :system_menus
drop_table :system_functions
end
end

class AddBaseMenus < ActiveRecord::Migration
class SystemMenu < ActiveRecord::Base
establish_connection :adapter => "sqlite3", :database => "db/system.sqlite3"
acts_as_tree
has_many :system_function
end

#-------------------- 002_add_base_menus.rb ------------------------
class SystemFunction < ActiveRecord::Base
establish_connection :adapter => "sqlite3", :database => "db/system.sqlite3"
belongs_to :system_menu
end

def self.up
homemenu = SystemMenu.create :name => "home", :title => "Home"
adminmenu = SystemMenu.create :name => "admin", :title => "Admin", :role => "Admin", :parent_id => homemenu.id
SystemFunction.create :system_menu_id => adminmenu.id, :name => "Menus", :title => "System Menus", :controller => "adminspace/system_menu", :role => "admin", :present => TRUE, :enable => TRUE
SystemFunction.create :system_menu_id => adminmenu.id, :name => "Functions", :title => "System Functions", :controller => "adminspace/system_function", :role => "admin", :present => TRUE, :enable => TRUE
end

def self.down
end
end

#----------------------- system_menu.rb ----------------------
class SystemMenu < ActiveRecord::Base
establish_connection :adapter => "sqlite3", :database => "db/system.sqlite3"
acts_as_tree
has_many :system_function

end

#---------------------- system_function.rb -------------------
class SystemFunction < ActiveRecord::Base
establish_connection :adapter => "sqlite3", :database => "db/system.sqlite3"
belongs_to :system_menu


public
def self.update_functions
app_directory = "./app/controllers"
verify_functions(app_directory)
system_function_process_dir(app_directory,"")
end


def self.verify_functions(thedir)
SystemFunction.find(:all).each do |record|
thepath = thedir + "/" + record.controller + "_controller.rb"
if File.exists?(thepath)
if record.present == FALSE
record.present = TRUE
record.save
end
else
if record.present == TRUE
record.present = FALSE
record.save
end
end
end
end

def self.system_function_process_entry(theparent,thedir, theentry)
if theentry == "."
return
end
if theentry == ".."
return
end
if theentry == "archive"
return
end
fullpath = thedir + "/" + theentry
if File.directory?(fullpath)
system_function_process_dir(fullpath,theentry)
return
end
if theentry.include? "_controller.rb"
thelen = theentry.index('_controller.rb')
thename = theentry[0,thelen]
if theparent == ""
mycontroller = thename
else
mycontroller = theparent + "/" + thename
end
myfunction = SystemFunction.find(:first, :conditions => "controller = '#{mycontroller}'")
if myfunction == nil # We dont exist
myfunction = SystemFunction.new
myfunction.name = thename
myfunction.system_menu_id = nil
myfunction.title = thename
myfunction.controller = mycontroller
myfunction.enable = FALSE
myfunction.present = TRUE
myfunction.role = ''
myfunction.save
return
end
end
end

def self.system_function_process_dir(thedir,theparent)
Dir.foreach(thedir){ |theentry| system_function_process_entry(theparent,thedir,theentry)}
end

end