Ruby MVC

Ruby MVC (rmvc) is a gem to help you use the MVC (Model-View-Controller) architecture in all your Ruby applications. It's not limited to web applications like Rails! In fact, it's like a Rails without Rack.

Get RMVC

It's an official gem now! If you want the last available gem, run this:

$ gem install rmvc

Depending on your setup, you might have to prefix the command with sudo.

If you want the last version and the gem isn't updated (look at the top of the README to know what version the gem is), just download the sources from GitHub:

$ git init
$ git clone https://github.com/unrar/rmvc.git

Now install the gem:

$ gem install rmvc-x.x.x.gem

Dependencies

RMVC uses colorize for text colorizing, and sqlite3 as the default database engine. Rubygems should automatically install colorize and sqlite3 for you.

Using Databases

The migrate command is provided, which eases the database creation. After generating a migration file (see below), you have to add the queries to it, creating a RMVC::Migration object. Here's an example of all the methods as of v3.2.2:

require 'rmvc'
migr = RMVC::Migration.new("database_name") # Opens or creates a SQLite3 database
migr.create_table("table_name") # Creates a void table
migr.add_column("table_name", "column_name", :kind) # Where kind is :text, :num or a custom string (e.g. "varchar(32)")
migr.insert("table_name", ["column_1", "column_x"], ["value_1", "value_x"]) # Adds a row to a column or more
migr.drop_table("table_name") # Drops (deletes) a table

You can run any migration at any time by running the following command:

$ rmvc migrate migration_name

After the database is created, you can all queries to the model, call them through the controller and show the results through a view.

Remember that in all the files, the routes are relative to the main file (project.rb). So, the route to a file in the db path will be always ./db/file.db, not relative to the file you're writing (in a model, you might think it's ../../db/file.db, but again, it's relative to the main file).

Example

An example of a project using a SQLite3 database can be find here.

Create a project

RMVC is made to be friendly to Rails developers. So, as you can guess, the only command you need to run to create a new project is new:

$ rmvc new ProjectName

This will create all the needed files in the ProjectName subdirectory. It will create a structure like the following:

ProjectName/
  app/
    controllers/
      default_controller.rb
    migrations/
    models/
      default.rb
    views/
      main.rb
  db/
ProjectName.rb

The file the user will run is ProjectName.rb. It has a very simple content.

require './app/controllers/default_controller'
DefaultController.main

The controller, which is the file that, obviously, controls everything, contains this by default:

require './app/models/default'
require './app/views/main'
class DefaultController
  class << self
    # Add your variables here!
    attr_accessor :name
  end
  @name = "James!"
  def main
    MainView.load
  end
end

And the contents of the view:

require './app/controllers/default_controller'
class MainView
  def load
    puts "Hello, hello {#DefaultController.name}!"
  end
end

The model is void by default, just a declaration of the class SomethingModel.

How does it work?

It's very simple. This is basically what happens:

1. The method main of DefaultController is invoked.
2. The method main of DefaultController, following the conventions, invokes the view main (MainView), using the method load as the RMVC conventions say.
3. The method load of the MainView shows a message through puts, using a variable declared at DefaultController.

Declaring Variables

It's very easy! Just add the variable at the attr_accessor statement of your controller:

attr_accessor :onevariable, :anothervariable, :myvariable

And declare it using an instance variable (@var) after the class << self block.

end
@onevariable, @anothervariable, @myvariable = "A", "B", "C"

This can sound stupid, but it's useful if you want to get data from a database and make it available for all the views under a controller (MVC rules!).

Generating new content

Of course, RMVC makes it easy for you to generate new models, views and controllers. It will take care of almost all the requires.

Important! Make sure to be at the root of your project, not at the app subdirectory or any other one! That's because RMVC looks for the .rmvc directory to make sure you're in an actual project, and that directory is on the root.

Important! The case issues are fixed. You can now do generate controller TheBoss, and it will generate a file theboss_controller.rb but the class name will be TheBossController.

Models

Models are the most simple component to create, since they're void by default. Use this command:

$ rmvc generate model mylovelymodel

This will create the file app/models/mylovelymodel.rb. Following the conventions, it will add a require statement to include a controller also named mylovelymodel (app/controllers/mylovelymodel_controller.rb). Keep in mind that it will NOT create the controller too, so you're free to change the require line of the model to "link" it to another controller. But we strongly recommend to follow the conventions!

The class of the model will be named MylovelymodelModel.

Views

This ones are a bit more complicated. You need to specify to which controller is any view. Keep in mind that, unlike Rails, there can't be two views with the same name. That's because RMVC is simple. So you can't have a view main for one controller and a view main for another controller. Use this command:

$ rmvc generate view intro sudokusolver

This one will create a file at app/views/intro.rb, with a require statement "linking" to app/controllers/sudokusolver_controller.rb. Its class will be named IntroView with the default method load.

Controllers

These are the most complicated! Use this command:

$ rmvc generate controller sudokusolver

And that's basically it! This creates a file app/controllers/sudokusolver_controller.rb. It assumes the following things:

• You'll be using a model named sudokusolver (app/models/sudokusolver.rb), whose class is SudokusolverModel. So it adds a require statement for that.
• You'll be using a view named sudokusolver (app/views/sudokusolver.rb), whose class is SudokusolverView. So it adds a require statement for that, AND it calls the load procedure of that view (SudokusolverView.load) at its main procedure.

That's how it should be following the conventions, but usually you won't really agree with that view if you're doing a big application. So you can just change everything refering to sudokusolver and SudokusolverView to intro and IntroView, to match the example above.

Of course, another convention thing is that its class is named SudokusolverController and it has a main method calling the view. You shouldn't change that.

There's also some code to let you add variables, as explained in the section above.

Migrations

Before running a migration, you have to create a base migration file:

$ rmvc generate migration migration_name database_name

A file migration_name.rb will be created in /app/migrations. See above (Using databases) for details on migrations.

Putting everything to work

As said above, you already have lots of requires in order to be able to use the model, control and view methods at all the generated files. But, that does nothing!

Indeed. You just have to do an extra step that has to be done manually. Not because of developer's lazyness, but because RMVC is simple and usually won't do anything you don't expect to.

It's as easy as linking to the controller at your main file (if your project is sudoku, say sudoku.rb).

require `./app/controllers/sudokusolver_controller`

Important! The ./ before app is very important, don't ignore it! Also, don't add a .rb extension to the file, that's how require wants it!

Now you have access to all the controller, model and view's methods from your main/executable file. But usually all what you want to do is call the main method of the controller, so all what you would do is:

SudokusolverController.main

Then add all the desired code under the controller, views and models. And you're done!