#### {% title "Blog" %}

# Aplikacja: Blog

Lista aplikacji implementujących blog:

* A ruby on rails blogging app forr the fashionable developer:
  [Enki](http://www.enkiblog.com/)

Aplikacja jest wykorzystywana w screencastach
R. Batesa. Repozytorium do ściągnięcia z Githuba:

    git://github.com/ryanb/railscasts-episodes.git
    cd railscasts-episodes/templates/blog

Katalog: *app*:

    |-- app
    |   |-- controllers
    |   |   |-- application_controller.rb
    |   |   |-- articles_controller.rb
    |   |   `-- comments_controller.rb
    |   |-- helpers
    |   |   |-- application_helper.rb
    |   |   |-- articles_helper.rb
    |   |   |-- comments_helper.rb
    |   |   `-- layout_helper.rb
    |   |-- models
    |   |   |-- article.rb
    |   |   `-- comment.rb
    |   `-- views
    |       |-- articles
    |       |   |-- _form.html.erb
    |       |   |-- edit.html.erb
    |       |   |-- index.html.erb
    |       |   |-- new.html.erb
    |       |   `-- show.html.erb
    |       |-- comments
    |       |   |-- _form.html.erb
    |       |   |-- edit.html.erb
    |       |   `-- new.html.erb
    |       `-- layouts
    |           `-- application.html.erb
    |-- config
    |   |-- boot.rb
    |   |-- database.yml
    |   |-- environment.rb
    |   |-- environments
    |   |   |-- development.rb
    |   |   |-- production.rb
    |   |   `-- test.rb
    |   |-- initializers
    |   |   |-- inflections.rb
    |   |   |-- mime_types.rb
    |   |   `-- new_rails_defaults.rb
    |   `-- routes.rb
    |-- db
    |   |-- migrate
    |   |   |-- 20080719200447_create_articles.rb
    |   |   `-- 20080719201435_create_comments.rb
    |   `-- schema.rb
    |-- lib
    |   `-- tasks
    |       `-- application.rake
    |-- public
    |   |-- 404.html
    |   |-- 422.html
    |   |-- 500.html
    .
    .    
    26 directories, 70 files

Tak jak w wypadku aplikacji TODO powinniśmy zacząć od przyjrzenia
się migracjom. Ale prościej będzie obejrzeć plik *schema.rb*:

    :::ruby
    # This file is auto-generated from the current state of the database.
    # Note that this schema.rb definition is the authoritative source for
    # your database schema. If you need to create the application database
    # on another system, you should be using db:schema:load, not running
    # all the migrations from scratch. The latter is a flawed and
    # unsustainable approach (the more migrations you'll amass, the slower
    # it'll run and the greater likelihood for issues).  It's strongly
    # recommended to check this file into your version control system.
    
    ActiveRecord::Schema.define(:version => 20080719201435) do
    
      create_table "articles", :force => true do |t|
        t.string   "name"
        t.text     "content"
        t.string   "author_name"
        t.datetime "created_at"
        t.datetime "updated_at"
      end
    
      create_table "comments", :force => true do |t|
        t.integer  "article_id"
        t.string   "author_name"
        t.string   "site_url"
        t.text     "content"
        t.datetime "created_at"
        t.datetime "updated_at"
      end
    
    end

I definicjom modeli:

    :::ruby
    class Article < ActiveRecord::Base
      has_many :comments, :dependent => :destroy
      validates_presence_of :name, :content
    end
    
    class Comment < ActiveRecord::Base
      belongs_to :article
      validates_presence_of :author_name, :content
    end

Teraz kolej na routing:

    :::ruby
    ActionController::Routing::Routes.draw do |map|
      map.resources :articles, :comments
      map.root :articles
    end

Teraz już możemy się przyjrzeć aplikacji:

    rake db:create
    rake db:migrate

Jeszcze dla przypomnienia:

    rake routes

i uruchamiamy aplikację:

    script/server thin -p 3000


## Kontrolery

Kontroler *ArticlesController*:

    :::ruby
    class ArticlesController < ApplicationController
      def index
        @articles = Article.find(:all)
      end
      
      # Ważne: 
      #   w widoku show.html.erb możemy edytować komentarze 
      #   do oglądanego artykułu
      def show
        @article = Article.find(params[:id])
        @comment = Comment.new(:article => @article)
      end
      
      def new
        @article = Article.new
      end
      
      def create
        @article = Article.new(params[:article])
        if @article.save
          flash[:notice] = "Successfully created article."
          redirect_to @article
        else
          render :action => 'new'
        end
      end
      
      def edit
        @article = Article.find(params[:id])
      end
      
      def update
        @article = Article.find(params[:id])
        if @article.update_attributes(params[:article])
          flash[:notice] = "Successfully updated article."
          redirect_to @article
        else
          render :action => 'edit'
        end
      end
      
      def destroy
        @article = Article.find(params[:id])
        @article.destroy
        flash[:notice] = "Successfully destroyed article."
        redirect_to articles_url
      end
    end
    
Kontroler *CommentsController*. 
Ten kontroler nie ma akcji *index* oraz *show*. 
Dlaczego? Jeśli nie znasz odpowiedzi, oznacza to, że 
za krótko „bawiłeś” się aplikacją.
    
    :::ruby
    class CommentsController < ApplicationController
      # Metoda new nie jest używana w aplikacji. 
      # Prawda to czy fałsz?
      def new
        @comment = Comment.new
      end

      # Jak powiązać komentarz z artykułem?      
      # Zakładamy, że do metody został przekazany jakoś id artykułu.
      # Jak? 
      def create
        @comment = Comment.new(params[:comment])
        if @comment.save
          flash[:notice] = "Successfully created comment."
          redirect_to article_url(@comment.article_id)
        else
          render :action => 'new'
        end
      end
      
      def edit
        @comment = Comment.find(params[:id])
      end
      
      # A jak tutaj jest przekazywany id artykułu?
      def update
        @comment = Comment.find(params[:id])
        if @comment.update_attributes(params[:comment])
          flash[:notice] = "Successfully updated comment."
          redirect_to article_url(@comment.article_id)
        else
          render :action => 'edit'
        end
      end
      
      # Metoda destroy nie jest używana w aplikacji.
      # Prawda to czy fałsz?
      def destroy
        @comment = Comment.find(params[:id])
        @comment.destroy
        flash[:notice] = "Successfully destroyed comment."
        redirect_to article_url(@comment.article_id)
      end
    end
   
## Widoki dla kontrolera *ArticlesController*


Widok *index.html.erb*:

    :::xml
    <% title "Articles" %>
    
    <div id="articles">
    <% for article in @articles %>
      <h2>
        <%= link_to h(article.name), article %>
        <span class="comments">(<%= pluralize(article.comments.size, 'comment') %>)</span>
      </h2>
      <div class="author">from <%=h article.author_name %> 
        on <%= article.created_at.strftime('%b %d, %Y') %></div>
      <div class="content"><%= simple_format(article.content) %></div>
    <% end %>
    </div>

Widok częściowy *_form.html.erb*:

    :::xml
    <%= error_messages_for :article %>
    <% form_for @article do |f| %>
      <p>
        <%= f.label :name %><br />
        <%= f.text_field :name %>
      </p>
      <p>
        <%= f.label :content %><br />
        <%= f.text_area :content %>
      </p>
      <p>
        <%= f.label :author_name %><br />
        <%= f.text_field :author_name %>
      </p>
      <p><%= f.submit "Submit" %></p>
    <% end %>

Widok *show.html.erb*:

    :::xml
    <% title @article.name %>
    
    <p class="author"><em>from <%=h @article.author_name %></em></p>
    
    <%=simple_format @article.content %>
    
    <p><%= link_to "Back to Articles", articles_path %></p>
    
    <% unless @article.comments.empty? %>
      <h2><%= pluralize(@article.comments.size, 'comment') %></h2>
    
      <div id="comments">
      <% for comment in @article.comments %>
        <div class="comment">
          <strong><%= link_to_unless comment.site_url.blank?, 
                        h(comment.author_name), h(comment.site_url) %></strong>
          <em>on <%= comment.created_at.strftime('%b %d, %Y at %H:%M') %></em>
          <%=simple_format comment.content %>
        </div>
      <% end %>
      </div>
    <% end %>
    
    <h3>Add your comment:</h3>
    <%= render :partial => 'comments/form' %>

Widok częściowy *comments/_form.html.erb*:

    :::xml
    <%= error_messages_for :comment %>
    <% form_for @comment do |f| %>
      <%= f.hidden_field :article_id %>
      <p>
        <%= f.label :author_name, 'Name' %><br />
        <%= f.text_field :author_name %>
      </p>
      <p>
        <%= f.label :site_url, 'Website URL' %><br />
        <%= f.text_field :site_url %>
      </p>
      <p>
        <%= f.label :content, 'Comment' %><br />
        <%= f.text_area :content, :rows => '12', :cols => 35 %>
      </p>
      <p><%= f.submit "Submit" %></p>
    <% end %>

Widok *edit.html.erb*:

    :::xml
    <% title "Edit Article" %>
    
    <%= render :partial => 'form' %>
    
    <p>
      <%= link_to "Show", @article %> |
      <%= link_to "View All", articles_path %>
    </p>

I na koniec, widok *new.html.erb*:

    :::xml
    <% title "New Article" %>
    
    <%= render :partial => 'form' %>
    
    <p><%= link_to "Back to List", articles_path %></p>


## Co jeszcze zostało do omówienia?

Gdzie można znaleźć definicję metody *simple_format*.

Jakie ciekawe metody zawiera *layout_helper.html.erb*?

Jakie pliki powinniśmy jeszcze obejrzeć?