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Removing HTML tags from a string in Ruby

Ruby posted 7 months ago by marko

I don’t take credit for the regexp. The source for it is Mastering Regular Expressions by Jeffrey E.F. Frield. 

   1  def remove_html_tags
   2      re = /<("[^"]*"|'[^']*'|[^'">])*>/
   3      self.title.gsub!(re, '')
   4      self.description.gsub!(re, '')
   5    end

Tagged regexp, ruby, removing html tags

Installing ImageMagick, mini-magick and rmagick on Mac OS X Leopard

Ruby posted 8 months ago by christian

I had no success installing ImageMagick and mini-magick with the instructions I found on this page but after some googling I found this blog post, which had the magic commands that worked for me: 

   1  sudo port install tiff -macosx  #disables the linkage with Apple's open gl
   2  sudo port install ImageMagick
   3  
   4  sudo gem install rmagick
   5  sudo gem install mini_magick

To test mini-magick, open an irb console and paste in the following code:

   1  require 'rubygems'
   2  require 'mini_magick'
   3  
   4  path = "public/images/0000/0003/logo.jpg"
   5  image = MiniMagick::Image.new(path)
   6  
   7  #print width and height
   8  puts image[:width]
   9  puts image[:height]

Tagged imagemagick, attachment_fu, rails, ruby, mac, osx, leopard, mini-magick, rmagick

Using the WWW::Mechanize RubyGem to scrape login protected pages

Ruby posted 8 months ago by christian

This is an example of how to access a login protected site with WWW ::Mechanize. In this example, the login form has two fields named user and password. In other words, the HTML contains the following code:

   1  <input name="user" .../>
   2  <input name="password" .../>

Note that this example also shows how to enable WWW ::Mechanize logging and how to capture the HTML response:

   1  require 'rubygems'
   2  require 'logger'
   3  require 'mechanize'
   4  
   5  agent = WWW::Mechanize.new{|a| a.log = Logger.new(STDERR) }
   6  #agent.set_proxy('a-proxy', '8080')
   7  page = agent.get 'http://bobthebuilder.com'
   8  
   9  form = page.forms.first
  10  form.user = 'bob'
  11  form.password = 'password'
  12  
  13  page = agent.submit form
  14  
  15  output = File.open("output.html", "w") { |file|  file << page.body }

Use the search method to scrape the page content. In this example I extract all text contained by span elements, which in turn are contained by a table element having a class attribute equal to ‘list-of-links’:

   1  puts page.search("//table[@class='list-of-links']//span/text()") # do |row|

The HTML looks like this (td, tr elements omitted for clarity):

   1  ...
   2  <table class="list-of-links">
   3  ...
   4  <span>The content</span>
   5  ...
   6  </table>
   7  ...

Tagged www, mechanize, scraping, scrape, login, ruby

How to add OpenID support to your Rails application with the open_id_authentication plugin

Ruby posted 8 months ago by christian

These instructions have been tested with Rails 2.0.2 and ruby-openid 2.0.4. The snippet is an adaptation of the instructions in Ryan Bates’ screencast on how to integrate OpenID with Rails.

Installing and configuring the restful_authentication plugin

Follow these instructions: How to install and use the restful_authentication Rails plugin.

Installing the ruby-openid gem

   1  gem install ruby-openid

Installing the open_id_authentication Rails plugin

   1  script/plugin source http://svn.techno-weenie.net/projects/plugins/
   2  script/plugin install open_id_authentication

Create the migration files

   1  rake open_id_authentication:db:create

Add the following to the self.up method in 002_add_open_id_authentication_tables.rb:

   1  add_column :users, :identity_url, :string

Configuring the routes

   1  map.open_id_complete 'session', :controller => "sessions", :action => "create", :requirements => { :method => :get }

Protect the identity_url field

Next protect the identity_url field, by adding the following to user.rb, account.rb or your custom user model:

   1  attr_accessible :login, :email, :password, :password_confirmation, :identity_url

Add the following to the self.down method in 002_add_open_id_authentication_tables.rb:

   1  remove_column :users, :identity_url

Integrating Open-id with the login page

Add the following to sessions/new.html.erb:

   1  <label for="openid_url">OpenID URL</label><br />
   2  <%= text_field_tag "openid_url" %>

Make sure you’re showing flash messages, otherwise you won’t see the error messages:

   1  <html>
   2    <head></head>
   3    <body>
   4      <%= [:notice, :error].collect {|type| content_tag('div', flash[type], :id => type) if flash[type] } %>
   5  
   6      <%= yield %>
   7    </body>
   8  </html>

Modifying the sessions controller

Copy & paste the following code in app/controllers/sessions_controller.rb:

   1  class SessionsController < ApplicationController
   2    # Hack to fix: No action responded to show
   3    def show
   4      create
   5    end
   6  
   7    def create
   8      if using_open_id?
   9        open_id_authentication(params[:openid_url])
  10      else
  11        password_authentication(params[:login], params[:password])
  12      end
  13    end
  14  
  15    def destroy
  16      self.current_user.forget_me if logged_in?
  17      cookies.delete :auth_token
  18      reset_session
  19      flash[:notice] = "You have been logged out."
  20      redirect_back_or_default('/')
  21    end
  22  
  23    protected
  24  
  25    def open_id_authentication(openid_url)
  26      authenticate_with_open_id(openid_url, :required => [:nickname, :email]) do |result, identity_url, registration|
  27        if result.successful?
  28          @user = User.find_or_initialize_by_identity_url(identity_url)
  29          if @user.new_record?
  30            @user.login = registration['nickname']
  31            @user.email = registration['email']
  32            @user.save(false)
  33          end
  34          self.current_user = @user
  35          successful_login
  36        else
  37          failed_login result.message
  38        end
  39      end
  40    end
  41  
  42    def password_authentication(login, password)
  43      self.current_user = User.authenticate(login, password)
  44      if logged_in?
  45        successful_login
  46      else
  47        failed_login
  48      end
  49    end
  50  
  51    def failed_login(message = "Authentication failed.")
  52      flash.now[:error] = message
  53      render :action => 'new'
  54    end
  55  
  56    def successful_login
  57      if params[:remember_me] == "1"
  58        self.current_user.remember_me
  59        cookies[:auth_token] = { :value => self.current_user.remember_token , :expires => self.current_user.remember_token_expires_at }
  60      end
  61      redirect_back_or_default('/')
  62      flash[:notice] = "Logged in successfully"
  63    end
  64  end

OpenID authentication from behind a proxy

First, set the HTTP _PROXY environment variable to the proxy URL :

   1  export HTTP_PROXY=http://proxy.aktagon.com:8080/

Then add the following to environment.rb:

   1  OpenID::fetcher_use_env_http_proxy

Tagged openid, authentication, rails, ruby, plugin, restful_authentication

How to install and use the restful_authentication Rails plugin

Ruby posted 8 months ago by christian

This is an adaptation of the restful_authentication screencast by Ryan Bates, which has an issue with Rails 2.0.3 that throws the following error:

   1  NameError (uninitialized constant SessionsController):
   2      /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:266:in `load_missing_constant'
   3      /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:453:in `const_missing'
   4      /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:465:in `const_missing'
   5      /usr/local/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/inflector.rb:257:in `constantize'

Installing the restful_authentication plugin

   1  script/plugin source http://svn.techno-weenie.net/projects/plugins/
   2  script/plugin install restful_authentication

Generating the model and controller

   1  script/generate authenticated user sessions

Now run the migration: 

   1  rake db:migrate

Configure routing

Open config/routes.rb and add the following routes:

   1  map.resources :users
   2  map.resource  :session
   3  
   4  map.signup '/signup', :controller => 'users', :action => 'new'
   5  map.login  '/login', :controller => 'sessions', :action => 'new'
   6  map.logout '/logout', :controller => 'sessions', :action => 'destroy'

Include restful_authentication in ApplicationController

First remove these lines from the users and sessions controllers:

   1  # Be sure to include AuthenticationSystem in Application Controller instead
   2    include AuthenticatedSystem

Now include restful_authentication in the application controller:

   1  class ApplicationController < ActionController::Base
   2    include AuthenticatedSystem

Integrate restful_authentication with your views

First let’s create a controller and view by executing the generate script:

   1  script/generate controller home index

Modify index.html.erb as follows:

   1  <h1>Welcome</h1>
   2  
   3  <% if logged_in? %>
   4    <p><strong>You are logged in as <%=h current_user.login %></strong></p>
   5    <p><%= link_to 'Logout', logout_path %></p>
   6  <% else %>
   7    <p><strong>You are currently not logged in.</strong></p>
   8    <p>
   9      <%= link_to 'Login', login_path %> or
  10      <%= link_to 'Sign Up', signup_path %>
  11    </p>
  12  <% end %>

Start Rails and access your application. If needed, add the following to config/routes.rb to make the home controller the default:

   1  map.root :controller => "home"

Login, sign up and logout should work.

Tagged rails, ruby, authentication, restful_authentication