forem: allow anonymous user to create post/topic

application_controller.rb

# app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  layout "general"
  helper_method :forem_user

  def forem_user
    current_user || anonymous_user
  end

  # creates anonymous user and store user_id in session
  def anonymous_user
    return @anonymous_user if @anonymous_user
    if session[:anonymous_user_id]
      @anonymous_user = User.find_by_id(session[:anonymous_user_id])
    else
      @anonymous_user = User.anonymous!
    end
    session[:anonymous_user_id] = @anonymous_user ? @anonymous_user.id : nil
    @anonymous_user
  end

  protect_from_forgery
end

application_controller_decorator.rb

# app/decorators/controllers/forem/application_controller_decorator.rb

Forem::ApplicationController.class_eval do

  private

  def authenticate_forem_user
    # there will be always anonymous user so check that also and redirect to sign_in path accordingly
    if !forem_user || forem_user.anonymous?
      session["user_return_to"] = request.fullpath
      flash.alert = t("forem.errors.not_signed_in")
      redirect_to Forem.sign_in_path || main_app.sign_in_path
    end
  end

  def forem_admin?
    forem_user && !forem_user.anonymous? && forem_user.forem_admin?
  end
  helper_method :forem_admin?

  def forem_admin_or_moderator?(forum)
    forem_user && !forem_user.anonymous? && (forem_user.forem_admin? || forum.moderator?(forem_user))
  end
  helper_method :forem_admin_or_moderator?

end

topics_controller_decorator.rb

# app/decorators/controllers/forem/topics_controller_decorator.rb

Forem::TopicsController.class_eval do
  before_filter :authenticate_forem_user, :except => [:new, :show, :create]
  skip_before_filter :block_spammers
end

user.rb

# app/models/user.rb

class User < ActiveRecord::Base
  has_many :posts, :class_name => "Forem::Post", :dependent => :destroy
  has_many :topics, :class_name => "Forem::Topic", :dependent => :destroy
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable,
  # :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :name, :username, :country, :gender, :password, :password_confirmation, :remember_me, :persistence_token

  def to_s
    name
  end

  # Creates an anonymous user.  An anonymous user is basically an auto-generated +User+ account that is created for the guest user
  def self.anonymous!
    token = User.generate_token(:persistence_token)
    User.create(:email => "#{token}@example.net", :password => token, :password_confirmation => token, :persistence_token => token, :username => "#{token}", :gender => "male", :name => "#{token}")
  end

  def anonymous?
    email =~ /@example.net$/
  end

  # override default permission to support allow_anonymous flag
  def can_create_forem_topics?(forum)
    self.anonymous? ? forum.allow_anonymous : true
  end

  private

  # Generate a friendly string randomically to be used as token.
  def self.friendly_token
    SecureRandom.base64(15).tr('+/=', '-_ ').strip.delete("\n")
  end

  # Generate a token by looping and ensuring does not already exist.
  def self.generate_token(column)
    loop do
      token = friendly_token
      break token unless find(:first, :conditions => { column => token })
    end
  end
end