application_controller.rb

# -*- encoding : utf-8 -*-
# controllers/application.rb:
# Parent class of all controllers in FOI site. Filters added to this controller
# apply to all controllers in the application. Likewise, all the methods added
# will be available for all controllers.
#
# Copyright (c) 2007 UK Citizens Online Democracy. All rights reserved.
# Email: hello@mysociety.org; WWW: http://www.mysociety.org/

require 'open-uri'

class ApplicationController < ActionController::Base
  class PermissionDenied < StandardError
  end
  class RouteNotFound < StandardError
  end
  protect_from_forgery :if => :user?, :with => :exception
  skip_before_action :verify_authenticity_token, :unless => :user?

  # Deal with access denied errors from CanCan
  rescue_from CanCan::AccessDenied do |exception|
    raise PermissionDenied
  end

  # assign our own handler method for non-local exceptions
  rescue_from Exception, :with => :render_exception

  # Standard headers, footers and navigation for whole site
  layout "default"
  include FastGettext::Translation # make functions like _, n_, N_ etc available)
  include AlaveteliPro::PostRedirectHandler

  # Note: a filter stops the chain if it redirects or renders something
  before_action :authentication_check
  before_action :set_gettext_locale
  before_action :check_in_post_redirect
  before_action :session_remember_me
  before_action :set_vary_header
  before_action :validate_session_timestamp
  before_action :collect_locales
  after_action  :persist_session_timestamp

  def set_vary_header
    response.headers['Vary'] = 'Cookie'
  end

  helper_method :anonymous_cache, :short_cache, :medium_cache, :long_cache
  def anonymous_cache(time)
    if session[:user_id].nil?
      headers['Cache-Control'] = "max-age=#{time}, public"
    end
  end

  def short_cache
    anonymous_cache(60.seconds)
  end

  def medium_cache
    anonymous_cache(60.minutes)
  end

  def long_cache
    anonymous_cache(24.hours)
  end

  # This is an override of the method provided by gettext_i18n_rails.
  # AlaveteliLocalization.set_session_locale explicitly sets I18n.locale,
  # required due to the I18nProxy used in Rails to trigger the
  # lookup_context and expire the template cache
  def set_gettext_locale
    if AlaveteliConfiguration.include_default_locale_in_urls == false
      params_locale = params.fetch(:locale) do
        AlaveteliLocalization.default_locale
      end
    else
      params_locale = params[:locale]
    end
    browser_locale = if AlaveteliConfiguration.use_default_browser_language
      request.env['HTTP_ACCEPT_LANGUAGE']
    else
      nil
    end
    AlaveteliLocalization.set_session_locale(params_locale,
                                             session[:locale],
                                             cookies[:locale],
                                             browser_locale)
    # set the currrent locale to the requested_locale
    session[:locale] = AlaveteliLocalization.locale
    if !@user.nil?
      if @user.locale != AlaveteliLocalization.locale
        @user.locale = AlaveteliLocalization.locale
        @user.save!
      end
    end
  end

  # Help work out which request causes RAM spike.
  # http://www.codeweblog.com/rails-to-monitor-the-process-of-memory-leaks-skills/
  # This shows the memory use increase of the Ruby process due to the request.
  # Since Ruby never returns memory to the OS, if the existing process previously
  # served a larger request, this won't show any consumption for the later request.
  # Ruby also grabs memory from the OS in variously sized jumps, so the extra
  # consumption of a request shown by this function will only appear in such
  # jumps.
  #
  # To find things that are using causing LOTS of peak memory, then do something like:
  # egrep "CONSUME MEMORY: [0-9]{7} KB" production.log
  around_action :record_memory
  def record_memory
    record_memory = AlaveteliConfiguration::debug_record_memory
    if record_memory
      logger.info "Processing request for #{request.url} with Rails process #{Process.pid}"
      File.read("/proc/#{Process.pid}/status").match(/VmRSS:\s+(\d+)/)
      rss_before_action = $1.to_i
      yield
      File.read("/proc/#{Process.pid}/status").match(/VmRSS:\s+(\d+)/)
      rss_after_action = $1.to_i
      logger.info("PID: #{Process.pid}\tCONSUME MEMORY: #{rss_after_action - rss_before_action} KB\tNow: #{rss_after_action} KB\t#{request.url}")
    else
      yield
    end
  end

  # Set cookie expiry according to "remember me" checkbox, as per "An easier
  # and more flexible hack" on this page:
  #   http://wiki.rubyonrails.org/rails/pages/HowtoChangeSessionOptions
  def session_remember_me
    # Reset the "sliding window" session expiry time.
    if request.env['rack.session.options']
      if session[:remember_me]
        request.env['rack.session.options'][:expire_after] = 1.month
      else
        request.env['rack.session.options'][:expire_after] = nil
      end
    end
  end

  # Set a TTL for non "remember me" sessions so that the cookie
  # is not replayable forever
  SESSION_TTL = 3.hours
  def validate_session_timestamp
    if session[:user_id] && session[:ttl] && session[:ttl] < SESSION_TTL.ago
      clear_session_credentials
    end
  end

  def persist_session_timestamp
    session[:ttl] = Time.zone.now if session[:user_id] && !session[:remember_me]
  end

  # Logout form
  def clear_session_credentials
    session[:user_id] = nil
    session[:user_circumstance] = nil
    session[:remember_me] = false
    session[:using_admin] = nil
    session[:admin_name] = nil
    session[:change_password_post_redirect_id] = nil
    session[:post_redirect_token] = nil
    session[:ttl] = nil
  end

  def render_exception(exception)
    # In development let Rails handle the exception with its stack trace
    # templates.
    if Rails.application.config.consider_all_requests_local
      raise exception
    end

    @exception_backtrace = exception.backtrace.join("\n")
    @exception_class = exception.class.to_s
    @exception_message = exception.message
    case exception
    when ActiveRecord::RecordNotFound, RouteNotFound, WillPaginate::InvalidPage
      @status = 404
      sanitize_path(params)
    when PermissionDenied
      @status = 403
    when ActionController::UnknownFormat
      @status = 406
    else
      message = "\n#{@exception_class} (#{@exception_message}):\n"
      backtrace = Rails.backtrace_cleaner.clean(exception.backtrace, :silent)
      message << "  " << backtrace.join("\n  ")
      Rails.logger.fatal("#{message}\n\n")
      if send_exception_notifications?
        ExceptionNotifier.notify_exception(exception, :env => request.env)
      end
      @status = 500
    end
    respond_to do |format|
      format.html{ render :template => "general/exception_caught", :status => @status }
      format.any{ head @status }
    end
  end

  def render_hidden(template='request/hidden', opts = {})
    response_code = opts.delete(:response_code) { 403 } # forbidden
    options = { :template => template, :status => response_code }.merge(opts)

    respond_to do |format|
      format.html { render(options) }
      format.any { head response_code }
    end
    false
  end

  # Used to work out where to cache fragments. We add an extra path to the
  # URL using the first three digits of the info request id, because we can't
  # have more than 32,000 entries in one directory on an ext3 filesystem.
  def foi_fragment_cache_part_path(param)
    if rails5?
      param =
        param.permit(:incoming_message_id, :part, :file_name, :id,
                     :only_path, :locale, :skip_cache)
    end
    path = url_for(param)
    id = param['id'] || param[:id]
    first_three_digits = id.to_s[0..2]
    path = path.sub("/request/", "/request/" + first_three_digits + "/")
    return path
  end

  def foi_fragment_cache_path(param)
    path = File.join(Rails.root, 'cache', 'views', foi_fragment_cache_part_path(param))
    max_file_length = 255 - 35 # we subtract 35 because tempfile
    # adds on a variable number of
    # characters
    return File.join(File.split(path).map{|x| x[0...max_file_length]})
  end

  def foi_fragment_cache_exists?(key_path)
    return File.exists?(key_path)
  end

  def foi_fragment_cache_read(key_path)
    logger.info "Reading from fragment cache #{key_path}"
    return File.read(key_path)
  end

  def foi_fragment_cache_write(key_path, content)
    FileUtils.mkdir_p(File.dirname(key_path))
    logger.info "Writing to fragment cache #{key_path}"
    File.atomic_write(key_path) do |f|
      f.write(content)
    end
  end

  # A helper method to set @in_pro_area, for controller actions which are
  # used in both a pro and non-pro context and depend on the :pro parameter
  # to know which one they're displaying.
  # Intended to be used as a before_action, see RequestController for example
  # usage.
  def set_in_pro_area
    @in_pro_area = params[:pro] == "1" && current_user.present? && current_user.is_pro?
  end

  private

  def user?
    !session[:user_id].nil?
  end

  # Override the Rails method to only set the CSRF form token if there is a
  # logged in user
  def form_authenticity_token(*args)
    if user?
      if rails5?
        super
      else
        super()
      end
    end
  end

  # Check the user is logged in
  def authenticated?(reason_params)
    unless session[:user_id]
      post_redirect = PostRedirect.new(:uri => request.fullpath, :post_params => params,
                                       :reason_params => reason_params)
      post_redirect.save!
      # Make sure this redirect does not get cached - it only applies to this user.
      # HTTP 1.1
      headers['Cache-Control'] = 'no-cache, no-store, max-age=0, must-revalidate'
      # HTTP 1.0
      headers['Pragma'] = 'no-cache'
      # Proxies
      headers['Expires'] = '0'
      # 'modal' controls whether the sign-in form will be displayed in the typical full-blown
      # page or on its own, useful for pop-ups
      redirect_to signin_url(:token => post_redirect.token, :modal => params[:modal])
      return false
    end
    return true
  end

  def authenticated_as_user?(user, reason_params)
    reason_params[:user_name] = user.name
    reason_params[:user_url] = show_user_url(:url_name => user.url_name)
    if session[:user_id]
      if session[:user_id] == user.id
        # They are logged in as the right user
        return true
      else
        # They are already logged in, but as the wrong user
        @reason_params = reason_params
        render :template => 'user/wrong_user'
        return
      end
    end
    # They are not logged in at all
    return authenticated?(reason_params)
  end

  # Return logged in user
  def authenticated_user
    if session[:user_id].nil?
      return nil
    else
      begin
        return User.find(session[:user_id])
      rescue ActiveRecord::RecordNotFound
        return nil
      end
    end
  end

  # For CanCanCan and other libs which need a Devise-like current_user method
  alias_method :current_user, :authenticated_user
  helper_method :current_user

  # Do a POST redirect. This is a nasty hack - we store the posted values in
  # the session, and when the GET redirect with "?post_redirect=1" happens,
  # load them in.
  def do_post_redirect(post_redirect, user=nil)
    uri = SafeRedirect.new(post_redirect.uri).path
    if feature_enabled?(:alaveteli_pro) &&
      user &&
      user.is_pro? &&
      session[:admin_confirmation] != 1
      uri = override_post_redirect_for_pro(uri,
                                           post_redirect,
                                           user)
    end
    session[:post_redirect_token] = post_redirect.token
    uri = add_post_redirect_param_to_uri(uri)
    session.delete(:admin_confirmation)
    redirect_to uri
  end

  def add_post_redirect_param_to_uri(uri)
    # TODO: what is the built in Ruby URI munging function that can do this
    # choice of & vs. ? more elegantly than this dumb if statement?
    if uri.include?("?")
      # TODO: This looks odd. What would a fragment identifier be doing server-side?
      #     But it also looks harmless, so I’ll leave it just in case.
      if uri.include?("#")
        uri.sub!("#", "&post_redirect=1#")
      else
        uri += "&post_redirect=1"
      end
    else
      if uri.include?("#")
        uri.sub!("#", "?post_redirect=1#")
      else
        uri += "?post_redirect=1"
      end
    end
    return uri
  end

  # If we are in a faked redirect to POST request, then set post params.
  def check_in_post_redirect
    if params[:post_redirect]
      if session[:post_redirect_token]
        post_redirect =
          PostRedirect.find_by_token(session[:post_redirect_token])
        if post_redirect
          post_redirect_params =
            params_to_unsafe_hash(post_redirect.post_params)
          if rails5?
            params.merge!(post_redirect_params)
          else
            params.update(post_redirect_params)
          end
          params[:post_redirect_user] = post_redirect.user
        end
      else
        logger.warn "Missing post redirect token. " \
                    "Session: #{session.to_hash} " \
                    "IP: #{user_ip} " \
                    "Params: #{params}"
      end
    end
  end

  # Default layout shows user in corner, so needs access to it
  def authentication_check
    if session[:user_id]
      @user = authenticated_user
    end
  end

  #
  def check_read_only
    if !AlaveteliConfiguration::read_only.empty?
      if feature_enabled?(:annotations)
        flash[:notice] = {
          :partial => "general/read_only_annotations.html.erb",
          :locals => {
            :site_name => site_name,
            :read_only => AlaveteliConfiguration.read_only
          }
        }
      else
        flash[:notice] = {
          :partial => "general/read_only.html.erb",
          :locals => {
            :site_name => site_name,
            :read_only => AlaveteliConfiguration.read_only
          }
        }
      end
      redirect_to frontpage_url
    end

  end

  # Convert URL name for sort by order, to Xapian query
  def order_to_sort_by(sortby)
    if sortby.nil?
      return [nil, nil]
    elsif sortby == 'newest'
      return ['created_at', true]
    elsif sortby == 'described'
      return ['described_at', true] # use this for some RSS
    elsif sortby == 'relevant'
      return [nil, nil]
    else
      raise "Unknown sort order " + @sortby
    end
  end

  # Function for search
  def perform_search(models, query, sortby, collapse, per_page = 25, this_page = nil)
    @query = query
    @sortby = sortby

    # Work out sorting method
    order, ascending = order_to_sort_by(@sortby)

    # Peform the search
    @per_page = per_page
    @page = this_page || get_search_page_from_params

    result = ActsAsXapian::Search.new(models, @query,
                                      :offset => (@page - 1) * @per_page,
                                      :limit => @per_page,
                                      :sort_by_prefix => order,
                                      :sort_by_ascending => ascending,
                                      :collapse_by_prefix => collapse
                                      )
    result.results # Touch the results to load them, otherwise accessing them from the view
    # might fail later if the database has subsequently been reopened.
    return result
  end

  def get_search_page_from_params
    page = (params[:page] || "1").to_i
    page = 1 if page < 1
    return page
  end

  def typeahead_search(query, options)
    @page = get_search_page_from_params
    @per_page = options[:per_page] || 25
    options.merge!( :page => @page,
                    :per_page => @per_page )
    typeahead_search = TypeaheadSearch.new(query, options)
    typeahead_search.xapian_search
  end

  # Store last visited pages, for contact form; but only for logged in users, as otherwise this breaks caching
  def set_last_request(info_request)
    if !session[:user_id].nil?
      cookies["last_request_id"] = info_request.id
      cookies["last_body_id"] = nil
    end
  end
  def set_last_body(public_body)
    if !session[:user_id].nil?
      cookies["last_request_id"] = nil
      cookies["last_body_id"] = public_body.id
    end
  end

  def country_from_ip
    return AlaveteliGeoIP.country_code_from_ip(user_ip) if user_ip
    AlaveteliConfiguration::iso_country_code
  end

  def user_ip
    begin
      request.remote_ip
    rescue ActionDispatch::RemoteIp::IpSpoofAttackError
      nil
    end
  end

  def alaveteli_git_commit
    `git log -1 --format="%H"`.strip
  end

  # URL Encode the path parameter for use in render_exception
  #
  # params - the params Hash
  #
  # Returns a Hash
  def sanitize_path(params)
    params.merge!(:path => Rack::Utils.escape(params[:path])) if params.key?(:path)
  end

  # Collect the current and available locales for the locale switcher
  #
  # Returns a Hash
  def collect_locales
    @locales = { :current => AlaveteliLocalization.locale, :available => [] }
    AlaveteliLocalization.available_locales.each do |possible_locale|
      if possible_locale == AlaveteliLocalization.locale
        @locales[:current] = possible_locale
      else
        @locales[:available] << possible_locale
      end
    end
  end

  # URL generating functions are needed by all controllers (for redirects),
  # views (for links) and mailers (for use in emails), so include them into
  # all of all.
  include LinkToHelper

  # Site-wide access to configuration settings
  include ConfigHelper

  include HashableParams
end