use a controller method to handle cancan denials

[rails.git] / app / controllers / application_controller.rb

class ApplicationController < ActionController::Base
  include SessionPersistence
  # check_authorization

  protect_from_forgery :with => :exception

  rescue_from CanCan::AccessDenied, :with => :deny_access

  before_action :fetch_body
  around_action :better_errors_allow_inline, :if => proc { Rails.env.development? }

  attr_accessor :current_user
  helper_method :current_user

  def authorize_web
    if session[:user]
      self.current_user = User.where(:id => session[:user]).where("status IN ('active', 'confirmed', 'suspended')").first

      if current_user.status == "suspended"
        session.delete(:user)
        session_expires_automatically

        redirect_to :controller => "user", :action => "suspended"

      # don't allow access to any auth-requiring part of the site unless
      # the new CTs have been seen (and accept/decline chosen).
      elsif !current_user.terms_seen && flash[:skip_terms].nil?
        flash[:notice] = t "user.terms.you need to accept or decline"
        if params[:referer]
          redirect_to :controller => "user", :action => "terms", :referer => params[:referer]
        else
          redirect_to :controller => "user", :action => "terms", :referer => request.fullpath
        end
      end
    elsif session[:token]
      session[:user] = current_user.id if self.current_user = User.authenticate(:token => session[:token])
    end
  rescue StandardError => ex
    logger.info("Exception authorizing user: #{ex}")
    reset_session
    self.current_user = nil
  end

  def require_user
    unless current_user
      if request.get?
        redirect_to :controller => "user", :action => "login", :referer => request.fullpath
      else
        head :forbidden
      end
    end
  end

  def require_oauth
    @oauth = current_user.access_token(OAUTH_KEY) if current_user && defined? OAUTH_KEY
  end

  ##
  # requires the user to be logged in by the token or HTTP methods, or have an
  # OAuth token with the right capability. this method is a bit of a pain to call
  # directly, since it's cumbersome to call filters with arguments in rails. to
  # make it easier to read and write the code, there are some utility methods
  # below.
  def require_capability(cap)
    # when the current token is nil, it means the user logged in with a different
    # method, otherwise an OAuth token was used, which has to be checked.
    unless current_token.nil?
      unless current_token.read_attribute(cap)
        set_locale
        report_error t("oauth.permissions.missing"), :forbidden
        false
      end
    end
  end

  ##
  # require the user to have cookies enabled in their browser
  def require_cookies
    if request.cookies["_osm_session"].to_s == ""
      if params[:cookie_test].nil?
        session[:cookie_test] = true
        redirect_to params.to_unsafe_h.merge(:cookie_test => "true")
        false
      else
        flash.now[:warning] = t "application.require_cookies.cookies_needed"
      end
    else
      session.delete(:cookie_test)
    end
  end

  # Utility methods to make the controller filter methods easier to read and write.
  def require_allow_read_prefs
    require_capability(:allow_read_prefs)
  end

  def require_allow_write_prefs
    require_capability(:allow_write_prefs)
  end

  def require_allow_write_diary
    require_capability(:allow_write_diary)
  end

  def require_allow_write_api
    require_capability(:allow_write_api)

    if REQUIRE_TERMS_AGREED && current_user.terms_agreed.nil?
      report_error "You must accept the contributor terms before you can edit.", :forbidden
      return false
    end
  end

  def require_allow_read_gpx
    require_capability(:allow_read_gpx)
  end

  def require_allow_write_gpx
    require_capability(:allow_write_gpx)
  end

  def require_allow_write_notes
    require_capability(:allow_write_notes)
  end

  ##
  # require that the user is a moderator, or fill out a helpful error message
  # and return them to the index for the controller this is wrapped from.
  def require_moderator
    unless current_user.moderator?
      if request.get?
        flash[:error] = t("application.require_moderator.not_a_moderator")
        redirect_to :action => "index"
      else
        head :forbidden
      end
    end
  end

  ##
  # sets up the current_user for use by other methods. this is mostly called
  # from the authorize method, but can be called elsewhere if authorisation
  # is optional.
  def setup_user_auth
    # try and setup using OAuth
    unless Authenticator.new(self, [:token]).allow?
      username, passwd = get_auth_data # parse from headers
      # authenticate per-scheme
      self.current_user = if username.nil?
                            nil # no authentication provided - perhaps first connect (client should retry after 401)
                          elsif username == "token"
                            User.authenticate(:token => passwd) # preferred - random token for user from db, passed in basic auth
                          else
                            User.authenticate(:username => username, :password => passwd) # basic auth
                          end
    end

    # have we identified the user?
    if current_user
      # check if the user has been banned
      user_block = current_user.blocks.active.take
      unless user_block.nil?
        set_locale
        if user_block.zero_hour?
          report_error t("application.setup_user_auth.blocked_zero_hour"), :forbidden
        else
          report_error t("application.setup_user_auth.blocked"), :forbidden
        end
      end

      # if the user hasn't seen the contributor terms then don't
      # allow editing - they have to go to the web site and see
      # (but can decline) the CTs to continue.
      if REQUIRE_TERMS_SEEN && !current_user.terms_seen && flash[:skip_terms].nil?
        set_locale
        report_error t("application.setup_user_auth.need_to_see_terms"), :forbidden
      end
    end
  end

  def authorize(realm = "Web Password", errormessage = "Couldn't authenticate you")
    # make the current_user object from any auth sources we have
    setup_user_auth

    # handle authenticate pass/fail
    unless current_user
      # no auth, the user does not exist or the password was wrong
      response.headers["WWW-Authenticate"] = "Basic realm=\"#{realm}\""
      render :plain => errormessage, :status => :unauthorized
      return false
    end
  end

  ##
  # to be used as a before_filter *after* authorize. this checks that
  # the user is a moderator and, if not, returns a forbidden error.
  #
  # NOTE: this isn't a very good way of doing it - it duplicates logic
  # from require_moderator - but what we really need to do is a fairly
  # drastic refactoring based on :format and respond_to? but not a
  # good idea to do that in this branch.
  def authorize_moderator(errormessage = "Access restricted to moderators")
    # check user is a moderator
    unless current_user.moderator?
      render :plain => errormessage, :status => :forbidden
      false
    end
  end

  def check_database_readable(need_api = false)
    if STATUS == :database_offline || (need_api && STATUS == :api_offline)
      if request.xhr?
        report_error "Database offline for maintenance", :service_unavailable
      else
        redirect_to :controller => "site", :action => "offline"
      end
    end
  end

  def check_database_writable(need_api = false)
    if STATUS == :database_offline || STATUS == :database_readonly ||
       (need_api && (STATUS == :api_offline || STATUS == :api_readonly))
      if request.xhr?
        report_error "Database offline for maintenance", :service_unavailable
      else
        redirect_to :controller => "site", :action => "offline"
      end
    end
  end

  def check_api_readable
    if api_status == :offline
      report_error "Database offline for maintenance", :service_unavailable
      false
    end
  end

  def check_api_writable
    unless api_status == :online
      report_error "Database offline for maintenance", :service_unavailable
      false
    end
  end

  def database_status
    if STATUS == :database_offline
      :offline
    elsif STATUS == :database_readonly
      :readonly
    else
      :online
    end
  end

  def api_status
    status = database_status
    if status == :online
      if STATUS == :api_offline
        status = :offline
      elsif STATUS == :api_readonly
        status = :readonly
      end
    end
    status
  end

  def gpx_status
    status = database_status
    status = :offline if status == :online && STATUS == :gpx_offline
    status
  end

  def require_public_data
    unless current_user.data_public?
      report_error "You must make your edits public to upload new data", :forbidden
      false
    end
  end

  # Report and error to the user
  # (If anyone ever fixes Rails so it can set a http status "reason phrase",
  #  rather than only a status code and having the web engine make up a
  #  phrase from that, we can also put the error message into the status
  #  message. For now, rails won't let us)
  def report_error(message, status = :bad_request)
    # TODO: some sort of escaping of problem characters in the message
    response.headers["Error"] = message

    if request.headers["X-Error-Format"] &&
       request.headers["X-Error-Format"].casecmp("xml").zero?
      result = OSM::API.new.get_xml_doc
      result.root.name = "osmError"
      result.root << (XML::Node.new("status") << "#{Rack::Utils.status_code(status)} #{Rack::Utils::HTTP_STATUS_CODES[status]}")
      result.root << (XML::Node.new("message") << message)

      render :xml => result.to_s
    else
      render :plain => message, :status => status
    end
  end

  def preferred_languages(reset = false)
    @preferred_languages = nil if reset
    @preferred_languages ||= if params[:locale]
                               Locale.list(params[:locale])
                             elsif current_user
                               current_user.preferred_languages
                             else
                               Locale.list(http_accept_language.user_preferred_languages)
                             end
  end

  helper_method :preferred_languages

  def set_locale(reset = false)
    if current_user && current_user.languages.empty? && !http_accept_language.user_preferred_languages.empty?
      current_user.languages = http_accept_language.user_preferred_languages
      current_user.save
    end

    I18n.locale = Locale.available.preferred(preferred_languages(reset))

    response.headers["Vary"] = "Accept-Language"
    response.headers["Content-Language"] = I18n.locale.to_s
  end

  def api_call_handle_error
    yield
  rescue ActiveRecord::RecordNotFound => ex
    head :not_found
  rescue LibXML::XML::Error, ArgumentError => ex
    report_error ex.message, :bad_request
  rescue ActiveRecord::RecordInvalid => ex
    message = "#{ex.record.class} #{ex.record.id}: "
    ex.record.errors.each { |attr, msg| message << "#{attr}: #{msg} (#{ex.record[attr].inspect})" }
    report_error message, :bad_request
  rescue OSM::APIError => ex
    report_error ex.message, ex.status
  rescue AbstractController::ActionNotFound => ex
    raise
  rescue StandardError => ex
    logger.info("API threw unexpected #{ex.class} exception: #{ex.message}")
    ex.backtrace.each { |l| logger.info(l) }
    report_error "#{ex.class}: #{ex.message}", :internal_server_error
  end

  ##
  # asserts that the request method is the +method+ given as a parameter
  # or raises a suitable error. +method+ should be a symbol, e.g: :put or :get.
  def assert_method(method)
    ok = request.send((method.to_s.downcase + "?").to_sym)
    raise OSM::APIBadMethodError, method unless ok
  end

  ##
  # wrap an api call in a timeout
  def api_call_timeout
    OSM::Timer.timeout(API_TIMEOUT, Timeout::Error) do
      yield
    end
  rescue Timeout::Error
    raise OSM::APITimeoutError
  end

  ##
  # wrap a web page in a timeout
  def web_timeout
    OSM::Timer.timeout(WEB_TIMEOUT, Timeout::Error) do
      yield
    end
  rescue ActionView::Template::Error => ex
    ex = ex.cause

    if ex.is_a?(Timeout::Error) ||
       (ex.is_a?(ActiveRecord::StatementInvalid) && ex.message =~ /execution expired/)
      render :action => "timeout"
    else
      raise
    end
  rescue Timeout::Error
    render :action => "timeout"
  end

  ##
  # ensure that there is a "user" instance variable
  def lookup_user
    render_unknown_user params[:display_name] unless @user = User.active.find_by(:display_name => params[:display_name])
  end

  ##
  # render a "no such user" page
  def render_unknown_user(name)
    @title = t "user.no_such_user.title"
    @not_found_user = name

    respond_to do |format|
      format.html { render :template => "user/no_such_user", :status => :not_found }
      format.all { head :not_found }
    end
  end

  ##
  # Unfortunately if a PUT or POST request that has a body fails to
  # read it then Apache will sometimes fail to return the response it
  # is given to the client properly, instead erroring:
  #
  #   https://issues.apache.org/bugzilla/show_bug.cgi?id=44782
  #
  # To work round this we call rewind on the body here, which is added
  # as a filter, to force it to be fetched from Apache into a file.
  def fetch_body
    request.body.rewind
  end

  def map_layout
    append_content_security_policy_directives(
      :child_src => %w[http://127.0.0.1:8111 https://127.0.0.1:8112],
      :frame_src => %w[http://127.0.0.1:8111 https://127.0.0.1:8112],
      :connect_src => %w[nominatim.openstreetmap.org overpass-api.de router.project-osrm.org graphhopper.com],
      :form_action => %w[render.openstreetmap.org],
      :script_src => %w[open.mapquestapi.com],
      :img_src => %w[developer.mapquest.com]
    )

    if STATUS == :database_offline || STATUS == :api_offline
      flash.now[:warning] = t("layouts.osm_offline")
    elsif STATUS == :database_readonly || STATUS == :api_readonly
      flash.now[:warning] = t("layouts.osm_read_only")
    end

    request.xhr? ? "xhr" : "map"
  end

  def allow_thirdparty_images
    append_content_security_policy_directives(:img_src => %w[*])
  end

  def preferred_editor
    editor = if params[:editor]
               params[:editor]
             elsif current_user && current_user.preferred_editor
               current_user.preferred_editor
             else
               DEFAULT_EDITOR
             end

    editor
  end

  helper_method :preferred_editor

  def update_totp
    if defined?(TOTP_KEY)
      cookies["_osm_totp_token"] = {
        :value => ROTP::TOTP.new(TOTP_KEY, :interval => 3600).now,
        :domain => "openstreetmap.org",
        :expires => 1.hour.from_now
      }
    end
  end

  def better_errors_allow_inline
    yield
  rescue StandardError
    append_content_security_policy_directives(
      :script_src => %w['unsafe-inline'],
      :style_src => %w['unsafe-inline']
    )

    raise
  end

  def current_ability
    Ability.new(current_user, current_token)
  end

  def deny_access(exception)
    if current_user
      raise "Access denied on #{exception.action} #{exception.subject.inspect}"
      # ...
    else
      require_user
    end
  end

  private

  # extract authorisation credentials from headers, returns user = nil if none
  def get_auth_data
    if request.env.key? "X-HTTP_AUTHORIZATION" # where mod_rewrite might have put it
      authdata = request.env["X-HTTP_AUTHORIZATION"].to_s.split
    elsif request.env.key? "REDIRECT_X_HTTP_AUTHORIZATION" # mod_fcgi
      authdata = request.env["REDIRECT_X_HTTP_AUTHORIZATION"].to_s.split
    elsif request.env.key? "HTTP_AUTHORIZATION" # regular location
      authdata = request.env["HTTP_AUTHORIZATION"].to_s.split
    end
    # only basic authentication supported
    user, pass = Base64.decode64(authdata[1]).split(":", 2) if authdata && authdata[0] == "Basic"
    [user, pass]
  end

  # override to stop oauth plugin sending errors
  def invalid_oauth_response; end
end