discourse/app/controllers/embed_controller.rb

# frozen_string_literal: true

class EmbedController < ApplicationController
  include TopicQueryParams

  skip_before_action :check_xhr, :preload_json, :verify_authenticity_token

  before_action :ensure_embeddable, except: [ :info, :topics ]
  before_action :prepare_embeddable, except: [ :info ]
  before_action :ensure_api_request, only: [ :info ]

  layout 'embed'

  rescue_from Discourse::InvalidAccess do
    response.headers.delete('X-Frame-Options')
    if current_user.try(:admin?)
      @setup_url = "#{Discourse.base_url}/admin/customize/embedding"
      @show_reason = true
      @hosts = EmbeddableHost.all
    end
    render 'embed_error', status: 400
  end

  def topics
    discourse_expires_in 1.minute

    response.headers.delete('X-Frame-Options')
    unless SiteSetting.embed_topics_list?
      render 'embed_topics_error', status: 400
      return
    end

    if @embed_id = params[:discourse_embed_id]
      raise Discourse::InvalidParameters.new(:embed_id) unless @embed_id =~ /^de\-[a-zA-Z0-9]+$/
    end

    if @embed_class = params[:embed_class]
      raise Discourse::InvalidParameters.new(:embed_class) unless @embed_class =~ /^[a-zA-Z0-9\-_]+$/
    end

    if params.has_key?(:template) && params[:template] == "complete"
      @template = "complete"
    else
      @template = "basic"
    end

    list_options = build_topic_list_options

    if params.has_key?(:per_page)
      list_options[:per_page] =
        [params[:per_page].to_i, SiteSetting.embed_topic_limit_per_page].min
    end

    if params[:allow_create]
      @allow_create = true
      create_url_params = {}
      create_url_params[:category_id] = params[:category] if params[:category].present?
      create_url_params[:tags] = params[:tags] if params[:tags].present?
      @create_url = "#{Discourse.base_url}/new-topic?#{create_url_params.to_query}"
    end

    topic_query = TopicQuery.new(current_user, list_options)
    top_period = params[:top_period]&.to_sym
    valid_top_period = TopTopic.periods.include?(top_period)

    @list = if valid_top_period
      topic_query.list_top_for(top_period)
    else
      topic_query.list_latest
    end
  end

  def comments
    embed_url = params[:embed_url]
    embed_username = params[:discourse_username]

    topic_id = nil
    if embed_url.present?
      topic_id = TopicEmbed.topic_id_for_embed(embed_url)
    else
      topic_id = params[:topic_id].to_i
    end

    if topic_id
      @topic_view = TopicView.new(topic_id,
                                  current_user,
                                  limit: SiteSetting.embed_post_limit,
                                  only_regular: true,
                                  exclude_first: true,
                                  exclude_deleted_users: true,
                                  exclude_hidden: true)

      @second_post_url = "#{@topic_view.topic.url}/2" if @topic_view
      @posts_left = 0
      if @topic_view && @topic_view.posts.size == SiteSetting.embed_post_limit
        @posts_left = @topic_view.topic.posts_count - SiteSetting.embed_post_limit - 1
      end

      if @topic_view
        @reply_count = @topic_view.topic.posts_count - 1
        @reply_count = 0 if @reply_count < 0
      end
    elsif embed_url.present?
      Jobs.enqueue(:retrieve_topic,
                      user_id: current_user.try(:id),
                      embed_url: embed_url,
                      author_username: embed_username,
                      referer: request.env['HTTP_REFERER']
                  )
      render 'loading'
    end

    discourse_expires_in 1.minute
  end

  def info
    embed_url = params.require(:embed_url)
    @topic_embed = TopicEmbed.where(embed_url: embed_url).first

    raise Discourse::NotFound if @topic_embed.nil?

    render_serialized(@topic_embed, TopicEmbedSerializer, root: false)
  end

  def count
    embed_urls = params[:embed_url]
    by_url = {}

    if embed_urls.present?
      urls = embed_urls.map { |u| u.sub(/#discourse-comments$/, '').sub(/\/$/, '') }
      topic_embeds = TopicEmbed.where(embed_url: urls).includes(:topic).references(:topic)

      topic_embeds.each do |te|
        url = te.embed_url
        url = "#{url}#discourse-comments" unless params[:embed_url].include?(url)
        if te.topic.present?
          by_url[url] = I18n.t('embed.replies', count: te.topic.posts_count - 1)
        else
          by_url[url] = I18n.t('embed.replies', count: 0)
        end
      end
    end

    render json: { counts: by_url }, callback: params[:callback]
  end

  private

  def prepare_embeddable
    @embeddable_css_class = ""
    embeddable_host = EmbeddableHost.record_for_url(request.referer)
    @embeddable_css_class = " class=\"#{embeddable_host.class_name}\"" if embeddable_host.present? && embeddable_host.class_name.present?

    @data_referer = request.referer
    @data_referer = '*' if SiteSetting.embed_any_origin? && @data_referer.blank?
  end

  def ensure_api_request
    raise Discourse::InvalidAccess.new('api key not set') if !is_api?
  end

  def ensure_embeddable
    if !(Rails.env.development? && current_user&.admin?)
      referer = request.referer

      unless referer && EmbeddableHost.url_allowed?(referer)
        raise Discourse::InvalidAccess.new('invalid referer host')
      end
    end

    response.headers.delete('X-Frame-Options')
  rescue URI::Error
    raise Discourse::InvalidAccess.new('invalid referer host')
  end

end