Class: TopicLinkClick

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
app/models/topic_link_click.rb

Constant Summary collapse

ALLOWED_REDIRECT_HOSTNAMES = 
Set.new(%W[www.youtube.com youtu.be])

Class Method Summary collapse

Class Method Details

.create_from(args = {}) ⇒ Object

Create a click from a URL and post_id



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# File 'app/models/topic_link_click.rb', line 15

def self.create_from(args = {})
  url = args[:url][0...TopicLink.max_url_length]
  return nil if url.blank?

  uri = UrlHelper.relaxed_parse(url)
  urls = Set.new
  urls << url
  if url =~ /\Ahttp/
    urls << url.sub(/\Ahttps/, "http")
    urls << url.sub(/\Ahttp:/, "https:")
    urls << UrlHelper.schemaless(url)
  end
  urls << UrlHelper.absolute_without_cdn(url)
  urls << uri.path if uri.try(:host) == Discourse.current_hostname

  query = url.index("?")
  unless query.nil?
    endpos = url.index("#") || url.size
    urls << url[0..query - 1] + url[endpos..-1]
  end

  # link can have query params, and analytics can add more to the end:
  i = url.length
  while i = url.rindex("&", i - 1)
    urls << url[0...i]
  end

  # add a cdn link
  if uri
    if Discourse.asset_host.present?
      cdn_uri =
        begin
          URI.parse(Discourse.asset_host)
        rescue URI::Error
        end

      if cdn_uri && cdn_uri.hostname == uri.hostname && uri.path.starts_with?(cdn_uri.path)
        is_cdn_link = true
        urls << uri.path[cdn_uri.path.length..-1]
      end
    end

    if SiteSetting.Upload.s3_cdn_url.present?
      cdn_uri =
        begin
          URI.parse(SiteSetting.Upload.s3_cdn_url)
        rescue URI::Error
        end

      if cdn_uri && cdn_uri.hostname == uri.hostname && uri.path.starts_with?(cdn_uri.path)
        is_cdn_link = true
        path = uri.path[cdn_uri.path.length..-1]
        urls << path
        urls << "#{Discourse.store.absolute_base_url}#{path}"
      end
    end
  end

  # test for all possible URLs
  link = TopicLink.where(url: urls)

  # Find the forum topic link
  link = link.where(post_id: args[:post_id]) if args[:post_id].present?

  # If we don't have a post, just find the first occurrence of the link
  link = link.where(topic_id: args[:topic_id]) if args[:topic_id].present?

  # select the TopicLink associated to first url
  link =
    link.order(
      "array_position(ARRAY[#{urls.map { |s| "#{ActiveRecord::Base.connection.quote(s)}" }.join(",")}], url::text)",
    ).first

  # If no link is found...
  unless link.present?
    # ... return the url for relative links or when using the same host
    return url if url =~ %r{\A/[^/]} || uri.try(:host) == Discourse.current_hostname

    # If we have it somewhere else on the site, just allow the redirect.
    # This is likely due to a onebox of another topic.
    link = TopicLink.find_by(url: url)
    return link.url if link.present?

    return nil unless uri

    # Only redirect to allowlisted hostnames
    return url if ALLOWED_REDIRECT_HOSTNAMES.include?(uri.hostname) || is_cdn_link

    return nil
  end

  return url if args[:user_id] && link.user_id == args[:user_id]

  # Rate limit the click counts to once in 24 hours
  rate_key = "link-clicks:#{link.id}:#{args[:user_id] || args[:ip]}"
  if Discourse.redis.setnx(rate_key, "1")
    Discourse.redis.expire(rate_key, 1.day.to_i)
    args[:ip] = nil if args[:user_id]
    create!(topic_link_id: link.id, user_id: args[:user_id], ip_address: args[:ip])
  end

  url
end