- # frozen_string_literal: true
-
- class FetchOEmbedService
- ENDPOINT_CACHE_EXPIRES_IN = 24.hours.freeze
- URL_REGEX = /(=(http[s]?(%3A|:)(\/\/|%2F%2F)))([^&]*)/i.freeze
-
- attr_reader :url, :options, :format, :endpoint_url
-
- def call(url, options = {})
- @url = url
- @options = options
-
- if @options[:cached_endpoint]
- parse_cached_endpoint!
- else
- discover_endpoint!
- end
-
- fetch!
- end
-
- private
-
- def discover_endpoint!
- return if html.nil?
-
- @format = @options[:format]
- page = Nokogiri::HTML(html)
-
- if @format.nil? || @format == :json
- @endpoint_url ||= page.at_xpath('//link[@type="application/json+oembed"]')&.attribute('href')&.value
- @format ||= :json if @endpoint_url
- end
-
- if @format.nil? || @format == :xml
- @endpoint_url ||= page.at_xpath('//link[@type="text/xml+oembed"]')&.attribute('href')&.value
- @format ||= :xml if @endpoint_url
- end
-
- return if @endpoint_url.blank?
-
- @endpoint_url = begin
- base_url = Addressable::URI.parse(@url)
-
- # If the OEmbed endpoint is given as http but the URL we opened
- # was served over https, we can assume OEmbed will be available
- # through https as well
-
- (base_url + @endpoint_url).tap do |absolute_url|
- absolute_url.scheme = base_url.scheme if base_url.scheme == 'https'
- end.to_s
- end
-
- cache_endpoint!
- rescue Addressable::URI::InvalidURIError
- @endpoint_url = nil
- end
-
- def parse_cached_endpoint!
- cached = @options[:cached_endpoint]
-
- return if cached[:endpoint].nil? || cached[:format].nil?
-
- @endpoint_url = Addressable::Template.new(cached[:endpoint]).expand(url: @url).to_s
- @format = cached[:format]
- end
-
- def cache_endpoint!
- return unless URL_REGEX.match?(@endpoint_url)
-
- url_domain = Addressable::URI.parse(@url).normalized_host
-
- endpoint_hash = {
- endpoint: @endpoint_url.gsub(URL_REGEX, '={url}'),
- format: @format,
- }
-
- Rails.cache.write("oembed_endpoint:#{url_domain}", endpoint_hash, expires_in: ENDPOINT_CACHE_EXPIRES_IN)
- end
-
- def fetch!
- return if @endpoint_url.blank?
-
- body = Request.new(:get, @endpoint_url).perform do |res|
- res.code != 200 ? nil : res.body_with_limit
- end
-
- validate(parse_for_format(body)) if body.present?
- rescue Oj::ParseError, Ox::ParseError
- nil
- end
-
- def parse_for_format(body)
- case @format
- when :json
- Oj.load(body, mode: :strict)&.with_indifferent_access
- when :xml
- Ox.load(body, mode: :hash_no_attrs)&.with_indifferent_access&.dig(:oembed)
- end
- end
-
- def validate(oembed)
- oembed if oembed[:version] == '1.0' && oembed[:type].present?
- end
-
- def html
- return @html if defined?(@html)
-
- @html = @options[:html] || Request.new(:get, @url).add_headers('Accept' => 'text/html').perform do |res|
- res.code != 200 || res.mime_type != 'text/html' ? nil : res.body_with_limit
- end
- end
- end
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