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