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|
# frozen_string_literal: true
class LinkDetailsExtractor
include ActionView::Helpers::TagHelper
class StructuredData
def initialize(data)
@data = data
end
def headline
json['headline']
end
def description
json['description']
end
def image
obj = first_of_value(json['image'])
return obj['url'] if obj.is_a?(Hash)
obj
end
def date_published
json['datePublished']
end
def date_modified
json['dateModified']
end
def author_name
author['name']
end
def author_url
author['url']
end
def publisher_name
publisher['name']
end
private
def author
first_of_value(json['author']) || {}
end
def publisher
first_of_value(json['publisher']) || {}
end
def first_of_value(arr)
arr.is_a?(Array) ? arr.first : arr
end
def json
@json ||= Oj.load(@data)
end
end
def initialize(original_url, html, html_charset)
@original_url = Addressable::URI.parse(original_url)
@html = html
@html_charset = html_charset
end
def to_preview_card_attributes
{
title: title || '',
description: description || '',
image_remote_url: image,
type: type,
width: width || 0,
height: height || 0,
html: html || '',
provider_name: provider_name || '',
provider_url: provider_url || '',
author_name: author_name || '',
author_url: author_url || '',
embed_url: embed_url || '',
}
end
def type
player_url.present? ? :video : :link
end
def html
player_url.present? ? content_tag(:iframe, nil, src: player_url, width: width, height: height, allowtransparency: 'true', scrolling: 'no', frameborder: '0') : nil
end
def width
opengraph_tag('twitter:player:width')
end
def height
opengraph_tag('twitter:player:height')
end
def title
structured_data&.headline || opengraph_tag('og:title') || document.xpath('//title').map(&:content).first
end
def description
structured_data&.description || opengraph_tag('og:description') || meta_tag('description')
end
def image
valid_url_or_nil(opengraph_tag('og:image'))
end
def canonical_url
valid_url_or_nil(opengraph_tag('og:url') || link_tag('canonical'), same_origin_only: true) || @original_url.to_s
end
def provider_name
structured_data&.publisher_name || opengraph_tag('og:site_name')
end
def provider_url
valid_url_or_nil(host_to_url(opengraph_tag('og:site')))
end
def author_name
structured_data&.author_name || opengraph_tag('og:author') || opengraph_tag('og:author:username')
end
def author_url
structured_data&.author_url
end
def embed_url
valid_url_or_nil(opengraph_tag('twitter:player:stream'))
end
private
def player_url
valid_url_or_nil(opengraph_tag('twitter:player'))
end
def host_to_url(str)
return if str.blank?
str.start_with?(/https?:\/\//) ? str : "http://#{str}"
end
def valid_url_or_nil(str, same_origin_only: false)
return if str.blank?
url = @original_url + Addressable::URI.parse(str)
return if url.host.blank? || !%w(http https).include?(url.scheme) || (same_origin_only && url.host != @original_url.host)
url.to_s
rescue Addressable::URI::InvalidURIError
nil
end
def link_tag(name)
document.xpath("//link[@rel=\"#{name}\"]").map { |link| link['href'] }.first
end
def opengraph_tag(name)
document.xpath("//meta[@property=\"#{name}\" or @name=\"#{name}\"]").map { |meta| meta['content'] }.first
end
def meta_tag(name)
document.xpath("//meta[@name=\"#{name}\"]").map { |meta| meta['content'] }.first
end
def structured_data
@structured_data ||= begin
json_ld = document.xpath('//script[@type="application/ld+json"]').map(&:content).first
json_ld.present? ? StructuredData.new(json_ld) : nil
end
end
def document
@document ||= Nokogiri::HTML(@html, nil, encoding)
end
def encoding
@encoding ||= begin
guess = detector.detect(@html, @html_charset)
guess&.fetch(:confidence, 0).to_i > 60 ? guess&.fetch(:encoding, nil) : nil
end
end
def detector
@detector ||= CharlockHolmes::EncodingDetector.new.tap do |detector|
detector.strip_tags = true
end
end
end
|
