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Fix structured data parsing from links choking on bad data (#17403)
* Fix structured data parsing from links choking on bad data - Fix og:url meta tag being prioritized over canonical link tag - Fix structured data parsing choking on commented-out CDATA declarations - Fix HTML entities in title, description, provider_name, author_name - Change structured data parsing to attempt every JSON-LD script tag * Remove unnecessary slash escapes from CDATA regex pattern
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Eugen Rochko
GitHub
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73a782391c
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f1f6ddd536
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@ -3,6 +3,19 @@
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class LinkDetailsExtractor
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include ActionView::Helpers::TagHelper
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# Some publications wrap their JSON-LD data in their <script> tags
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# in commented-out CDATA blocks, they need to be removed before
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# attempting to parse JSON
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CDATA_JUNK_PATTERN = %r{^[\s]*(
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(/\*[\s]*<!\[CDATA\[[\s]*\*/) # Block comment style opening
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(//[\s]*<!\[CDATA\[) # Single-line comment style opening
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(/\*[\s]*\]\]>[\s]*\*/) # Block comment style closing
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(//[\s]*\]\]>) # Single-line comment style closing
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)[\s]*$}x
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class StructuredData
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SUPPORTED_TYPES = %w(
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NewsArticle
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@ -61,6 +74,10 @@ class LinkDetailsExtractor
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publisher.dig('logo', 'url')
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end
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def valid?
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json.present?
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end
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private
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def author
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@ -134,11 +151,11 @@ class LinkDetailsExtractor
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end
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def title
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structured_data&.headline || opengraph_tag('og:title') || document.xpath('//title').map(&:content).first
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html_entities.decode(structured_data&.headline || opengraph_tag('og:title') || document.xpath('//title').map(&:content).first)
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end
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def description
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structured_data&.description || opengraph_tag('og:description') || meta_tag('description')
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html_entities.decode(structured_data&.description || opengraph_tag('og:description') || meta_tag('description'))
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end
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def image
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@ -146,11 +163,11 @@ class LinkDetailsExtractor
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end
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def canonical_url
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valid_url_or_nil(opengraph_tag('og:url') || link_tag('canonical'), same_origin_only: true) || @original_url.to_s
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valid_url_or_nil(link_tag('canonical') || opengraph_tag('og:url'), same_origin_only: true) || @original_url.to_s
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end
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def provider_name
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structured_data&.publisher_name || opengraph_tag('og:site_name')
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html_entities.decode(structured_data&.publisher_name || opengraph_tag('og:site_name'))
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end
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def provider_url
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@ -158,7 +175,7 @@ class LinkDetailsExtractor
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end
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def author_name
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structured_data&.author_name || opengraph_tag('og:author') || opengraph_tag('og:author:username')
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html_entities.decode(structured_data&.author_name || opengraph_tag('og:author') || opengraph_tag('og:author:username'))
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end
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def author_url
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@ -223,10 +240,24 @@ class LinkDetailsExtractor
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def structured_data
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@structured_data ||= begin
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json_ld = document.xpath('//script[@type="application/ld+json"]').map(&:content).first
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json_ld.present? ? StructuredData.new(json_ld) : nil
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rescue Oj::ParseError
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nil
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# Some publications have more than one JSON-LD definition on the page,
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# and some of those definitions aren't valid JSON either, so we have
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# to loop through here until we find something that is the right type
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# and doesn't break
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document.xpath('//script[@type="application/ld+json"]').filter_map do |element|
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json_ld = element.content&.gsub(CDATA_JUNK_PATTERN, '')
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next if json_ld.blank?
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structured_data = StructuredData.new(html_entities.decode(json_ld))
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next unless structured_data.valid?
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structured_data
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rescue Oj::ParseError, EncodingError
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Rails.logger.debug("Invalid JSON-LD in #{@original_url}")
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next
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end.first
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end
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end
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@ -246,4 +277,8 @@ class LinkDetailsExtractor
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detector.strip_tags = true
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end
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end
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def html_entities
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@html_entities ||= HTMLEntities.new
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end
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end
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@ -26,4 +26,126 @@ RSpec.describe LinkDetailsExtractor do
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end
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end
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end
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context 'when structured data is present' do
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let(:original_url) { 'https://example.com/page.html' }
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context 'and is wrapped in CDATA tags' do
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let(:html) { <<-HTML }
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<!doctype html>
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<html>
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<head>
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<script type="application/ld+json">
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//<![CDATA[
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{"@context":"http://schema.org","@type":"NewsArticle","mainEntityOfPage":"https://example.com/page.html","headline":"Foo","datePublished":"2022-01-31T19:53:00+00:00","url":"https://example.com/page.html","description":"Bar","author":{"@type":"Person","name":"Hoge"},"publisher":{"@type":"Organization","name":"Baz"}}
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//]]>
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</script>
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</head>
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</html>
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HTML
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describe '#title' do
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it 'returns the title from structured data' do
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expect(subject.title).to eq 'Foo'
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end
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end
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describe '#description' do
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it 'returns the description from structured data' do
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expect(subject.description).to eq 'Bar'
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end
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end
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describe '#provider_name' do
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it 'returns the provider name from structured data' do
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expect(subject.provider_name).to eq 'Baz'
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end
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end
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describe '#author_name' do
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it 'returns the author name from structured data' do
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expect(subject.author_name).to eq 'Hoge'
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end
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end
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end
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context 'but the first tag is invalid JSON' do
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let(:html) { <<-HTML }
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<!doctype html>
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<html>
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<body>
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<script type="application/ld+json">
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{
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"@context":"https://schema.org",
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"@type":"ItemList",
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"url":"https://example.com/page.html",
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"name":"Foo",
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"description":"Bar"
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},
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{
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"@context": "https://schema.org",
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"@type": "BreadcrumbList",
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"itemListElement":[
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{
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"@type":"ListItem",
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"position":1,
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"item":{
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"@id":"https://www.example.com",
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"name":"Baz"
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}
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}
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]
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}
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</script>
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<script type="application/ld+json">
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{
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"@context":"https://schema.org",
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"@type":"NewsArticle",
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"mainEntityOfPage": {
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"@type":"WebPage",
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"@id": "http://example.com/page.html"
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},
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"headline": "Foo",
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"description": "Bar",
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"datePublished": "2022-01-31T19:46:00+00:00",
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"author": {
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"@type": "Organization",
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"name": "Hoge"
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},
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"publisher": {
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"@type": "NewsMediaOrganization",
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"name":"Baz",
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"url":"https://example.com/"
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}
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}
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</script>
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</body>
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</html>
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HTML
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describe '#title' do
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it 'returns the title from structured data' do
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expect(subject.title).to eq 'Foo'
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end
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end
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describe '#description' do
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it 'returns the description from structured data' do
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expect(subject.description).to eq 'Bar'
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end
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end
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describe '#provider_name' do
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it 'returns the provider name from structured data' do
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expect(subject.provider_name).to eq 'Baz'
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end
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end
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describe '#author_name' do
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it 'returns the author name from structured data' do
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expect(subject.author_name).to eq 'Hoge'
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end
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end
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end
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end
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end
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