Improve handling of encoding problems when creating link previews (#30929)

pull/2768/head
David Roetzel 2024-07-05 13:54:38 +02:00 committed by GitHub
parent 05f0d51005
commit 016c1e4e78
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5 changed files with 76 additions and 10 deletions

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@ -156,11 +156,11 @@ class LinkDetailsExtractor
end
def title
html_entities.decode(structured_data&.headline || opengraph_tag('og:title') || document.xpath('//title').map(&:content).first).strip
html_entities_decode(structured_data&.headline || opengraph_tag('og:title') || document.xpath('//title').map(&:content).first).strip
end
def description
html_entities.decode(structured_data&.description || opengraph_tag('og:description') || meta_tag('description'))
html_entities_decode(structured_data&.description || opengraph_tag('og:description') || meta_tag('description'))
end
def published_at
@ -180,7 +180,7 @@ class LinkDetailsExtractor
end
def provider_name
html_entities.decode(structured_data&.publisher_name || opengraph_tag('og:site_name'))
html_entities_decode(structured_data&.publisher_name || opengraph_tag('og:site_name'))
end
def provider_url
@ -188,7 +188,7 @@ class LinkDetailsExtractor
end
def author_name
html_entities.decode(structured_data&.author_name || opengraph_tag('og:author') || opengraph_tag('og:author:username'))
html_entities_decode(structured_data&.author_name || opengraph_tag('og:author') || opengraph_tag('og:author:username'))
end
def author_url
@ -257,7 +257,7 @@ class LinkDetailsExtractor
next if json_ld.blank?
structured_data = StructuredData.new(html_entities.decode(json_ld))
structured_data = StructuredData.new(html_entities_decode(json_ld))
next unless structured_data.valid?
@ -273,10 +273,11 @@ class LinkDetailsExtractor
end
def detect_encoding_and_parse_document
[detect_encoding, nil, @html_charset, 'UTF-8'].uniq.each do |encoding|
[detect_encoding, nil, @html_charset].uniq.each do |encoding|
document = Nokogiri::HTML(@html, nil, encoding)
return document if document.to_s.valid_encoding?
end
Nokogiri::HTML(@html, nil, 'UTF-8')
end
def detect_encoding
@ -290,6 +291,15 @@ class LinkDetailsExtractor
end
end
def html_entities_decode(string)
return if string.nil?
unicode_string = string.encode('UTF-8')
raise EncodingError, 'cannot convert string to valid UTF-8' unless unicode_string.valid_encoding?
html_entities.decode(unicode_string)
end
def html_entities
@html_entities ||= HTMLEntities.new(:expanded)
end

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@ -32,7 +32,7 @@ class FetchLinkCardService < BaseService
end
attach_card if @card&.persisted?
rescue HTTP::Error, OpenSSL::SSL::SSLError, Addressable::URI::InvalidURIError, Mastodon::HostValidationError, Mastodon::LengthValidationError, Encoding::UndefinedConversionError => e
rescue HTTP::Error, OpenSSL::SSL::SSLError, Addressable::URI::InvalidURIError, Mastodon::HostValidationError, Mastodon::LengthValidationError, EncodingError => e
Rails.logger.debug { "Error fetching link #{@original_url}: #{e}" }
nil
end

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@ -0,0 +1,17 @@
HTTP/1.1 200 OK
server: nginx
date: Thu, 13 Jun 2024 14:33:13 GMT
content-type: text/html; charset=utf-8
content-length: 158
accept-ranges: bytes
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Tofu á l'orange</title>
</head>
<body>
<h2>Tofu á l'orange</h2>
</body>
</html>

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@ -0,0 +1,17 @@
HTTP/1.1 200 OK
server: nginx
date: Thu, 13 Jun 2024 14:33:13 GMT
content-type: text/html; charset=utf-8
content-length: 158
accept-ranges: bytes
<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Tofu with orange sauce</title>
</head>
<body>
<h2>Tofu á l'orange</h2>
</body>
</html>

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@ -27,6 +27,8 @@ RSpec.describe FetchLinkCardService do
stub_request(:get, 'http://example.com/koi8-r').to_return(request_fixture('koi8-r.txt'))
stub_request(:get, 'http://example.com/windows-1251').to_return(request_fixture('windows-1251.txt'))
stub_request(:get, 'http://example.com/low_confidence_latin1').to_return(request_fixture('low_confidence_latin1.txt'))
stub_request(:get, 'http://example.com/latin1_posing_as_utf8_broken').to_return(request_fixture('latin1_posing_as_utf8_broken.txt'))
stub_request(:get, 'http://example.com/latin1_posing_as_utf8_recoverable').to_return(request_fixture('latin1_posing_as_utf8_recoverable.txt'))
stub_request(:get, 'http://example.com/aergerliche-umlaute').to_return(request_fixture('redirect_with_utf8_url.txt'))
Rails.cache.write('oembed_endpoint:example.com', oembed_cache) if oembed_cache
@ -159,10 +161,30 @@ RSpec.describe FetchLinkCardService do
end
context 'with a URL of a page in ISO-8859-1 encoding, that charlock_holmes cannot detect' do
let(:status) { Fabricate(:status, text: 'Check out http://example.com/low_confidence_latin1') }
context 'when encoding in http header is correct' do
let(:status) { Fabricate(:status, text: 'Check out http://example.com/low_confidence_latin1') }
it 'decodes the HTML' do
expect(status.preview_card.title).to eq("Tofu á l'orange")
it 'decodes the HTML' do
expect(status.preview_card.title).to eq("Tofu á l'orange")
end
end
context 'when encoding in http header is incorrect' do
context 'when encoding problems appear in unrelated tags' do
let(:status) { Fabricate(:status, text: 'Check out http://example.com/latin1_posing_as_utf8_recoverable') }
it 'decodes the HTML' do
expect(status.preview_card.title).to eq('Tofu with orange sauce')
end
end
context 'when encoding problems appear in title tag' do
let(:status) { Fabricate(:status, text: 'Check out http://example.com/latin1_posing_as_utf8_broken') }
it 'does not create a preview card' do
expect(status.preview_card).to be_nil
end
end
end
end