catstodon/app/services/fetch_atom_service.rb

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Ruby
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class FetchAtomService < BaseService
def call(url)
response = http_client.head(url)
Rails.logger.debug "Remote status HEAD request returned code #{response.code}"
return nil if response.code != 200
if response.mime_type == 'application/atom+xml'
return [url, fetch(url)]
elsif !response['Link'].blank?
return process_headers(url, response)
else
return process_html(fetch(url))
end
rescue OpenSSL::SSL::SSLError => e
Rails.logger.debug "SSL error: #{e}"
end
private
def process_html(body)
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Rails.logger.debug 'Processing HTML'
page = Nokogiri::HTML(body)
alternate_link = page.xpath('//link[@rel="alternate"]').find { |link| link['type'] == 'application/atom+xml' }
return nil if alternate_link.nil?
return [alternate_link['href'], fetch(alternate_link['href'])]
end
def process_headers(url, response)
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Rails.logger.debug 'Processing link header'
link_header = LinkHeader.parse(response['Link'].is_a?(Array) ? response['Link'].first : response['Link'])
alternate_link = link_header.find_link(['rel', 'alternate'], ['type', 'application/atom+xml'])
return process_html(fetch(url)) if alternate_link.nil?
return [alternate_link.href, fetch(alternate_link.href)]
end
def fetch(url)
http_client.get(url).to_s
end
def http_client
HTTP.timeout(:per_operation, write: 20, connect: 20, read: 50).follow
end
end