mirror of
https://github.com/discourse/discourse.git
synced 2024-11-27 13:33:44 +08:00
68 lines
1.7 KiB
Ruby
68 lines
1.7 KiB
Ruby
require_dependency 'final_destination'
|
|
|
|
module RetrieveTitle
|
|
class ReadEnough < StandardError; end
|
|
|
|
def self.crawl(url)
|
|
extract_title(fetch_beginning(url))
|
|
rescue Exception
|
|
# If there was a connection error, do nothing
|
|
end
|
|
|
|
def self.extract_title(html)
|
|
title = nil
|
|
if doc = Nokogiri::HTML(html)
|
|
|
|
title = doc.at('title')&.inner_text
|
|
|
|
if !title && node = doc.at('meta[property="og:title"]')
|
|
title = node['content']
|
|
end
|
|
end
|
|
|
|
if title.present?
|
|
title.gsub!(/\n/, ' ')
|
|
title.gsub!(/ +/, ' ')
|
|
title.strip!
|
|
return title
|
|
end
|
|
nil
|
|
end
|
|
|
|
private
|
|
|
|
def self.max_chunk_size(uri)
|
|
# Amazon leaves the title until very late. Normally it's a bad idea to make an exception for
|
|
# one host but amazon is a big one.
|
|
return 80 if uri.host =~ /amazon\.(com|ca|co\.uk|es|fr|de|it|com\.au|com\.br|cn|in|co\.jp|com\.mx)$/
|
|
|
|
# default is 10k
|
|
10
|
|
end
|
|
|
|
# Fetch the beginning of a HTML document at a url
|
|
def self.fetch_beginning(url)
|
|
fd = FinalDestination.new(url)
|
|
uri = fd.resolve
|
|
return "" unless uri
|
|
|
|
result = ""
|
|
streamer = lambda do |chunk, _, _|
|
|
result << chunk
|
|
|
|
# Using exceptions for flow control is really bad, but there really seems to
|
|
# be no sane way to get a stream to stop reading in Excon (or Net::HTTP for
|
|
# that matter!)
|
|
raise ReadEnough.new if result.size > (max_chunk_size(uri) * 1024)
|
|
end
|
|
Excon.get(uri.to_s, response_block: streamer, read_timeout: 20, headers: fd.request_headers)
|
|
result
|
|
|
|
rescue Excon::Errors::SocketError => ex
|
|
return result if ex.socket_error.is_a?(ReadEnough)
|
|
raise
|
|
rescue ReadEnough
|
|
result
|
|
end
|
|
end
|