70 行
2.3 KiB
Ruby
70 行
2.3 KiB
Ruby
require 'net/http'
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module Preview
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class HttpFetcher
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class FetchFailed < StandardError; end
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class FetchTimeout < FetchFailed; end
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class ResponseTooLarge < FetchFailed; end
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MAX_REDIRECTS = 5
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DEFAULT_MAX_BYTES = 5.megabytes
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Response = Data.define(:body, :content_type, :url)
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def self.fetch(raw_url, max_bytes: DEFAULT_MAX_BYTES, redirects: MAX_REDIRECTS)
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uri, addresses = UrlSafety.validate(raw_url)
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response = request(uri, addresses.first, max_bytes)
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if response.is_a?(Net::HTTPRedirection)
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raise FetchFailed, 'redirect が多すぎます．' if redirects.zero?
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location = response['location']
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raise FetchFailed, 'redirect 先が不正です．' if location.blank?
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return fetch(URI.join(uri, location).to_s,
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max_bytes:,
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redirects: redirects - 1)
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end
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unless response.is_a?(Net::HTTPSuccess)
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raise FetchFailed, "外部サーバーが HTTP #{ response.code } を返しました．"
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end
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Response.new(response.body, response['content-type'].to_s, uri.to_s)
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rescue Net::OpenTimeout, Net::ReadTimeout, Timeout::Error => e
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raise FetchTimeout, e.message
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rescue SocketError, SystemCallError, OpenSSL::SSL::SSLError, EOFError => e
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raise FetchFailed, e.message
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end
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def self.request(uri, ip_address, max_bytes)
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http = Net::HTTP.new(uri.host, uri.port)
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http.ipaddr = ip_address
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http.use_ssl = uri.scheme == 'https'
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http.open_timeout = 5
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http.read_timeout = 8
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http.write_timeout = 5
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request = Net::HTTP::Get.new(uri)
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request['User-Agent'] = 'BTRC-Hub thumbnail preview'
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request['Accept'] = 'text/html,image/*;q=0.9,*/*;q=0.1'
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http.request(request) do |response|
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length = response['content-length'].to_i
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raise ResponseTooLarge, '外部データが大きすぎます．' if length > max_bytes
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body = +''
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response.read_body do |chunk|
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body << chunk
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raise ResponseTooLarge, '外部データが大きすぎます．' if body.bytesize > max_bytes
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end
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response.instance_variable_set(:@body, body)
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response.instance_variable_set(:@read, true)
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return response
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end
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end
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private_class_method :request
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end
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end
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