98 lines
2.4 KiB
Ruby
98 lines
2.4 KiB
Ruby
# frozen_string_literal: true
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class Webfinger
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class Error < StandardError; end
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class GoneError < Error; end
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class RedirectError < StandardError; end
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class Response
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def initialize(body)
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@json = Oj.load(body, mode: :strict)
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end
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def subject
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@json['subject']
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end
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def link(rel, attribute)
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links.dig(rel, attribute)
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end
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private
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def links
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@links ||= @json['links'].index_by { |link| link['rel'] }
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end
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end
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def initialize(uri)
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_, @domain = uri.split('@')
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raise ArgumentError, 'Webfinger requested for local account' if @domain.nil?
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@uri = uri
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end
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def perform
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Response.new(body_from_webfinger)
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rescue Oj::ParseError
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raise Webfinger::Error, "Invalid JSON in response for #{@uri}"
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rescue Addressable::URI::InvalidURIError
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raise Webfinger::Error, "Invalid URI for #{@uri}"
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end
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private
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def body_from_webfinger(url = standard_url, use_fallback = true)
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webfinger_request(url).perform do |res|
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if res.code == 200
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res.body_with_limit
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elsif res.code == 404 && use_fallback
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body_from_host_meta
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elsif res.code == 410
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raise Webfinger::GoneError, "#{@uri} is gone from the server"
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else
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raise Webfinger::Error, "Request for #{@uri} returned HTTP #{res.code}"
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end
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end
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end
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def body_from_host_meta
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host_meta_request.perform do |res|
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if res.code == 200
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body_from_webfinger(url_from_template(res.body_with_limit), false)
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else
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raise Webfinger::Error, "Request for #{@uri} returned HTTP #{res.code}"
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end
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end
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end
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def url_from_template(str)
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link = Nokogiri::XML(str).at_xpath('//xmlns:Link[@rel="lrdd"]')
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if link.present?
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link['template'].gsub('{uri}', @uri)
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else
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raise Webfinger::Error, "Request for #{@uri} returned host-meta without link to Webfinger"
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end
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rescue Nokogiri::XML::XPath::SyntaxError
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raise Webfinger::Error, "Invalid XML encountered in host-meta for #{@uri}"
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end
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def host_meta_request
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Request.new(:get, host_meta_url).add_headers('Accept' => 'application/xrd+xml, application/xml, text/xml')
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end
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def webfinger_request(url)
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Request.new(:get, url).add_headers('Accept' => 'application/jrd+json, application/json')
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end
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def standard_url
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"https://#{@domain}/.well-known/webfinger?resource=#{@uri}"
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end
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def host_meta_url
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"https://#{@domain}/.well-known/host-meta"
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end
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end
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