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80 lines
2.4 KiB
Ruby
80 lines
2.4 KiB
Ruby
#
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# Given a string, tell us whether or not is acceptable.
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#
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class TextSentinel
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attr_accessor :text
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ENTROPY_SCALE ||= 0.7
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def initialize(text, opts=nil)
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@opts = opts || {}
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@text = text.to_s.encode('UTF-8', invalid: :replace, undef: :replace, replace: '')
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end
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def self.body_sentinel(text, opts={})
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entropy = SiteSetting.body_min_entropy
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if opts[:private_message]
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scale_entropy = SiteSetting.min_private_message_post_length.to_f / SiteSetting.min_post_length.to_f
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entropy = (entropy * scale_entropy).to_i
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entropy = (SiteSetting.min_private_message_post_length.to_f * ENTROPY_SCALE).to_i if entropy > SiteSetting.min_private_message_post_length
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else
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entropy = (SiteSetting.min_post_length.to_f * ENTROPY_SCALE).to_i if entropy > SiteSetting.min_post_length
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end
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TextSentinel.new(text, min_entropy: entropy)
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end
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def self.title_sentinel(text)
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entropy = if SiteSetting.min_topic_title_length > SiteSetting.title_min_entropy
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SiteSetting.title_min_entropy
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else
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(SiteSetting.min_topic_title_length.to_f * ENTROPY_SCALE).to_i
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end
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TextSentinel.new(text, min_entropy: entropy, max_word_length: SiteSetting.max_word_length)
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end
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# Entropy is a number of how many unique characters the string needs.
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# Non-ASCII characters are weighted heavier since they contain more "information"
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def entropy
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chars = @text.to_s.strip.split('')
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@entropy ||= chars.pack('M*'*chars.size).gsub("\n",'').split('=').uniq.size
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end
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def valid?
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@text.present? &&
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seems_meaningful? &&
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seems_pronounceable? &&
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seems_unpretentious? &&
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seems_quiet?
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end
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private
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def symbols_regex
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/[\ -\/\[-\`\:-\@\{-\~]/m
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end
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def seems_meaningful?
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# Minimum entropy if entropy check required
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@opts[:min_entropy].blank? || (entropy >= @opts[:min_entropy])
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end
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def seems_pronounceable?
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# At least some non-symbol characters
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# (We don't have a comprehensive list of symbols, but this will eliminate some noise)
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@text.gsub(symbols_regex, '').size > 0
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end
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def seems_unpretentious?
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# Don't allow super long words if there is a word length maximum
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@opts[:max_word_length].blank? || @text.split(/\s/).map(&:size).max <= @opts[:max_word_length]
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end
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def seems_quiet?
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# We don't allow all upper case content in english
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not((@text =~ /[A-Z]+/) && !(@text =~ /[^[:ascii:]]/) && (@text == @text.upcase))
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end
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end
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