4b68e82a19
Ditto for ending with \b.
Consider muting the phrase "(hot take)". I stipulate it is reasonable
to enter this with the default "match whole word" behavior. Under the
old behavior, this would be encoded as
\b\(hot\ take\)\b
However, if \b is before the first character in the string and the first
character in the string is not a word character, then the match will
fail. Ditto for after. In our example, "(" is not a word character, so
this will not match statuses containing "(hot take)", and that's a very
surprising behavior.
To address this, we only add leading and trailing \b to keywords that
start or end with word characters.
68 lines
1.6 KiB
Ruby
68 lines
1.6 KiB
Ruby
# frozen_string_literal: true
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# == Schema Information
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#
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# Table name: glitch_keyword_mutes
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#
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# id :integer not null, primary key
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# account_id :integer not null
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# keyword :string not null
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# whole_word :boolean default(TRUE), not null
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# created_at :datetime not null
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# updated_at :datetime not null
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#
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class Glitch::KeywordMute < ApplicationRecord
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belongs_to :account, required: true
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validates_presence_of :keyword
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after_commit :invalidate_cached_matcher
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def self.matcher_for(account_id)
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Matcher.new(account_id)
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end
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private
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def invalidate_cached_matcher
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Rails.cache.delete("keyword_mutes:regex:#{account_id}")
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end
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class Matcher
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attr_reader :account_id
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attr_reader :regex
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def initialize(account_id)
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@account_id = account_id
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@regex = Rails.cache.fetch("keyword_mutes:regex:#{account_id}") { regex_for_account }
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end
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def keywords
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Glitch::KeywordMute.
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where(account_id: account_id).
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select(:keyword, :id, :whole_word)
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end
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def regex_for_account
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re_text = [].tap do |arr|
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keywords.find_each do |kw|
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arr << (kw.whole_word ? boundary_regex_for_keyword(kw.keyword) : Regexp.escape(kw.keyword))
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end
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end.join('|')
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/#{re_text}/i unless re_text.empty?
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end
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def boundary_regex_for_keyword(keyword)
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sb = keyword =~ /\A[[:word:]]/ ? '\b' : ''
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eb = keyword =~ /[[:word:]]\Z/ ? '\b' : ''
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"#{sb}#{Regexp.escape(keyword)}#{eb}"
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end
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def =~(str)
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regex ? regex =~ str : false
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end
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end
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end
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