discourse/app/services/word_watcher.rb

251 lines
6.3 KiB
Ruby

# frozen_string_literal: true
class WordWatcher
REPLACEMENT_LETTER ||= CGI.unescape_html("■")
CACHE_VERSION = 2
def initialize(raw)
@raw = raw
end
@cache_enabled = true
def self.disable_cache
@cache_enabled = false
end
def self.cache_enabled?
@cache_enabled
end
def self.words_for_action(action)
WatchedWord
.where(action: WatchedWord.actions[action.to_sym])
.limit(WatchedWord::MAX_WORDS_PER_ACTION)
.order(:id)
.pluck(:word, :replacement, :case_sensitive)
.map { |w, r, c| [w, { replacement: r, case_sensitive: c }.compact] }
.to_h
end
def self.words_for_action_exists?(action)
WatchedWord.where(action: WatchedWord.actions[action.to_sym]).exists?
end
def self.get_cached_words(action)
if cache_enabled?
Discourse.cache.fetch(word_matcher_regexp_key(action), expires_in: 1.day) do
words_for_action(action).presence
end
else
words_for_action(action).presence
end
end
def self.serializable_word_matcher_regexp(action)
word_matcher_regexp_list(action)
.map { |r| { r.source => { case_sensitive: !r.casefold? } } }
end
# This regexp is run in miniracer, and the client JS app
# Make sure it is compatible with major browsers when changing
# hint: non-chrome browsers do not support 'lookbehind'
def self.word_matcher_regexp_list(action, raise_errors: false)
words = get_cached_words(action)
return [] if words.blank?
grouped_words = { case_sensitive: [], case_insensitive: [] }
words.each do |w, attrs|
word = word_to_regexp(w)
word = "(#{word})" if SiteSetting.watched_words_regular_expressions?
group_key = attrs[:case_sensitive] ? :case_sensitive : :case_insensitive
grouped_words[group_key] << word
end
regexps = grouped_words
.select { |_, w| w.present? }
.transform_values { |w| w.join("|") }
if !SiteSetting.watched_words_regular_expressions?
regexps.transform_values! do |regexp|
regexp = "(#{regexp})"
"(?:\\W|^)#{regexp}(?=\\W|$)"
end
end
regexps
.map { |c, regexp| Regexp.new(regexp, c == :case_sensitive ? nil : Regexp::IGNORECASE) }
rescue RegexpError
raise if raise_errors
[] # Admin will be alerted via admin_dashboard_data.rb
end
def self.word_matcher_regexps(action)
if words = get_cached_words(action)
words.map { |w, opts| [word_to_regexp(w, whole: true), opts] }.to_h
end
end
def self.word_to_regexp(word, whole: false)
if SiteSetting.watched_words_regular_expressions?
# Strip ruby regexp format if present
regexp = word.start_with?("(?-mix:") ? word[7..-2] : word
regexp = "(#{regexp})" if whole
return regexp
end
regexp = Regexp.escape(word).gsub("\\*", '\S*')
if whole && !SiteSetting.watched_words_regular_expressions?
regexp = "(?:\\W|^)(#{regexp})(?=\\W|$)"
end
regexp
end
def self.word_matcher_regexp_key(action)
"watched-words-list:v#{CACHE_VERSION}:#{action}"
end
def self.censor(html)
regexps = word_matcher_regexp_list(:censor)
return html if regexps.blank?
doc = Nokogiri::HTML5::fragment(html)
doc.traverse do |node|
regexps.each do |regexp|
node.content = censor_text_with_regexp(node.content, regexp) if node.text?
end
end
doc.to_s
end
def self.censor_text(text)
return text if text.blank?
regexps = word_matcher_regexp_list(:censor)
return text if regexps.blank?
regexps.inject(text) { |txt, regexp| censor_text_with_regexp(txt, regexp) }
end
def self.replace_text(text)
return text if text.blank?
%i[replace link]
.flat_map { |type| word_matcher_regexps(type).to_a }
.reduce(text) do |t, (word_regexp, attrs)|
case_flag = attrs[:case_sensitive] ? nil : Regexp::IGNORECASE
replace_text_with_regexp(t, Regexp.new(word_regexp, case_flag), attrs[:replacement])
end
end
def self.apply_to_text(text)
text = censor_text(text)
text = replace_text(text)
text
end
def self.clear_cache!
WatchedWord.actions.each do |a, i|
Discourse.cache.delete word_matcher_regexp_key(a)
end
end
def requires_approval?
word_matches_for_action?(:require_approval)
end
def should_flag?
word_matches_for_action?(:flag)
end
def should_block?
word_matches_for_action?(:block, all_matches: true)
end
def should_silence?
word_matches_for_action?(:silence)
end
def word_matches_for_action?(action, all_matches: false)
regexps = self.class.word_matcher_regexp_list(action)
return if regexps.blank?
match_list = []
regexps.each do |regexp|
match = regexp.match(@raw)
if !all_matches
return match if match
next
end
next if !match
if SiteSetting.watched_words_regular_expressions?
set = Set.new
@raw.scan(regexp).each do |m|
if Array === m
set.add(m.find(&:present?))
elsif String === m
set.add(m)
end
end
matches = set.to_a
else
matches = @raw.scan(regexp)
matches.flatten!
end
match_list.concat(matches)
end
return if match_list.blank?
match_list.compact!
match_list.uniq!
match_list.sort!
match_list
end
def word_matches?(word, case_sensitive: false)
Regexp
.new(WordWatcher.word_to_regexp(word, whole: true), case_sensitive ? nil : Regexp::IGNORECASE)
.match?(@raw)
end
def self.replace_text_with_regexp(text, regexp, replacement)
text.gsub(regexp) do |match|
prefix = ""
# match may be prefixed with a non-word character from the non-capturing group
# Ensure this isn't replaced if watched words regular expression is disabled.
if !SiteSetting.watched_words_regular_expressions? && (match[0] =~ /\W/) != nil
prefix = "#{match[0]}"
end
"#{prefix}#{replacement}"
end
end
private_class_method :replace_text_with_regexp
def self.censor_text_with_regexp(text, regexp)
text.gsub(regexp) do |match|
# the regex captures leading whitespaces
padding = match.size - match.lstrip.size
if padding > 0
match[0..padding - 1] + REPLACEMENT_LETTER * (match.size - padding)
else
REPLACEMENT_LETTER * match.size
end
end
end
private_class_method :censor_text_with_regexp
end