discourse/lib/user_name_suggester.rb

169 lines
4.9 KiB
Ruby

# frozen_string_literal: true
module UserNameSuggester
GENERIC_NAMES = ['i', 'me', 'info', 'support', 'admin', 'webmaster', 'hello', 'mail', 'office', 'contact', 'team']
LAST_RESORT_USERNAME = "user"
def self.suggest(name_or_email, current_username = nil)
name = parse_name_from_email(name_or_email)
name = fix_username(name)
find_available_username_based_on(name, current_username)
end
def self.parse_name_from_email(name_or_email)
return name_or_email if name_or_email.to_s !~ User::EMAIL
# When 'walter@white.com' take 'walter'
name = Regexp.last_match[1]
# When 'me@eviltrout.com' take 'eviltrout'
name = Regexp.last_match[2] if GENERIC_NAMES.include?(name)
name
end
def self.find_available_username_based_on(name, current_username = nil)
offset = nil
i = 1
attempt = name
normalized_attempt = User.normalize_username(attempt)
original_allowed_username = current_username
current_username = User.normalize_username(current_username) if current_username
until (
normalized_attempt == current_username ||
User.username_available?(attempt) ||
i > 100
)
if offset.nil?
normalized = User.normalize_username(name)
similar = "#{normalized}(0|1|2|3|4|5|6|7|8|9)+"
count = DB.query_single(<<~SQL, like: "#{normalized}%", similar: similar).first
SELECT count(*) FROM users
WHERE username_lower LIKE :like AND
username_lower SIMILAR TO :similar
SQL
if count > 0
params = {
count: count + 10,
name: normalized,
allowed_normalized: current_username || ''
}
# increasing the search space a bit to allow for some extra noise
available = DB.query_single(<<~SQL, params).first
WITH numbers AS (SELECT generate_series(1, :count) AS n)
SELECT n FROM numbers
LEFT JOIN users ON (
username_lower = :name || n::varchar
) AND (
username_lower <> :allowed_normalized
)
WHERE users.id IS NULL
ORDER by n ASC
LIMIT 1
SQL
# we start at 1
offset = available.to_i - 1
offset = 0 if offset < 0
else
offset = 0
end
end
suffix = (i + offset).to_s
max_length = User.username_length.end - suffix.length
attempt = "#{truncate(name, max_length)}#{suffix}"
normalized_attempt = User.normalize_username(attempt)
i += 1
end
until normalized_attempt == current_username || User.username_available?(attempt) || i > 200
attempt = SecureRandom.hex[1..SiteSetting.max_username_length]
normalized_attempt = User.normalize_username(attempt)
i += 1
end
if current_username == normalized_attempt
original_allowed_username
else
attempt
end
end
def self.fix_username(name)
fixed_username = sanitize_username(name)
if fixed_username.empty?
fixed_username << sanitize_username(I18n.t('fallback_username'))
fixed_username << LAST_RESORT_USERNAME if fixed_username.empty?
end
rightsize_username(fixed_username)
end
def self.sanitize_username(name)
name = name.to_s.dup
if SiteSetting.unicode_usernames
name.unicode_normalize!
# TODO: Jan 2022, review if still needed
# see: https://meta.discourse.org/t/unicode-username-with-as-the-final-char-leads-to-an-error-loading-profile-page/173182
if name.include?('Σ')
ctx = MiniRacer::Context.new
name = ctx.eval("#{name.to_s.to_json}.toLowerCase()")
ctx.dispose
end
else
name = ActiveSupport::Inflector.transliterate(name)
end
name.gsub!(UsernameValidator.invalid_char_pattern, '_')
name = apply_allowlist(name) if UsernameValidator.char_allowlist_exists?
name.gsub!(UsernameValidator::INVALID_LEADING_CHAR_PATTERN, '')
name.gsub!(UsernameValidator::CONFUSING_EXTENSIONS, "_")
name.gsub!(UsernameValidator::INVALID_TRAILING_CHAR_PATTERN, '')
name.gsub!(UsernameValidator::REPEATED_SPECIAL_CHAR_PATTERN, '_')
name
end
def self.apply_allowlist(name)
name.grapheme_clusters
.map { |c| UsernameValidator.allowed_char?(c) ? c : '_' }
.join
end
def self.rightsize_username(name)
name = truncate(name, User.username_length.end)
name.gsub!(UsernameValidator::INVALID_TRAILING_CHAR_PATTERN, '')
missing_char_count = User.username_length.begin - name.grapheme_clusters.size
name << '1' * missing_char_count if missing_char_count > 0
name
end
def self.truncate(name, max_grapheme_clusters)
clusters = name.grapheme_clusters
if clusters.size > max_grapheme_clusters
clusters = clusters[0..max_grapheme_clusters - 1]
name = clusters.join
end
while name.length > UsernameValidator::MAX_CHARS
clusters.pop
name = clusters.join
end
name
end
end