123 lines
4.0 KiB
Ruby
123 lines
4.0 KiB
Ruby
# frozen_string_literal: true
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#
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# Copyright (C) 2013 - present Instructure, Inc.
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#
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# This file is part of Canvas.
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#
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# Canvas is free software: you can redistribute it and/or modify it under
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# the terms of the GNU Affero General Public License as published by the Free
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# Software Foundation, version 3 of the License.
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#
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# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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# details.
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#
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# You should have received a copy of the GNU Affero General Public License along
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# with this program. If not, see <http://www.gnu.org/licenses/>.
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module SearchTermHelper
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MIN_SEARCH_TERM_LENGTH = 2
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module ClassMethods
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# Searches the given scope for rows with column values
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# like the search term.
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#
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# @param scope The scope to limit the search to
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# @param attr The attribute (column) the search should consider
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# @param search_term The term being searched for
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# @param normalize_unicode Defaults to false. If set to true, the
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# search will consider the NFC and NFD representations of the
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# given search_term
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#
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# @returns A new scope with the search filter applied. If the given
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# scope was something like an AR relation (i.e. responds to 'where')
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# returns a new scope of the same type. Otherwise returns an Array
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def search_by_attribute(scope, attr, search_term, normalize_unicode: false)
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return scope unless search_term.present?
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SearchTermHelper.validate_search_term(search_term)
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filtered_scope(scope, attr, search_term, normalize_unicode)
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end
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private
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def filtered_scope(*filter_args, normalize_unicode)
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# Return the filter query, don't bother worrying about unicode
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# normalization.
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return non_normalized_results(*filter_args) unless normalize_unicode
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# Return the filter query, but do worry about doing basic
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# unicode normalization. Adds an OR to the query to take into
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# account both NFC and NFD representations of the search_term
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#
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# See https://www.win.tue.nl/~aeb/linux/uc/nfc_vs_nfd.html
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normalized_results(*filter_args)
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end
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def non_normalized_results(scope, attr, search_term)
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return scope.where(wildcard("#{table_name}.#{attr}", search_term)) if scope.respond_to?(:where)
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scope.select { |item| item.matches_attribute?(attr, search_term) }
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end
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def normalized_results(scope, attr, search_term)
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# TODO: investigate the PG "NORMALIZE" function once on PG 13
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nfc_search_term, nfd_search_term = normalized_search_terms(search_term)
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if scope.respond_to?(:where)
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# Consider the NFC and NFD representations of the search_term by using an
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# OR operator
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return scope.where(wildcard("#{table_name}.#{attr}", nfc_search_term)).or(
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scope.where(wildcard("#{table_name}.#{attr}", nfd_search_term))
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)
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end
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scope.select do |item|
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item.matches_attribute?(attr, nfc_search_term) ||
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item.matches_attribute?(attr, nfd_search_term)
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end
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end
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def normalized_search_terms(search_term)
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[
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search_term.unicode_normalize,
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search_term.unicode_normalize(:nfd)
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]
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end
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end
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def self.included(klass)
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klass.extend(ClassMethods)
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end
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class SearchTermTooShortError < ArgumentError
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def response_status
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:bad_request
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end
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def error_json
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{
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"errors" => [{
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"field" => "search_term",
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"code" => "invalid",
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"message" => "#{SearchTermHelper::MIN_SEARCH_TERM_LENGTH} or more characters is required"
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}]
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}
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end
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end
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def self.valid_search_term?(search_term)
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search_term.is_a?(String) && search_term.length >= MIN_SEARCH_TERM_LENGTH
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end
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def self.validate_search_term(search_term)
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raise SearchTermTooShortError unless valid_search_term?(search_term)
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end
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def matches_attribute?(attr, search_term)
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self[attr].to_s.downcase.include?(search_term.downcase)
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end
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end
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