141 lines
4.7 KiB
Ruby
141 lines
4.7 KiB
Ruby
# frozen_string_literal: true
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module AccountSearch
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extend ActiveSupport::Concern
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DISALLOWED_TSQUERY_CHARACTERS = /['?\\:‘’]/
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TEXT_SEARCH_RANKS = <<~SQL.squish
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(
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setweight(to_tsvector('simple', accounts.display_name), 'A') ||
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setweight(to_tsvector('simple', accounts.username), 'B') ||
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setweight(to_tsvector('simple', coalesce(accounts.domain, '')), 'C')
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)
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SQL
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REPUTATION_SCORE_FUNCTION = <<~SQL.squish
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(
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greatest(0, coalesce(s.followers_count, 0)) / (
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greatest(0, coalesce(s.following_count, 0)) + 1.0
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)
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)
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SQL
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FOLLOWERS_SCORE_FUNCTION = <<~SQL.squish
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log(
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greatest(0, coalesce(s.followers_count, 0)) + 2
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)
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SQL
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TIME_DISTANCE_FUNCTION = <<~SQL.squish
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(
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case
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when s.last_status_at is null then 0
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else exp(
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-1.0 * (
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(
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greatest(0, abs(extract(DAY FROM age(s.last_status_at))) - 30.0)^2) /#{' '}
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(2.0 * ((-1.0 * 30^2) / (2.0 * ln(0.3)))
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)
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)
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)
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end
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)
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SQL
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BOOST = <<~SQL.squish
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(
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(#{REPUTATION_SCORE_FUNCTION} + #{FOLLOWERS_SCORE_FUNCTION} + #{TIME_DISTANCE_FUNCTION}) / 3.0
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)
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SQL
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BASIC_SEARCH_SQL = <<~SQL.squish
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SELECT
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accounts.*,
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#{BOOST} * ts_rank_cd(#{TEXT_SEARCH_RANKS}, to_tsquery('simple', :tsquery), 32) AS rank
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FROM accounts
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LEFT JOIN users ON accounts.id = users.account_id
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LEFT JOIN account_stats AS s ON accounts.id = s.account_id
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WHERE to_tsquery('simple', :tsquery) @@ #{TEXT_SEARCH_RANKS}
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AND accounts.suspended_at IS NULL
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AND accounts.moved_to_account_id IS NULL
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AND (accounts.domain IS NOT NULL OR (users.approved = TRUE AND users.confirmed_at IS NOT NULL))
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ORDER BY rank DESC
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LIMIT :limit OFFSET :offset
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SQL
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ADVANCED_SEARCH_WITH_FOLLOWING = <<~SQL.squish
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WITH first_degree AS (
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SELECT target_account_id
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FROM follows
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WHERE account_id = :id
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UNION ALL
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SELECT :id
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)
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SELECT
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accounts.*,
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(count(f.id) + 1) * #{BOOST} * ts_rank_cd(#{TEXT_SEARCH_RANKS}, to_tsquery('simple', :tsquery), 32) AS rank
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FROM accounts
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LEFT OUTER JOIN follows AS f ON (accounts.id = f.account_id AND f.target_account_id = :id)
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LEFT JOIN account_stats AS s ON accounts.id = s.account_id
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WHERE accounts.id IN (SELECT * FROM first_degree)
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AND to_tsquery('simple', :tsquery) @@ #{TEXT_SEARCH_RANKS}
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AND accounts.suspended_at IS NULL
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AND accounts.moved_to_account_id IS NULL
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GROUP BY accounts.id, s.id
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ORDER BY rank DESC
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LIMIT :limit OFFSET :offset
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SQL
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ADVANCED_SEARCH_WITHOUT_FOLLOWING = <<~SQL.squish
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SELECT
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accounts.*,
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#{BOOST} * ts_rank_cd(#{TEXT_SEARCH_RANKS}, to_tsquery('simple', :tsquery), 32) AS rank,
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count(f.id) AS followed
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FROM accounts
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LEFT OUTER JOIN follows AS f ON
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(accounts.id = f.account_id AND f.target_account_id = :id) OR (accounts.id = f.target_account_id AND f.account_id = :id)
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LEFT JOIN users ON accounts.id = users.account_id
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LEFT JOIN account_stats AS s ON accounts.id = s.account_id
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WHERE to_tsquery('simple', :tsquery) @@ #{TEXT_SEARCH_RANKS}
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AND accounts.suspended_at IS NULL
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AND accounts.moved_to_account_id IS NULL
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AND (accounts.domain IS NOT NULL OR (users.approved = TRUE AND users.confirmed_at IS NOT NULL))
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GROUP BY accounts.id, s.id
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ORDER BY followed DESC, rank DESC
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LIMIT :limit OFFSET :offset
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SQL
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class_methods do
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def search_for(terms, limit: 10, offset: 0)
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tsquery = generate_query_for_search(terms)
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find_by_sql([BASIC_SEARCH_SQL, { limit: limit, offset: offset, tsquery: tsquery }]).tap do |records|
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ActiveRecord::Associations::Preloader.new.preload(records, :account_stat)
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end
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end
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def advanced_search_for(terms, account, limit: 10, following: false, offset: 0)
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tsquery = generate_query_for_search(terms)
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sql_template = following ? ADVANCED_SEARCH_WITH_FOLLOWING : ADVANCED_SEARCH_WITHOUT_FOLLOWING
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find_by_sql([sql_template, { id: account.id, limit: limit, offset: offset, tsquery: tsquery }]).tap do |records|
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ActiveRecord::Associations::Preloader.new.preload(records, :account_stat)
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end
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end
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private
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def generate_query_for_search(unsanitized_terms)
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terms = unsanitized_terms.gsub(DISALLOWED_TSQUERY_CHARACTERS, ' ')
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# The final ":*" is for prefix search.
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# The trailing space does not seem to fit any purpose, but `to_tsquery`
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# behaves differently with and without a leading space if the terms start
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# with `./`, `../`, or `.. `. I don't understand why, so, in doubt, keep
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# the same query.
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"' #{terms} ':*"
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end
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end
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end
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