discourse/lib/score_calculator.rb

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class ScoreCalculator
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def self.default_score_weights
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{
reply_count: 5,
like_count: 15,
incoming_link_count: 5,
bookmark_count: 2,
avg_time: 0.05,
reads: 0.2
}
end
def initialize(weightings=nil)
@weightings = weightings || ScoreCalculator.default_score_weights
end
# Calculate the score for all posts based on the weightings
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def calculate
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# First update the scores of the posts
exec_sql(post_score_sql, @weightings)
# Update the percent rankings of the posts
exec_sql("UPDATE posts SET percent_rank = x.percent_rank
FROM (SELECT id, percent_rank()
OVER (PARTITION BY topic_id ORDER BY SCORE DESC) as percent_rank
FROM posts) AS x
WHERE x.id = posts.id")
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# Update the best of flag
exec_sql "
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UPDATE topics SET has_best_of =
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CASE
WHEN like_count >= :likes_required AND
posts_count >= :posts_required AND
EXISTS(SELECT * FROM posts AS p
WHERE p.topic_id = topics.id
AND p.score >= :score_required) THEN true
ELSE false
END",
likes_required: SiteSetting.best_of_likes_required,
posts_required: SiteSetting.best_of_posts_required,
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score_required: SiteSetting.best_of_score_threshold
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end
private
def exec_sql(sql, params=nil)
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ActiveRecord::Base.exec_sql(sql, params)
end
# Generate a SQL statement to update the scores of all posts
def post_score_sql
"UPDATE posts SET score = ".tap do |sql|
components = []
@weightings.keys.each do |k|
components << "COALESCE(#{k.to_s}, 0) * :#{k.to_s}"
end
sql << components.join(" + ")
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end
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end
end