docbrown/app/services/articles/suggest.rb
2021-04-27 14:30:06 -04:00

73 lines
2.1 KiB
Ruby

module Articles
class Suggest
MAX_DEFAULT = 4
def self.call(article, max: MAX_DEFAULT)
new(article, max: max).call
end
def initialize(article, max: MAX_DEFAULT)
@article = article
@max = max
@total_articles_count = Article.published.estimated_count
end
def call
if cached_tag_list_array.any?
# avoid loading more data if we don't need to
tagged_suggestions = suggestions_by_tag(max: max)
return tagged_suggestions if tagged_suggestions.size == max
# if there are not enough tagged articles, load other suggestions
# ignoring tagged articles that might be relevant twice, hence avoiding duplicates
num_remaining_needed = max - tagged_suggestions.size
other_articles = other_suggestions(
max: num_remaining_needed,
ids_to_ignore: tagged_suggestions.map(&:id),
)
tagged_suggestions.union(other_articles)
else
other_suggestions
end
end
private
attr_reader :article, :max, :total_articles_count
def other_suggestions(max: MAX_DEFAULT, ids_to_ignore: [])
ids_to_ignore << article.id
Article.published
.where.not(id: ids_to_ignore)
.where.not(user_id: article.user_id)
.order(hotness_score: :desc)
.offset(rand(0..offset))
.first(max)
end
def suggestions_by_tag(max: MAX_DEFAULT)
Article
.published
.cached_tagged_with_any(cached_tag_list_array)
.where.not(user_id: article.user_id)
.where(tag_suggestion_query)
.order(hotness_score: :desc)
.offset(rand(0..offset))
.first(max)
end
def offset
total_articles_count > 1000 ? 200 : (total_articles_count / 10)
end
def tag_suggestion_query
# Fore big communities like DEV we can look at organic page views for indicator.
# For smaller communities, we'll a basic score check.
total_articles_count > 1000 ? "organic_page_views_past_month_count > 5" : "score > 1"
end
def cached_tag_list_array
(article.cached_tag_list || "").split(", ")
end
end
end