434f1a0b85
Favoriting posts sometimes fails with ActiveRecord::LockWaitTimeout errors. This happens when a user tries to favorite multiple posts in short succession. In that case we want the lock to block and wait for the other favorite to go through, not to immediately fail.
44 lines
1.6 KiB
Ruby
44 lines
1.6 KiB
Ruby
class Favorite < ApplicationRecord
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class Error < Exception ; end
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belongs_to :post
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belongs_to :user
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scope :for_user, ->(user_id) {where("user_id % 100 = #{user_id.to_i % 100} and user_id = #{user_id.to_i}")}
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def self.add(post:, user:)
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Favorite.transaction do
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User.where(id: user.id).select("id").lock("FOR UPDATE").first
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if user.favorite_count >= user.favorite_limit
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raise Error, "You can only keep up to #{user.favorite_limit} favorites. Upgrade your account to save more."
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elsif Favorite.for_user(user.id).where(:user_id => user.id, :post_id => post.id).exists?
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raise Error, "You have already favorited this post"
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end
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Favorite.create!(:user_id => user.id, :post_id => post.id)
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Post.where(:id => post.id).update_all("fav_count = fav_count + 1")
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post.append_user_to_fav_string(user.id)
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User.where(:id => user.id).update_all("favorite_count = favorite_count + 1")
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user.favorite_count += 1
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end
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end
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def self.remove(user:, post: nil, post_id: nil)
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Favorite.transaction do
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if post && post_id.nil?
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post_id = post.id
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end
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User.where(id: user.id).select("id").lock("FOR UPDATE").first
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return unless Favorite.for_user(user.id).where(:user_id => user.id, :post_id => post_id).exists?
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Favorite.for_user(user.id).where(post_id: post_id).delete_all
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Post.where(:id => post_id).update_all("fav_count = fav_count - 1")
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post.delete_user_from_fav_string(user.id) if post
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User.where(:id => user.id).update_all("favorite_count = favorite_count - 1")
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user.favorite_count -= 1
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post.fav_count -= 1 if post
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end
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end
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end
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