discourse/plugins/poll/db/post_migrate/20180820080623_migrate_poll...

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# frozen_string_literal: true
class MigratePollsData < ActiveRecord::Migration[5.2]
def escape(text)
PG::Connection.escape_string(text)
end
POLL_TYPES ||= {
"regular" => 0,
"multiple" => 1,
"number" => 2,
}
PG_INTEGER_MAX ||= 2_147_483_647
def up
# Ensure we don't have duplicate polls
DB.exec <<~SQL
WITH duplicates AS (
SELECT id, row_number() OVER (PARTITION BY post_id) r
FROM post_custom_fields
WHERE name = 'polls'
ORDER BY created_at
)
DELETE FROM post_custom_fields
WHERE id IN (SELECT id FROM duplicates WHERE r > 1)
SQL
# Ensure we don't have duplicate votes
DB.exec <<~SQL
WITH duplicates AS (
SELECT id, row_number() OVER (PARTITION BY post_id) r
FROM post_custom_fields
WHERE name = 'polls-votes'
ORDER BY created_at
)
DELETE FROM post_custom_fields
WHERE id IN (SELECT id FROM duplicates WHERE r > 1)
SQL
# Ensure we have votes records
DB.exec <<~SQL
INSERT INTO post_custom_fields (post_id, name, value, created_at, updated_at)
SELECT post_id, 'polls-votes', '{}', created_at, updated_at
FROM post_custom_fields
WHERE name = 'polls'
AND post_id NOT IN (SELECT post_id FROM post_custom_fields WHERE name = 'polls-votes')
SQL
sql = <<~SQL
SELECT polls.post_id
, polls.created_at
, polls.updated_at
, polls.value::json "polls"
, votes.value::json "votes"
FROM post_custom_fields polls
JOIN post_custom_fields votes
ON polls.post_id = votes.post_id
WHERE polls.name = 'polls'
AND votes.name = 'polls-votes'
ORDER BY polls.post_id
SQL
DB.query(sql).each do |r|
# for some reasons, polls or votes might be an array
r.polls = r.polls[0] if Array === r.polls && r.polls.size > 0
r.votes = r.votes[0] if Array === r.votes && r.votes.size > 0
existing_user_ids = User.where(id: r.votes.keys).pluck(:id).to_set
# Poll votes are stored in a JSON object with the following hierarchy
# user_id -> poll_name -> options
# Since we're iterating over polls, we need to change the hierarchy to
# poll_name -> user_id -> options
votes = {}
r.votes.each do |user_id, user_votes|
# don't migrate votes from deleted/non-existing users
next unless existing_user_ids.include?(user_id.to_i)
user_votes.each do |poll_name, options|
votes[poll_name] ||= {}
votes[poll_name][user_id] = options
end
end
r.polls.values.each do |poll|
name = poll["name"].presence || "poll"
type = POLL_TYPES[(poll["type"].presence || "")[/(regular|multiple|number)/, 1] || "regular"]
status = poll["status"] == "open" ? 0 : 1
visibility = poll["public"] == "true" ? 1 : 0
close_at = (Time.zone.parse(poll["close"]) rescue nil)
min = poll["min"].to_i.clamp(0, PG_INTEGER_MAX)
max = poll["max"].to_i.clamp(0, PG_INTEGER_MAX)
step = poll["step"].to_i.clamp(0, max)
anonymous_voters = poll["anonymous_voters"].to_i.clamp(0, PG_INTEGER_MAX)
poll_id = execute(<<~SQL
INSERT INTO polls (
post_id,
name,
type,
status,
visibility,
close_at,
min,
max,
step,
anonymous_voters,
created_at,
updated_at
) VALUES (
#{r.post_id},
'#{escape(name)}',
#{type},
#{status},
#{visibility},
#{close_at ? "'#{close_at}'" : "NULL"},
#{min > 0 ? min : "NULL"},
#{max > min ? max : "NULL"},
#{step > 0 ? step : "NULL"},
#{anonymous_voters > 0 ? anonymous_voters : "NULL"},
'#{r.created_at}',
'#{r.updated_at}'
) RETURNING id
SQL
)[0]["id"]
option_ids = Hash[*DB.query_single(<<~SQL
INSERT INTO poll_options
(poll_id, digest, html, anonymous_votes, created_at, updated_at)
VALUES
#{poll["options"].map { |option|
"(#{poll_id}, '#{escape(option["id"])}', '#{escape(option["html"].strip)}', #{option["anonymous_votes"].to_i}, '#{r.created_at}', '#{r.updated_at}')" }.join(",")
}
RETURNING digest, id
SQL
)]
if votes[name].present?
poll_votes = votes[name].map do |user_id, options|
options
.select { |o| option_ids.has_key?(o) }
.map { |o| "(#{poll_id}, #{option_ids[o]}, #{user_id.to_i}, '#{r.created_at}', '#{r.updated_at}')" }
end
poll_votes.flatten!
poll_votes.uniq!
if poll_votes.present?
execute <<~SQL
INSERT INTO poll_votes (poll_id, poll_option_id, user_id, created_at, updated_at)
VALUES #{poll_votes.join(",")}
SQL
end
end
end
end
execute <<~SQL
INSERT INTO post_custom_fields (name, value, post_id, created_at, updated_at)
SELECT 'has_polls', 't', post_id, MIN(created_at), MIN(updated_at)
FROM polls
GROUP BY post_id
SQL
end
def down
end
end