Class: Miscellany::ComplexQuery

Inherits:
Object
  • Object
show all
Defined in:
lib/miscellany/active_record/complex_query.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ ComplexQuery

Returns a new instance of ComplexQuery.



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# File 'lib/miscellany/active_record/complex_query.rb', line 5

def initialize(options)
  @options = options.with_indifferent_access
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/miscellany/active_record/complex_query.rb', line 3

def options
  @options
end

Instance Method Details

#count ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 9

def count
  res = ActiveRecord::Base.connection.execute(build_count_query)
  res[0].to_h.values[0]
end

#find_each(batch_size: 1000, &block) ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 76

def find_each(batch_size: 1000, &block)
  in_batches(of: batch_size) do |batch|
    batch.each(&block)
  end
end

#in_batches(of: 1000) ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 55

def in_batches(of: 1000)
  conn = ActiveRecord::Base.connection
  tbl = "#{self.class.name.split('::').last.underscore}_#{SecureRandom.hex[0..10]}"

  conn.execute("CREATE TEMP TABLE #{tbl} AS (#{sql})")

  offset = 0
  loop do
    batch = ActiveRecord::Base.connection.exec_query(
      "SELECT * FROM #{tbl} LIMIT #{of} OFFSET #{offset}",
    )
    batch = batch.map(&:with_indifferent_access)
    augment_batch(batch)
    yield batch
    offset += of
    break if batch.empty?
  end
ensure
  conn.execute("DROP TABLE IF EXISTS #{tbl}")
end

#page(page, page_size: 40) ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 14

def page(page, page_size: 40)
  total_items = count

  page = page.to_i || 1
  page = 1 if page < 1
  page_size = page_size.to_i
  page_size = 10 if page_size < 2
  offset = (page - 1) * page_size

  psql = sql
  psql += " LIMIT #{page_size} OFFSET #{offset}"

  records = ActiveRecord::Base.connection.exec_query(psql).to_a
  augment_batch(records)

  {
    page: page,
    total_count: total_items,
    page_count: (total_items.to_f / page_size).ceil,
    page_size: page_size,
    sort: parsed_sort&.map do |s|
      "#{s[:key] || s[:column]} #{s[:order] || 'ASC'}"
    end&.join(', '),
    records: records,
  }
end

#slice(start, length, raw_sort: nil) ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 41

def slice(start, length, raw_sort: nil)
  psql = build_query
  if raw_sort.present?
    psql += " ORDER BY #{raw_sort}"
  elsif sort_sql.present?
    psql += " ORDER BY #{sort_sql}"
  end
  psql += " LIMIT #{length} OFFSET #{start}"
  records = ActiveRecord::Base.connection.exec_query(psql).to_a
  records = records.map(&:with_indifferent_access)
  augment_batch(records)
  records
end

#sql ⇒ Object 



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# File 'lib/miscellany/active_record/complex_query.rb', line 82

def sql
  sql = build_query
  sql += " ORDER BY #{sort_sql}" if sort_sql.present?
  sql
end

#valid_sort?(sort) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/miscellany/active_record/complex_query.rb', line 88

def valid_sort?(sort)
  sort_parser.valid?(sort)
  return false unless sort.present?
end