68 lines
2.0 KiB
Ruby
68 lines
2.0 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
# transforms "english like" text queries into a where clause with regex
|
|
# https://www.postgresql.org/docs/9.5/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES
|
|
|
|
class TextToRegexQuery
|
|
def initialize(text, fields, default_field, fields_mappings = {})
|
|
@text = text.to_s.strip
|
|
@fields = fields.map(&:to_sym)
|
|
@default_field = default_field.to_sym
|
|
@fields_mappings = fields_mappings.merge(@fields.reduce({}) do |mappings, field|
|
|
table_name, field_name = field.to_s.split(".")
|
|
mappings[field_name.to_sym] = field
|
|
mappings
|
|
end)
|
|
end
|
|
|
|
def where_clause(query)
|
|
@cleared_text = @text.dup
|
|
@column_chunks = []
|
|
remove_duplicated_spaces
|
|
extract_columns
|
|
escape_special_characters
|
|
generate_where_clause(query)
|
|
end
|
|
|
|
private
|
|
|
|
def remove_duplicated_spaces
|
|
@cleared_text.gsub!(/\s+/, ' ')
|
|
end
|
|
|
|
def escape_special_characters
|
|
@cleared_text.gsub!(/\_/, '\_')
|
|
@cleared_text.tr!('\\', '\\')
|
|
@cleared_text.gsub!(/%/, '\%')
|
|
end
|
|
|
|
def extract_columns
|
|
column_search_term_pairs = @cleared_text.scan(/([A-Za-z0-9_]+:[\w\_-]+)/)
|
|
|
|
@column_chunks = (column_search_term_pairs.flatten.map do |pair|
|
|
column, term = pair.split(':')
|
|
next unless @fields_mappings.include?(column.to_sym)
|
|
@cleared_text.gsub!(pair, '')
|
|
{ @fields_mappings[column.to_sym] => term }
|
|
end).compact
|
|
unless @cleared_text.strip.empty?
|
|
@column_chunks = [{ @default_field.to_s => @cleared_text.strip }] + @column_chunks
|
|
end
|
|
@column_chunks
|
|
end
|
|
|
|
def generate_where_clause(query)
|
|
where_clause = ''
|
|
columns = @column_chunks.map { |c| c.keys.first }
|
|
values = @column_chunks.map { |c| c.values.first }
|
|
|
|
columns.each do |column|
|
|
quoted_column = '"' + column.to_s.gsub(".",'"."') + '"'
|
|
where_clause += "#{quoted_column} ILIKE ? OR "
|
|
end
|
|
where_clause += " 1<>1 "
|
|
regexed_values = values.map { |v| "%#{v}%" }
|
|
query.where([where_clause] + regexed_values)
|
|
end
|
|
end
|