Class: PgMigrate::SqlReader

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_migrate/sql_reader.rb

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SqlReader

Returns a new instance of SqlReader.



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# File 'lib/pg_migrate/sql_reader.rb', line 5

def initialize

end

Instance Method Details

#load_migration(migration_path) ⇒ Object

read in a migration file, converting lines of text into SQL statements that can be executed with our database connection



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# File 'lib/pg_migrate/sql_reader.rb', line 12

def load_migration(migration_path)
  statements = []

  current_statement = ""

  migration_lines = IO.readlines(migration_path)
  migration_lines.each_with_index do |line, index|
    line_stripped = line.strip

    if line_stripped.empty? || line_stripped.start_with?('--')
      # it's a comment; ignore
    elsif line_stripped.start_with?("\\")
      # it's a psql command; ignore
    else
      current_statement += " " + line_stripped;

      if line_stripped.end_with?(";")
        if current_statement =~ /^\s*CREATE\s+(OR\s+REPLACE\s+)?FUNCTION/i || current_statement =~ /^\s*DO\s+/i
          # if we are in a function, a ';' isn't enough to end.  We need to see if the last word was one of
          # pltcl, plperl, plpgsql, plpythonu, sql
          # you can extend languages in postgresql; detecting these isn't supported yet.

          # we also detect anonymous functions (DO) and their ending sequence.
          if current_statement =~ /(plpgsql|plperl|plpythonu|pltcl|sql)\s*;$/i || current_statement =~ /END\s*\$\$\s+(LANGUAGE\s+(plpgsql|plperl|plpythonu|pltcl|sql))?\s*;$/i
            statements.push(current_statement[0...-1]) # strip off last ;
            current_statement = ""
          end

        else
          statements.push(current_statement[0...-1]) # strip off last ;
          current_statement = ""
        end
      end
    end
  end

  return statements

end