Extend Ruby String to support PostGIS

postgistr.rb

require 'rubygems'
require 'postgres'

class String
  def sql(&block)
    result = PostGIS::sql(self).result[0]
    return result unless block
    result.each do |r|
      yield r
    end
  end

  def geom(srid = 4326)
    "SELECT ST_GeometryFromText('#{self}', #{srid})".sql[0]
  end

  def wkt
    "SELECT ST_AsText('#{self}')".sql[0]
  end

  def buffer(distance)
    "SELECT ST_Buffer('#{self}', #{distance})".sql[0]
  end
end

module PostGIS
  def PostGIS::connect(pghost, pgport, pgoptions, pgtty, dbname, login, passwd, &block)
    @@conn = PGconn.connect(pghost, pgport, pgoptions, pgtty, dbname, login, passwd)
    if block
      yield PostGIS
      close
    end
  end

  def PostGIS::close
    @@conn.close
  end

  def PostGIS::sql(str)
    @@conn.exec(str)
  end
end