j2bson

#!/usr/bin/ruby
# encoding: UTF-8

# --
# Copyright (C) 2008-2010 10gen Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ++

require 'rubygems'
require 'bson'

# We don't use YAJL because we need to specify the class
# to store the JSON object in.  BSON is ordered so we need BSON::OrderedHash
#
# We use json/pure because json/ext is broken with BSON::OrderedHash
# (probably for the same reasons that we can't use YAJL).
#
# Note that, at the moment, this will not properly round-trip
# in all cases from the output generated by b2json.
begin
require 'json/pure'  # broken with 'json/ext'
rescue LoadError
  puts "This script requires json/pure. Please install one of the following:"
  puts "  gem install json_pure" 
  puts "  gem install json" 
  Process.exit
end

# Convert all JSON objects in an IO into BSON.
def print_j2bson(io)
  io.each_line do |line|
    jsonobj = JSON.parse(line, { :object_class => BSON::OrderedHash } )
    bsonobj = BSON.serialize(jsonobj)
    STDOUT << bsonobj.to_s
  end
end

# print usage
def usage()
    STDERR << <<END_OF_USAGE
usage:  j2bson [-h] [file1 [file2]]

   Converts a JSON file to BSON on STDOUT.
   You can pass multiple filenames.
   If no filenames are passed, then STDIN is consumed.

END_OF_USAGE
    exit
end

# no arg, use STDIN
# -h, print usage and exit
# otherwise loop of filenames
if ARGV.empty? then
    print_j2bson(STDIN)
    exit
elsif ARGV[0] == "-h" then
    usage()
else
    ARGV.each { |fname| print_j2bson(File.new(fname)) }
end