Convert a MongoDB BSON file to a python file that can be imported.

bson_to_python_file.py

#!/usr/bin/env python
import argparse
import bson
import datetime
import struct
import sys

INDENT_SPACES = '  '

def read_bson_file(file, as_class=dict, tz_aware=True, uuid_subtype=bson.OLD_UUID_SUBTYPE):
    try:
        while True:
            obj_size_bytes = file.read(4)
            if len(obj_size_bytes) < 4:
                break
            obj_size = struct.unpack("<i", obj_size_bytes)[0]
            data = file.read(obj_size - 4)
            obj_size -= 4
            if len(data) < obj_size:
                raise bson.InvalidBSON("objsize too large")
            if len(data) != obj_size:
                raise bson.InvalidBSON("objsize incorrect")
            if data[-1] != bson.ZERO:
                raise bson.InvalidBSON("bad eoo")
            elements = data[:-1]
            yield bson._elements_to_dict(elements, as_class=as_class, tz_aware=tz_aware, uuid_subtype=uuid_subtype)
    except IOError, e:
        pass
    return

def read_bson_filename(input_filename):
    with open(input_filename, 'rb') as f:
        for d in read_bson_file(f):
            yield d

def dump_value_to_python(fd, v, depth=0):
    if v is None:
        fd.write('None')
    elif isinstance(v, basestring):
        fd.write(repr(v).encode('utf-8'))
    elif isinstance(v, (int, float, long)):
        fd.write(repr(v))
    elif isinstance(v, (list, tuple, set)):
        dump_list_to_python(fd, v, depth=depth+1)
    elif isinstance(v, dict):
        dump_dict_to_python(fd, v, depth=depth+1)
    elif isinstance(v, datetime.datetime):
        v = datetime.datetime(v.year, v.month, v.day, v.hour, v.minute, v.second, v.microsecond)
        fd.write(repr(v))
    elif isinstance(v, bson.objectid.ObjectId):
        fd.write('bson.objectid.ObjectId("')
        fd.write(str(v))
        fd.write('")')
    elif isinstance(v, bson.dbref.DBRef):
        fd.write('bson.dbref.DBRef("')
        fd.write(str(v.collection))
        fd.write('", bson.objectid.ObjectId("')
        fd.write(str(v.id))
        fd.write('"))')
    else:
        sys.stderr.write('Unknown type: %r\n' % v)
        sys.stderr.flush()
        sys.exit(1)


def dump_list_to_python(fd, arr, depth=0):
    indent = INDENT_SPACES * depth
    fd.write('[')
    if len(arr) > 1:
        for v in arr:
            fd.write('\n')
            fd.write(indent)
            fd.write(INDENT_SPACES)
            dump_value_to_python(fd, v, depth=depth)
            fd.write(',')
        fd.write('\n')
        fd.write(indent)
    else:
        for v in arr:
            dump_value_to_python(fd, v, depth=depth)
    fd.write(']')

def dump_dict_to_python(fd, d, depth=0):
    indent = INDENT_SPACES * depth
    fd.write('{')
    if len(d) > 1:
        for k, v in d.iteritems():
            fd.write('\n')
            fd.write(indent)
            fd.write(INDENT_SPACES)
            dump_value_to_python(fd, k, depth=depth)
            fd.write(': ')
            dump_value_to_python(fd, v, depth=depth)
            fd.write(',')
        fd.write('\n')
        fd.write(indent)
    else:
        for k, v in d.iteritems():
            dump_value_to_python(fd, k, depth=depth)
            fd.write(': ')
            dump_value_to_python(fd, v, depth=depth)
    fd.write('}')

def dump_bson_to_python(input_filename, output_file):
    output_file.write('import bson\n')
    output_file.write('import datetime\n')
    output_file.write('import json\n')
    #output_file.write('import tz\n')
    output_file.write('\n')
    output_file.write('items = [\n')
    for d in read_bson_filename(input_filename):
        output_file.write(INDENT_SPACES)
        dump_dict_to_python(output_file, d, depth=1)
        output_file.write(',\n')
    output_file.write(']\n')

def parse_args(argv=sys.argv[1:]):
    parser = argparse.ArgumentParser(description='Dump a BSON file to an importable Python file')
    parser.add_argument('--input', metavar='FILE', required=True, help='Input BSON filename')
    parser.add_argument('--output', metavar='FILE', help='Output python filename')
    options = parser.parse_args(argv)
    return options.input, options.output

def main(argv=sys.argv[1:]):
    input_filename, output_filename = parse_args(argv)
    if output_filename:
        with open(output_filename, 'w') as fd:
            dump_bson_to_python(input_filename, fd)
    else:
        dump_bson_to_python(input_filename, sys.stdout)
    return 0

if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))