son – Tools for working with SON, an ordered mapping

Tools for creating and manipulating SON, the Serialized Ocument Notation.

Regular dictionaries can be used instead of SON objects, but not when the order of keys is important. A SON object can be used just like a normal Python dictionary.

class bson.son.SON(data=None, **kwargs)

SON data.

A subclass of dict that maintains ordering of keys and provides a few extra niceties for dealing with SON. SON objects can be converted to and from BSON.

The mapping from Python types to BSON types is as follows:

Python Type BSON Type Supported Direction
None null both
bool boolean both
int [1] int32 / int64 py -> bson
long int64 both
float number (real) both
string string py -> bson
unicode string both
list array both
dict / SON object both
datetime.datetime [2] [3] date both
bson.regex.Regex / compiled re [4] regex both
bson.binary.Binary binary both
bson.objectid.ObjectId oid both
bson.dbref.DBRef dbref both
None undefined bson -> py
unicode code bson -> py
bson.code.Code code py -> bson
unicode symbol bson -> py
bytes (Python 3) [5] binary both

Note that to save binary data it must be wrapped as an instance of bson.binary.Binary. Otherwise it will be saved as a BSON string and retrieved as unicode.

[1]A Python int will be saved as a BSON int32 or BSON int64 depending on its size. A BSON int32 will always decode to a Python int. In Python 2.x a BSON int64 will always decode to a Python long. In Python 3.x a BSON int64 will decode to a Python int since there is no longer a long type.
[2]datetime.datetime instances will be rounded to the nearest millisecond when saved
[3]all datetime.datetime instances are treated as naive. clients should always use UTC.
[4]Regex instances and regular expression objects from re.compile() are both saved as BSON regular expressions. BSON regular expressions are decoded as Python regular expressions by default, or as Regex instances if the compile_re option is set to False.
[5]The bytes type from Python 3.x is encoded as BSON binary with subtype 0. In Python 3.x it will be decoded back to bytes. In Python 2.x it will be decoded to an instance of Binary with subtype 0.
to_dict()

Convert a SON document to a normal Python dictionary instance.

This is trickier than just dict(...) because it needs to be recursive.

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