NAME
BSON - BSON serialization and deserialization
VERSION
version v1.6.4
SYNOPSIS
use BSON;
use BSON::Types ':all';
use boolean;
my $codec = BSON->new;
my $document = {
_id => bson_oid(),
creation_time => bson_time(), # now
zip_code => bson_string("08544"),
hidden => false,
};
my $bson = $codec->encode_one( $document );
my $doc = $codec->decode_one( $bson );
DESCRIPTION
This class implements a BSON encoder/decoder ("codec"). It consumes
"documents" (typically hash references) and emits BSON strings and vice
versa in accordance with the BSON Specification <http://bsonspec.org>.
BSON is the primary data representation for MongoDB. While this module
has several features that support MongoDB-specific needs and
conventions, it can be used as a standalone serialization format.
The codec may be customized through attributes on the codec option as
well as encode/decode specific options on methods:
my $codec = BSON->new( \%global_attributes );
my $bson = $codec->encode_one( $document, \%encode_options );
my $doc = $codec->decode_one( $bson , \%decode_options );
Because BSON is strongly-typed and Perl is not, this module supports a
number of "type wrappers" – classes that wrap Perl data to indicate how
they should serialize. The BSON::Types module describes these and
provides associated helper functions. See "PERL-BSON TYPE MAPPING" for
more details.
When decoding, type wrappers are used for any data that has no native
Perl representation. Optionally, all data may be wrapped for precise
control of round-trip encoding.
Please read the configuration attributes carefully to understand more
about how to control encoding and decoding.
At compile time, this module will select an implementation backend. It
will prefer "BSON::XS" (released separately) if available, or will fall
back to BSON::PP (bundled with this module). See "ENVIRONMENT" for a way
to control the selection of the backend.
ATTRIBUTES
error_callback
This attribute specifies a function reference that will be called with
three positional arguments:
* an error string argument describing the error condition
* a reference to the problematic document or byte-string
* the method in which the error occurred (e.g. "encode_one" or
"decode_one")
Note: for decoding errors, the byte-string is passed as a reference to
avoid copying possibly large strings.
If not provided, errors messages will be thrown with "Carp::croak".
invalid_chars
A string containing ASCII characters that must not appear in keys. The
default is the empty string, meaning there are no invalid characters.
max_length
This attribute defines the maximum document size. The default is 0,
which disables any maximum.
If set to a positive number, it applies to both encoding and decoding
(the latter is necessary for prevention of resource consumption
attacks).
op_char
This is a single character to use for special MongoDB-specific query
operators. If a key starts with "op_char", the "op_char" character will
be replaced with "$".
The default is "$", meaning that no replacement is necessary.
ordered
If set to a true value, then decoding will return a reference to a tied
hash that preserves key order. Otherwise, a regular (unordered) hash
reference will be returned.
IMPORTANT CAVEATS:
* When 'ordered' is true, users must not rely on the return value
being any particular tied hash implementation. It may change in the
future for efficiency.
* Turning this option on entails a significant speed penalty as tied
hashes are slower than regular Perl hashes.
The default is false.
prefer_numeric
When false, scalar values will be encoded as a number if they were
originally a number or were ever used in a numeric context. However, a
string that looks like a number but was never used in a numeric context
(e.g. "42") will be encoded as a string.
If "prefer_numeric" is set to true, the encoder will attempt to coerce
strings that look like a number into a numeric value. If the string
doesn't look like a double or integer, it will be encoded as a string.
IMPORTANT CAVEAT: the heuristics for determining whether something is a
string or number are less accurate on older Perls. See BSON::Types for
wrapper classes that specify exact serialization types.
The default is false.
wrap_dbrefs
If set to true, during decoding, documents with the fields '$id' and
'$ref' (literal dollar signs, not variables) will be wrapped as
BSON::DBRef objects. If false, they are decoded into ordinary hash
references (or ordered hashes, if "ordered" is true).
The default is true.
wrap_numbers
If set to true, during decoding, numeric values will be wrapped into
BSON type-wrappers: BSON::Double, BSON::Int64 or BSON::Int32. While very
slow, this can help ensure fields can round-trip if unmodified.
The default is false.
wrap_strings
If set to true, during decoding, string values will be wrapped into a
BSON type-wrappers, BSON::String. While very slow, this can help ensure
fields can round-trip if unmodified.
The default is false.
dt_type (Discouraged)
Sets the type of object which is returned for BSON DateTime fields. The
default is "undef", which returns objects of type BSON::Time. This is
overloaded to be the integer epoch value when used as a number or
string, so is somewhat backwards compatible with "dt_type" in the
MongoDB driver.
Other acceptable values are BSON::Time (explicitly), DateTime,
Time::Moment, DateTime::Tiny, Mango::BSON::Time.
Because BSON::Time objects have methods to convert to DateTime,
Time::Moment or DateTime::Tiny, use of this field is discouraged. Users
should use these methods on demand. This option is provided for
backwards compatibility only.
METHODS
encode_one
$byte_string = $codec->encode_one( $doc );
$byte_string = $codec->encode_one( $doc, \%options );
Takes a "document", typically a hash reference, an array reference, or a
Tie::IxHash object and returns a byte string with the BSON
representation of the document.
An optional hash reference of options may be provided. Valid options
include:
* first_key – if "first_key" is defined, it and "first_value" will be
encoded first in the output BSON; any matching key found in the
document will be ignored.
* first_value - value to assign to "first_key"; will encode as Null if
omitted
* error_callback – overrides codec default
* invalid_chars – overrides codec default
* max_length – overrides codec default
* op_char – overrides codec default
* prefer_numeric – overrides codec default
decode_one
$doc = $codec->decode_one( $byte_string );
$doc = $codec->decode_one( $byte_string, \%options );
Takes a byte string with a BSON-encoded document and returns a hash
reference representing the decoded document.
An optional hash reference of options may be provided. Valid options
include:
* dt_type – overrides codec default
* error_callback – overrides codec default
* max_length – overrides codec default
* ordered - overrides codec default
* wrap_dbrefs - overrides codec default
* wrap_numbers - overrides codec default
* wrap_strings - overrides codec default
clone
$copy = $codec->clone( ordered => 1 );
Constructs a copy of the original codec, but allows changing attributes
in the copy.
create_oid
$oid = BSON->create_oid;
This class method returns a new BSON::OID. This abstracts OID generation
away from any specific Object ID class and makes it an interface on a
BSON codec. Alternative BSON codecs should define a similar class method
that returns an Object ID of whatever type is appropriate.
inflate_extjson
use JSON::MaybeXS;
$data = decode_json( $json_string );
$bson->inflate_extjson( $data );
Given a hash reference, this method walks the hash, replacing any
MongoDB extended JSON
<https://docs.mongodb.org/manual/reference/mongodb-extended-json/> items
with BSON type-wrapper equivalents. Additionally, any JSON boolean
objects (e.g. "JSON::PP::Boolean") will be replaced with boolean.pm true
or false values.
FUNCTIONS
encode
my $bson = encode({ bar => 'foo' }, \%options);
This is the legacy, functional interface and is only exported on demand.
It takes a hashref and returns a BSON string. It uses an internal codec
singleton with default attributes.
decode
my $hash = decode( $bson, \%options );
This is the legacy, functional interface and is only exported on demand.
It takes a BSON string and returns a hashref. It uses an internal codec
singleton with default attributes.
PERL-BSON TYPE MAPPING
BSON has numerous data types and Perl does not.
When decoding, each BSON type should result in a single, predictable
Perl type. Where no native Perl type is appropriate, BSON decodes to an
object of a particular class (a "type wrapper").
When encoding, for historical reasons, there may be many Perl
representations that should encode to a particular BSON type. For
example, all the popular "boolean" type modules on CPAN should encode to
the BSON boolean type. Likewise, as this module is intended to supersede
the type wrappers that have shipped with the MongoDB module, those type
wrapper are supported by this codec.
The table below describes the BSON/Perl mapping for both encoding and
decoding.
On the left are all the Perl types or classes this BSON codec knows how
to serialize to BSON. The middle column is the BSON type for each class.
The right-most column is the Perl type or class that the BSON type
deserializes to. Footnotes indicate variations or special behaviors.
Perl type/class -> BSON type -> Perl type/class
-------------------------------------------------------------------
float[1] 0x01 DOUBLE float[2]
BSON::Double
-------------------------------------------------------------------
string[3] 0x02 UTF8 string[2]
BSON::String
-------------------------------------------------------------------
hashref 0x03 DOCUMENT hashref[4][5]
BSON::Doc
BSON::Raw
MongoDB::BSON::Raw[d]
Tie::IxHash
-------------------------------------------------------------------
arrayref 0x04 ARRAY arrayref
-------------------------------------------------------------------
BSON::Bytes 0x05 BINARY BSON::Bytes
scalarref
BSON::Binary[d]
MongoDB::BSON::Binary[d]
-------------------------------------------------------------------
n/a 0x06 UNDEFINED[d] undef
-------------------------------------------------------------------
BSON::OID 0x07 OID BSON::OID
BSON::ObjectId[d]
MongoDB::OID[d]
-------------------------------------------------------------------
boolean 0x08 BOOL boolean
BSON::Bool[d]
JSON::XS::Boolean
JSON::PP::Boolean
JSON::Tiny::_Bool
Mojo::JSON::_Bool
Cpanel::JSON::XS::Boolean
Types::Serialiser::Boolean
-------------------------------------------------------------------
BSON::Time 0x09 DATE_TIME BSON::Time
DateTime
DateTime::Tiny
Time::Moment
Mango::BSON::Time
-------------------------------------------------------------------
undef 0x0a NULL undef
-------------------------------------------------------------------
BSON::Regex 0x0b REGEX BSON::Regex
qr// reference
MongoDB::BSON::Regexp[d]
-------------------------------------------------------------------
n/a 0x0c DBPOINTER[d] BSON::DBRef
-------------------------------------------------------------------
BSON::Code[6] 0x0d CODE BSON::Code
MongoDB::Code[6]
-------------------------------------------------------------------
n/a 0x0e SYMBOL[d] string
-------------------------------------------------------------------
BSON::Code[6] 0x0f CODEWSCOPE BSON::Code
MongoDB::Code[6]
-------------------------------------------------------------------
integer[7][8] 0x10 INT32 integer[2]
BSON::Int32
-------------------------------------------------------------------
BSON::Timestamp 0x11 TIMESTAMP BSON::Timestamp
MongoDB::Timestamp[d]
-------------------------------------------------------------------
integer[7] 0x12 INT64 integer[2][9]
BSON::Int64
Math::BigInt
Math::Int64
-------------------------------------------------------------------
BSON::MaxKey 0x7F MAXKEY BSON::MaxKey
MongoDB::MaxKey[d]
-------------------------------------------------------------------
BSON::MinKey 0xFF MINKEY BSON::MinKey
MongoDB::MinKey[d]
[d] Deprecated or soon to be deprecated.
[1] Scalar with "NV" internal representation or a string that looks
like a float if the 'prefer_numeric' option is true.
[2] If the 'wrap_numbers' option is true, numeric types will be wrapped
as BSON::Double, BSON::Int32 or BSON::Int64 as appropriate to ensure
round-tripping. If the 'wrap_strings' option is true, strings will
be wrapped as BSON::String, likewise.
[3] Scalar without "NV" or "IV" representation and not identified as a
number by notes [1] or [7].
[4] If 'ordered' option is set, will return a tied hash that preserves
order (deprecated 'ixhash' option still works).
[5] If the document appears to contain a DBRef and a 'dbref_callback'
exists, that callback is executed with the deserialized document.
[6] Code is serialized as CODE or CODEWSCOPE depending on whether a
scope hashref exists in BSON::Code/MongoDB::Code.
[7] Scalar with "IV" internal representation or a string that looks like
an integer if the 'prefer_numeric' option is true.
[8] Only if the integer fits in 32 bits.
[9] On 32-bit platforms, 64-bit integers are deserialized to
Math::BigInt objects (even if subsequently wrapped into
BSON::Int64 if 'wrap_scalars' is true).
THREADS
Threads are never recommended in Perl, but this module is thread safe.
ENVIRONMENT
* PERL_BSON_BACKEND – if set at compile time, this will be treated as
a module name. The module will be loaded and used as the BSON
backend implementation. It must implement the same API as
"BSON::PP".
SEMANTIC VERSIONING SCHEME
Starting with BSON "v0.999.0", this module is using a "tick-tock"
three-part version-tuple numbering scheme: "vX.Y.Z"
* In stable releases, "X" will be incremented for incompatible API
changes.
* Even-value increments of "Y" indicate stable releases with new
functionality. "Z" will be incremented for bug fixes.
* Odd-value increments of "Y" indicate unstable ("development")
releases that should not be used in production. "Z" increments have
no semantic meaning; they indicate only successive development
releases. Development releases may have API-breaking changes,
usually indicated by "Y" equal to "999".
HISTORY AND ROADMAP
This module was originally written by Stefan G. In 2014, he graciously
transferred ongoing maintenance to MongoDB, Inc.
The "bson_xxxx" helper functions in BSON::Types were inspired by similar
work in Mango::BSON by Sebastian Riedel.
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at
<https://jira.mongodb.org/browse/PERL>. You will be notified
automatically of any progress on your issue.
Source Code
This is open source software. The code repository is available for
public review and contribution under the terms of the license.
<https://github.com/mongodb/mongo-perl-bson>
git clone https://github.com/mongodb/mongo-perl-bson.git
AUTHORS
* David Golden <david@mongodb.com>
* Stefan G. <minimalist@lavabit.com>
CONTRIBUTORS
* Eric Daniels <eric.daniels@mongodb.com>
* Olivier Duclos <odc@cpan.org>
* Pat Gunn <pgunn@mongodb.com>
* Petr Písař <ppisar@redhat.com>
* Yury Zavarin <yury.zavarin@gmail.com>
* Oleg Kostyuk <cub@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2018 by Stefan G. and MongoDB, Inc.
This is free software, licensed under:
The Apache License, Version 2.0, January 2004