BSON - BSON serialization and deserialization
version v1.2.2
use BSON; use BSON::Types ':all'; use boolean; my $codec = BSON->new; my $document = { _id => bson_oid(), creation_time => bson_time(), zip_code => bson_string("08544"), hidden => false, }; my $bson = $codec->encode_one( $document ); my $doc = $codec->decode_one( $bson );
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.
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( $bson , \%decode_options );
Because BSON is strongly-typed and Perl is not, this module supports a number of "type wrappers" – classes that wrap Perl data to indicate how they should serialize. The BSON::Types module describes these and provides associated helper functions. See "PERL-BSON TYPE MAPPING" for more details.
When decoding, type wrappers are used for any data that has no native Perl representation. Optionally, all data may be wrapped for precise control of round-trip encoding.
Please read the configuration attributes carefully to understand more about how to control encoding and decoding.
At compile time, this module will select an implementation backend. It will prefer BSON::XS (released separately) if available, or will fall back to BSON::PP (bundled with this module). See "ENVIRONMENT" for a way to control the selection of the backend.
BSON::XS
This attribute specifies a function reference that will be called with three positional arguments:
an error string argument describing the error condition
a reference to the problematic document or byte-string
the method in which the error occurred (e.g. encode_one or decode_one)
encode_one
decode_one
Note: for decoding errors, the byte-string is passed as a reference to avoid copying possibly large strings.
If not provided, errors messages will be thrown with Carp::croak.
Carp::croak
A string containing ASCII characters that must not appear in keys. The default is the empty string, meaning there are no invalid characters.
This attribute defines the maximum document size. The default is 0, which disables any maximum.
If set to a positive number, it applies to both encoding and decoding (the latter is necessary for prevention of resource consumption attacks).
This is a single character to use for special MongoDB-specific query operators. If a key starts with op_char, the op_char character will be replaced with "$".
op_char
The default is "$", meaning that no replacement is necessary.
If set to a true value, then decoding will return a reference to a tied hash that preserves key order. Otherwise, a regular (unordered) hash reference will be returned.
IMPORTANT CAVEATS:
When 'ordered' is true, users must not rely on the return value being any particular tied hash implementation. It may change in the future for efficiency.
Turning this option on entails a significant speed penalty as tied hashes are slower than regular Perl hashes.
The default is false.
If set to true, scalar values that look like a numeric value will be encoded as a BSON numeric type. When false, if the scalar value was ever used as a string, it will be encoded as a BSON UTF-8 string, otherwise it will be encoded as a numeric type.
IMPORTANT CAVEAT: the heuristics for determining whether something is a string or number are less accurate on older Perls. See BSON::Types for wrapper classes that specify exact serialization types.
If set to true, during decoding, documents with the fields '$id' and '$ref' (literal dollar signs, not variables) will be wrapped as BSON::DBRef objects. If false, they are decoded into ordinary hash references (or ordered hashes, if ordered is true).
'$id'
'$ref'
ordered
The default is true.
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.
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.
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.
undef
dt_type
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.
$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_key
first_value
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
$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.
dt_type – overrides codec default
ordered - overrides codec default
wrap_dbrefs - overrides codec default
wrap_numbers - overrides codec default
wrap_strings - overrides codec default
$copy = $codec->clone( ordered => 1 );
Constructs a copy of the original codec, but allows changing attributes in the copy.
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 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.
JSON::PP::Boolean
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.
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.
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 no "PV" 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 with "PV" 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 and no "PV" 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 are never recommended in Perl, but this module is thread safe for Perl 5.8.5 or later. Threads are not supported on older Perls.
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.
BSON::PP
Starting with BSON v0.999.0, this module is using a "tick-tock" three-part version-tuple numbering scheme: vX.Y.Z
v0.999.0
vX.Y.Z
In stable releases, X will be incremented for incompatible API changes.
X
Even-value increments of Y indicate stable releases with new functionality. Z will be incremented for bug fixes.
Y
Z
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".
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.
bson_xxxx
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.
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
David Golden <david@mongodb.com>
Stefan G. <minimalist@lavabit.com>
Eric Daniels <eric.daniels@mongodb.com>
Olivier Duclos <odc@cpan.org>
Pat Gunn <pgunn@mongodb.com>
Yury Zavarin <yury.zavarin@gmail.com>
Oleg Kostyuk <cub@cpan.org>
This software is Copyright (c) 2016 by Stefan G. and MongoDB, Inc.
This is free software, licensed under:
The Apache License, Version 2.0, January 2004
To install BSON, copy and paste the appropriate command in to your terminal.
cpanm
cpanm BSON
CPAN shell
perl -MCPAN -e shell install BSON
For more information on module installation, please visit the detailed CPAN module installation guide.