man MongoDB::BSON (3): Tools for serializing and deserializing data in BSON form

VERSION

version v1.2.3

SYNOPSIS

my $codec = MongoDB::BSON->new;
my $bson = $codec->encode_one( $document );
my $doc = $codec->decode_one( $bson );

DESCRIPTION

This class implements a BSON encoder/decoder (``codec''). It consumes documents and emits BSON strings and vice versa.

ATTRIBUTES

dbref_callback

A document with keys $ref and $id is a special MongoDB convention representing a DBRef <http://docs.mongodb.org/manual/applications/database-references/#dbref>.

This attribute specifies a function reference that will be called with a hash reference argument representing a DBRef.

The hash reference will have keys $ref and $id and may have $db and other keys. The callback must return a scalar value representing the dbref (e.g. a document, an object, etc.)

The default "dbref_callback" returns the DBRef hash reference without modification.

Note: in MongoDB::MongoClient, when no MongoDB::BSON object is provided as the "bson_codec" attribute, <MongoDB:MongoClient> creates a custom MongoDB::BSON object that inflates DBRefs into MongoDB::DBRef objects using a custom "dbref_callback":

    dbref_callback => sub { return MongoDB::DBRef->new(shift) },

Object-database mappers may wish to implement alternative "dbref_callback" attributes to provide whatever semantics they require.

dt_type

Sets the type of object which is returned for BSON DateTime fields. The default is DateTime. Other acceptable values are Time::Moment, DateTime::Tiny and "undef". The latter will give you the raw epoch value (possibly as a floating point value) rather than an object.

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 operators. If a key starts with "op_char", the "op_char" character will be replaced with ``$''.

The default is ``$''.

prefer_numeric

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.

The default is false.

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 representin the decoded document.