MongoDB::BSON::Binary(3) MongoDB binary type

VERSION

version v1.2.3

SYNOPSIS

Creates an instance of binary data with a specific subtype.

USAGE

For example, suppose we wanted to store a profile pic. 

    my $pic = MongoDB::BSON::Binary->new(data => $pic_bytes);
    $collection->insert({name => "profile pic", pic => $pic});

You can also, optionally, specify a subtype: 

    my $pic = MongoDB::BSON::Binary->new(data => $pic_bytes,
        subtype => MongoDB::BSON::Binary->SUBTYPE_GENERIC);
    $collection->insert({name => "profile pic", pic => $pic});

Overloading

MongoDB::BSON::Binary objects have stringification overloaded to return the binary data.

ATTRIBUTES

data

A string of binary data.

subtype

A subtype. Defaults to "SUBTYPE_GENERIC".

SUBTYPES

MongoDB allows you to specify the ``flavor'' of binary data that you are storing by providing a subtype. The subtypes are purely cosmetic: the database treats them all the same.

There are several subtypes defined in the BSON spec:

"SUBTYPE_GENERIC" (0x00) is the default used by the driver (as of 0.46).
"SUBTYPE_FUNCTION" (0x01) is for compiled byte code.
"SUBTYPE_GENERIC_DEPRECATED" (0x02) is deprecated. It was used by the driver prior to version 0.46, but this subtype wastes 4 bytes of space so "SUBTYPE_GENERIC" is preferred. This is the only type that is parsed differently based on type.
"SUBTYPE_UUID_DEPRECATED" (0x03) is deprecated. It is for UUIDs.
"SUBTYPE_UUID" (0x04) is for UUIDs.
"SUBTYPE_MD5" can be (0x05) is for MD5 hashes.
"SUBTYPE_USER_DEFINED" (0x80) is for user-defined binary types.

Why is SUBTYPE_GENERIC_DEPRECATED deprecated?

Binary data is stored with the length of the binary data, the subtype, and the actually data. "SUBTYPE_GENERIC DEPRECATED" stores the length of the data a second time, which just wastes four bytes.

If you have been using "SUBTYPE_GENERIC_DEPRECATED" for binary data, moving to "SUBTYPE_GENERIC" should be painless: just use the driver normally and all new/resaved data will be stored as "SUBTYPE_GENERIC".

It gets a little trickier if you've been querying by binary data fields: "SUBTYPE_GENERIC" won't match "SUBTYPE_GENERIC_DEPRECATED", even if the data itself is the same.

Why is SUBTYPE_UUID_DEPRECATED deprecated?

Other languages were using the UUID type to deserialize into their languages' native UUID type. They were doing this in different ways, so to standardize, they decided on a deserialization format for everyone to use and changed the subtype for UUID to the universal format.

This should not affect Perl users at all, as Perl does not deserialize it into any native UUID type.

AUTHORS

COPYRIGHT AND LICENSE

This software is Copyright (c) 2016 by MongoDB, Inc..

This is free software, licensed under: 

  The Apache License, Version 2.0, January 2004

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