Bson

Description:

bson

bson #
Bson library for Dart programming language
Version 5.0.0 has breaking API changes. See changelog for details.
Package #
This package allows the conversion of a map of dart elements into a binary Bson representation and viceversa.
The input can be a standard dart map with key name of the value and the value itself, or an ejson representation of the value or a mixed source.
It is also possible to serialize objects that uses the BsonSerializable mixin.
There is a Codec class that allows to define which kind of serialization we want to perform (depending on the source) + three specialized classes that preset the parameters dependig on the source that we are providing. These classes (shortcuts for the Codec one) are:

BsonCodec
EjsonCodec
ObjectCode

BSON #
This is the most important converter. It converts from a document of objects into the BSON format. The objects must be of a supported type. The actually managed objects are:

Dart Type
Internal Type
Bson Byte
Returned internal
Returned Dart
Notes

double
BsonDouble
1 / 0x01
BsonDouble
double

String
BsonString
2 / 0x02
BsonString
String

Map
BsonMap
3 / 0x03
BsonMap
Map

DbRef
BsonDbRef
Map convention
BsonDbRef
DbRef
Map containing keys "$id" and "$ref"

List
BsonArray
4 / 0x04
BsonArray
List

LegacyUuid
BsonLegacyUuid
5 / 0x05
BsonLegacyUuid
LegacyUuid
Sub Type 3 / 0x03

UuidValue
BsonUuid
5 / 0x05
BsonUuid
UuidValue
Sub Type 4 / 0x04

ObjectId
BsonObjectId
7 / 0x07
BsonObjectId
ObjectId

bool
BsonBoolean
8 / 0x08
BsonBoolean
bool

DateTime
BsonDate
9 / 0x09
BsonDate
DateTime

Null
BsonNull
10 / 0x0A
BsonNull
Null

RegExp
BsonRegexp
11 / 0x0B
BsonRegexp
RegExp

DBPointer
DBPointer
12 / 0x0C
DBPointer
DBPointer
@Deprecated

JsCode
BsonCode
13 / 0x0D
BsonCode
JsCode

int
BsonInt
16 / 0x10
BsonInt
int
when bitLength <= 31

Int32
BsonInt
16 / 0x10
BsonInt
int

Timestamp
BsonTimestamp
17 / 0x11
BsonTimestamp
Timestamp

int
BsonLong
18 / 0x12
BsonLong
Int64
when bitLength > 31

Int64
BsonLong
18 / 0x12
BsonLong
Int64

Decimal
BsonDecimal128
19 / 0x13
BsonDecimal128
Decimal

The objects expected are those of the column "Dart Type", while the objects returned are those of the column "Returned Dart". The other types are intended to be used internally. The Bson Types are eventually accepted in input instead of the corresponding Dart types.
Most of the types expected are from the Dart language itself, with these exceptions:

Class
Package

DbRef
Bson

LegacyUuid
Bson

UuidValue
Uuid

ObjectId
Bson

DBPointer
Bson

JsCode
Bson

Timestamp
Bson

Int32
Fixnum

Int64
Fixnum

Decimal
Decimal

To serialize an bson map you have to use the serialize method of the BsonCodec class.
Ex. var bsonBinary = BsonCodec.serialize(bsonDocument);
You can see a serialization example here
To deserialize an bson map you have to use the deserialize method of the BsonCodec class.
Ex. var result = BsonCodec.deserialize(bsonBinary);
You can see a deserialization example here
EJSON #
It converts from a document in format ejson into the BSON format. Only ejson version 2 is supported. The objects must be of a supported type. The actually managed objects are:

EJson
Internal Type
Bson Byte
Returned internal
Returned EJson
Notes

"$numberDouble"
BsonDouble
1 / 0x01
BsonDouble
"$numberDouble"

String
BsonString
2 / 0x02
BsonString
String

Map
BsonMap
3 / 0x03
BsonMap
Map

"$ref" - "$id"
BsonDbRef
Map convention
BsonDbRef
"$ref" - "$id"
Map containing keys "$id" and "$ref"

List
BsonArray
4 / 0x04
BsonArray
List

"$binary"
BsonBinary
5 / 0x05
BsonBinary
"$binary"
Sub Type 0 / 0x00

"$binary"
BsonLegacyUuid
5 / 0x05
BsonLegacyUuid
"$binary"
Sub Type 3 / 0x03

"$binary"
BsonUuid
5 / 0x05
BsonUuid
"$binary"
Sub Type 4 / 0x04

"$oid"
BsonObjectId
7 / 0x07
BsonObjectId
"$oid"

bool
BsonBoolean
8 / 0x08
BsonBoolean
bool

"$date"
BsonDate
9 / 0x09
BsonDate
"$date"

Null
BsonNull
10 / 0x0A
BsonNull
Null

"$regularExpression"
BsonRegexp
11 / 0x0B
BsonRegexp
"$regularExpression"

"$dbPointer"
DBPointer
12 / 0x0C
DBPointer
"$dbPointer"
@Deprecated

"$code"
BsonCode
13 / 0x0D
BsonCode
"$code"

int
BsonInt
16 / 0x10
BsonInt
"$numberInt"
when bitLength <= 31

"$numberInt"
BsonInt
16 / 0x10
BsonInt
"$numberInt"

"$timestamp"
BsonTimestamp
17 / 0x11
BsonTimestamp
"$timestamp"

int
BsonLong
18 / 0x12
BsonLong
"$numberLong"
when bitLength > 31

"$numberLong"
BsonLong
18 / 0x12
BsonLong
"$numberLong"

"$numberDecimal"
BsonDecimal128
19 / 0x13
BsonDecimal128
"$numberDecimal"

To serialize an ejson map you have to use the serialize method of the EjsonCodec class.
Serialization accept relaxed values, if present.
Ex. var bsonBinary = EJsonCodec.serialize(ejsonMap);
You can see a serialization example here
To deserialize an ejson map you have to use the deserialize method of the EjsonCodec class.
Ex. var result = EJsonCodec.deserialize(bsonBinary);
You can see a deserialization example here
To extract the ejson in "relaxed" format you have to set the relaxed parameter to true.
Ex var result = EJsonCodec.deserialize(bsonBinary, relaxed: true);
There are also two convenient methods that you can use to convert from a ejson map into a Bson Map (EJsonCodec.eJson2Doc(ejsonMap)) and viceversa (EJsonCodec.doc2eJson(document)).
There are also two convenient method to transform an ejson map into a string (EJsonCodec.stringify) and vice-versa (EJsonCodec.parse).
Dart Object #
You can also convert dart objects into BSON Format.
The requirements are the following:

The object must use the BsonSerializable mixin.
Override the toBson method where, for each field, the corresponding value must be given. The value of one of the Bson managed ones or another object with the BsonSerializable mixin
Register the class with a unique number and the method you use for recreating the instance

To serialize a BsonSerializable object you have to use the serialize method of the object instance (inherithed from BsonSerializable).
Ex. BsonBinary result = < bsonSerializable >.serialize();
You can see a serialization example here
To deserialize BsonSerializable object you have to use the deserialize method of the ObjectCodec class.
Ex. ObjectCodec.deserialize(bsonBinary)
You can see a deserialization example here