BinData

BinData is binary data object that use in mongoDB. BinData consists of subType and base64str.

help misc
b = new BinData(subtype,base64str)  create a BSON BinData value

The BSON BinData datatype is represented via class BinData in the shell, each value represent specipic kind. like below :

binary  ::=   int32 subtype (byte*)   Binary - The int32 is the number of bytes in the (byte*).
subtype ::=   "\x00"  Generic binary subtype
  |   "\x01"  Function
  |   "\x02"  Binary (Old)
  |   "\x03"  UUID (Old)
  |   "\x04"  UUID
  |   "\x05"  MD5
  |   "\x80"  User defined

example

Insert a BinData() Object

Use the BinData() constructor to create the bdata variable.

var bdata = BinData(0, "gf1UcxdHTJ2HQ/EGQrO7mQ==")

Insert the object into the testbin collection.

db.testbin.insertOne( { _id : 1, bin_data: bdata } )

Query the testbin collection for the inserted document.

db.testbin.find()

You can see the binary buffer stored in the collection.

{
  _id: 1,
  bin_data: Binary(Buffer.from("81fd547317474c9d8743f10642b3bb99", "hex"), 0)
}

Get the Length of BinData() Object

Use the BinData() constructor to create the bdata variable.

var bdata = BinData(0, "gf1UcxdHTJ2HQ/EGQrO7mQ==")

Use .length() to return the bit length of the object.

bdata.length()

The returned value is:

16

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reference

• http://bsonspec.org/#/specification
• http://docs.mongodb.org/manual/reference/mongodb-extended-json/#binary