OctetString conversion to String

[vbob]

I want to do a generic SNMP Subtree, but I am having problems with OctetString conversion:

• MAC Adresses are decoded with .toString('hex')
• Text is decoded with .toString('utf8')

My code is the following:

this.connection.subtree(oid, (varbinds: Array<any>) => {
  varbinds.forEach(varbind => {
    if (snmp.isVarbindError(varbind))
      message.push({
        'oid': varbind.oid,
        'value': snmp.varbindError(varbind)
      })

    else {
      if (varbind['type'])
        varbind['type'] = snmp.ObjectType[varbind['type']]

      // How to make this statement generic?
      if (varbind['value'] instanceof Buffer)
        varbind['value'] = varbind['value'].toString("hex")

      message.push(varbind)
    }
  })
})

And my responses are:

[{
    oid: "1.3.6.1.2.1.2.2.1.2.2",
    type: "OctetString",
    value: "526564204861742c20496e63204465766963652030303031"
},
// [...]
{
    oid: "1.3.6.1.2.1.2.2.1.6.2",
    type: "OctetString",
    value: "82f8c67920e6"
}]

The expected snmpget responses are:

1.3.6.1.2.1.2.2.1.2.2 = STRING: Red Hat, Inc Device 0001
1.3.6.1.2.1.2.2.1.6.2 = STRING: 82:f8:c6:79:20:e6

How can I distinguish one from the other and create a generic subtree function with correct string conversion?

[stephenwvickers]

You will need to know the data type you are dealing with if they are both instances of OctetString.

If you can load the MIB file somehow, then you can use that to determine how to parse OctetString instances.