ndn::MetadataObject Class Reference

Class for RDR-style metadata encoding/decoding. More...

#include <ndn-cxx/metadata-object.hpp>

Classes
class	Error

Public Member Functions
	MetadataObject ()
	Create an empty metadata object. More...
	MetadataObject (const Data &data)
	Construct a metadata object by decoding of the given Data packet. More...
const Name &	getVersionedName () const
	Return the versioned name (i.e., the name inside the content) More...
Data	makeData (Name discoveryInterestName, KeyChain &keyChain, const ndn::security::SigningInfo &si=security::SigningInfo(), std::optional< uint64_t > version=std::nullopt, time::milliseconds freshnessPeriod=10_ms) const
	Create a Data packet representing this metadata object. More...
MetadataObject &	setVersionedName (const Name &name)
	Set the versioned name. More...

Static Public Member Functions
static const name::Component &	getKeywordComponent ()
	Returns the well-known keyword name component used for metadata objects (32=metadata) More...
static bool	isValidName (const Name &name)
	Check whether name can be a valid metadata name. More...
static Interest	makeDiscoveryInterest (Name name)
	Generate a discovery interest packet based on name. More...

Detailed Description

Class for RDR-style metadata encoding/decoding.

Realtime Data Retrieval (RDR) is a protocol for discovering the latest version number of a given data collection. The Interest and Data packets dealing with metadata (called "discovery interest" and "metadata object", respectively) follow a specific format.

There are two names in an RDR metadata object:

• the versioned name is a prefix of the data collection, and generally contains a version component. It appears in the Content element of the metadata object.
• the metadata name is the name of the metadata object itself, and includes a keyword name component 32=metadata, as well as version and segment components.

See also

https://redmine.named-data.net/projects/ndn-tlv/wiki/RDR

Definition at line 48 of file metadata-object.hpp.

Constructor & Destructor Documentation

MetadataObject() [1/2]

ndn::MetadataObject::MetadataObject ( )

default

Create an empty metadata object.

MetadataObject() [2/2]

ndn::MetadataObject::MetadataObject ( const Data &  data )

explicit

Construct a metadata object by decoding of the given Data packet.

Exceptions

tlv::Error

the Data is not a valid metadata packet

Definition at line 30 of file metadata-object.cpp.

Member Function Documentation

getKeywordComponent()

const name::Component & ndn::MetadataObject::getKeywordComponent ( )

static

Returns the well-known keyword name component used for metadata objects (32=metadata)

Definition at line 79 of file metadata-object.cpp.

getVersionedName()

const Name& ndn::MetadataObject::getVersionedName ( ) const

inline

Return the versioned name (i.e., the name inside the content)

Definition at line 93 of file metadata-object.hpp.

isValidName()

bool ndn::MetadataObject::isValidName ( const Name &  name )

static

Check whether name can be a valid metadata name.

Definition at line 86 of file metadata-object.cpp.

makeData()

Data ndn::MetadataObject::makeData	(	Name	discoveryInterestName,
		KeyChain &	keyChain,
		const ndn::security::SigningInfo &	si = security::SigningInfo(),
		std::optional< uint64_t >	version = std::nullopt,
		time::milliseconds	freshnessPeriod = 10_ms
	)		const

Create a Data packet representing this metadata object.

Parameters

discoveryInterestName	the discovery Interest's name, which must end with a keyword name component 32=metadata
keyChain	KeyChain to sign the Data
si	signing parameters
version	version number of metadata packet; if nullopt, use current Unix timestamp (in milliseconds) as the version number
freshnessPeriod	freshness period of metadata packet

Exceptions

tlv::Error

discoveryInterestName is not valid

Definition at line 50 of file metadata-object.cpp.

makeDiscoveryInterest()

Interest ndn::MetadataObject::makeDiscoveryInterest ( Name  name )

static

Generate a discovery interest packet based on name.

Parameters

name	prefix of data collection

Definition at line 93 of file metadata-object.cpp.

setVersionedName()

MetadataObject & ndn::MetadataObject::setVersionedName

(

const Name &

name

)

Set the versioned name.

Any metadata packet carries a versioned name in its payload where it shows the name and the latest version of a data stream. For instance, /ndn/test/v=2538020460 is a versioned name that shows the latest version of /ndn/test.

Definition at line 72 of file metadata-object.cpp.