5. Data Structures#

Triplet graphs similar to linked data fragments with envelopes. decoupling content addressing from versioning

  • Merkel DAGs

  • Envelopes

  • Versioning

  • Typed objects with formatting

5.1. Containers#

  • Packets of LD-triplets that contain

    • Hash of triplets

    • Encryption Info (if applicable)

    • Permissions scope

    • Signature

  • Anything that can be directly referenced without local qualifier is a container.

    • Triplets within a container can be referenced with the query syntax

  • Containers also behave like “feeds”

    • Eg. one might put their blog posts in @user:blog or

  • The account identifier is the top-level container.

  • Ordering:

    • Every triple within a scope is ordered by default by the time it is declared

    • A container can declare its ordering (see Container)

  • Naming:

    • Each container intended to be directly referenced SHOULD contain a name so it can be referenced w.r.t its parent: @<ACCOUNT>:<name>

    • Each container can also be indicated numerically

  • Identity: Each container is uniquely identified by the hash of its contents and the hash of the account identifier.

  • Format: A container can specify one or several ways it can be displayed

  • Capabilities: A container can specify different capabilities that another account can take (eg. “Like”, “Upvote”, “Reply”)

    • Capabilities should also contain a permissions scope, if none is present, the global scope is assumed.

    • Since Identities are just a special form of container, they too can advertise different actions that they support with capabilities.

  • Basically a container is a merkle DAG with binary data at its leaves a la the Linked Data; Platform

  • Re: Ordering - https://github.com/ssbc/ssb-tangle

Re hashing a graph: the container always has one root node that is the container’s identity from which a graph traversal starts. A Merkle DAG is then constructed starting from the leaves.

5.2. Triplets#

  • Triplet format

    • Objects require a shortname that can be hierarchically indexed from

  • Types/Schema

  • Including intrinsic notion of nesting

    • every object can have blank/positionally indexed children

    • every triple can have blank/positionally indexed “qualifiers” like RDF-star or wikidata’s qualifiers.

5.3. Schema#

5.4. Codecs#

See IPLD Codecs and Linked Data Platform spec

Means of interacting with binary data.

Describes

  • Format

5.5. Versioning#

  • A given container has an identity hash from its first packing

  • A given triple can be contained by