@synonymdev/slashtags-docid v0.0.2-alpha.0

Slashtags Document IDs

Contains Slashtags Document IDs ceration, serializing, and parsing

Abstract

DocIDs are composed of a multicodec-slashtags-docid, and type-code varint, followed by identifying bytes.

Motivation

A specific encoding for Slashtags' DocIDs allows us to distinguish them from other forms of identifiers as well distinguishing the type of data and how to parse the identifying bytes.

Specification

<slashtags-docid> ::= <mb><mc-docid><type-code><idx>
// or, expanded:
<slashtags-docid> ::= <multibase-prefix><multicodec-slashtags-docid><type-code><index-bytes>

Where

• <multibase-prefix> is a multibase code (1 or 2 bytes), to ease encoding CIDs into various bases. NOTE: Binary (not text-based) protocols and formats may omit the multibase prefix when the encoding is unambiguous.

• <multicodec-slashtags-docid>: 0xd2 indicates that this is a Slashtags identifier and representing.

• <type-code> Distinguish types data (static / stream) and how to parse the indentfiying bytes.
• <index-bytes> are used to index the document and address it according to its corrisponding type-code.

SlashtagsID multicodec

// TODO: add slashtags Document ID <multicodec-slashtags-docid> to multicodec

DocID type

Used to encode multiple attributes about the ID and the document it represents:

• Mutability: Static content or updatable Streams.
• Index bytes format: How to interpret the index bytes.
• More: Any future special kinds of documents with their own rules for verification ..etc

Static vs Stream documents

Static documents are immutable and relatively small piece of data, mainly used in Slashtags for schemas and labeling predefined Actions.

Unlike streams, static documents are not assumed to be stored as append only log nor any other format, so they require less overhaed.

Types

CID

A Slashtags DocID of type CID has four parts:

<docid> ::= <mb><mc-docid><type-code=0><cid>
// or, expanded:
<docid> ::= <multibase-prefix><multicodec-slashtags-docid><type-code=0><multicodec-cid><multicodec-content-type><multihash-content-address>

Where

• <multibase-prefix>: defaults to base32
• <type-code> is 0
• <identifying-bytes> is a CID

Usage

Create a CID typed DocID from json

import { DocID } from '@slashtags/ids';
const docID = DocID.CID.fromJSON({ foo: 'bar' });

Or create it by passing a CID bytes

import { DocID } from '@slashtags/ids';
import { CID } from 'multiformats/cid';
import * as json from 'multiformats/codecs/json';
import { sha256 } from 'multiformats/hashes/sha2';

const bytes = json.encode({ hello: 'world' });
const hash = await sha256.digest(bytes);
const cid = CID.create(1, json.code, hash);

const docID = DocID.create(0, cid.bytes);

FeedID

A Slashtags DocID of type FeedID has four parts:

<docid> ::= <mb><mc-docid><type-code=0><feed-key>
// or, expanded:
<docid> ::= <multibase-prefix><multicodec-slashtags-docid><type-code=1><hypercore-feed-key>

Usage

import hypercore from 'hypercore';

var feed = new Hypercore('./my-first-dataset');

// You can pass the type name instead of the type code
const docID = DocID.create('FeedID', feed.key);