@dsnp/frequency-schemas

Official DSNP over Frequency Schemas

Matching DSNP Version: v1.3.0

Use Schemas as Library

Install

npm install @dsnp/frequency-schemas

Use Parquet or Avro Schema

import { dsnp } from "@dsnp/frequency-schemas";

console.log(dsnp.getSchema("broadcast"));

Get Schema Id for Connected Chain

import { dsnp } from "@dsnp/frequency-schemas";
import { ApiPromise } from "@polkadot/api";

const api = ApiPromise.create(/* ... */);
console.log(await dsnp.getSchemaId(api, "broadcast"));

The API connection is used only to identify the chain by its genesis hash.

Frequency chains have well-known Ids defined in dsnp/index.ts. However, it is possible to configure a custom mapping if needed:

dsnp.setSchemaMapping(api.genesisHash.toString(), {
  // format is dsnpName: { version: schemaId, ... }
  "tombstone": { "1.2": 64 },
  "broadcast": { "1.2": 67 },
  // ...
});

console.log(await dsnp.getSchemaId(api, "broadcast")); // yields 67

With Parquet Writer

npm install @dsnp/parquetjs

import { parquet } from "@dsnp/frequency-schemas";
import { ParquetWriter } from "@dsnp/parquetjs";

const [parquetSchema, writerOptions] = parquet.fromFrequencySchema("broadcast");
const writer = await ParquetWriter.openFile(parquetSchema, "./file.parquet", writerOptions);
writer.appendRow({
  announcementType: 2,
  contentHash: "0x1234567890abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
  fromId: 78187493520,
  url: "https://spec.dsnp.org/DSNP/Types/Broadcast.html",
});
await writer.close();

Use to Deploy Schemas

Setup

• Pull the repository
• Install dependencies npm install

Usage

To register a single schema

e.g. To register the "profile-resources" schema

npm run deploy profile-resources

by default it will deploy to the localhost node on port 9944 using the Alice sudo test account.

Two environment variables allow you to change these defaults:

DEPLOY_SCHEMA_ACCOUNT_URI="//Alice"
DEPLOY_SCHEMA_ENDPOINT_URL="ws://localhost:9944"

e.g.

DEPLOY_SCHEMA_ACCOUNT_URI="//Bob" DEPLOY_SCHEMA_ENDPOINT_URL="ws://127.0.0.1:9944" npm run deploy profile-resources

Note: Requires a sudo key if deploying to a testnet. Mainnet will use the proposal system (proposeToCreateSchema).

Additional Tools

Help

npm run deploy help

Read all Schemas from a Chain

DEPLOY_SCHEMA_ENDPOINT_URL="ws://127.0.0.1:9944" npm run read

Will output various information about the schemas on the chain as well as attempt to match known DSNP schemas.

Example Output

## Connection Information
┌─────────┬─────────────────────┬────────────────────────────────────────────┐
│ (index) │         key         │                   value                    │
├─────────┼─────────────────────┼────────────────────────────────────────────┤
│    0    │    'endpointUrl'    │ 'wss://frequency-seal.liberti.social:9944' │
│    1    │   'clientVersion'   │            '0.1.0-377bbe37fbe'             │
│    2    │     'specName'      │             'frequency'                    │
│    3    │    'specVersion'    │                    '1'                     │
│    4    │ 'latestBlockNumber' │                    '16'                    │
└─────────┴─────────────────────┴────────────────────────────────────────────┘

## Schema Information
There are 8 schemas on the connected chain.

## Schema Id 1
┌─────────┬──────────────────────┬───────────────────────────────┐
│ (index) │         key          │             value             │
├─────────┼──────────────────────┼───────────────────────────────┤
│    0    │     'schema_id'      │              '1'              │
│    1    │     'model_type'     │           'Parquet'           │
│    2    │  'payload_location'  │            'IPFS'             │
│    3    │ 'matchesDSNPSchemas' │       'dsnp.broadcast'        │
└─────────┴──────────────────────┴───────────────────────────────┘

## Schema Model
[
  {
    "name": "announcementType",
    "column_type": {"INTEGER": {"bit_width": 32, "sign": true}},
    "compression": "GZIP",
    "bloom_filter": false
  },
  {
    "name": "contentHash",
    "column_type": "BYTE_ARRAY",
    "compression": "GZIP",
    "bloom_filter": true
  },
  {
    "name": "fromId",
    "column_type": {"INTEGER": {"bit_width": 64, "sign": false}},
    "compression": "GZIP",
    "bloom_filter": true
  },
  {
    "name": "url",
    "column_type": "STRING",
    "compression": "GZIP",
    "bloom_filter": false
  }
]
...

Find Frequency Schema Ids that Match DSNP Schema Versions

This script will look up and verify schemas in the schema registry that match the DSNP names and versions defined in dsnp/index.ts.

DEPLOY_SCHEMA_ENDPOINT_URL="ws://127.0.0.1:9944" npm run find