Clients

Dedot exposes 3 high-level clients offering powerful API that abstracting over the complexities of on-making chain interactions (queries, transactions...) or sending raw JSON-RPC request to a blockchain nodes.

• DedotClient: High-level Substrate client built on top of the new JSON-RPC API

• LegacyClient: High-level Substrate client built on top of the legacy JSON-RPC API

• JsonRpcClient: High-level JSON-RPC client to help making raw JSON-RPC requests or subscriptions seamlessly. Both DedotClient and LegacyClient are also a JsonRpcClient.

Both DedotClient and LegacyClient are both implementing theISubstrateClient<ChainApi, ApiEvent> interface, so they are sharing a list of common APIs of a client to interact with Subtrated-based blockchains.

DedotClient

DedotClient's high-level APIs are built on top of the new JSON-RPC API, beside implementing the common client APIs, DedotClient are also exposing access to JsonRpcGroup instances like ChainHead or ChainSpec.

import { DedotClient, WsProvider, PinnedBlock } from 'dedot';
import type { PolkadotApi } from '@dedot/chaintypes';

// Initialize providers & clients
const provider = new WsProvider('wss://rpc.polkadot.io');
const client = await DedotClient.new<PolkadotApi>(provider);

// Get current best runtime version
const currentBestRuntimeVersion = await client.getRuntimeVersion();

// Execute JSON-RPC methods
const metadata = await client.rpc.state_getMetadata();

// On-chain interactions
const balance = client.query.system.balance('<address>');
const transferTx = client.tx.balances.transferKeepAlive(<address>, 2_000_000_000_000n);

// Fetch ChainSpec information
const genesisHash = await client.chainSpec.genesisHash();
const chainProps = await client.chainSpec.properties();

// Access ChainHead data
const currentBestBlock = await client.chainHead.bestBlock();
const currentFinalizedBlock = await client.chainHead.finalizedBlock();
const finalizedRuntimeVersion = await client.chainHead.runtimeVersion();
const bestRuntimeVersion = await client.chainHead.bestRuntimeVersion();
// ...

// Listen to ChainHead events (best blocks, finalized block, ...)
const unsub = client.chainHead.on('bestBlock', (block: PinnedBlock, bestChainChanged: boolean) => {
    console.log(`Current best block: ${block.number}, hash: ${block.hash}, bestChainChanged: ${bestChainChanged}`);
});

// Other ChainHead events available like: 
//    'finalizedBlock': new best finalized block
//    'bestChainChanged': new best chain changed, a fork happened

// Or broadcast a raw transaction
const rawTxHex = '0x...';
const unsub = await client.chainHead.txBroadcaster.broadcastTx(rawTxHex);

LegacyClient

Similarly to DedotClient, LegacyClient is also another client that Dedot offers, but its high-level APIs are built on of the legacy JSON-RPC API.

import { LegacyClient, WsProvider } from 'dedot';
import type { PolkadotApi } from '@dedot/chaintypes';

// Initialize providers & clients
const provider = new WsProvider('wss://rpc.polkadot.io');
const client = await LegacyClient.new<PolkadotApi>(provider);

// Get current best runtime version
const currentBestRuntimeVersion = await client.getRuntimeVersion();

// Execute JSON-RPC methods
const metadata = await client.rpc.state_getMetadata();

// On-chain interactions
const balance = client.query.system.balance('<address>');
const transferTx = client.tx.balances.transferKeepAlive(<address>, 2_000_000_000_000n);

// Fetch ChainSpec information
const genesisHash = await client.rpc.chain_getBlockHash(0);
const chainProps = await client.rpc.system_properties();

// Access ChainHead data
const currentBestBlock = await client.rpc.chain_getBlock();
const currentFinalizedHash = await client.rpc.chain_getFinalizedHead();
const finalizedBlock = await client.rpc.chain_getBlock(currentFinalizedHash);
// ...

// Or broadcast a raw transaction
const rawTxHex = '0x...';
const txHash = await client.rpc.author_submitExtrinsic(rawTxHex);
// or
const unsub = await client.rpc.author_submitAndWatchExtrinsic(rawTxHex, (txStatus) => {});

JsonRpcClient

JsonRpcClient is a light-weight JSON-RPC client. Both DedotClient and LegacyClient are also extending JsonRpcClient, so one can access all the methods and props of a JsonRpcClient on DedotClient or LegacyClient. So unless for advanced interaction intensively via raw JSON-RPC, we recommend using high-level abstraction APIs on DedotClient or LegacyClient.

import { JsonRpcClient, WsProvider } from 'dedot';
import type { PolkadotApi } from '@dedot/chaintypes';

// Initialize providers & clients
const provider = new WsProvider('wss://rpc.polkadot.io');
const client = await JsonRpcClient.new<PolkadotApi>(provider);

// Get current best runtime version
console.log('Connection status:', client.status);

// Execute JSON-RPC methods
const metadata = await client.rpc.state_getMetadata();
const chain = await client.rpc.system_chain();
const nodeVersion = await client.rpc.system_version();

// Submit raw tx
const txHash = await client.rpc.author_submitExtrinsic('0x...');

---

Connection Status

Clients keep track of connection status, and it can be access via client.status with type ConnectionStatus

import { ConnectionStatus } from 'dedot';

// client: DedotClient, LegacyClient or JsonRpcClient
const status: ConnectionStatus = client.status;

There are 3 available statues:

• connected: The client is connected to the network

• disconnected: The client is disconnected from the network

• reconnecting: The client is trying to reconnect to the network

Client Events

Clients will emit the following events in specific situations:

type ApiEvent = 'connected' | 'disconnected' | 'reconnecting' | 
                'error' | 'ready' | 'runtimeUpgraded';

• connected: The client is connected to the network

• disconnected: The client is disconnected from the network

• reconnecting: The client is trying to reconnect to the network

• error: There is a connection error occurred (e.g: WebSocket error)

• ready: Client's initialization process (download metadata, current runtime version...) is completed and ready to perform on-chain interactions

• runtimeUpgraded: A runtime upgrade occurred

import { SubstrateRuntimeVersion } from 'dedot';

// Listen to client/api events
client.on('connected', (connectedEndpoint: string) => {});
client.on('disconnected', () => {});
client.on('reconnecting', () => {});
client.on('ready', () => {});
client.on('error', (e: Error) => {});
client.on('runtimeUpgraded', (runtimeVersion: SubstrateRuntimeVersion) => {});

ApiOptions & JsonRpcClientOptions

TODO