Jaco Greeff
b313614935
* Pull in latest @polkadot/dev, cleanup existing *.html * Cleanups (old gitbook interfaces) * Bump, WIP * Ready for testing * Update examples * Include source * Cleanup links * Adjust links * Add typedoc exclusions * Default classes from class files * Adjust imports * Adjust config * Re-add types split * Update links to substrate interfaces * Anchors for metadata * Adjust links * Restore HTML (to be deleted on CI) * Bump deps * Re-gen yarn.lock * Remove a in links * Adjust interfaces
72 lines
1.7 KiB
Markdown
72 lines
1.7 KiB
Markdown
# @polkadot/rpc-core
|
|
|
|
This library provides a clean wrapper around all the methods exposed by a Polkadot network client.
|
|
|
|
## Usage
|
|
|
|
Installation -
|
|
|
|
```
|
|
yarn add @polkadot/rpc-core
|
|
```
|
|
|
|
Initialisation -
|
|
|
|
```js
|
|
import Rpc from '@polkadot/rpc-core';
|
|
import WsProvider from '@polkadot/rpc-provider/ws';
|
|
|
|
const provider = new WsProvider('http://127.0.0.1:9944');
|
|
const api = new Rpc(provider);
|
|
```
|
|
|
|
Retrieving the block header object for a given block header hash (a 0x-prefixed hex string with length of 64) -
|
|
|
|
```js
|
|
api.chain
|
|
.getHeader('0x1234567890')
|
|
.then((header) => console.log(header))
|
|
.catch((error) => console.error(error));
|
|
```
|
|
|
|
Retrieving the best block number, parent hash, state root hash, extrinsics root hash, and digest (once-off) -
|
|
|
|
```js
|
|
api.chain
|
|
.getHead()
|
|
.then((headerHash) => {
|
|
return api.chain.getHeader(headerHash);
|
|
})
|
|
.then((header) => {
|
|
console.log(`best #${header.blockNumber.toString()}`);
|
|
console.log(`parentHash: ${header.parentHash.toString()}`);
|
|
console.log(`stateRoot: ${header.stateRoot.toString()}`);
|
|
console.log(`extrinsicsRoot: ${header.extrinsicsRoot.toString()}`);
|
|
console.log(`digest: ${header.digest.toString()}`);
|
|
})
|
|
.catch((error) => {
|
|
console.error('error:', error);
|
|
});
|
|
```
|
|
|
|
Retrieving best header via subscription -
|
|
|
|
```js
|
|
api.chain
|
|
.subscribeNewHead((header) => {
|
|
console.log(`best #${header.blockNumber}`);
|
|
})
|
|
.then((subscriptionId) => {
|
|
console.log(`subscriptionId: ${subscriptionId}`);
|
|
// id for the subscription, can unsubscribe via
|
|
// api.chain.subscribeNewHead.unsubscribe(subscriptionId);
|
|
})
|
|
.catch((error) => {
|
|
console.error('error subscribing:', error);
|
|
});
|
|
```
|
|
|
|
## Classes
|
|
|
|
[Classes](SUMMARY.md)
|