CES JS Parser

@make-software/ces-js-parser parses contract-level events that follow the Casper Event Standard.

The library is built on top of the casper-js-sdk and operates on types defined by the SDK.

Prerequisites

- Node.js Version: >12.22.10
- OS: Linux, MacOS

Install

npm install --save @make-software/ces-js-parser

Usage

Here is an example of parsing CES events using ces-js-parser from a real Integration net transaction loaded with casper-js-sdk:

``typescript
import { HttpHandler, RpcClient } from 'casper-js-sdk';
import { Parser } from '@make-software/ces-js-parser';

(async() => {
const rpcHandler = new HttpHandler('http://${process.env.NODE_ADDRESS}:7777/rpc');

const rpcClient = new RpcClient(rpcHandler);

const parser = await Parser.create(rpcClient, [
'333f0e776995a27ad8502e29b141b875951f92fe6b61329a59f1f875ef48e16a'
]);

const transaction = await rpcClient.getTransactionByTransactionHash(
'1592814db95151bb9366112dea6e10fe5d8043ba2b1efd28545a0b6e53839a70'
);

const events = parser.parseExecutionResult(
transaction.executionInfo!.executionResult,
);

events.forEach(console.log);
})()
`

API

CES JS Parser provides several public types and functions:

- CES JS Parser
- Prerequisites
- Install
- Usage
- API
- Parser
- create
- parseExecutionResults
- fetchContractSchemasBytes
- parseSchemasFromBytes
- parseEventNameAndData
- Event
- ParseResult
- Schema
- Schemas
- Tests
- License
- Contributing

$3

Parser that accepts a list of observed contracts and provides possibility to parse CES events out of deploy execution results

#### create

create is a async factory function that accepts CasperServiceByJsonRPC and contractHashes array and created a Parser instance:

| Argument | Type | Description |
| --- | --- | --- |
| rpcClient | CasperServiceByJsonRPC | Instance of the CasperServiceByJsonRPC client |
| contractHashes | string[] | List of the observed contract hashes |

Example

`typescript
import { HttpHandler, RpcClient } from 'casper-js-sdk';
import { Parser } from '@make-software/ces-js-parser';

const rpcHandler = new HttpHandler('http://${process.env.NODE_ADDRESS}:7777/rpc');

const rpcClient = new RpcClient(rpcHandler);

const parser = await Parser.create(rpcClient, [
'214a0e730e14501d1e3e03504d3a2f940ef32830b13fa47f9d85a40f73b78161'
]);
`

#### parseExecutionResults

parseExecutionResults method that accepts deploy execution results and returns ParseResult[]:

| Argument | Type | Description |
| ------------------ | ------------------ | ------------------------ |
| executionResults | ExecutionResults | Deploy execution results |

#### fetchContractSchemasBytes

fetchContractSchemasBytes method that accepts contract hash and return bytes representation of stored schema:

| Argument | Type | Description |
| --- | --- | --- |
| contractHash | string | Contract hash schema want to be fetched |
| stateRootHash | string | State root hash of the data (takes latest if not provided) |

$3

parseSchemasFromBytes function that accepts raw CES schema bytes stored under the contract __events_schema URef and returns Schemas:

| Argument | Type | Description |
| ---------- | ------------ | -------------------------- |
| rawBytes | Uint8Array | Raw contract schemas bytes |

$3

Function that accepts raw event bytes and contract event schemas and returns Event, that contains name and data:

| Argument | Type | Description |
| ---------- | --------- | ---------------------------- |
| rawEvent | string | Raw event bytes in hex |
| schemas | Schemas | The list of contract schemas |

Example

`typescript
import { decodeBase16 } from 'casper-js-sdk';
import {
parseSchemasFromBytes,
parseEventNameAndData
} from '@make-software/ces-js-parser';

const schemas = parseSchemasFromBytes(rawBytes);
const rawEvent = decodeBase16('some real example here');

const event = parseEventNameAndData(rawEvent, schemas);
`

$3

Type that represents an event:

| Property | Type | Description |
| --- |--------------------------|-----------------------------------------------------|
| contractHash | Uint8Array | Event ContractHash |
| contractPackageHash | Uint8Array | Event ContractHash |
| name | string | Event name |
| eventId | number | Event identifier |
| transformIdx | number | Transaction transform index of the event |
| data | Record | Event Data |

$3

Value-object that represents a parse result. Contains error representing weather parsing was successful or not.

| Property | Type | Description |
| -------- | ----------------- | ------------------ |
| error | string | Parse result error |
| event | Event | ces Event |

$3

Schema is slice of PropertyDefinition - value-object that represents an schema item.

| Property | Type | Description |
| ---------- | -------- | --------------------------- |
| Property | string | Name of the schema property |
| Value | CLType | casper CLType |

$3

Schemas represent a map of event name and its Schema.

Tests

To run unit tests for the library, make sure you are in the root of the library:

npm run test`

License

This project is licensed under the terms of the Apache-2.0 license.

Contributing

We welcome contributions from anyone interested in improving this project. Before getting started, please take a moment to read our contributing guidelines to learn more about how to contribute to this project, including how to report bugs, suggest enhancements, and submit pull requests.

We look forward to collaborating with you!