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 Testnet deploy loaded with casper-js-sdk:

import { CasperServiceByJsonRPC } from 'casper-js-sdk';
import { Parser } from '@make-software/ces-js-parser';

const rpcClient = new CasperServiceByJsonRPC(
  `http://${process.env.NODE_ADDRESS}:7777/rpc`
);

const parser = await Parser.create(rpcClient, [
  '0640eb43bd95d5c88b799862bc9fb42d7a241f1a8aae5deaa03170a27ee8eeaa'
]);

const deploy = await rpcClient.getDeployInfo(
  'c1bb9ae27877f5ecf4ef71307e7ee3c403bcace065565c3645b81ec0a9bc8978'
);

const events = await parser.parseExecutionResult(
  deploy.execution_results[0].result as 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

Parser

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

import { CasperServiceByJsonRPC } from 'casper-js-sdk';
import { Parser } from '@make-software/ces-js-parser';

const rpcClient = new CasperServiceByJsonRPC(
  `http://${process.env.NODE_ADDRESS}:7777/rpc`
);

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)

parseSchemasFromBytes

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

parseEventNameAndData

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

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);

Event

Type that represents an event:

Property	Type	Description
contractHash	Uint8Array	Event ContractHash
contractPackageHash	Uint8Array	Event ContractHash
name	string	Event name
data	Record<string,CLValue>	Event Data

ParseResult

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

Schema

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

Schemas

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!