Litmus Example App

This an example app that uses the Litmus Service Worker to fetch and validate data on Casper blockchain.

About Litmus

One of the core features of any blockchain is the ability to verify data. Typically, data about a block, transaction, or account is obtained by querying an RPC node and parsing its response. However, this method does not guarantee the validity of the returned data. Litmus' mission is to empower DApps with the ability to verify any response from the blockchain directly in the browser, enhancing the security and reliability of decentralized applications.

Preparing the Service Worker

Litmus demo app comes with a precompiled service worker and WASM module. However, it is recommended to compile the service worker and WASM module yourself. Please see the following repositories: https://github.com/cspr-rad/litmus-worker https://github.com/cspr-rad/litmus-wasm

Communication with Service Worker

The app communicates with the Service Worker using the postMessage API. The Service Worker listens for messages from the app and responds with the requested data.

Service Worker updates the WorkerState object, that has followng properties:

last_block Returns the last fetched block in the JSON format.

trusted_hash Returns the currently set trusted block hash.

trusted_block Trusted switch block.

last_validated Last validated switch block height and era is.

fetch_blocks Number of blocks to fetch.

validate_blocks Number of blocks to validate.

fetch_progress Progress of fetching blocks.

fetch_eta Estimated time to fetch all blocks.

validate_progress Progress of validating blocks.

validate_eta Estimated time to validate all blocks.

status Status of the worker.

last_switch_block Last found switch block.

total_rpcs Number of RPCs nodes.

available_rpcs Number of available RPCs nodes.

account Account address to validate.

balance_CSPR Balance of the account.

balance_motes Balance of the account in motes.

account_state_root_hash Account state root hash.

merkle_proof_parsed Merkle proof parsed as JSON.

error Error message. Cleared on any message to Worker.

info Information message. Cleared on any message to Worker.

Developing locally

Install packages,run the development server and open http://localhost:3000

npm i
npm run dev