rusk: Introduce JSON-RPC Endpoints

[HDauven]

Summary

This issue proposes the addition of new JSON-RPC endpoints to be compatible with existing 3rd party tooling. These endpoints will use the ledger_ prefix to distinguish core blockchain operations from other subsystems.

Proposed Endpoints

ledger_getBalance

• Description: Returns the balance of a specified public (Moonlight) account.
• Parameters: ["oCqYsUMRqpRn2kSabH52Gt6FQCwH5JXj5MtRdYVtjMSJ73AFvdbPf98p3gz98fQwNy9ZBiDem6m9BivzURKFSKLYWP3N9JahSPZs9PnZ996P18rTGAjQTNFsxtbrKx79yWu"]
• Response:

{
  "jsonrpc": "2.0",
  "result": 150000, // Balance in LUX
  "id": 1
}

ledger_getBlock

• Description: Retrieves a block by height or hash.
• Parameters:
  • For block height: [101]
  • For block hash: ["ce50a4bb5727a530f38f0cfd9ae6eb4ceeb7538c12619aee1d747cb1f98160a0"]
• Response:

{
  "jsonrpc": "2.0",
  "result": {
    "hash": "ce50a4bb...",
    "height": 54321,
    "transactions": [...],
    ...
  },
  "id": 1
}

ledger_getBlockHeight

• Description: Returns the current block height.
• Parameters: []
• Response:

{
  "jsonrpc": "2.0",
  "result": 54321, // Block height as an integer
  "id": 1
}

ledger_getTransaction

• Description: Fetches details of a transaction by its hash.
• Parameters: ["74f5cca0894765a2c5309c3ed6e29c52ea1f26f8dd418c7c6ad62c49931f3169"]
• Response:

{
  "jsonrpc": "2.0",
  "result": {
    "hash": "74f5cca08...",
    "type": "phoenix/moonlight",
    ...
  },
  "id": 1
}

Mapping to Internal Functions

JSON-RPC Endpoint	Internal Database Function
ledger_getBalance	fn get_account(&self, pk: &str) -> anyhow::Result
ledger_getBlock	block_by_height(&self, height: u64) -> Result<Option<Block>> block(&self, hash: &[u8]) -> Result<Option<Block>>
ledger_getBlockHeight	block_hash_by_height(&self, height: u64) -> Result<Option<[u8; 32]>>
ledger_getTransaction	ledger_tx(&self, tx_id: &[u8]) -> Result<Option<SpentTransaction>>

Rationale for Prefixes

The use of prefixes in JSON-RPC are common to explicitly identify subsystems in RPC calls. This allows us to introduce id_ for Citadel/SSI in the future, stake_ for RPC calls to the staking contract, and potentially other future subsystems. Both SUI and Ethereum use these. Solana does not make use of this.

Tasks

• Implement ledger_getBalance
• Implement ledger_getBlock
• Implement ledger_getBlockHeight
• Implement ledger_getTransaction

[welf]

Why do we need to prefix endpoints with the ledger_? Why not to create a /ledger endpoint and get a function/method name from the JSON payload as per the JSON-RPC specification?