Oracle System

The Savitri Oracle system provides verified external data feeds to on-chain contracts. It supports data requests, provider responses, proof verification, and schema validation.

Architecture

External Data Source
       │
Oracle Provider (off-chain)
       │
   submit_response()
       │
Oracle Registry Contract (on-chain)
       │
   verify_data() + proof
       │
Consumer Contract

Components

Oracle Registry (oracle_registry.rs)

Central registry for oracle providers and data feeds:

• Provider registration and management
• Data feed configuration
• Access control

Oracle Feed (oracle/feed.rs)

Data feed management:

• Feed creation and updates
• Historical data tracking
• Aggregation support

Oracle Proof (oracle/proof.rs)

Cryptographic verification of oracle data:

• Signature-based proofs
• Multi-provider consensus
• Tamper detection

Oracle Schema (oracle/schema.rs)

Data format validation:

• Schema definitions for data types
• Input/output validation
• Type checking

Using Oracles via SDK

Request Data

use savitri_sdk::ContractClient;

let contract = ContractClient::from_url_and_wallet(url, wallet)?;
let oracle = contract.oracle();

// Request temperature data
let tx = oracle.request_data(
    &oracle_address,
    "temperature",
    b"sensor_001",
).await?;

Submit Response (Provider)

let tx = oracle.submit_response(
    &oracle_address,
    request_id,         // u64
    b"25.5",            // response bytes
).await?;

Verify Data

let is_valid = oracle.verify_data(
    &oracle_address,
    b"data_to_verify",
).await?;

Using TransactionBuilder

use savitri_sdk::TransactionBuilder;

let tx = TransactionBuilder::new()
    .oracle_call(
        "oracle_contract_address",
        "request_data",
        b"params",
    )
    .nonce(nonce)
    .fee(5_000_000_000_000_000)
    .build_and_sign(&wallet)?;

Oracle Data Types

Type	Format	Use Case
Price feed	u128 (18 decimals)	Token prices, exchange rates
Sensor data	bytes	IoT temperature, humidity, etc.
Random number	[u8; 32]	Verifiable randomness
Timestamp	u64	External event timestamps
Binary	bool	Yes/no outcomes

Integration with IoT

The oracle system integrates with the IoT connector for sensor data:

let tx = TransactionBuilder::new()
    .oracle_call(
        "iot_oracle_address",
        "submit_sensor_data",
        &encode_sensor_data(sensor_id, value, timestamp),
    )
    .nonce(nonce)
    .fee(50_000_000_000_000)  // IoT rate: 0.00005 SAVT
    .build_and_sign(&wallet)?;