FactRequest

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Fields

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Usage Example

use taple_core::{
    EventRequest, FactRequest,
    DigestIdentifier, ValueWrapper
};
use serde_json::json;

// Add a temperature reading to a sensor subject
let fact_request = EventRequest::Fact(FactRequest {
    subject_id: DigestIdentifier::from_str(
        "JXtZRpNgBWVg9v5YG9AaTNfCpPd-rCTTKrFW9cV8-JKs"
    ).unwrap(),
    payload: ValueWrapper(json!({
        "temperature": 23.5,
        "timestamp": "2024-03-15T10:30:00Z"
    })),
});

// Add a transfer record to a supply chain subject
let transfer_fact = EventRequest::Fact(FactRequest {
    subject_id: subject_id.clone(),
    payload: ValueWrapper(json!({
        "action": "transfer",
        "from": "warehouse_a",
        "to": "warehouse_b",
        "quantity": 100
    })),
});

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Notes

• FactRequest is wrapped in the EventRequest::Fact variant
• Requires evaluation and approval: Unlike other request types, fact requests must be evaluated by the governance contract and may require approval from designated approvers
• The payload structure must match the schema defined for the subject
• The governance contract’s evaluation logic will process the payload and generate a state patch
• The subject’s state will be updated by applying the generated patch
• Each successful fact increments the subject’s sequence number (sn)

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Evaluation Process

1. The fact request is submitted to the network
2. The governance contract’s evaluation logic is executed with the current state and the payload
3. The evaluator generates a patch representing the state changes
4. If required by governance rules, the request goes through an approval process
5. Once approved, the patch is applied to the subject’s state
6. A new event is created and added to the subject’s event chain

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Related Types

• EventRequest
• DigestIdentifier
• ValueWrapper