How to Run a Pre-flight Check in Rust

Add the SDK to your Cargo.toml:

[dependencies]
ckb-transaction-firewall-sdk = "0.3"

Fetch the live registry cell via HTTP (the Rust SDK has no built-in RPC client — use ureq, reqwest, or similar), parse it, and run the check:

use ckb_transaction_firewall_sdk::{
    check_transaction, parse_registry_payload,
    CellDepLike, FirewallConfig, HashType, RegistrySpec,
    ScriptLike, TxOutputLike, UnsignedTxLike,
};

// Fetch the live cell data from your CKB node
// (RPC: get_live_cell with with_data=true)
let registry_data: Vec<u8> = fetch_registry_cell_data()?;

// Parse the BLKL v2 payload
let payload = parse_registry_payload(&registry_data)?;

// Build the firewall config
let spec = RegistrySpec {
    code_hash:     hex_to_32("493f1700508125b0e281b8fb1d168b03bd5ef71480399dd59221224901a9cd09")?,
    hash_type:     HashType::Type,
    type_id_value: hex_to_32("9be0ad6e4e5039a64d9725ff037057c16ef59f126e3bdd9841b802f0e0a112fe")?,
    required:      true,
};
let cfg = FirewallConfig { registries: vec![spec] };

// Build the transaction with the registry as a cell dep
let tx = UnsignedTxLike {
    cell_deps: vec![CellDepLike {
        type_script: Some(ScriptLike {
            code_hash: spec.code_hash,
            hash_type:  spec.hash_type.clone(),
            args:       registry_type_args, // full 66-byte v2 type args
        }),
        data: registry_data.clone(),
    }],
    outputs: vec![TxOutputLike {
        lock_args: recipient_lock_args,
        type_args: None,
    }],
};

let now_secs = std::time::SystemTime::now()
    .duration_since(std::time::UNIX_EPOCH)
    .unwrap()
    .as_secs();

match check_transaction(&cfg, &tx, now_secs) {
    Ok(())  => { /* safe to sign */ }
    Err(e)  => eprintln!("blocked: {} (code {})", e, e.code()),
}

See the preflight-service example for a complete working implementation including the RPC fetch. See Rust SDK API for full type signatures.