multiversx-blockchain-data（multiversx 区块链数据）

MultiversX Blockchain Data — self.blockchain() API Reference

Complete reference for reading on-chain state in MultiversX smart contracts (SDK v0.64+).

Caller & Account Info

// Owner-only guard (manual alternative to #[only_owner])
self.blockchain().check_caller_is_owner();

// Prevent contract-to-contract calls (anti-flash-loan)
self.blockchain().check_caller_is_user_account();

// Check if target is a SC before sending
let is_sc = self.blockchain().is_smart_contract(&target);

Balances

// Check own EGLD balance
let egld = self.blockchain().get_balance(&self.blockchain().get_sc_address());

// Check own ESDT balance (simpler via get_sc_balance)
let balance = self.blockchain().get_sc_balance(&my_token_id, 0u64);

Block Info

Current Block

Previous Block

Epoch Start Info

Deprecated Timestamp Methods (Do NOT Use)

Transaction Info

ESDT Token Metadata

// EsdtTokenData fields:
pub struct EsdtTokenData<M: ManagedTypeApi> {
    pub token_type: EsdtTokenType,
    pub amount: BigUint<M>,
    pub frozen: bool,
    pub hash: ManagedBuffer<M>,
    pub name: ManagedBuffer<M>,
    pub attributes: ManagedBuffer<M>,  // raw bytes — use get_token_attributes for typed
    pub creator: ManagedAddress<M>,
    pub royalties: BigUint<M>,         // 0-10000 (basis points)
    pub uris: ManagedVec<M, ManagedBuffer<M>>,
}

// Read NFT attributes as a typed struct
#[derive(TopDecode)]
struct MyNftAttributes {
    level: u8,
    power: u64,
}

let attrs: MyNftAttributes = self.blockchain()
    .get_token_attributes::<MyNftAttributes>(&nft_token_id, nft_nonce);

ESDT Status & Roles

// Check roles before minting
let roles = self.blockchain().get_esdt_local_roles(&token_id);
require!(
    roles.has_role(&EsdtLocalRole::NftCreate),
    "Contract lacks NftCreate role"
);

Code Inspection

Native Token

Validators

Back-Transfers (After Cross-Contract Calls)

See the multiversx-cross-contract-calls skill for full back-transfer patterns.

Common Patterns

Time-Based Logic

let now = self.blockchain().get_block_timestamp_seconds();
let deadline = self.deadline().get();
require!(now < deadline, "Deadline passed");

Shard-Aware Operations

let caller_shard = self.blockchain().get_shard_of_address(
    &self.blockchain().get_caller()
);
let sc_shard = self.blockchain().get_shard_of_address(
    &self.blockchain().get_sc_address()
);
let same_shard = caller_shard == sc_shard;
// If same shard, can use sync calls; otherwise need async

Token Property Validation

fn validate_nft(&self, token_id: &EsdtTokenIdentifier, nonce: u64) {
    let sc_addr = self.blockchain().get_sc_address();
    let data = self.blockchain().get_esdt_token_data(&sc_addr, token_id, nonce);
    require!(data.amount > 0u64, "NFT not owned");
    require!(!data.frozen, "Token is frozen");
}

Balance Check Before Transfer

let sc_balance = self.blockchain().get_sc_balance(&token_id, 0u64);
require!(sc_balance >= amount, "Insufficient contract balance");
self.tx().to(&recipient).esdt((token_id, 0u64, amount)).transfer();

Anti-Patterns

// BAD: Using deprecated get_block_timestamp() — returns raw u64
let ts = self.blockchain().get_block_timestamp();

// GOOD: Use typed timestamp (v0.63+)
let ts = self.blockchain().get_block_timestamp_seconds();

// BAD: Storing raw u64 timestamps, mixing seconds/millis
self.last_action().set(self.blockchain().get_block_timestamp_millis().as_u64_millis());

// GOOD: Store typed timestamps
self.last_action().set(self.blockchain().get_block_timestamp_seconds());

// BAD: get_balance to check own EGLD — requires passing own address
let bal = self.blockchain().get_balance(&self.blockchain().get_sc_address());

// GOOD: Use get_sc_balance which handles EGLD via native token detection
let bal = self.blockchain().get_sc_balance(&self.blockchain().get_native_token(), 0u64);