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Docs /
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Provider /
Querying the Chain

Icon LinkQuerying the Chain

Once you have set up a provider, you're ready to interact with the Fuel blockchain.

We can connect to either a local or an external node:

Icon InfoCircle
  1. Running a local node
  2. Connecting to an external node

Let's look at a few examples below.

Icon LinkgetBaseAssetId

The base asset is the underlying asset used to perform any transaction on a chain. This should be fetched from a provider to then be used in transactions. 

// #import { Provider, FUEL_NETWORK_URL, ScriptTransactionRequest };
 
// Fetch the base asset ID using the provider
const provider = await Provider.create(FUEL_NETWORK_URL);
const baseAssetId = provider.getBaseAssetId();
// 0x...
 
// Create a transaction request
const transactionRequest = new ScriptTransactionRequest();
// Use the base asset for an operation
transactionRequest.addCoinOutput(recipientAddress, 100, baseAssetId);

Icon LinkgetCoins

Returns UTXOs coins from an account address, optionally filtered by asset ID. This method supports pagination . 

// #import { Provider, FUEL_NETWORK_URL, generateTestWallet };
 
const provider = await Provider.create(FUEL_NETWORK_URL);
const assetIdA = '0x0101010101010101010101010101010101010101010101010101010101010101';
const baseAssetId = provider.getBaseAssetId();
 
const wallet = await generateTestWallet(provider, [
  [42, baseAssetId],
  [100, assetIdA],
]);
 
// fetches up to 100 coins from baseAssetId
const { coins, pageInfo } = await provider.getCoins(wallet.address, baseAssetId);
// [
//   { amount: bn(42), assetId: baseAssetId },
//   ...
// ]
 
// fetches up to 100 coins from all assets
await provider.getCoins(wallet.address);
// [
//   { amount: bn(42), assetId: baseAssetId }
//   { amount: bn(100), assetId: assetIdA }
//   ...
// ]

This method is also implemented on the Account class and can be used without providing the address: 

await wallet.getCoins(baseAssetId);

Icon LinkgetResourcesToSpend

Returns spendable resources (coins or messages) for a transaction request. It accepts an optional third parameter, excludedIds, to exclude specific UTXO IDs or coin message nonces: 

// #import { Provider, FUEL_NETWORK_URL, generateTestWallet, ScriptTransactionRequest, CoinQuantityLike, ExcludeResourcesOption };
 
const provider = await Provider.create(FUEL_NETWORK_URL);
const assetIdA = '0x0101010101010101010101010101010101010101010101010101010101010101';
const baseAssetId = provider.getBaseAssetId();
 
const wallet = await generateTestWallet(provider, [
  [42, baseAssetId],
  [100, assetIdA],
]);
 
const quantities: CoinQuantityLike[] = [
  { amount: 32, assetId: baseAssetId, max: 42 },
  { amount: 50, assetId: assetIdA },
];
 
const utxoId = '0x00000000000000000000000000000000000000000000000000000000000000010001';
const messageNonce = '0x381de90750098776c71544527fd253412908dec3d07ce9a7367bd1ba975908a0';
const excludedIds: ExcludeResourcesOption = {
  utxos: [utxoId],
  messages: [messageNonce],
};
 
const spendableResources = await provider.getResourcesToSpend(
  wallet.address,
  quantities,
  excludedIds
);
 
const tx = new ScriptTransactionRequest();
tx.addResources(spendableResources);

This method is also available in the Account class and can be used without providing the address: 

await wallet.getResourcesToSpend(spendableResources, excludedIds);

Icon LinkgetBalances

Returns the sum of all UTXOs coins and unspent message coins amounts for all assets. Unlike getCoins, it only returns the total amounts, not the individual coins: 

// #import { Provider, FUEL_NETWORK_URL, generateTestWallet };
 
const provider = await Provider.create(FUEL_NETWORK_URL);
const assetIdA = '0x0101010101010101010101010101010101010101010101010101010101010101';
const baseAssetId = provider.getBaseAssetId();
 
const wallet = await generateTestWallet(provider, [
  [42, baseAssetId],
  [100, assetIdA],
]);
 
const { balances } = await provider.getBalances(wallet.address);
// [
//   { amount: bn(42), assetId: baseAssetId } // total amount of baseAssetId
//   { amount: bn(100), assetId: assetIdA } // total amount of assetIdA
// ]

This method is also available in the Account class and can be used without providing the address parameter: 

await wallet.getBalances();

Icon LinkgetBlocks

The getBlocks method returns blocks from the blockchain matching the given paginationArgs parameter, supporting pagination . The below code snippet shows how to get the last 10 blocks. 

// #import { Provider, FUEL_NETWORK_URL };
 
const provider = await Provider.create(FUEL_NETWORK_URL);
const blockToProduce = 3;
 
// Force-producing some blocks to make sure that 10 blocks exist
await provider.produceBlocks(blockToProduce);
 
const { blocks } = await provider.getBlocks({
  last: blockToProduce,
});

Icon LinkgetMessageByNonce

You can use the getMessageByNonce method to retrieve a message by its nonce. 

// #import { FUEL_NETWORK_URL, Provider };
 
const provider = await Provider.create(FUEL_NETWORK_URL);
 
const nonce = '0x381de90750098776c71544527fd253412908dec3d07ce9a7367bd1ba975908a0';
const message = await provider.getMessageByNonce(nonce);