Solana: What is the difference between .rpc() and .instruction() in an anchor test?

Solana: What is the difference between .rpc() and .instruction() in Anchor Test?

As a Solana developer, you’re likely familiar with the anchor library, which provides a convenient interface for interacting with the Solana blockchain. Two common functions that can be used to send instructions are .rpc() (Remote Procedure Call) and .instruction(). While they may seem similar, there’s an important difference between them.

.rpc()

The .rpc() function is designed to send requests to the Solana blockchain in a specific way. When you call .rpc(), it creates a request that can be executed on the blockchain. The request contains metadata about the instruction, such as its name, signature, and arguments. This metadata allows the request to be matched with existing instructions on the blockchain.

Here’s an example of how to use .rpc():

const anchor = require('@anchor-protocol/anchors');


// Create a new account

const accountId = anchor.web3.eth.accounts._new();


// Define the instruction

const instruction = {

  name: 'My Instruction',

  args: [1, 2, 3],

};


// Send the request to .rpc()

anchor.rpc().instruction({

  address: accountId,

  signature: 'your_signature_here',

  data: instruction,

}).then((response) => console.log(response));

.instruction()

The .instruction() function is designed to send instructions directly from a program or a script. When you call .instruction(), it creates an instruction that can be executed on the blockchain without any additional metadata.

Here’s an example of how to use .instruction():

const anchor = require('@anchor-protocol/anchors');


// Create a new account

const accountId = anchor.web3.eth.accounts._new();


// Define the script

const script = {

  code: 'function () { self.addAccount(accountId); }',

};


// Send the instruction to .instruction()

anchor.rpc().instruction(script).then((response) => console.log(response));

Key differences

So, what’s the key difference between .rpc() and .instruction()?

• Metadata

  : .rpc() requires metadata about the instruction, while .instruction() does not.

• Execution: .rpc() executes the request on the blockchain, while .instruction() can be executed directly by a program or script.

In your case, if you’re sending an instruction directly using .rpc(), it’s likely that the issue is related to how you’re creating and executing the instruction. Make sure you’re providing the correct metadata, such as the address of the account and any additional arguments.

Here’s an example of how to create a new instruction with .instruction() and execute it:

const anchor = require('@anchor-protocol/anchors');


// Create a new account

const accountId = anchor.web3.eth.accounts._new();


// Define the script

const script = {

  code: 'function () { self.addAccount(accountId); }',

};


// Send the instruction to .instruction()

anchor.rpc().instruction(script).then((response) => console.log(response));

In summary, .rpc() is used for sending requests to the blockchain, while .instruction() is used to send instructions directly from a program or script. Make sure you’re using the correct function and providing the correct metadata when creating and executing your instruction.