在链上读取另一个 Anchor 程序的账户数据

在 Solidity 中，读取其他合约的存储需通过 view 函数或公共变量，而在 Solana 中，链下客户端可直接访问存储账户。本文展示如何在链上通过一个 Solana 程序读取另一个程序的账户数据。示例将涉及两个程序：data_holder 初始化并拥有数据账户，data_reader 读取其数据。

设置存储数据的 data_holder 程序

data_holder 初始化一个包含 u64 字段 x 的 PDA 账户，并赋值为 9。以下是实现代码：

Rust 代码

use anchor_lang::prelude::*;
use std::mem::size_of;

declare_id!("B2ygCyDthArX1FqVqfzo2BuBBvAd1eSkMovagAQdrH8K");

#[program]
pub mod data_holder {
    use super::*;

    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        let storage = &mut ctx.accounts.storage;
        storage.x = 9;
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(
        init,
        payer = signer,
        space = size_of::<Storage>() + 8,
        seeds = [],
        bump
    )]
    pub storage: Account<'info, Storage>,
    #[account(mut)]
    pub signer: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[account]
pub struct Storage {
    pub x: u64,
}

Typescript 代码

import * as anchor from "@coral-xyz/anchor";
import { Program } from "@coral-xyz/anchor";
import { DataHolder } from "../target/types/data_holder";

describe("data-holder", () => {
  anchor.setProvider(anchor.AnchorProvider.env());
  const program = anchor.workspace.DataHolder as Program<DataHolder>;

  it("Is initialized!", async () => {
    const seeds = [];
    const [storage, _bump] = anchor.web3.PublicKey.findProgramAddressSync(seeds, program.programId);

    await program.methods.initialize().accounts({ storage: storage }).rpc();

    let storageStruct = await program.account.storage.fetch(storage);
    console.log("The value of x is: ", storageStruct.x.toString());
    console.log("Storage account address: ", storage.toBase58());
  });
});

输出

The value of x is: 9
Storage account address: 8bxHxSAfw3CRFrog3DjFytW7u4KJSc7DdGjALEE5xUWf

此 PDA 地址将用于 data_reader。

data_reader 程序

data_reader 通过 Context 获取外部账户公钥并读取数据。数据以字节形式存储，需反序列化为与 data_holder 相同的 Storage 结构体：

#[account]
pub struct Storage {
    x: u64,
}

关键读取逻辑如下：

let mut data_slice: &[u8] = &data_account.data.borrow();
let data_struct: Storage = AccountDeserialize::try_deserialize(&mut data_slice)?;

Rust 完整代码

use anchor_lang::prelude::*;

declare_id!("Bav1fsb6K3XqhZ6W2Vj4vs5G1tPyjCfLE3FPYpFrRFKn");

#[program]
pub mod data_reader {
    use super::*;

    pub fn read_other_data(ctx: Context<ReadOtherData>) -> Result<()> {
        let data_account = &ctx.accounts.other_data;

        if data_account.data_is_empty() {
            retu...