Rust区块链开发库polkadot-node-primitives使用指南

概述

polkadot-node-primitives是Polkadot节点实现中使用的核心原语库，它为Substrate框架提供了基础组件，是构建Polkadot兼容区块链的重要工具。这个库包含了Polkadot网络运行所需的基本数据类型和功能。

主要功能

1. 提供Polkadot共识相关的核心数据类型
2. 包含平行链验证相关的原语
3. 实现Polkadot运行时接口
4. 提供区块构建和验证工具

使用方法

添加依赖

首先在Cargo.toml中添加依赖：

[dependencies]
polkadot-node-primitives = { git = "https://github.com/paritytech/polkadot-sdk.git", branch = "master" }

核心类型使用示例

use polkadot_node_primitives::{
    BlockWeight, AvailableData, ErasureChunk, PoV, 
    ValidationResult, InvalidDisputeStatementKind
};

// 创建区块权重
let block_weight = BlockWeight::max();

// 创建可用数据
let available_data = AvailableData {
    pov: Arc::new(PoV { block_data: vec![1, 2, 3].into() }),
    validation_data: Default::default(),
};

// 创建擦除编码块
let chunk = ErasureChunk {
    chunk: vec![1, 2, 3].into(),
    index: 0,
    proof: vec![].into(),
};

验证功能示例

use polkadot_node_primitives::{
    ValidDisputeStatementKind, ValidatorIndex, 
    ValidatorSignature, SigningContext
};

// 创建验证上下文
let signing_context = SigningContext {
    parent_hash: Default::default(),
    session_index: 1,
};

// 验证签名
let validator_index = ValidatorIndex(0);
let signature = ValidatorSignature::dummy();
let kind = ValidDisputeStatementKind::Explicit;

if kind.check_signature(
    &validator_public_key,
    &signature,
    &signing_context,
    validator_index,
) {
    println!("签名验证通过");
}

平行链验证示例

use polkadot_node_primitives::{
    MaybeCompressedPoV, CompressedPoV, UncompressedPoV,
    pov_decompress, pov_compress
};

// 压缩PoV数据
let uncompressed = UncompressedPoV {
    block_data: vec![1, 2, 3, 4, 5].into(),
};
let compressed = pov_compress(&uncompressed).unwrap();

// 解压PoV数据
let decompressed = pov_decompress(&compressed).unwrap();
assert_eq!(decompressed.block_data, uncompressed.block_data);

高级用法

自定义验证逻辑

use polkadot_node_primitives::{
    CandidateReceipt, PersistedValidationData, ValidationCode
};

fn validate_candidate(
    candidate: &CandidateReceipt,
    validation_data: &PersistedValidationData,
    validation_code: &ValidationCode,
) -> bool {
    // 实现自定义验证逻辑
    true
}

创建自定义声明

use polkadot_node-primitives::{
    DisputeStatement, DisputeStatementSet, SignedDisputeStatement
};

let statement = DisputeStatement::Valid(ValidDisputeStatementKind::Explicit);
let signed_statement = SignedDisputeStatement::sign(
    statement,
    &validator_id,
    &signing_context,
    validator_index,
    &key_pair,
).unwrap();

let statement_set = DisputeStatementSet {
    candidate_hash: Default::default(),
    session: 1,
    statements: vec![(validator_index, signed_statement)].into_iter().collect(),
};

完整示例Demo

下面是一个综合使用polkadot-node-primitives的完整示例：

use polkadot_node_primitives::{
    BlockWeight, AvailableData, PoV, 
    ValidDisputeStatementKind, ValidatorIndex,
    SigningContext, ValidatorSignature,
    MaybeCompressedPoV, pov_compress, pov_decompress
};
use sp_core::crypto::Pair;
use sp_application_crypto::sr25519;
use std::sync::Arc;

fn main() {
    // 1. 创建区块权重和可用数据
    let block_weight = BlockWeight::max();
    println!("创建区块权重: {:?}", block_weight);

    let available_data = AvailableData {
        pov: Arc::new(PoV { block_data: vec![1, 2, 3].into() }),
        validation_data: Default::default(),
    };
    println!("创建可用数据: {:?}", available_data);

    // 2. 签名验证示例
    let signing_context = SigningContext {
        parent_hash: Default::default(),
        session_index: 1,
    };

    let key_pair = sr25519::Pair::generate().0;
    let validator_index = ValidatorIndex(0);
    let kind = ValidDisputeStatementKind::Explicit;
    
    let signature = ValidatorSignature::dummy(); // 实际使用时应该用真实签名
    
    if kind.check_signature(
        &key_pair.public(),
        &signature,
        &signing_context,
        validator_index,
    ) {
        println!("签名验证通过");
    } else {
        println!("签名验证失败");
    }

    // 3. PoV数据压缩示例
    let uncompressed = MaybeCompressedPoV::Uncompressed(UncompressedPoV {
        block_data: vec![1, 2, 3, 4, 5].into(),
    });
    
    let compressed = pov_compress(&uncompressed).unwrap();
    println!("PoV数据压缩成功");
    
    let decompressed = pov_decompress(&compressed).unwrap();
    assert_eq!(decompressed.uncompressed().unwrap().block_data, uncompressed.uncompressed().unwrap().block_data);
    println!("PoV数据解压并验证成功");
}

注意事项

1. 这个库主要面向Polkadot节点开发者和Substrate高级用户
2. 需要熟悉Substrate框架的基本概念
3. API可能会随着Polkadot版本更新而变化
4. 生产环境使用时建议锁定特定版本