使用Hyperledger Composer查看区块链块

Question

使用Hyperledger Composer时，如何获取和查看添加到区块链的块？

Answer 1

这可以使用composer-client完成。虽然没有可用于此目的的便捷方法，但可以调用底层的Hyperledger Fabric SDK API。

下面是一些示例代码，用于按编号获取块并将其打印到控制台：

const { inspect } = require('util');
const { BusinessNetworkConnection } = require('composer-client');

async function run() {
  const connection = new BusinessNetworkConnection();

  // Connect to the blockchain using admin credentials.
  // These credentials should be available in your local keystore.
  await connection.connect('admin@network');

  // Native API provided through the Fabric SDK, allows much more low-level operations than Composer.
  const nativeApi = connection.getNativeAPI();

  // Connect to the channel where the transactions are happening, the default is "composerchannel".
  const channel = nativeApi.getChannel('composerchannel');

  // Grab a block by it's number
  const block = await channel.queryBlock(4);

  // Enter the matrix
  console.log(inspect(block, { depth: null, colors: true, compact: false }));

  await connection.disconnect();
}

run();

有关通过此API公开的功能的更多信息，请参阅fabric-sdk-node documentation。

Answer 2

Hyperledger Explorer可以做到这一点，但它不是Hyperledger Composer的一部分。这是一个原生的Fabric工具。