Hyperledger区块数据的访问

简介

本文介绍了访问Hyperledger区块数据的几种方法.

REST API

Hyperledger提供了多个REST API (https://hyperledger-fabric.readthedocs.io/en/latest/API/CoreAPI/#rest-api) 用于访问Hyperledger区块数据.

示例1： 获取区块链长度

请求

http://192.168.99.100:7050/chain/

响应

{
    "height": 5,
    "currentBlockHash": "9UIs99F9Qq0RvwOzCEDG0SHvBrdoOHy0rexOICJ56aiIQbnszEO9y2QpjbMnrzIp3ehGh6W8FWY8eqbBFqaOVA==",
    "previousBlockHash": "AABHooEnVMuv4JO4roHqgcNAOf3mcUqOV6sTrCWeuPcKf/ji4tYXJ5cONgcQTwoIowf1wAqhZObFmjkT1QLmsQ=="
}

示例2： 获取区块数据

请求

http://192.168.99.100:7050/chain/blocks/4

响应

{
    "transactions": [
        {
            "type": 2,
            "chaincodeID": "EgRteWNj",
            "payload": "CigIARIGEgRteWNjGhwKBmludm9rZQoHdGVzdEtleQoJdGVzdFZhbHVl",
            "txid": "4a05fbd2-f17d-46eb-abec-a6218b404117",
            "timestamp": {
                "seconds": 1476704491,
                "nanos": 740300402
            },
            "nonce": "jYFNo67ks3JhWh3PwxCJG0qK0rnBojwe",
            "cert": "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",
            "signature": "MEUCIHRnWCQmt+4QoiY01aiDU+0567xUgaiEZ6zZr+gDg8D2AiEA+OgCGGxWbQTkmC0IB4nJoiU65Dv/pR27XDirhtXgStU="
        }
    ],
    "stateHash": "cxUZAjaQar85ZGvgt4z3soRMpQjJpDrpLBkFbwqQSVb1rebXcMT1kMzNA45MX9ybB/sILXCslN1C9yprmhAVng==",
    "previousBlockHash": "9UIs99F9Qq0RvwOzCEDG0SHvBrdoOHy0rexOICJ56aiIQbnszEO9y2QpjbMnrzIp3ehGh6W8FWY8eqbBFqaOVA==",
    "nonHashData": {
        "localLedgerCommitTimestamp": {
            "seconds": 1476704492,
            "nanos": 779081508
        },
        "chaincodeEvents": [
            {}
        ]
    }
}

Java Client API

Hyperledger Java Client API (https://github.com/hyperledger/fabric-api)提供较为底层的接口来访问Hyperledger区块数据. 以下示例代码显示如何解析Invocation类的区块中的payload.

private void decodeChaincodeInvocationSpec() {
	try {
		String base64String = "CigIARIGEgRteWNjGhwKBmludm9rZQoHdGVzdEtleQoJdGVzdFZhbHVl";
		byte[] decoded = javax.xml.bind.DatatypeConverter.parseBase64Binary(base64String);

		Chaincode.ChaincodeInvocationSpec invocationSpec =
				Chaincode.ChaincodeInvocationSpec.parseFrom(decoded);

		Map<Descriptors.FieldDescriptor, Object> fields = invocationSpec.getAllFields();
		for (Descriptors.FieldDescriptor key : fields.keySet()) {
			Chaincode.ChaincodeSpec value = (Chaincode.ChaincodeSpec) fields.get(key);
			System.out.println("key:" + key);
			System.out.println("value:" + value);
		}
	} catch (Exception ex) {
		ex.printStackTrace();
	}
}

相应的输出为：

key:protos.ChaincodeInvocationSpec.chaincodeSpec
value:type: GOLANG
chaincodeID {
  name: "mycc"
}
ctorMsg {
  args: "invoke"
  args: "testKey"
  args: "testValue"
}

总结

本文介绍了使用Hyperledger REST和Java Client API访问Hyperledger区块数据的方法.