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.