本文已在我的公众号Fabric技术分享原创首发。
转载请标明出处：
https://blog.csdn.net/qq_27818541/article/details/78455642
本文出自:【BigManing的博客】
前言
第六个文章已经成功执行了转账（A->B），这次我们来查询下A账户现在有多少资产。查询最终会通过channel.queryByChaincode(request, target)来执行chaincode的query方法，我们来看下该方法的实现：
//查询账户 Query callback representing the query of a chaincode
func (t *SimpleChaincode) query(stub shim.ChaincodeStubInterface, args []string) pb.Response {
var A string // Entities
var err error
if len(args) != 1 {
return shim.Error("Incorrect number of arguments. Expecting name of the person to query")
}
A = args[0]
//从账簿中获取A账户的资产
// Get the state from the ledger
Avalbytes, err := stub.GetState(A)
if err != nil {
jsonResp := "{\"Error\":\"Failed to get state for " + A + "\"}"
return shim.Error(jsonResp)
}
if Avalbytes == nil {
jsonResp := "{\"Error\":\"Nil amount for " + A + "\"}"
return shim.Error(jsonResp)
}
//转换数据并返回
jsonResp := "{\"Name\":\"" + A + "\",\"Amount\":\"" + string(Avalbytes) + "\"}"
logger.Infof("Query Response:%s\n", jsonResp)
return shim.Success(Avalbytes)
}路由
app.js
//查询chaincode Query on chaincode on target peers
app.get('/channels/:channelName/chaincodes/:chaincodeName', function(req, res) {
logger.debug('==================== QUERY BY CHAINCODE ==================');
//1 参数校验
var channelName = req.params.channelName;
var chaincodeName = req.params.chaincodeName;
let args = req.query.args;
let fcn = req.query.fcn;
let peer = req.query.peer; // 指定在哪个peer节点上查询
logger.debug('channelName : ' + channelName);
logger.debug('chaincodeName : ' + chaincodeName);
logger.debug('fcn : ' + fcn);
logger.debug('args : ' + args);
if (!chaincodeName) {
res.json(getErrorMessage('\'chaincodeName\''));
return;
}
if (!channelName) {
res.json(getErrorMessage('\'channelName\''));
return;
}
if (!fcn) {
res.json(getErrorMessage('\'fcn\''));
return;
}
if (!args) {
res.json(getErrorMessage('\'args\''));
return;
}
args = args.replace(/'/g, '"');
args = JSON.parse(args);
logger.debug(args);
//2 具体实现
query.queryChaincode(peer, channelName, chaincodeName, args, fcn, req.username, req.orgname)
.then(function(message) {
res.send(message);
});
});具体实现
query.js
var queryChaincode = function(peer, channelName, chaincodeName, args, fcn, username, org) {
var channel = helper.getChannelForOrg(org);
var client = helper.getClientForOrg(org);
var target = buildTarget(peer, org);
//1 获取 jim 用户（ 内部会设置为上下文环境）
return helper.getRegisteredUsers(username, org).then((user) => {
tx_id = client.newTransactionID();
//2 封装查询请求
var request = {
chaincodeId: chaincodeName,
txId: tx_id,
fcn: fcn,
args: args
};
//3 发送请求
return channel.queryByChaincode(request, target);
}, (err) => {
logger.info('Failed to get submitter \''+username+'\'');
return 'Failed to get submitter \''+username+'\'. Error: ' + err.stack ? err.stack :
err;
}).then((response_payloads) => {
//4 处理结果
if (response_payloads) {
for (let i = 0; i < response_payloads.length; i++) {
logger.info(args[0]+' now has ' + response_payloads[i].toString('utf8') +
' after the move');
return args[0]+' now has ' + response_payloads[i].toString('utf8') +
' after the move';
}
} else {
logger.error('response_payloads is null');
return 'response_payloads is null';
}
}, (err) => {
logger.error('Failed to send query due to error: ' + err.stack ? err.stack :
err);
return 'Failed to send query due to error: ' + err.stack ? err.stack : err;
}).catch((err) => {
logger.error('Failed to end to end test with error:' + err.stack ? err.stack :
err);
return 'Failed to end to end test with error:' + err.stack ? err.stack :
err;
});
};基本流程
API访问
echo "GET query chaincode on peer1 of Org1"
echo
curl -s -X GET \
"http://localhost:4000/channels/mychannel/chaincodes/mycc?peer=peer1&fcn=query&args=["a"]" \
-H "authorization: Bearer $ORG1_TOKEN" \
-H "content-type: application/json"
echo
echo
控制台打印：
GET query chaincode on peer1 of Org1
a now has 90 after the move
后台打印：
[2017-10-16 11:07:43.062] [DEBUG] SampleWebApp - Decoded from JWT token: username - Jim, orgname - org1
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - ==================== QUERY BY CHAINCODE ==================
// 获取到的参数
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - channelName : mychannel
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - chaincodeName : mycc
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - fcn : query
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - args : ["a"]
[2017-10-16 11:07:43.063] [DEBUG] SampleWebApp - [ 'a' ]
//设置user Context
[2017-10-16 11:07:43.064] [DEBUG] Helper - [FileKeyValueStore.js]: FileKeyValueStore.js - constructor
[2017-10-16 11:07:43.065] [DEBUG] Helper - [FileKeyValueStore.js]: FileKeyValueStore -- getValue
[2017-10-16 11:07:43.065] [DEBUG] Helper - [crypto_ecdsa_aes]: importKey - start
[2017-10-16 11:07:43.066] [DEBUG] Helper - [crypto_ecdsa_aes]: importKey - have the key [Circular]
[2017-10-16 11:07:43.066] [DEBUG] Helper - [utils.CryptoKeyStore]: _getKeyStore resolving store
[2017-10-16 11:07:43.066] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param X: b3e2a75b9a4fd2b081589b1c45bde49f583aea9d7d466798c7b765c4ca96973d
[2017-10-16 11:07:43.066] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param Y: c58820e5a9db75ab17841ac158e9389ad0d130a6827dc0682dcb2d2c5dccb349
[2017-10-16 11:07:43.066] [DEBUG] Helper - [FileKeyValueStore.js]: FileKeyValueStore -- setValue
[2017-10-16 11:07:43.067] [DEBUG] Helper - [utils.CryptoKeyStore]: _getKeyStore resolving store
[2017-10-16 11:07:43.067] [DEBUG] Helper - [FileKeyValueStore.js]: FileKeyValueStore -- getValue
[2017-10-16 11:07:43.067] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param X: b3e2a75b9a4fd2b081589b1c45bde49f583aea9d7d466798c7b765c4ca96973d
[2017-10-16 11:07:43.067] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param Y: c58820e5a9db75ab17841ac158e9389ad0d130a6827dc0682dcb2d2c5dccb349
[2017-10-16 11:07:43.068] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param X: b3e2a75b9a4fd2b081589b1c45bde49f583aea9d7d466798c7b765c4ca96973d
[2017-10-16 11:07:43.068] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param Y: c58820e5a9db75ab17841ac158e9389ad0d130a6827dc0682dcb2d2c5dccb349
[2017-10-16 11:07:43.068] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param X: b3e2a75b9a4fd2b081589b1c45bde49f583aea9d7d466798c7b765c4ca96973d
[2017-10-16 11:07:43.068] [DEBUG] Helper - [ecdsa/key.js]: ECDSA curve param Y: c58820e5a9db75ab17841ac158e9389ad0d130a6827dc0682dcb2d2c5dccb349
[2017-10-16 11:07:43.068] [DEBUG] Helper - [FileKeyValueStore.js]: FileKeyValueStore -- setValue
[2017-10-16 11:07:43.069] [INFO] Helper - Successfully loaded member from persistence
[2017-10-16 11:07:43.074] [DEBUG] Helper - [crypto_ecdsa_aes]: ecdsa signature: Signature {
r: <BN: ef77aa291a7322316d81eac973dfaebbe65f1fd92680b11108b4d7614da3547d>,
s: <BN: 2b0119915f46c53b1eabfcadf4b6cbc0a38a8f188e14ebbc1a30c3866f4f5205>,
recoveryParam: 0 }
//查询结果
[2017-10-16 11:07:43.084] [INFO] Query - a now has 90 after the move