Hyperledger Fabric SDK 示例fabric-samples-《balance-transfer》之七《查询chaincode》

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 chaincodefunc (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 peersapp.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"echocurl -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"echoecho

控制台打印：

GET query chaincode on peer1 of Org1a 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