Fabric開發(四) 基於Fabirc1.4.3編寫你的第一個應用

2020-09-27 09:00:24

寫在前面(到到底什麼是Fabric?)

第一節的最後,我粗略地說了說到底什麼是Fabirc。在這裡,我得再問自己一遍。到底什麼是Fabirc?
我這個人比較喜歡望文生義,見文知意,顧名思義。。。找Gu爸問問,給如下結果:
在這裡插入圖片描述
具體是什麼意思,我們暫且按下不表。來看看,我們的另外一個角兒,Hyperledger(超級賬本)。對,我們這裡講Fabric確切的說只是Hyperledger下的一個專案而已。中文官網描述如下:
在這裡插入圖片描述
到這裡,我們應該對Hyperledger Fabirc(以下簡稱Fabric)有了進一步的認識,他本質就是一項分散式賬本技術,結合上文的翻譯,Fabric就是一個分散式賬本技術框架。至於對該技術的分析,我們後續文章會進行連載,再問億遍什麼是Fabirc。 這裡,我們先來編寫一個應用,看看他到底在做什麼,能做什麼吧。

基於Fabric編寫第一個應用程式

我們寫這個程式要幹什麼呢?
最基本的功能就是要給使用者提供查詢賬本(包含特定記錄)和更新賬本(新增記錄)。

而這個程式會基於javascript,通過Node.js SDK與賬本所在的網路進行互動。

Hyperledger中文檔案給出了以下步驟,我們可以照貓畫虎來試試。(畢竟是入門文章,刪除線覆蓋部分可以先不看)

  1. 啟動一個Hyperledger Fabric區塊鏈測試網路。
    在我們的網路中,我們需要一些最基本的元件來查詢和更新賬本。這些元件<peer節點、ordering節點以及證書管理>是我們網路的基礎。而CLI容器則用來傳送一些管理命令。有個簡單的指令碼將下載並啟動這個測試網路。
  2. 學習應用程式中所用到的智慧合約例子的引數。
    智慧合約包含的各種功能讓我們可以用多種方式和賬本進行互動。如,我們可以讀取整體的資料或者某一部分詳盡的資料。
  3. 開發能夠查詢以及更新記錄的應用程式。
    我們提供兩個程式例子 —— 一個用於查詢賬本,另一個使用者更新賬本。我們的程式將使用SDK APIs來和網路進行互動,並最終呼叫這些功能。

好了,廢話不多說,正文開始

1、首先,啟動測試網路

上節我們已經下載了的fabric中已經包含了fabric-samples,執行下面操作

cd fabric-samples/fabcar ; ls

可以看到fabcar樣例包含的指令碼和程式程式碼
在這裡插入圖片描述

2、下載並解壓Hyperledger Fabric Docker images

下載映象

./startFabric.sh

執行過程如下:

halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar$ ./startFabric.sh 
Stopping for channel 'mychannel' with CLI timeout of '10' seconds and CLI delay of '3' seconds
proceeding ...
WARNING: The BYFN_CA2_PRIVATE_KEY variable is not set. Defaulting to a blank string.
WARNING: The BYFN_CA1_PRIVATE_KEY variable is not set. Defaulting to a blank string.
Stopping cli                    ... done
Stopping peer0.org2.example.com ... done
Stopping orderer.example.com    ... done
Stopping peer1.org2.example.com ... done
Stopping peer1.org1.example.com ... done
Stopping peer0.org1.example.com ... done
Removing cli                    ... done
Removing peer0.org2.example.com ... done
Removing orderer.example.com    ... done
Removing peer1.org2.example.com ... done
Removing peer1.org1.example.com ... done
Removing peer0.org1.example.com ... done
Removing network net_byfn
Removing volume net_peer0.org3.example.com
WARNING: Volume net_peer0.org3.example.com not found.
Removing volume net_peer1.org3.example.com
WARNING: Volume net_peer1.org3.example.com not found.
Removing volume net_orderer2.example.com
WARNING: Volume net_orderer2.example.com not found.
Removing volume net_orderer.example.com
Removing volume net_peer0.org2.example.com
Removing volume net_peer0.org1.example.com
Removing volume net_peer1.org1.example.com
Removing volume net_peer1.org2.example.com
Removing volume net_orderer5.example.com
WARNING: Volume net_orderer5.example.com not found.
Removing volume net_orderer4.example.com
WARNING: Volume net_orderer4.example.com not found.
Removing volume net_orderer3.example.com
WARNING: Volume net_orderer3.example.com not found.
57da35e62075
7727893af4a0
b1fab6da4a8c
Untagged: dev-peer1.org2.example.com-mycc-1.0-26c2ef32838554aac4f7ad6f100aca865e87959c9a126e86d764c8d01f8346ab:latest
Deleted: sha256:a361bdbae52fd3897a325606f2c3f1d7a23fb737d8b12f987a0d927f1e7ddfb2
Deleted: sha256:41880d8787311ec41d2162219382b44ce4c656513c4d8cc5ea8bdb6a1379c51f
Deleted: sha256:d8c907db9d43ebefb2f1c76d89ad11546ca186b55bd3f1cb2ed9ec99eed2d26e
Deleted: sha256:2c4c8355d0acd14eff6fa105568de64b27a9b5cce3523c31a57a32a1afa28891
Untagged: dev-peer0.org1.example.com-mycc-1.0-384f11f484b9302df90b453200cfb25174305fce8f53f4e94d45ee3b6cab0ce9:latest
Deleted: sha256:3425e36582cdcb3d0da871f71976622ab353b9c8a512e0555a73b790bec1ee22
Deleted: sha256:e98f3c309f14bc6306be86a137e11166ee83abdd96ecac89698e658f225be899
Deleted: sha256:cbfe5ddde265d8294e77bdde9314e9bb6a384dae9085922ecab85cb6ceae4547
Deleted: sha256:e962aafc8595469a2b3ec55f05e3e042b0bda3dca52f1e600d0f7311c21f4732
Untagged: dev-peer0.org2.example.com-mycc-1.0-15b571b3ce849066b7ec74497da3b27e54e0df1345daff3951b94245ce09c42b:latest
Deleted: sha256:714e8f05a4ffaf0f544cc710e865022e8c513e95c060a55eacb7a2b818540c64
Deleted: sha256:0a43b52a03c8d649886ad62bb923494c3fc9c7badf65977d816bd7994ecebb0c
Deleted: sha256:2d4758a2f6ea8c70a747bf7b4beb31b199b05f2b7f09ddef3a097e2844151f41
Deleted: sha256:1fae417e6afb0a2e4178d2b43ab673997d66cad0cb55ced26b07e092b5ec8642

Starting for channel 'mychannel' with CLI timeout of '10' seconds and CLI delay of '3' seconds and using database 'couchdb'
proceeding ...
./byfn.sh: line 124: configtxlator: command not found
LOCAL_VERSION=
DOCKER_IMAGE_VERSION=1.4.3
=================== WARNING ===================
  Local fabric binaries and docker images are  
  out of  sync. This may cause problems.       
===============================================
/home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/../bin/cryptogen

##########################################################
##### Generate certificates using cryptogen tool #########
##########################################################
+ cryptogen generate --config=./crypto-config.yaml
org1.example.com
org2.example.com
+ res=0
+ set +x

Generate CCP files for Org1 and Org2
/home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/../bin/configtxgen
##########################################################
#########  Generating Orderer Genesis block ##############
##########################################################
CONSENSUS_TYPE=solo
+ '[' solo == solo ']'
+ configtxgen -profile TwoOrgsOrdererGenesis -channelID byfn-sys-channel -outputBlock ./channel-artifacts/genesis.block
2020-09-25 10:38:25.424 CST [common.tools.configtxgen] main -> INFO 001 Loading configuration
2020-09-25 10:38:25.638 CST [common.tools.configtxgen.localconfig] completeInitialization -> INFO 002 orderer type: solo
2020-09-25 10:38:25.638 CST [common.tools.configtxgen.localconfig] Load -> INFO 003 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:25.768 CST [common.tools.configtxgen.localconfig] completeInitialization -> INFO 004 orderer type: solo
2020-09-25 10:38:25.768 CST [common.tools.configtxgen.localconfig] LoadTopLevel -> INFO 005 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:25.770 CST [common.tools.configtxgen] doOutputBlock -> INFO 006 Generating genesis block
2020-09-25 10:38:25.771 CST [common.tools.configtxgen] doOutputBlock -> INFO 007 Writing genesis block
+ res=0
+ set +x

#################################################################
### Generating channel configuration transaction 'channel.tx' ###
#################################################################
+ configtxgen -profile TwoOrgsChannel -outputCreateChannelTx ./channel-artifacts/channel.tx -channelID mychannel
2020-09-25 10:38:25.815 CST [common.tools.configtxgen] main -> INFO 001 Loading configuration
2020-09-25 10:38:25.953 CST [common.tools.configtxgen.localconfig] Load -> INFO 002 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.139 CST [common.tools.configtxgen.localconfig] completeInitialization -> INFO 003 orderer type: solo
2020-09-25 10:38:26.139 CST [common.tools.configtxgen.localconfig] LoadTopLevel -> INFO 004 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.139 CST [common.tools.configtxgen] doOutputChannelCreateTx -> INFO 005 Generating new channel configtx
2020-09-25 10:38:26.141 CST [common.tools.configtxgen] doOutputChannelCreateTx -> INFO 006 Writing new channel tx
+ res=0
+ set +x

#################################################################
#######    Generating anchor peer update for Org1MSP   ##########
#################################################################
+ configtxgen -profile TwoOrgsChannel -outputAnchorPeersUpdate ./channel-artifacts/Org1MSPanchors.tx -channelID mychannel -asOrg Org1MSP
2020-09-25 10:38:26.188 CST [common.tools.configtxgen] main -> INFO 001 Loading configuration
2020-09-25 10:38:26.322 CST [common.tools.configtxgen.localconfig] Load -> INFO 002 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.451 CST [common.tools.configtxgen.localconfig] completeInitialization -> INFO 003 orderer type: solo
2020-09-25 10:38:26.451 CST [common.tools.configtxgen.localconfig] LoadTopLevel -> INFO 004 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.451 CST [common.tools.configtxgen] doOutputAnchorPeersUpdate -> INFO 005 Generating anchor peer update
2020-09-25 10:38:26.452 CST [common.tools.configtxgen] doOutputAnchorPeersUpdate -> INFO 006 Writing anchor peer update
+ res=0
+ set +x

#################################################################
#######    Generating anchor peer update for Org2MSP   ##########
#################################################################
+ configtxgen -profile TwoOrgsChannel -outputAnchorPeersUpdate ./channel-artifacts/Org2MSPanchors.tx -channelID mychannel -asOrg Org2MSP
2020-09-25 10:38:26.491 CST [common.tools.configtxgen] main -> INFO 001 Loading configuration
2020-09-25 10:38:26.632 CST [common.tools.configtxgen.localconfig] Load -> INFO 002 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.767 CST [common.tools.configtxgen.localconfig] completeInitialization -> INFO 003 orderer type: solo
2020-09-25 10:38:26.767 CST [common.tools.configtxgen.localconfig] LoadTopLevel -> INFO 004 Loaded configuration: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/first-network/configtx.yaml
2020-09-25 10:38:26.767 CST [common.tools.configtxgen] doOutputAnchorPeersUpdate -> INFO 005 Generating anchor peer update
2020-09-25 10:38:26.767 CST [common.tools.configtxgen] doOutputAnchorPeersUpdate -> INFO 006 Writing anchor peer update
+ res=0
+ set +x

Creating network "net_byfn" with the default driver
Creating volume "net_peer0.org2.example.com" with default driver
Creating volume "net_peer1.org2.example.com" with default driver
Creating volume "net_peer1.org1.example.com" with default driver
Creating volume "net_peer0.org1.example.com" with default driver
Creating volume "net_orderer.example.com" with default driver
Creating couchdb1 ... 
Creating ca_peerOrg1 ... 
Creating ca_peerOrg2 ... 
Creating couchdb2 ... 
Creating couchdb3 ... 
Creating orderer.example.com ... 
Creating couchdb0 ... 
Creating couchdb1
Creating ca_peerOrg1
Creating orderer.example.com
Creating ca_peerOrg2
Creating couchdb0
Creating couchdb3
Creating couchdb3 ... done
Creating couchdb1 ... done
Creating peer0.org2.example.com ... 
Creating peer1.org2.example.com ... 
Creating peer1.org1.example.com ... 
Creating peer0.org2.example.com
Creating peer0.org1.example.com
Creating peer1.org2.example.com
Creating peer1.org1.example.com ... done
Creating cli ... 
Creating cli ... done
CONTAINER ID        IMAGE                               COMMAND                  CREATED             STATUS                  PORTS                                        NAMES
25db1f49bd0d        hyperledger/fabric-tools:latest     "/bin/bash"              3 seconds ago       Up Less than a second                                                cli
ffa08fe12f45        hyperledger/fabric-peer:latest      "peer node start"        10 seconds ago      Up 3 seconds            0.0.0.0:10051->10051/tcp                     peer1.org2.example.com
db986456e3f1        hyperledger/fabric-peer:latest      "peer node start"        10 seconds ago      Up 3 seconds            0.0.0.0:8051->8051/tcp                       peer1.org1.example.com
6b58e2f9f0fd        hyperledger/fabric-peer:latest      "peer node start"        10 seconds ago      Up 3 seconds            0.0.0.0:7051->7051/tcp                       peer0.org1.example.com
99f1a6861f29        hyperledger/fabric-peer:latest      "peer node start"        10 seconds ago      Up 5 seconds            0.0.0.0:9051->9051/tcp                       peer0.org2.example.com
083ad91dc52d        hyperledger/fabric-couchdb          "tini -- /docker-ent…"   16 seconds ago      Up 10 seconds           4369/tcp, 9100/tcp, 0.0.0.0:7984->5984/tcp   couchdb2
278bd416710a        hyperledger/fabric-couchdb          "tini -- /docker-ent…"   16 seconds ago      Up 10 seconds           4369/tcp, 9100/tcp, 0.0.0.0:5984->5984/tcp   couchdb0
e027cdca24ae        hyperledger/fabric-ca:latest        "sh -c 'fabric-ca-se…"   16 seconds ago      Up 10 seconds           7054/tcp, 0.0.0.0:8054->8054/tcp             ca_peerOrg2
40ba0e78f3a2        hyperledger/fabric-couchdb          "tini -- /docker-ent…"   16 seconds ago      Up 10 seconds           4369/tcp, 9100/tcp, 0.0.0.0:8984->5984/tcp   couchdb3
302ff3534644        hyperledger/fabric-orderer:latest   "orderer"                16 seconds ago      Up 10 seconds           0.0.0.0:7050->7050/tcp                       orderer.example.com
6875e13d9078        hyperledger/fabric-ca:latest        "sh -c 'fabric-ca-se…"   16 seconds ago      Up 10 seconds           0.0.0.0:7054->7054/tcp                       ca_peerOrg1
dfa539ffb0b5        hyperledger/fabric-couchdb          "tini -- /docker-ent…"   16 seconds ago      Up 10 seconds           4369/tcp, 9100/tcp, 0.0.0.0:6984->5984/tcp   couchdb1

 ____    _____      _      ____    _____ 
/ ___|  |_   _|    / \    |  _ \  |_   _|
\___ \    | |     / _ \   | |_) |   | |  
 ___) |   | |    / ___ \  |  _ <    | |  
|____/    |_|   /_/   \_\ |_| \_\   |_|  

Build your first network (BYFN) end-to-end test

Channel name : mychannel
Creating channel...
+ peer channel create -o orderer.example.com:7050 -c mychannel -f ./channel-artifacts/channel.tx --tls true --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
+ res=0
+ set +x
2020-09-25 02:38:45.449 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:38:45.677 UTC [cli.common] readBlock -> INFO 002 Got status: &{NOT_FOUND}
2020-09-25 02:38:45.679 UTC [channelCmd] InitCmdFactory -> INFO 003 Endorser and orderer connections initialized
2020-09-25 02:38:45.916 UTC [cli.common] readBlock -> INFO 004 Received block: 0
===================== Channel 'mychannel' created ===================== 

Having all peers join the channel...
+ peer channel join -b mychannel.block
+ res=1
+ set +x
Error: error getting endorser client for channel: endorser client failed to connect to peer0.org1.example.com:7051: failed to create new connection: connection error: desc = "transport: error while dialing: dial tcp 172.20.0.11:7051: connect: connection refused"
peer0.org1 failed to join the channel, Retry after 3 seconds
+ peer channel join -b mychannel.block
+ res=1
+ set +x
Error: error getting endorser client for channel: endorser client failed to connect to peer0.org1.example.com:7051: failed to create new connection: connection error: desc = "transport: error while dialing: dial tcp 172.20.0.11:7051: connect: connection refused"
peer0.org1 failed to join the channel, Retry after 3 seconds
+ peer channel join -b mychannel.block
+ res=0
+ set +x
2020-09-25 02:38:52.604 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:38:53.046 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
===================== peer0.org1 joined channel 'mychannel' ===================== 

+ peer channel join -b mychannel.block
+ res=0
+ set +x
2020-09-25 02:38:56.141 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:38:56.324 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
===================== peer1.org1 joined channel 'mychannel' ===================== 

+ peer channel join -b mychannel.block
+ res=0
+ set +x
2020-09-25 02:38:59.461 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:38:59.669 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
===================== peer0.org2 joined channel 'mychannel' ===================== 

+ peer channel join -b mychannel.block
+ res=0
+ set +x
2020-09-25 02:39:02.781 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:39:03.110 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
===================== peer1.org2 joined channel 'mychannel' ===================== 

Updating anchor peers for org1...
+ peer channel update -o orderer.example.com:7050 -c mychannel -f ./channel-artifacts/Org1MSPanchors.tx --tls true --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
+ res=0
+ set +x
2020-09-25 02:39:06.210 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:39:06.392 UTC [channelCmd] update -> INFO 002 Successfully submitted channel update
===================== Anchor peers updated for org 'Org1MSP' on channel 'mychannel' ===================== 

Updating anchor peers for org2...
+ peer channel update -o orderer.example.com:7050 -c mychannel -f ./channel-artifacts/Org2MSPanchors.tx --tls true --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
+ res=0
+ set +x
2020-09-25 02:39:09.469 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2020-09-25 02:39:09.496 UTC [channelCmd] update -> INFO 002 Successfully submitted channel update
===================== Anchor peers updated for org 'Org2MSP' on channel 'mychannel' ===================== 


========= All GOOD, BYFN execution completed =========== 


 _____   _   _   ____   
| ____| | \ | | |  _ \  
|  _|   |  \| | | | | | 
| |___  | |\  | | |_| | 
|_____| |_| \_| |____/  

+ echo 'Installing smart contract on peer0.org1.example.com'
Installing smart contract on peer0.org1.example.com
+ docker exec -e CORE_PEER_LOCALMSPID=Org1MSP -e CORE_PEER_ADDRESS=peer0.org1.example.com:7051 -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp -e CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt cli peer chaincode install -n fabcar -v 1.0 -p github.com/chaincode/fabcar/go -l golang
2020-09-25 02:39:13.810 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-09-25 02:39:13.810 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
2020-09-25 02:39:16.156 UTC [chaincodeCmd] install -> INFO 003 Installed remotely response:<status:200 payload:"OK" > 
+ echo 'Installing smart contract on peer1.org1.example.com'
Installing smart contract on peer1.org1.example.com
+ docker exec -e CORE_PEER_LOCALMSPID=Org1MSP -e CORE_PEER_ADDRESS=peer1.org1.example.com:8051 -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp -e CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt cli peer chaincode install -n fabcar -v 1.0 -p github.com/chaincode/fabcar/go -l golang
2020-09-25 02:39:16.543 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-09-25 02:39:16.543 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
2020-09-25 02:39:16.793 UTC [chaincodeCmd] install -> INFO 003 Installed remotely response:<status:200 payload:"OK" > 
+ echo 'Installing smart contract on peer0.org2.example.com'
Installing smart contract on peer0.org2.example.com
+ docker exec -e CORE_PEER_LOCALMSPID=Org2MSP -e CORE_PEER_ADDRESS=peer0.org2.example.com:9051 -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp -e CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt cli peer chaincode install -n fabcar -v 1.0 -p github.com/chaincode/fabcar/go -l golang
2020-09-25 02:39:17.188 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-09-25 02:39:17.188 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
2020-09-25 02:39:17.458 UTC [chaincodeCmd] install -> INFO 003 Installed remotely response:<status:200 payload:"OK" > 
+ echo 'Installing smart contract on peer1.org2.example.com'
Installing smart contract on peer1.org2.example.com
+ docker exec -e CORE_PEER_LOCALMSPID=Org2MSP -e CORE_PEER_ADDRESS=peer1.org2.example.com:10051 -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp -e CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt cli peer chaincode install -n fabcar -v 1.0 -p github.com/chaincode/fabcar/go -l golang
2020-09-25 02:39:17.774 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-09-25 02:39:17.774 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
2020-09-25 02:39:18.016 UTC [chaincodeCmd] install -> INFO 003 Installed remotely response:<status:200 payload:"OK" > 
+ echo 'Instantiating smart contract on mychannel'
Instantiating smart contract on mychannel
+ docker exec -e CORE_PEER_LOCALMSPID=Org1MSP -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp cli peer chaincode instantiate -o orderer.example.com:7050 -C mychannel -n fabcar -l golang -v 1.0 -c '{"Args":[]}' -P 'AND('\''Org1MSP.member'\'','\''Org2MSP.member'\'')' --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem --peerAddresses peer0.org1.example.com:7051 --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt
2020-09-25 02:39:18.397 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 001 Using default escc
2020-09-25 02:39:18.398 UTC [chaincodeCmd] checkChaincodeCmdParams -> INFO 002 Using default vscc
+ echo 'Waiting for instantiation request to be committed ...'
Waiting for instantiation request to be committed ...
+ sleep 10
+ echo 'Submitting initLedger transaction to smart contract on mychannel'
Submitting initLedger transaction to smart contract on mychannel
+ echo 'The transaction is sent to all of the peers so that chaincode is built before receiving the following requests'
The transaction is sent to all of the peers so that chaincode is built before receiving the following requests
+ docker exec -e CORE_PEER_LOCALMSPID=Org1MSP -e CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp cli peer chaincode invoke -o orderer.example.com:7050 -C mychannel -n fabcar -c '{"function":"initLedger","Args":[]}' --waitForEvent --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem --peerAddresses peer0.org1.example.com:7051 --peerAddresses peer1.org1.example.com:8051 --peerAddresses peer0.org2.example.com:9051 --peerAddresses peer1.org2.example.com:10051 --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org1.example.com/peers/peer0.org1.example.com/tls/ca.crt --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt --tlsRootCertFiles /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt
2020-09-25 02:41:52.030 UTC [chaincodeCmd] ClientWait -> INFO 002 txid [526e4e9e4df22f304b49bbe0e93b8cdd0b523afc273d7a5277f8ca7e0087e7b2] committed with status (VALID) at peer1.org1.example.com:8051
2020-09-25 02:41:51.979 UTC [chaincodeCmd] ClientWait -> INFO 003 txid [526e4e9e4df22f304b49bbe0e93b8cdd0b523afc273d7a5277f8ca7e0087e7b2] committed with status (VALID) at peer1.org2.example.com:10051
2020-09-25 02:41:51.983 UTC [chaincodeCmd] ClientWait -> INFO 001 txid [526e4e9e4df22f304b49bbe0e93b8cdd0b523afc273d7a5277f8ca7e0087e7b2] committed with status (VALID) at peer0.org2.example.com:9051
2020-09-25 02:41:52.061 UTC [chaincodeCmd] ClientWait -> INFO 004 txid [526e4e9e4df22f304b49bbe0e93b8cdd0b523afc273d7a5277f8ca7e0087e7b2] committed with status (VALID) at peer0.org1.example.com:7051
2020-09-25 02:41:52.100 UTC [chaincodeCmd] chaincodeInvokeOrQuery -> INFO 005 Chaincode invoke successful. result: status:200 
+ set +x

Total setup execution time : 225 secs ...

Next, use the FabCar applications to interact with the deployed FabCar contract.
The FabCar applications are available in multiple programming languages.
Follow the instructions for the programming language of your choice:

JavaScript:

  Start by changing into the "javascript" directory:
    cd javascript

  Next, install all required packages:
    npm install

  Then run the following applications to enroll the admin user, and register a new user
  called user1 which will be used by the other applications to interact with the deployed
  FabCar contract:
    node enrollAdmin
    node registerUser

  You can run the invoke application as follows. By default, the invoke application will
  create a new car, but you can update the application to submit other transactions:
    node invoke

  You can run the query application as follows. By default, the query application will
  return all cars, but you can update the application to evaluate other transactions:
    node query

TypeScript:

  Start by changing into the "typescript" directory:
    cd typescript

  Next, install all required packages:
    npm install

  Next, compile the TypeScript code into JavaScript:
    npm run build

  Then run the following applications to enroll the admin user, and register a new user
  called user1 which will be used by the other applications to interact with the deployed
  FabCar contract:
    node dist/enrollAdmin
    node dist/registerUser

  You can run the invoke application as follows. By default, the invoke application will
  create a new car, but you can update the application to submit other transactions:
    node dist/invoke

  You can run the query application as follows. By default, the query application will
  return all cars, but you can update the application to evaluate other transactions:
    node dist/query

Java:

  Start by changing into the "java" directory:
    cd java

  Then, install dependencies and run the test using:
    mvn test

  The test will invoke the sample client app which perform the following:
    - Enroll admin and user1 and import them into the wallet (if they don't already exist there)
    - Submit a transaction to create a new car
    - Evaluate a transaction (query) to return details of this car
    - Submit a transaction to change the owner of this car
    - Evaluate a transaction (query) to return the updated details of this car

halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar$ 

分析上面的紀錄檔,我們主要做了哪些事情呢?

  • 停止了上次開啟的網路
  • 啟動peer節點、Ordering節點、證書頒發機構以及CLI容器】
  • 建立一個通道,並將peer加入該通道
  • 將智慧合約(即鏈碼)安裝到peer節點的檔案系統上,並在通道上範例化該鏈碼;範例化會啟動鏈碼容器
  • 呼叫initLedger功能來向通道賬本寫入10個不同的汽車

最後,還想我們展示瞭如何來跑這個應用程式 ,以javascript為例,那我們按照命令來試試吧

3、查詢賬本

查詢是指如何從賬本中讀取資料。您可以查詢單個或者多個鍵的值,如果賬本是以類似於JSON這樣的資料儲存格式寫入的,則可以執行更復雜的搜尋(如查詢包含某些關鍵字的所有資產)。

1.具體操作,在javascript中執行以下命令

halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript$ npm install
npm WARN fabcar@1.0.0 No repository field.

up to date in 4.15s

4 packages are looking for funding
  run `npm fund` for details

halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript$ node enrollAdmin
Wallet path: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript/wallet
An identity for the admin user "admin" already exists in the wallet
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript$ node registerUser
Wallet path: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript/wallet
Successfully registered and enrolled admin user "user1" and imported it into the wallet
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript$ node invoke
Wallet path: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript/wallet
Transaction has been submitted
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript$ node query
Wallet path: /home/halfape/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/fabcar/javascript/wallet
Transaction has been evaluated, result is: [{"Key":"CAR0", "Record":{"colour":"blue","make":"Toyota","model":"Prius","owner":"Tomoko"}},{"Key":"CAR1", "Record":{"colour":"red","make":"Ford","model":"Mustang","owner":"Brad"}},{"Key":"CAR12", "Record":{"colour":"Black","make":"Honda","model":"Accord","owner":"Tom"}},{"Key":"CAR2", "Record":{"colour":"green","make":"Hyundai","model":"Tucson","owner":"Jin Soo"}},{"Key":"CAR3", "Record":{"colour":"yellow","make":"Volkswagen","model":"Passat","owner":"Max"}},{"Key":"CAR4", "Record":{"colour":"black","make":"Tesla","model":"S","owner":"Adriana"}},{"Key":"CAR5", "Record":{"colour":"purple","make":"Peugeot","model":"205","owner":"Michel"}},{"Key":"CAR6", "Record":{"colour":"white","make":"Chery","model":"S22L","owner":"Aarav"}},{"Key":"CAR7", "Record":{"colour":"violet","make":"Fiat","model":"Punto","owner":"Pari"}},{"Key":"CAR8", "Record":{"colour":"indigo","make":"Tata","model":"Nano","owner":"Valeria"}},{"Key":"CAR9", "Record":{"colour":"brown","make":"Holden","model":"Barina","owner":"Shotaro"}}]

我們可以看到
這裡有10輛車,一輛屬於Adriana的黑色Tesla Model S、一輛屬於Brad的紅色Ford Mustang、一輛屬於Pari的紫羅蘭色Fiat Punto等等。賬本是基於Key/Value 的,在這裡,關鍵字是從CAR0到CAR9。這一點特別重要。

2.程式碼分析

我們可以大佬query.js裡面的程式碼具體做了什麼。

const path = require('path');
  
const ccpPath = path.resolve(__dirname, '..', '..', 'first-network', 'connection-org1.json');

async function main() {
    try {

        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = new FileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const userExists = await wallet.exists('user1');
        if (!userExists) {
            console.log('An identity for the user "user1" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: true } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Evaluate the specified transaction.
        // queryCar transaction - requires 1 argument, ex: ('queryCar', 'CAR4')
        // queryAllCars transaction - requires no arguments, ex: ('queryAllCars')
        const result = await contract.evaluateTransaction('queryAllCars');
        console.log(`Transaction has been evaluated, result is: ${result.toString()}`);

    } catch (error) {
        console.error(`Failed to evaluate transaction: ${error}`);
        process.exit(1);
    }
}

main();

簡單分析:

會發現主要做了建立錢包,給錢包中新增使用者,獲取通道,獲取合約,呼叫合約函數`queryAllCars`的操作完成了查詢。

那我們這個查詢函數具體實現在哪呢?如下

halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric$ ls
bccsp          CODE_OF_CONDUCT.md  devenv         examples    gotools.mk   LICENSE   peer       release_notes    testingInfo.rst   unit-test
CHANGELOG.md   common              discovery      Gopkg.lock  idemix       Makefile  protos     sampleconfig     test-pyramid.png  vendor
ci.properties  CONTRIBUTING.md     docker-env.mk  Gopkg.toml  images       msp       README.md  scripts          token
cmd            core                docs           gossip      integration  orderer   release    settings.gradle  tox.ini
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric$ cd scripts/
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts$ ls
bootstrap.sh  check_deps.sh     check_spelling.sh        compile_protos.sh  generateHelpDocs.sh  goListFiles.sh  multiarch.sh             run-integration-tests.sh
changelog.sh  check_license.sh  check_trailingspaces.sh  fabric-samples     golinter.sh          metrics_doc.sh  pull_build_artifacts.sh
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts$ cd fabric-samples/
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples$ ls
balance-transfer  bin        chaincode-docker-devmode  CODE_OF_CONDUCT.md  CONTRIBUTING.md  fabcar         high-throughput      Jenkinsfile  MAINTAINERS.md  README.md
basic-network     chaincode  ci.properties             commercial-paper    docs             first-network  interest_rate_swaps  LICENSE      off_chain_data  scripts
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples$ cd chaincode
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode$ ls
abac  chaincode_example02  fabcar  marbles02  marbles02_private  sacc
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode$ cd fabcar/
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar$ ls
go  java  javascript  javascript-low-level  typescript
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar$ cd javascript
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar/javascript$ ls
index.js  lib  package.json
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar/javascript$ cd lib/
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar/javascript/lib$ ls
fabcar.js
halfape@halfape-VirtualBox:~/go/src/github.com/hyperledger/fabric/scripts/fabric-samples/chaincode/fabcar/javascript/lib$ 

開啟fabric.js,具體程式碼如下

   /*
 * SPDX-License-Identifier: Apache-2.0
 */

'use strict';

const { Contract } = require('fabric-contract-api');

class FabCar extends Contract {

    async initLedger(ctx) {
        console.info('============= START : Initialize Ledger ===========');
        const cars = [
            {
                color: 'blue',
                make: 'Toyota',
                model: 'Prius',
                owner: 'Tomoko',
            },
            {
                color: 'red',
                make: 'Ford',
                model: 'Mustang',
                owner: 'Brad',
            },
            {
                color: 'green',
                make: 'Hyundai',
                model: 'Tucson',
                owner: 'Jin Soo',
            },
            {
                color: 'yellow',
                make: 'Volkswagen',
                model: 'Passat',
                owner: 'Max',
            },
            {
                color: 'black',
                make: 'Tesla',
                model: 'S',
                owner: 'Adriana',
            },
            {
                color: 'purple',
                make: 'Peugeot',
                model: '205',
                owner: 'Michel',
            },
            {
                color: 'white',
                make: 'Chery',
                model: 'S22L',
                owner: 'Aarav',
            },
            {
                color: 'violet',
                make: 'Fiat',
                model: 'Punto',
                owner: 'Pari',
            },
            {
                color: 'indigo',
                make: 'Tata',
                model: 'Nano',
                owner: 'Valeria',
            },
            {
                color: 'brown',
                make: 'Holden',
                model: 'Barina',
                owner: 'Shotaro',
            },
        ];

        for (let i = 0; i < cars.length; i++) {
            cars[i].docType = 'car';
            await ctx.stub.putState('CAR' + i, Buffer.from(JSON.stringify(cars[i])));
            console.info('Added <--> ', cars[i]);
        }
        console.info('============= END : Initialize Ledger ===========');
    }

    async queryCar(ctx, carNumber) {
        const carAsBytes = await ctx.stub.getState(carNumber); // get the car from chaincode state
        if (!carAsBytes || carAsBytes.length === 0) {
            throw new Error(`${carNumber} does not exist`);
        }
        console.log(carAsBytes.toString());
        return carAsBytes.toString();
    }

    async createCar(ctx, carNumber, make, model, color, owner) {
        console.info('============= START : Create Car ===========');

        const car = {
            color,
            docType: 'car',
            make,
            model,
            owner,
        };

        await ctx.stub.putState(carNumber, Buffer.from(JSON.stringify(car)));
        console.info('============= END : Create Car ===========');
    }

    async queryAllCars(ctx) {
        const startKey = 'CAR0';
        const endKey = 'CAR999';

        const iterator = await ctx.stub.getStateByRange(startKey, endKey);

        const allResults = [];
        while (true) {
            const res = await iterator.next();

            if (res.value && res.value.value.toString()) {
                console.log(res.value.value.toString('utf8'));

                const Key = res.value.key;
                let Record;
                try {
                    Record = JSON.parse(res.value.value.toString('utf8'));
                } catch (err) {
                    console.log(err);
                    Record = res.value.value.toString('utf8');
                }
                allResults.push({ Key, Record });
            }
            if (res.done) {
                console.log('end of data');
                await iterator.close();
                console.info(allResults);
                return JSON.stringify(allResults);
            }
        }
    }

    async changeCarOwner(ctx, carNumber, newOwner) {
        console.info('============= START : changeCarOwner ===========');

        const carAsBytes = await ctx.stub.getState(carNumber); // get the car from chaincode state
        if (!carAsBytes || carAsBytes.length === 0) {
            throw new Error(`${carNumber} does not exist`);
        }
        const car = JSON.parse(carAsBytes.toString());
        car.owner = newOwner;

        await ctx.stub.putState(carNumber, Buffer.from(JSON.stringify(car)));
        console.info('============= END : changeCarOwner ===========');
    }

}
mdule.exports = FabCar;

會發現,除了我們的queryCar函數 queryAllCars函數,還有createCar函數和changeCarOwner函數。另外還可以看到在初始化的時候出現了10輛汽車的原因。

queryAllCars中有這麼一段

const startKey = 'CAR0';
        const endKey = 'CAR999';
        const iterator = await ctx.stub.getStateByRange(startKey, endKey);

該函數呼叫shim介面函數GetStateByRange來返回引數在startKey和endKey間的賬本資料。這兩個鍵值分別定義為CAR0和CAR999。因此,我們理論上可以建立1,000輛汽車(假設Keys都被正確使用),queryAllCars函數將會顯示出每一輛汽車的資訊。

既然看懂了程式碼,我們來做點小改動,回到剛才的query.js,編輯如下:

const result = await contract.evaluateTransaction('queryCar','CAR4');

然後再來執行,應當只查出CAR4的資訊,我們來看看吧
在這裡插入圖片描述
果然結果也是對的。因為車輛資訊是從0開始的,所以這裡是黑色特斯拉。

4、更新賬本

我們來看看另外一個獨立的用於交易的程式invoke.js,進行開啟

/*
 * SPDX-License-Identifier: Apache-2.0
 */

'use strict';

const { FileSystemWallet, Gateway } = require('fabric-network');
const path = require('path');

const ccpPath = path.resolve(__dirname, '..', '..', 'first-network', 'connection-org1.json');

const ccpPath = path.resolve(__dirname, '..', '..', 'first-network', 'connection-org1.json');

async function main() {
    try {

        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = new FileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const userExists = await wallet.exists('user1');
        if (!userExists) {
            console.log('An identity for the user "user1" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccpPath, { wallet, identity: 'user1', discovery: { enabled: true, asLocalhost: true } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Submit the specified transaction.
        // createCar transaction - requires 5 argument, ex: ('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom')
        // changeCarOwner transaction - requires 2 args , ex: ('changeCarOwner', 'CAR10', 'Dave')
        await contract.submitTransaction('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom');
        console.log('Transaction has been submitted');

        // Disconnect from the gateway.
        await gateway.disconnect();

    } catch (error) {
        console.error(`Failed to submit transaction: ${error}`);
        process.exit(1);
    }
}

main();
簡單分析會發現主要做了建立錢包,給錢包中新增使用者,呼叫合約函數`createCar`的操作完成了提交交易的操作。

另外我們做一個簡單的修改,然後執行node invoke.js,會顯示交易已經被提交。

await contract.submitTransaction('createCar', 'CAR10', 'Aodi', 'Accord', 'Blue', 'halfape');

此時,我們在vim query.js,修改為查詢CAR10資訊,執行node query.js,則會顯示以下資訊。
在這裡插入圖片描述
還有一個chanegCarOwner,大家可以自己試試哈。

Fabric互動應用程式原理分析

下圖演示了一個應用程式如何在鏈碼(智慧合約)中呼叫不同功能。
在這裡插入圖片描述
從上圖以及上面的例子就可以看出:應用程式通過智慧合約(在Fabric中叫做鏈碼)從區塊鏈上獲取資訊或者更新資訊。

在來看一張圖,展示了應用程式是如何我們的Fabric網路進行互動的。
在這裡插入圖片描述
相信跟著我一步步偵錯到這裡,你已經對Fabric又有了新的認識,對區塊鏈又有了新的認識。Say Goodbye~

參考文章:

https://blog.csdn.net/dalang1010/article/details/78940200
https://cn.hyperledger.org/
https://hyperledgercn.github.io/hyperledgerDocs/build_network_zh/

寫在最後

最後,還是得感謝眾多前輩所給的案例以及親身踩過的坑,我才得以成功測試這個小應用。如果你覺得這篇文章對你有所幫助,關注微信公眾號半路猿,拉你進我們的學習交流群,一起學習,一同成長。