兄弟连区块链教程Fabric1.0源代码分析Peer peer channel命令及子命令实现，2018年下半年，区块链行业正逐渐褪去发展之初的浮躁、回归理性，表面上看相关人才需求与身价似乎正在回落。但事实上，正是初期泡沫的渐退，让人们更多的关注点放在了区块链真正的技术之上。

Fabric1.0源代码笔记之Peer peer channel命令及子命令实现

1、peer channel create子命令实现（创建通道）

1.1、初始化Orderer客户端

const (     EndorserRequired EndorserRequirement = true     EndorserNotRequired EndorserRequirement = false     OrdererRequired OrdererRequirement = true     OrdererNotRequired OrdererRequirement = false ) cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired) //代码在peer/channel/create.go

cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired)代码如下：

type ChannelCmdFactory struct {     EndorserClient pb.EndorserClient //EndorserClient     Signer msp.SigningIdentity //Signer     BroadcastClient common.BroadcastClient //BroadcastClient     DeliverClient deliverClientIntf //DeliverClient     BroadcastFactory BroadcastClientFactory //BroadcastClientFactory，type BroadcastClientFactory func() (common.BroadcastClient, error) } func InitCmdFactory(isEndorserRequired EndorserRequirement, isOrdererRequired OrdererRequirement) (*ChannelCmdFactory, error) {     var err error     cmdFact := &ChannelCmdFactory{}     cmdFact.Signer, err = common.GetDefaultSignerFnc() //GetDefaultSignerFnc = GetDefaultSigner     cmdFact.BroadcastFactory = func() (common.BroadcastClient, error) {         return common.GetBroadcastClientFnc(orderingEndpoint, tls, caFile) //GetBroadcastClientFnc = GetBroadcastClient     }     //peer channel join或list需要endorser，本处暂未使用     if isEndorserRequired {         cmdFact.EndorserClient, err = common.GetEndorserClientFnc()     }     //peer channel create或fetch需要orderer     if isOrdererRequired {         var opts []grpc.DialOption         if tls {             if caFile != "" {                 creds, err := credentials.NewClientTLSFromFile(caFile, "")                 opts = append(opts, grpc.WithTransportCredentials(creds))             }         } else {             opts = append(opts, grpc.WithInsecure())         }         conn, err := grpc.Dial(orderingEndpoint, opts...)         client, err := ab.NewAtomicBroadcastClient(conn).Deliver(context.TODO())         cmdFact.DeliverClient = newDeliverClient(conn, client, chainID) //构造deliverClient     }     return cmdFact, nil } //代码在peer/channel/channel.go

1.2、发送创建区块链的交易

err = sendCreateChainTransaction(cf) //代码在peer/channel/create.go

sendCreateChainTransaction(cf)代码如下：

func sendCreateChainTransaction(cf *ChannelCmdFactory) error {     var err error     var chCrtEnv *cb.Envelope     if channelTxFile != "" { //peer channel create -f指定通道交易配置文件         chCrtEnv, err = createChannelFromConfigTx(channelTxFile) //获取创世区块     } else {         chCrtEnv, err = createChannelFromDefaults(cf) //没有指定通道交易配置文件     }     chCrtEnv, err = sanityCheckAndSignConfigTx(chCrtEnv) //检查和签名交易配置     var broadcastClient common.BroadcastClient     broadcastClient, err = cf.BroadcastFactory()     defer broadcastClient.Close()     err = broadcastClient.Send(chCrtEnv)     return err } //代码在peer/channel/create.go

1.3、获取创世区块并写入文件

var block *cb.Block block, err = getGenesisBlock(cf) //获取创世区块 b, err := proto.Marshal(block) //块序列化 err = ioutil.WriteFile(file, b, 0644) //写入文件 //代码在peer/channel/create.go

2、peer channel join子命令实现（加入通道）

2.1、初始化Endorser客户端

cf, err = InitCmdFactory(EndorserRequired, OrdererNotRequired) //代码在peer/channel/join.go

2.2、构造ChaincodeInvocationSpec消息（cscc.JoinChain）

spec, err := getJoinCCSpec() invocation := &pb.ChaincodeInvocationSpec{ChaincodeSpec: spec} //代码在peer/channel/join.go

spec, err := getJoinCCSpec()代码如下：

func getJoinCCSpec() (*pb.ChaincodeSpec, error) {     gb, err := ioutil.ReadFile(genesisBlockPath)     input := &pb.ChaincodeInput{Args: [][]byte{[]byte(cscc.JoinChain), gb}}     spec := &pb.ChaincodeSpec{         Type: pb.ChaincodeSpec_Type(pb.ChaincodeSpec_Type_value["GOLANG"]),         ChaincodeId: &pb.ChaincodeID{Name: "cscc"},         Input: input,     }     return spec, nil } //代码在peer/channel/join.go

2.3、创建cscc Proposal并签名

creator, err := cf.Signer.Serialize() //从CIS创建Proposal，CIS即ChaincodeInvocationSpec //调用CreateChaincodeProposal(typ, chainID, cis, creator) //而后调用CreateChaincodeProposalWithTransient(typ, chainID, cis, creator, nil) prop, _, err = putils.CreateProposalFromCIS(pcommon.HeaderType_CONFIG, "", invocation, creator) var signedProp *pb.SignedProposal signedProp, err = putils.GetSignedProposal(prop, cf.Signer) //代码在peer/channel/join.go

CreateChaincodeProposalWithTransient(typ, chainID, cis, creator, nil)代码如下：

func CreateChaincodeProposalWithTransient(typ common.HeaderType, chainID string, cis *peer.ChaincodeInvocationSpec, creator []byte, transientMap map[string][]byte) (*peer.Proposal, str ing, error) {     //创建随机Nonce     nonce, err := crypto.GetRandomNonce()     //计算交易ID     //digest, err := factory.GetDefault().Hash(append(nonce, creator...),&bccsp.SHA256Opts{})     txid, err := ComputeProposalTxID(nonce, creator)     return CreateChaincodeProposalWithTxIDNonceAndTransient(txid, typ, chainID, cis, nonce, creator, transientMap) } //代码在protos/utils/proputils.go

CreateChaincodeProposalWithTxIDNonceAndTransient(txid, typ, chainID, cis, nonce, creator, transientMap)代码如下：

func CreateChaincodeProposalWithTxIDNonceAndTransient(txid string, typ common.HeaderType, chainID string, cis *peer.ChaincodeInvocationSpec, nonce, creator []byte, transientMap map[string][]byte) (*peer.Proposal, string, error) {     ccHdrExt := &peer.ChaincodeHeaderExtension{ChaincodeId: cis.ChaincodeSpec.ChaincodeId}     ccHdrExtBytes, err := proto.Marshal(ccHdrExt)     cisBytes, err := proto.Marshal(cis)     ccPropPayload := &peer.ChaincodeProposalPayload{Input: cisBytes, TransientMap: transientMap}     ccPropPayloadBytes, err := proto.Marshal(ccPropPayload)     var epoch uint64 = 0     timestamp := util.CreateUtcTimestamp()     hdr := &common.Header{ChannelHeader: MarshalOrPanic(&common.ChannelHeader{         Type: int32(typ),         TxId: txid,         Timestamp: timestamp,         ChannelId: chainID,         Extension: ccHdrExtBytes,         Epoch: epoch}),         SignatureHeader: MarshalOrPanic(&common.SignatureHeader{Nonce: nonce, Creator: creator})}     hdrBytes, err := proto.Marshal(hdr)     return &peer.Proposal{Header: hdrBytes, Payload: ccPropPayloadBytes}, txid, nil } //代码在protos/utils/proputils.go

2.4、提交并处理Proposal

var proposalResp *pb.ProposalResponse proposalResp, err = cf.EndorserClient.ProcessProposal(context.Background(), signedProp) //代码在peer/channel/join.go

3、peer channel update（更新锚节点配置）

cf, err = InitCmdFactory(EndorserNotRequired, OrdererRequired) fileData, err := ioutil.ReadFile(channelTxFile) ctxEnv, err := utils.UnmarshalEnvelope(fileData) sCtxEnv, err := sanityCheckAndSignConfigTx(ctxEnv) var broadcastClient common.BroadcastClient broadcastClient, err = cf.BroadcastFactory() defer broadcastClient.Close() return broadcastClient.Send(sCtxEnv) //代码在peer/channel

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