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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