Fabric 1.0源代码分析(37) Peer #DeliverClient（Deliver客户端）
# Fabric 1.0源代码笔记 之 Peer #DeliverClient（Deliver客户端）
## 1、DeliverClient概述
DeliverClient代码分布如下：
* peer/channel/deliverclient.go，deliverClientIntf接口定义及实现，以及DeliverClient工具函数。
* protos/orderer/ab.pb.go，AtomicBroadcast_DeliverClient接口定义和实现。
## 2、deliverClientIntf接口定义及实现
### 2.1、DeliverClient工具函数
```go
//构造deliverClient
func newDeliverClient(conn *grpc.ClientConn, client ab.AtomicBroadcast_DeliverClient, chainID string) *deliverClient
//代码在peer/channel/deliverclient.go
```
### 2.2、deliverClientIntf接口定义及实现
```go
type deliverClientIntf interface {
getSpecifiedBlock(num uint64) (*common.Block, error)
getOldestBlock() (*common.Block, error)
getNewestBlock() (*common.Block, error)
Close() error
}
type deliverClient struct {
conn *grpc.ClientConn
client ab.AtomicBroadcast_DeliverClient
chainID string
}
//构造查询Envelope
func seekHelper(chainID string, position *ab.SeekPosition) *common.Envelope
//r.client.Send(seekHelper(r.chainID, &ab.SeekPosition{Type: &ab.SeekPosition_Specified{Specified: &ab.SeekSpecified{Number: blockNumber}}}))
func (r *deliverClient) seekSpecified(blockNumber uint64) error
//r.client.Send(seekHelper(r.chainID, &ab.SeekPosition{Type: &ab.SeekPosition_Oldest{Oldest: &ab.SeekOldest{}}}))
func (r *deliverClient) seekOldest() error
//return r.client.Send(seekHelper(r.chainID, &ab.SeekPosition{Type: &ab.SeekPosition_Newest{Newest: &ab.SeekNewest{}}}))
func (r *deliverClient) seekNewest() error
//r.client.Recv()读取块
func (r *deliverClient) readBlock() (*common.Block, error)
//r.seekSpecified(num)和r.readBlock()
func (r *deliverClient) getSpecifiedBlock(num uint64) (*common.Block, error)
//r.seekOldest()和r.readBlock()
func (r *deliverClient) getOldestBlock() (*common.Block, error)
//r.seekNewest()和r.readBlock()
func (r *deliverClient) getNewestBlock() (*common.Block, error)
//r.conn.Close()
func (r *deliverClient) Close() error
//cf.DeliverClient.getSpecifiedBlock(0)获取创世区块
func getGenesisBlock(cf *ChannelCmdFactory) (*common.Block, error)
//代码在peer/channel/deliverclient.go
```
func seekHelper(chainID string, position *ab.SeekPosition) *common.Envelope代码如下：
```go
func seekHelper(chainID string, position *ab.SeekPosition) *common.Envelope {
seekInfo := &ab.SeekInfo{
Start: position,
Stop: position,
Behavior: ab.SeekInfo_BLOCK_UNTIL_READY,
}
msgVersion := int32(0)
epoch := uint64(0)
env, err := utils.CreateSignedEnvelope(common.HeaderType_CONFIG_UPDATE, chainID, localmsp.NewSigner(), seekInfo, msgVersion, epoch)
return env
}
//代码在peer/channel/deliverclient.go
```
网址：http://www.qukuailianxueyuan.io/
欲领取造币技术与全套虚拟机资料
区块链技术交流QQ群：756146052 备注：****
尹成学院微信：备注：****
网址：http://www.qukuailianxueyuan.io/
欲领取造币技术与全套虚拟机资料
区块链技术交流QQ群：756146052 备注：****
尹成学院微信：备注：****