正文
从源码中解析fabric区块数据结构（一）
前言
最近打算基于fabric-sdk-go实现hyperledger fabric浏览器，其中最重要的一步就是解析fabric的上链区块。虽说fabric是Golang实现的，但直到2021年2月1号才发布了第一个稳定版fabric-sdk-go，而且官方几乎没有响应的文档介绍。对于fabric-sdk-go，基本都是参照源码中的测试用例来使用；而要实现区块链浏览器，仅靠测试用例还差好多，特别是对出块信息的解析。
通过event.Client.RegisterBlockEvent()可以监听fabric的出块事件，但返回的信息中有用的是一个BlockEvent类型的chan，定义如下：
// BlockEvent contains the data for the block event
type BlockEvent struct {
// Block is the block that was committed
Block *cb.Block
// SourceURL specifies the URL of the peer that produced the event
SourceURL string
}
区块链浏览器需要的所有信息基本都包含在Block中，其定义如下：
// This is finalized block structure to be shared among the orderer and peer
// Note that the BlockHeader chains to the previous BlockHeader, and the BlockData hash is embedded
// in the BlockHeader. This makes it natural and obvious that the Data is included in the hash, but
// the Metadata is not.
type Block struct {
Header *BlockHeader `protobuf:"bytes,1,opt,name=header,proto3" json:"header,omitempty"`
Data *BlockData `protobuf:"bytes,2,opt,name=data,proto3" json:"data,omitempty"`
Metadata *BlockMetadata `protobuf:"bytes,3,opt,name=metadata,proto3" json:"metadata,omitempty"`
}
本文作为区块链浏览器系列的开篇，结构体中各字段的含义会在之后的文章中一一介绍，这里就不再过多介绍。接下来将以类图的形式来解析区块中包含的信息。
classDiagram
class Block{
Header *BlockHeader
Data *BlockData
Metadata *BlockMetadata
}
class BlockHeader{
Number uint64
PreviousHash []byte
DataHash []byte
}
class BlockData{
Data [][]byte
}
class BlockMetadata{
Metadata [][]byte
}
class Metadata{
Value []byte
Signatures []*MetadataSignature
}
class MetadataSignature{
SignatureHeader []byte
Signature []byte
IdentifierHeader []byte
}
class SignatureHeader{
Creator []byte
Nonce []byte
}
class SerializedIdentity{
Mspid string
IdBytes []byte
}
class Certificate{
crypto/x509.Certificate
}
class IdentifierHeader{
Identifier uint32
Nonce []byte
}
class Envelope{
Payload []byte
Signature []byte
}
class Payload{
Header *Header
Data []byte
}
class Header{
ChannelHeader []byte
SignatureHeader []byte
}
class ChannelHeader{
Type int32
Version int32
Timestamp *timestamp.Timestamp
TxId string
Epoch uint64
Extension []byte
TlsCertHash []byte
}
class Transaction{
Actions []*TransactionAction
}
class TransactionAction{
Header []byte
Payload []byte
}
class ChaincodeActionPayload{
ChaincodeProposalPayload []byte
Action *ChaincodeEndorsedAction
}
class ChaincodeEndorsedAction{
ProposalResponsePayload []byte
Endorsements []*Endorsement
}
class ProposalResponsePayload{
ProposalHash []byte
Extension []byte
}
class Endorsement{
Endorser []byte
Signature []byte
}
class ChaincodeProposalPayload{
Input []byte
TransientMap map[string][]byte
}
class ChaincodeInvocationSpec{
ChaincodeSpec *ChaincodeSpec
}
class ChaincodeSpec{
Type ChaincodeSpec_Type
ChaincodeId *ChaincodeID
Input *ChaincodeInput
Timeout int32
}
class ChaincodeID{
Path string
Name string
Version string
}
class ChaincodeInput{
Args [][]byte
Decorations map[string][]byte
IsInit bool
}
class ChaincodeAction{
Results []byte
Events []byte
Response *Response
ChaincodeId *ChaincodeID
}
class TxReadWriteSet{
DataModel TxReadWriteSet_DataModel
NsRwset []*NsReadWriteSet
}
class NsReadWriteSet{
Namespace string
Rwset []byte
CollectionHashedRwset []*CollectionHashedReadWriteSet
}
class KVRWSet{
Reads []*KVRead
RangeQueriesInfo []*RangeQueryInfo
Writes []*KVWrite
MetadataWrites []*KVMetadataWrite
}
Block --* BlockHeader
Block --* BlockData
Block --* BlockMetadata
BlockMetadata --* Metadata
Metadata --* MetadataSignature
MetadataSignature --* SignatureHeader
MetadataSignature --* IdentifierHeader
SignatureHeader --* SerializedIdentity
SerializedIdentity --* Certificate
BlockData --* Envelope
Envelope --* Payload
Payload --* Header
Payload --* Transaction
Transaction --* TransactionAction
TransactionAction --* ChaincodeActionPayload
ChaincodeActionPayload --* ChaincodeEndorsedAction
ChaincodeActionPayload --* ChaincodeProposalPayload
ChaincodeProposalPayload --* ChaincodeInvocationSpec
ChaincodeInvocationSpec --* ChaincodeSpec
ChaincodeSpec --* ChaincodeID
ChaincodeSpec --* ChaincodeInput
ChaincodeEndorsedAction --* Endorsement
ChaincodeEndorsedAction --* ProposalResponsePayload
ProposalResponsePayload --* ChaincodeAction
ChaincodeAction --* TxReadWriteSet
TxReadWriteSet --* NsReadWriteSet
NsReadWriteSet --* KVRWSet
Header --* ChannelHeader
Header --* SignatureHeader
声明：本作品采用署名-非商业性使用-相同方式共享 4.0 国际 (CC BY-NC-SA 4.0)进行许可，使用时请注明出处。
Author: mengbin92
Github: mengbin92
cnblogs: 恋水无意
