get_payload.go

package main

import (
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"github.com/golang/protobuf/proto"
	"github.com/hyperledger/fabric-protos-go/common"
	"github.com/hyperledger/fabric-protos-go/msp"
	"github.com/hyperledger/fabric-protos-go/peer"
	"github.com/pkg/errors"
)

func GetPayloadJson(payload *common.Payload) (Payload, error) {

	/*
		type Payload struct {
			Header *Header
			Data   []byte
		}
	*/

	/*
		type Header struct {
			ChannelHeader   []byte
			SignatureHeader []byte
		}
	*/

	// 1. ChannelHeader

	channelHeader := &common.ChannelHeader{}
	err := proto.Unmarshal(payload.Header.ChannelHeader, channelHeader)
	if err != nil {
		return Payload{}, errors.WithMessage(err, "unmarshaling Channel Header error: ")
	}

	channelHeaderJson, err := GetChannelHeaderJson(channelHeader)
	if err != nil {
		return Payload{}, errors.WithMessage(err, "failed get Channel Header")
	}

	// 2. SignatureHeader

	// Creator is the marshalled object of msp.SerializedIdentity
	signatureHeader := &common.SignatureHeader{}
	err = proto.Unmarshal(payload.Header.SignatureHeader, signatureHeader)
	if err != nil {
		return Payload{}, errors.WithMessage(err, "unmarshaling Signature Header error: ")
	}

	signatureHeaderJson, err := GetSignatureHeaderJson(signatureHeader)
	if err != nil {
		return Payload{}, errors.WithMessage(err, "failed get Signature Header")
	}

	payloadJson := Payload{
		ChannelHeader:   channelHeaderJson,
		SignatureHeader: signatureHeaderJson,
	}

	return payloadJson, nil
}

func GetChannelHeaderJson(channelHeader *common.ChannelHeader) (ChannelHeader, error) {

	/*
		type ChannelHeader struct {
			Type      int32
			Version   int32
			Timestamp *google_protobuf.Timestamp
			ChannelId string
			TxId      string
			Epoch     uint64
			Extension []byte
		}
	*/

	// The Exension field marshalled object from ChaincodeHeaderExtension

	/*
		type ChaincodeHeaderExtension struct {
			PayloadVisibility []byte
			ChaincodeId  *ChaincodeID
		}

		type ChaincodeID struct {
			Path    string
			Name    string
			Version string
		}
	*/
	extension := &peer.ChaincodeHeaderExtension{}
	err := proto.Unmarshal(channelHeader.Extension, extension)
	if err != nil {
		return ChannelHeader{}, errors.WithMessage(err, "unmarshaling Channel Header error: ")
	}
	
	chaincodeIdJson := ChaincodeID{
		Path:    extension.ChaincodeId.Path,
		Name:    extension.ChaincodeId.Name,
		Version: extension.ChaincodeId.Version,
	}

	chaincodeHeaderExtensionJson := ChaincodeHeaderExtension{
		ChaincodeId: chaincodeIdJson,
	}

	HeaderType := [7]string{"MESSAGE", "CONFIG", "CONFIG_UPDATE", "ENDORSER_TRANSACTION",
		"ORDERER_TRANSACTION", "DELIVER_SEEK_INFO", "CHAINCODE_PACKAGE"}

	channelHeaderJson := ChannelHeader{
		Type:      HeaderType[channelHeader.Type],
		Version:   channelHeader.Version,
		ChannelId: channelHeader.ChannelId,
		TxId:      channelHeader.TxId,
		Epoch:     channelHeader.Epoch,
		Extension: chaincodeHeaderExtensionJson,
	}

	return channelHeaderJson, nil
}

func GetSignatureHeaderJson(signatureHeader *common.SignatureHeader) (SignatureHeader, error) {

	/*
		type SignatureHeader struct {
			Creator []byte
			Nonce   []byte
		}
	*/

	creator := &msp.SerializedIdentity{}
	err := proto.Unmarshal(signatureHeader.Creator, creator)
	if err != nil {
		return SignatureHeader{}, errors.WithMessage(err, "unmarshaling Creator error: ")
	}

	// Extracting Identifier Certificate

	uEnc := base64.URLEncoding.EncodeToString([]byte(creator.IdBytes))

	// Base64 Url Decoding
	certHash, err := base64.URLEncoding.DecodeString(uEnc)
	if err != nil {
		return SignatureHeader{}, errors.WithMessage(err, "Error decoding string: ")
	}

	end, _ := pem.Decode([]byte(string(certHash)))
	if end == nil {
		return SignatureHeader{}, errors.New("Error Pem decoding: ")
	}
	cert, err := x509.ParseCertificate(end.Bytes)
	if err != nil {
		return SignatureHeader{}, errors.New("failed to parse certificate:: ")
	}

	certificateJson := Certificate{
		Country:            cert.Issuer.Country,
		Organization:       cert.Issuer.Organization,
		OrganizationalUnit: cert.Issuer.OrganizationalUnit,
		Locality:           cert.Issuer.Locality,
		Province:           cert.Issuer.Province,
		SerialNumber:       cert.Issuer.SerialNumber,
		NotBefore:          cert.NotBefore,
		NotAfter:           cert.NotAfter,
	}

	creatorJson := Creator{
		Mspid:       creator.Mspid,
		CertHash:    string(certHash),
		Certificate: certificateJson,
	}

	signatureHeaderJson := SignatureHeader{
		Creator: creatorJson,
	}

	return signatureHeaderJson, nil
}