fabric-samples/off_chain_data/application-go/processor/transaction.go

package processor

import (
	"fmt"
	"offChainData/parser"
	"offChainData/store"
	"slices"
)

type transactionProcessor struct {
	blockNumber  uint64
	transaction  *parser.Transaction
	writeToStore store.Writer
	channelName  string
}

func (t *transactionProcessor) process() {
	transactionId := t.transaction.ChannelHeader().GetTxId()

	writes := t.writes()
	if len(writes) == 0 {
		fmt.Println("Skipping read-only or system transaction", transactionId)
		return
	}

	fmt.Println("Process transaction", transactionId)

	t.writeToStore(store.LedgerUpdate{
		BlockNumber:   t.blockNumber,
		TransactionId: transactionId,
		Writes:        writes,
	})
}

func (t *transactionProcessor) writes() []store.Write {
	t.channelName = t.transaction.ChannelHeader().GetChannelId()

	nonSystemCCReadWriteSets := []parser.NamespaceReadWriteSet{}
	for _, nsReadWriteSet := range t.transaction.NamespaceReadWriteSets() {
		if !t.isSystemChaincode(nsReadWriteSet.Namespace()) {
			nonSystemCCReadWriteSets = append(nonSystemCCReadWriteSets, nsReadWriteSet)
		}
	}

	writes := []store.Write{}
	for _, readWriteSet := range nonSystemCCReadWriteSets {
		namespace := readWriteSet.Namespace()

		for _, kvWrite := range readWriteSet.ReadWriteSet().GetWrites() {
			writes = append(writes, store.Write{
				ChannelName: t.channelName,
				Namespace:   namespace,
				Key:         kvWrite.GetKey(),
				IsDelete:    kvWrite.GetIsDelete(),
				Value:       string(kvWrite.GetValue()), // Convert bytes to text, purely for readability in output
			})
		}
	}

	return writes
}

func (t *transactionProcessor) isSystemChaincode(chaincodeName string) bool {
	systemChaincodeNames := []string{
		"_lifecycle",
		"cscc",
		"escc",
		"lscc",
		"qscc",
		"vscc",
	}
	return slices.Contains(systemChaincodeNames, chaincodeName)
}