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go-libra

A golang client library for Libra blockchain.

Thanks to gopherjs, go-libra is also available as a Javascript client library: gopherjs-libra. It works for both NodeJS and browsers.

It has all cryptographic verification algorithms, including validator-signature-based consensus verification, ledger history accumulator proof, and account state sparse Merkle tree proof, etc.

Features

Compatible with testnet 2020/4/8 (commit hash 718ace82).

• Data models with all necessary cryptographic verification algorithms
  • Ledger state: signature-based consensus verification
  • Ledger consistency verification: detects reset or hard-forks
  • Transaction info and event: Merkle tree accumulator proof
  • Transaction list: Merkle tree accumulator proof on a range of transactions
  • Transaction signature: ed25519 signature
  • Account state: sparse Merkle tree proof
  • Events: event list hash based on Merkle tree accumulator
• RPC functions
  • Query account states
  • Make P2P transaction, and wait for ledger inclusion
  • Query transaction list by ledger version
  • Query account transaction by sequence number
  • Query sent or received event list by account

Installation

$ # download the code
$ go get -u github.com/the729/go-libra

$ # build example client
$ cd example/cli_client && go build

$ # see example/cli_client/README.md
$ ./cli_client a ls

Usage

Godoc reference to client package and types package.

Get account balance, cryptographically proven

package main

import (
	"context"
	"log"

	"github.com/the729/go-libra/client"
)

const (
	defaultServer = "ac.testnet.libra.org:8000"
	waypoint      = "0:4d4d0feaa9378069f8fcee71980e142273837e108702d8d7f93a8419e2736f3f"
)

func main() {
	c, err := client.New(defaultServer, waypoint)
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()

	addrStr := "42f5745128c05452a0c68272de8042b1"
	addr := client.MustToAddress(addrStr)

	// provenState is cryptographically proven state of account
	provenState, err := c.QueryAccountState(context.TODO(), addr)
	if err != nil {
		log.Fatal(err)
	}

	if provenState.IsNil() {
		log.Printf("Account %s does not exist at version %d.", addrStr, provenState.GetVersion())
		return
	}

	ar, br, err := provenState.GetAccountBlob().GetLibraResources()
	if err != nil {
		log.Fatal(err)
	}

	log.Printf("Balance: %d", br.Coin)
	log.Printf("Sequence Number: %d", ar.SequenceNumber)
	log.Printf("Authentication key: %v", hex.EncodeToString(ar.AuthenticationKey))
}

Make peer-to-peer transaction

log.Printf("Get current account sequence of sender...")
seq, err := c.QueryAccountSequenceNumber(context.TODO(), senderAddr)
if err != nil {
	log.Fatal(err)
}
log.Printf("... is %d", seq)

rawTxn, err := client.NewRawP2PTransaction(
	senderAddr, recvAddr, recvAuthKeyPrefix, seq,
	amountMicro, maxGasAmount, gasUnitPrice, expiration,
)
if err != nil {
	log.Fatal(err)
}

log.Printf("Submit transaction...")
expectedSeq, err := c.SubmitRawTransaction(context.TODO(), rawTxn, priKey)
if err != nil {
	log.Fatal(err)
}

log.Printf("Waiting until transaction is included in ledger...")
err = c.PollSequenceUntil(context.TODO(), senderAddr, expectedSeq, expiration)
if err != nil {
	log.Fatal(err)
}
log.Printf("done.")

Other examples

Several examples are included in example folder.

• cli_client: A fully functional Libra CLI client
• query_account: Query specific account states
• query_txn_range: Query a range of transactions
• query_txn_by_seq: Query a transaction by specific account and sequence number
• p2p_transaction: Make P2P transaction
• NodeJS examples based on gopherjs-libra
• web_client: a pure front-end libra explorer based on gopherjs-libra. See it in action

Contributions are welcome