BNC Chain Go SDK

The Binance Chain GO SDK provides a thin wrapper around the BNC Chain API for readonly endpoints, in addition to creating and submitting different transactions. It includes the following core components:

• client - implementations of Binance Chain transaction types and query, such as for transfers and trading.
• common - core cryptographic functions, uuid functions and other useful functions.
• e2e - end-to-end test package for go-sdk developer. For common users, it is also a good reference to use go-sdk.
• keys - implement KeyManage to manage private key and accounts.
• types - core type of Binance Chain, such as coin, account, tx and msg.

Install

Requirement

Go version above 1.11

Use go mod(recommend)

Add "github.com/binance-chain/go-sdk" dependency into your go.mod file. Example:

require (
	github.com/binance-chain/go-sdk latest
)
replace github.com/tendermint/go-amino => github.com/binance-chain/bnc-go-amino v0.14.1-binance.1

NOTE: Please make sure you use binance-chain amino repo instead of tendermint amino.

Usage

Key Manager

Before start using API, you should construct a Key Manager to help sign the transaction msg or verify signature. Key Manager is an Identity Manger to define who you are in the bnbchain. It provide following interface:

type KeyManager interface {
	Sign(tx.StdSignMsg) ([]byte, error)
	GetPrivKey() crypto.PrivKey
	GetAddr() txmsg.AccAddress
	
	ExportAsMnemonic() (string, error)
	ExportAsPrivateKey() (string, error)
	ExportAsKeyStore(password string) (*EncryptedKeyJSON, error)
}

We provide four construct functions to generate Key Manger:

NewKeyManager() (KeyManager, error)

NewMnemonicKeyManager(mnemonic string) (KeyManager, error)

NewMnemonicPathKeyManager(mnemonic, keyPath string) (KeyManager, error) 

NewKeyStoreKeyManager(file string, auth string) (KeyManager, error)

NewPrivateKeyManager(priKey string) (KeyManager, error) 

NewLedgerKeyManager(path ledger.DerivationPath) (KeyManager, error)

• NewKeyManager. You will get a new private key without provide anything, you can export and save this KeyManager.
• NewMnemonicKeyManager. You should provide your mnemonic, usually is a string of 24 words.
• NewMnemonicPathKeyManager. The difference between NewMnemonicKeyManager is that you can use custom keypath to generate different keyManager while using the same mnemonic. 5 levels in BIP44 path: "purpose' / coin_type' / account' / change / address_index", "purpose' / coin_type'" is fixed as "44'/714'/", you can customize the rest part.
• NewKeyStoreKeyManager. You should provide a keybase json file and you password, you can download the key base json file when your create a wallet account.
• NewPrivateKeyManager. You should provide a Hex encoded string of your private key.
• NewLedgerKeyManager. You must have a ledger device with binance ledger app and connect it to your machine.

Examples:

From mnemonic:

mnemonic := "lock globe panda armed mandate fabric couple dove climb step stove price recall decrease fire sail ring media enhance excite deny valid ceiling arm"
keyManager, _ := keys.NewMnemonicKeyManager(mnemonic)

From key base file:

file := "testkeystore.json"
keyManager, err := NewKeyStoreKeyManager(file, "your password")

From raw private key string:

priv := "9579fff0cab07a4379e845a890105004ba4c8276f8ad9d22082b2acbf02d884b"
keyManager, err := NewPrivateKeyManager(priv)

From ledger device:

bip44Params := keys.NewBinanceBIP44Params(0, 0)
keyManager, err := NewLedgerKeyManager(bip44Params.DerivationPath())

We provide three export functions to persistent a Key Manger:

ExportAsMnemonic() (string, error)

ExportAsPrivateKey() (string, error)

ExportAsKeyStore(password string) (*EncryptedKeyJSON, error)

Examples:

km, _ := NewKeyManager()
encryPlain1, _ := km.GetPrivKey().Sign([]byte("test plain"))
keyJSONV1, err := km.ExportAsKeyStore("testpassword")
bz, _ := json.Marshal(keyJSONV1)
ioutil.WriteFile("TestGenerateKeyStoreNoError.json", bz, 0660)
newkm, _ := NewKeyStoreKeyManager("TestGenerateKeyStoreNoError.json", "testpassword")
encryPlain2, _ := newkm.GetPrivKey().Sign([]byte("test plain"))
assert.True(t, bytes.Equal(encryPlain1, encryPlain2))

As for ledger key, it can't be exported. Because its private key is saved on ledger device and no one can directly access it outside.

Init Client

import sdk "github.com/binance-chain/go-sdk/client"

mnemonic := "lock globe panda armed mandate fabric couple dove climb step stove price recall decrease fire sail ring media enhance excite deny valid ceiling arm"
//-----   Init KeyManager  -------------
keyManager, _ := keys.NewMnemonicKeyManager(mnemonic)

//-----   Init sdk  -------------
client, err := sdk.NewDexClient("testnet-dex.binance.org", types.TestNetwork, keyManager)

For sdk init, you should know the famous api address. Besides, you should know what kind of network the api gateway is in, since we have different configurations for test network and production network.

ChainNetwork	ApiAddr
TestNetwork	testnet-dex.binance.org
ProdNetwork	dex.binance.org

If you want broadcast some transactions, like send coins, create orders or cancel orders, you should construct a key manager.

Example

Create a buy order:

createOrderResult, err := client.CreateOrder(tradeSymbol, nativeSymbol, txmsg.OrderSide.BUY, 100000000, 100000000, true)

If want to attach memo or source to the transaction, more WithSource and WithMemo options are required:

createOrderResult, err := client.CreateOrder(tradeSymbol, nativeSymbol, msg.OrderSide.BUY, 100000000, 100000000, true, transaction.WithSource(100),transaction.WithMemo("test memo"))

In some scenarios, continuously send multi transactions very fast. Before the previous transaction being included in the chain, the next transaction is being sent, to avoid sequence mismatch error, option WithAcNumAndSequence is required:

acc,err:=client.GetAccount(client.GetKeyManager().GetAddr().String())
_, err = client.CreateOrder(tradeSymbol, nativeSymbol, msg.OrderSide.BUY, 100000000, 100000000, true, transaction.WithAcNumAndSequence(acc.Number,acc.Sequence))
_, err = client.CreateOrder(tradeSymbol, nativeSymbol, msg.OrderSide.BUY, 100000000, 100000000, true, transaction.WithAcNumAndSequence(acc.Number,acc.Sequence+1))
_, err = client.CreateOrder(tradeSymbol, nativeSymbol, msg.OrderSide.BUY, 100000000, 100000000, true, transaction.WithAcNumAndSequence(acc.Number,acc.Sequence+2))

For more API usage documentation, please check the wiki..

RPC Client(Beta)

RPC endpoints may be used to interact with a node directly over HTTP or websockets. Using RPC, you may perform low-level operations like executing ABCI queries, viewing network/consensus state or broadcasting a transaction against full node or light client.

Example

nodeAddr := "tcp://127.0.0.1:27147"
testClientInstance := rpc.NewRPCClient(nodeAddr,types.TestNetwork)
status, err := c.Status()