AddInvoice

AddInvoice is a wrapper around lnd's lnrpc.AddInvoice method with asset specific parameters. It allows RPC users to create invoices that correspond to the specified asset amount. If a peer pubkey is specified, then only that peer will be used for RFQ negotiations. If none is specified then RFQ quotes for all peers with suitable asset channels will be created.

Source: tapchannelrpc/tapchannel.proto

gRPC

rpc AddInvoice (AddInvoiceRequest) returns (AddInvoiceResponse);

REST

HTTP Method	Path
POST	/v1/taproot-assets/channels/invoice

Code Samples

gRPC

Javascript

const fs = require('fs');
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');

const GRPC_HOST = 'localhost:10029'
const MACAROON_PATH = 'TAPROOT-ASSETS_DIR/regtest/taproot-assets.macaroon'
const TLS_PATH = 'TAPROOT-ASSETS_DIR/tls.cert'

const loaderOptions = {
  keepCase: true,
  longs: String,
  enums: String,
  defaults: true,
  oneofs: true,
};
const packageDefinition = protoLoader.loadSync('tapchannelrpc/tapchannel.proto', loaderOptions);
const tapchannelrpc = grpc.loadPackageDefinition(packageDefinition).tapchannelrpc;
process.env.GRPC_SSL_CIPHER_SUITES = 'HIGH+ECDSA';
const tlsCert = fs.readFileSync(TLS_PATH);
const sslCreds = grpc.credentials.createSsl(tlsCert);
const macaroon = fs.readFileSync(MACAROON_PATH).toString('hex');
const macaroonCreds = grpc.credentials.createFromMetadataGenerator(function(args, callback) {
  let metadata = new grpc.Metadata();
  metadata.add('macaroon', macaroon);
  callback(null, metadata);
});
let creds = grpc.credentials.combineChannelCredentials(sslCreds, macaroonCreds);
let client = new tapchannelrpc.TaprootAssetChannels(GRPC_HOST, creds);
let request = {
  asset_id: <bytes>,
  asset_amount: <uint64>,
  peer_pubkey: <bytes>,
  invoice_request: <Invoice>,
  hodl_invoice: <HodlInvoice>,
  group_key: <bytes>,
};
client.addInvoice(request, function(err, response) {
  console.log(response);
});
// Console output:
//  {
//    "accepted_buy_quote": <PeerAcceptedBuyQuote>,
//    "invoice_result": <AddInvoiceResponse>,
//  }

Python

import codecs, grpc, os
# Generate the following 2 modules by compiling the tapchannelrpc/tapchannel.proto with the grpcio-tools.
# See https://github.com/lightningnetwork/lnd/blob/master/docs/grpc/python.md for instructions.
import tapchannel_pb2 as tapchannelrpc, tapchannel_pb2_grpc as tapchannelstub

GRPC_HOST = 'localhost:10029'
MACAROON_PATH = 'TAPROOT-ASSETS_DIR/regtest/taproot-assets.macaroon'
TLS_PATH = 'TAPROOT-ASSETS_DIR/tls.cert'

# create macaroon credentials
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
def metadata_callback(context, callback):
  callback([('macaroon', macaroon)], None)
auth_creds = grpc.metadata_call_credentials(metadata_callback)
# create SSL credentials
os.environ['GRPC_SSL_CIPHER_SUITES'] = 'HIGH+ECDSA'
cert = open(TLS_PATH, 'rb').read()
ssl_creds = grpc.ssl_channel_credentials(cert)
# combine macaroon and SSL credentials
combined_creds = grpc.composite_channel_credentials(ssl_creds, auth_creds)
# make the request
channel = grpc.secure_channel(GRPC_HOST, combined_creds)
stub = tapchannelstub.TaprootAssetChannelsStub(channel)
request = tapchannelrpc.AddInvoiceRequest(
  asset_id=<bytes>,
  asset_amount=<uint64>,
  peer_pubkey=<bytes>,
  invoice_request=<Invoice>,
  hodl_invoice=<HodlInvoice>,
  group_key=<bytes>,
)
response = stub.AddInvoice(request)
print(response)
# {
#    "accepted_buy_quote": <PeerAcceptedBuyQuote>,
#    "invoice_result": <AddInvoiceResponse>,
# }

REST

Javascript

const fs = require('fs');
const request = require('request');

const REST_HOST = 'localhost:8089'
const MACAROON_PATH = 'TAPROOT-ASSETS_DIR/regtest/taproot-assets.macaroon'

let requestBody = {
  asset_id: <string>, // <bytes> (base64 encoded)
  asset_amount: <string>, // <uint64> 
  peer_pubkey: <string>, // <bytes> (base64 encoded)
  invoice_request: <object>, // <Invoice> 
  hodl_invoice: <object>, // <HodlInvoice> 
  group_key: <string>, // <bytes> (base64 encoded)
};
let options = {
  url: `https://${REST_HOST}/v1/taproot-assets/channels/invoice`,
  // Work-around for self-signed certificates.
  rejectUnauthorized: false,
  json: true,
  headers: {
    'Grpc-Metadata-macaroon': fs.readFileSync(MACAROON_PATH).toString('hex'),
  },
  form: JSON.stringify(requestBody),
}
request.post(options, function(error, response, body) {
  console.log(body);
});
// Console output:
//  {
//    "accepted_buy_quote": <object>, // <PeerAcceptedBuyQuote> 
//    "invoice_result": <object>, // <AddInvoiceResponse> 
//  }

Python

import base64, codecs, json, requests

REST_HOST = 'localhost:8089'
MACAROON_PATH = 'TAPROOT-ASSETS_DIR/regtest/taproot-assets.macaroon'
TLS_PATH = 'TAPROOT-ASSETS_DIR/tls.cert'

url = f'https://{REST_HOST}/v1/taproot-assets/channels/invoice'
macaroon = codecs.encode(open(MACAROON_PATH, 'rb').read(), 'hex')
headers = {'Grpc-Metadata-macaroon': macaroon}
data = {
  'asset_id': base64.b64encode(<bytes>),
  'asset_amount': <uint64>,
  'peer_pubkey': base64.b64encode(<bytes>),
  'invoice_request': <Invoice>,
  'hodl_invoice': <HodlInvoice>,
  'group_key': base64.b64encode(<bytes>),
}
r = requests.post(url, headers=headers, data=json.dumps(data), verify=TLS_PATH)
print(r.json())
# {
#    "accepted_buy_quote": <PeerAcceptedBuyQuote>,
#    "invoice_result": <AddInvoiceResponse>,
# }

Shell

$ litcli ln addinvoice --help

NAME:
   litcli ln addinvoice - Add a new invoice to receive Taproot Assets.

USAGE:
   litcli ln addinvoice [command options] [--asset_id=X | --group_key=X] --asset_amount=Y [--rfq_peer_pubkey=Z] 

CATEGORY:
   Invoices

DESCRIPTION:
   
  Add a new invoice, expressing intent for a future payment, received in
  Taproot Assets.
  

OPTIONS:
   --memo value                     a description of the payment to attach along with the invoice (default="")
   --preimage value                 the hex-encoded preimage (32 byte) which will allow settling an incoming HTLC payable to this preimage. If not set, a random preimage will be created.
   --amt value                      the amt of satoshis in this invoice (default: 0)
   --amt_msat value                 the amt of millisatoshis in this invoice (default: 0)
   --description_hash value         SHA-256 hash of the description of the payment. Used if the purpose of payment cannot naturally fit within the memo. If provided this will be used instead of the description(memo) field in the encoded invoice.
   --fallback_addr value            fallback on-chain address that can be used in case the lightning payment fails
   --expiry value                   the invoice's expiry time in seconds. If not specified, an expiry of 86400 seconds (24 hours) is implied. (default: 0)
   --cltv_expiry_delta value        The minimum CLTV delta to use for the final hop. If this is set to 0, the default value is used. The default value for cltv_expiry_delta is configured by the 'bitcoin.timelockdelta' option. (default: 0)
   --private                        encode routing hints in the invoice with private channels in order to assist the payer in reaching you. If amt and amt_msat are zero, a large number of hints with these channels can be included, which might not be desirable.
   --amp                            creates an AMP invoice. If true, preimage should not be set.
   --blind                          creates an invoice that contains blinded paths. Note that invoices with blinded paths will be signed using a random ephemeral key so as not to reveal the real node ID of this node.
   --min_real_blinded_hops --blind  The minimum number of real hops to use in a blinded path. This option will only be used if --blind has also been set. (default: 0)
   --num_blinded_hops --blind       The number of hops to use for each blinded path included in the invoice. This option will only be used if --blind has also been set. Dummy hops will be used to pad paths shorter than this. (default: 0)
   --max_blinded_paths --blind      The maximum number of blinded paths to add to an invoice. This option will only be used if --blind has also been set. (default: 0)
   --blinded_path_omit_node value   The pub key (in hex) of a node not to use on a blinded path. The flag may be specified multiple times.
   --asset_id value                 the asset ID of the asset to receive; cannot be used at the same time as --group_key
   --group_key value                the group key of the asset to receive; cannot be used at the same time as --asset_id
   --asset_amount value             the amount of assets to receive (default: 0)
   --rfq_peer_pubkey value          (optional) the public key of the peer to ask for a quote when converting from assets to sats for the invoice; must be set if there are multiple channels with the same asset ID present
   

Messages

tapchannelrpc.AddInvoiceRequest

Source: tapchannelrpc/tapchannel.proto

Field	gRPC Type	REST Type	REST Placement
asset_id The asset ID to use for the invoice. Mutually exclusive to group_key.	bytes	string	body
asset_amount The asset amount to receive.	uint64	string	body
peer_pubkey The node identity public key of the peer to ask for a quote for receiving assets and converting them from satoshis. When specified only quotes with this peer will be negotiated.	bytes	string	body
invoice_request The full lnd invoice request to send. All fields behave the same way as they do for lnd's lnrpc.AddInvoice RPC method (see the API docs at https://lightning.engineering/api-docs/api/lnd/lightning/add-invoice for more details). Only one of the asset_amount/value/value_msat may be set to dictate the value of the invoice. When using asset_amount, the value/value_msat fields will be overwritten by the satoshi (or milli-satoshi) equivalent of the asset amount, after negotiating a quote with a peer that supports the given asset ID. If the value/value_msat are used, we still receive assets, but they will exactly evaluate to the defined amount in sats/msats.	Invoice	object	body
hodl_invoice If set, then this will make the invoice created a hodl invoice, which won't be settled automatically. Instead, users will need to use the invoicesrpc.SettleInvoice call to manually settle the invoice.	HodlInvoice	object	body
group_key The group key which dictates which assets may be accepted for this invoice. If set, any asset that belongs to this group may be accepted to settle this invoice. Mutually exclusive to asset_id.	bytes	string	body

tapchannelrpc.AddInvoiceResponse

Source: tapchannelrpc/tapchannel.proto

Field	gRPC Type	REST Type
accepted_buy_quote The quote for the purchase of assets that was accepted by the peer.	PeerAcceptedBuyQuote	object
invoice_result The result of the invoice creation.	AddInvoiceResponse	object

Nested Messages

rfqrpc.FixedPoint

Field	gRPC Type	REST Type
coefficient The coefficient is the fractional value scaled-up as an integer. This integer is represented as a string as it may be too large to fit in a uint64.	string	string
scale The scale is the component that determines how many decimal places the coefficient should be divided by to obtain the fractional value.	uint32	integer

rfqrpc.PeerAcceptedBuyQuote

Field	gRPC Type	REST Type
peer Quote counterparty peer.	string	string
id The unique identifier of the quote request.	bytes	string
scid The short channel ID of the channel over which the payment for the quote should be made.	uint64	string
asset_max_amount The maximum exchange amount denoted in the subject asset. This includes the user-configured maximum routing fees, so the actual payment amount will be less than this. This just defines the maximum volume that the edge node has accepted to divest with the given rate.	uint64	string
ask_asset_rate ask_asset_rate is the asset to BTC conversion rate represented as a fixed-point number.	FixedPoint	object
expiry The unix timestamp in seconds after which the quote is no longer valid.	uint64	string
min_transportable_units The smallest amount of asset units that can be transported within a single HTLC over the Lightning Network with the given rate. This is the asset unit equivalent of 354 satoshis, which is the minimum amount for an HTLC to be above the dust limit.	uint64	string

tapchannelrpc.HodlInvoice

Field	gRPC Type	REST Type
payment_hash	bytes	string