BOLT07

Utilities for working with Lightning Network BOLT 07

Methods

• chanFormat - convert number or raw bytes format channel id to standard format
• chanNumber - convert standard, raw bytes format channel id to number format
• decodeChanId - decode block height and index components of a channel id
• encodeChanId - encode block height and index components into a channel id
• hopsFromChannels - derive policy hops from a list of channels
• rawChanId - convert numeric or standard channel id into a raw wire form
• routeFromChannels - derive a route from a sequence of channels
• routeFromHops - derive a route from a sequence of policy hops

Examples

Sample code for working with bolt07 utility functions:

Formats

• Channel: x delimited format designed to be readable.
• Id: The raw channel id format specified by bolt07.
• Number: Interpreting the raw channel id format as a uint64.

Chan Format

const {chanFormat} = require('bolt07');

const id = '15fbe70000260000';
const number = '1584113681139367936';

try {
  const fromNumber = chanFormat({number}).channel;
  // fromNumber === '1440743x38x0'
} catch (err) {
  // valid channel, no error
}

try {
  const fromId = chanFormat({id}).channel;
  // fromId === '1440743x38x0'
} catch (err) {
  // valid id, no error
}

Chan Number

const {chanNumber} = require('bolt07');

const channel = '1440743x38x0';
const id = '15fbe70000260000';

try {
  const fromChannel = chanNumber({channel}).number;
  // fromChannel === '1584113681139367936'
} catch (err) {
  // valid channel, no error
}

try {
  const fromId = chanNumber({id}).number;
  // fromId === '1584113681139367936'
} catch (err) {
  // valid id, no error
}

decodeChanId

Returns components of a channel id or channel number.

const {decodeChanId} = require('bolt07');

const channel = '1440743x38x0';
const id = '15fbe70000260000';
const number = '1584113681139367936';

try {
  const fromChannel = decodeChanId({channel});
  // fromChannel.block_height === 1440743
  // fromChannel.block_index === 38
  // fromChannel.output_index === 0
} catch (err) {
  // valid channel, no error
}

try {
  const fromId = decodeChanId({id});
  // fromId.block_height === 1440743
  // fromId.block_index === 38
  // fromId.output_index === 0
} catch (err) {
  // valid id, no error
}

try {
  const fromNumber = decodeChanId({channel});
  // fromNumber.block_height === 1440743
  // fromNumber.block_index === 38
  // fromNumber.output_index === 0
} catch (err) {
  // valid number, no error
}

encodeChanId

Returns channel id when components are specified

const {encodeChanId} = require('bolt07');

try {
  const encoded = encodeChanId({
    block_height: 1440743,
    block_index: 38,
    output_index: 0,
  });

  // encoded.channel === '1440743x38x0'
  // encoded.id === '15fbe70000260000'
  // encoded.number === '1584113681139367936'
} catch (err) {
  // valid components, no error
}

Raw Chan Id

Returns a raw channel id in numeric format.

const {rawChanId} = require('bolt07');

const channel = '1440743x38x0';
const number = '1584113681139367936';

try {
  const idFromNumber = rawChanId({number}).id;
  // idFromNumber === '15fbe70000260000'
} catch (err) {
  // valid number, no error
}

try {
  const idFromChannel = rawChanId({channel}).id;
  // idFromChannel === '15fbe70000260000'
} catch (err) {
  // valid channel, no error
}

Methods

chanFormat

Get channel components formatted string

{
  [id]: <Raw Channel Id String>
  [number]: <Number Format Channel Id String>
}

@throws
<Error>

@returns
{
  channel: <Components Channel Format String>
}

chanNumber

Channel id in numeric format

{
  [channel]: <Channel Components String>
  [id]: <Channel Id Hex String>
}

@throws
<ExpectedChannelIdOrComponentsToConvertToNumber Error>

@returns
{
  number: <Channel Id Number String>
}

decodeChanId

Decode a short channel id into components

{
  [channel]: <Channel Components String>
  [id]: <Channel Id Hex String>
  [number]: <Channel Id Number Format String>
}

@throws
<ExpectedShortChannelIdToDecode Error>
<UnexpectedErrorDecodingChannelIdNumber Error>
<UnexpectedLengthOfShortChannelId Error>

@returns
{
  block_height: <Channel Funding Transaction Inclusion Block Height Number>
  block_index: <Channel Funding Transaction Inclusion Block Position Number>
  output_index: <Channel Funding Transaction Output Index Number>
}

encodeChanId

Encode a short channel id from components

{
  block_height: <Channel Funding Transaction Inclusion Block Height Number>
  block_index: <Channel Funding Transaction Inclusion Block Position Number>
  output_index: <Channel Funding Transaction Output Index Number>
}

@throws
<ExpectedBlockHeightForChannelId Error>
<ExpectedBlockIndexForChannelId Error>
<ExpectedTransactionOutputIndexForChannelId Error>

@returns
{
  channel: <Channel Components Format String>
  id: <Channel Id Hex String>
  number: <Channel Number String>
}

rawChanId

Raw channel id

{
  [channel]: <Channel Components String>
  [number]: <Channel Id In Number Format String>
}

@throws
<Error>

@returns
{
  id: <Raw Channel Id Hex String>
}

routeFromChannels

Get a route from a sequence of channels

Either next hop destination in channels or final destination is required

{
  channels: [{
    capacity: <Maximum Tokens Number>
    [destination]: <Next Node Public Key Hex String>
    id: <Standard Format Channel Id String>
    policies: [{
      base_fee_mtokens: <Base Fee Millitokens String>
      cltv_delta: <Locktime Delta Number>
      fee_rate: <Fees Charged in Millitokens Per Million Number>
      is_disabled: <Channel Is Disabled Bool>
      max_htlc_mtokens: <Maximum HTLC Millitokens Value String>
      min_htlc_mtokens: <Minimum HTLC Millitokens Value String>
      public_key: <Node Public Key String>
    }]
  }]
  [cltv_delta]: <Final CLTV Delta Number>
  [destination]: <Destination Public Key Hex String>
  height: <Current Block Height Number>
  [messages]: [{
    type: <Message Type Number String>
    value: <Message Raw Value Hex Encoded String>
  }]
  mtokens: <Millitokens To Send String>
  [payment]: <Payment Identification Value Hex String>
  [total_mtokens]: <Sum of Shards Millitokens String>
}

@throws
<Error>

@returns
{
  route: {
    fee: <Total Fee Tokens To Pay Number>
    fee_mtokens: <Total Fee Millitokens To Pay String>
    hops: [{
      channel: <Standard Format Channel Id String>
      channel_capacity: <Channel Capacity Tokens Number>
      fee: <Fee Number>
      fee_mtokens: <Fee Millitokens String>
      forward: <Forward Tokens Number>
      forward_mtokens: <Forward Millitokens String>
      [public_key]: <Public Key Hex String>
      timeout: <Timeout Block Height Number>
    }]
    [messages]: [{
      type: <Message Type Number String>
      value: <Message Raw Value Hex Encoded String>
    }]
    mtokens: <Total Fee-Inclusive Millitokens String>
    [payment]: <Payment Identification Value Hex String>
    timeout: <Timeout Block Height Number>
    tokens: <Total Fee-Inclusive Tokens Number>
    [total_mtokens]: <Sum of Shards Millitokens String>
  }
}

routeFromHops

Given hops to a destination, construct a payable route

{
  [cltv_delta]: <Final Cltv Delta Number>
  height: <Current Block Height Number>
  hops: [{
    base_fee_mtokens: <Base Fee Millitokens String>
    channel: <Standard Format Channel Id String>
    [channel_capacity]: <Channel Capacity Tokens Number>
    cltv_delta: <CLTV Delta Number>
    fee_rate: <Fee Rate In Millitokens Per Million Number>
    public_key: <Next Hop Public Key Hex String>
  }]
  initial_cltv: <Initial CLTV Delta Number>
  [messages]: [{
    type: <Message Type Number String>
    value: <Message Raw Value Hex Encoded String>
  }]
  mtokens: <Millitokens To Send String>
  [payment]: <Payment Identification Value Hex String>
  [total_mtokens]: <Total Millitokens For Sharded Payments String>
}

@throws
<Error>

@returns
{
  fee: <Route Fee Tokens Number>
  fee_mtokens: <Route Fee Millitokens String>
  hops: [{
    channel: <Standard Format Channel Id String>
    channel_capacity: <Channel Capacity Tokens Number>
    fee: <Fee Number>
    fee_mtokens: <Fee Millitokens String>
    forward: <Forward Tokens Number>
    forward_mtokens: <Forward Millitokens String>
    [public_key]: <Public Key Hex String>
    timeout: <Timeout Block Height Number>
  }]
  [messages]: [{
    type: <Message Type Number String>
    value: <Message Raw Value Hex Encoded String>
  }]
  mtokens: <Total Fee-Inclusive Millitokens String>
  [payment]: <Payment Identification Value Hex String>
  timeout: <Timeout Block Height Number>
  tokens: <Total Fee-Inclusive Tokens Number>
  [total_mtokens]: <Sharded Payments Total Millitokens String>
}