ilp-plugin-payment-channel-framework/src/model/custom-rpc.js

ILP virtual ledger plugin for directly transacting connectors

const Btp = require('btp-packet')

module.exports = class CustomRpc {
  constructor ({ btpRpc }) {
    this._btpRpc = btpRpc
    this._methods = {}
  }

  // prefix argument is included for backwards-compatibility
  async call (method, prefix, args) {
    const response = await this._btpRpc.message(
      [{
        protocolName: method,
        contentType: Btp.MIME_APPLICATION_JSON,
        data: Buffer.from(JSON.stringify(args))
      }]
    )

    // TODO: handle errors
    const protocolResponse = response.protocolData.filter((x) => x.protocolName === method)
    if (protocolResponse.length === 0) {
      // TODO: should it throw an error if there is no resopnse for the sub-protocol?
      return {}
    } else if (protocolResponse.length === 1) {
      return JSON.parse(Buffer.from(protocolResponse[0].data, 'utf8'))
    } else {
      throw new Error(`Ambigious response for ${method} request with data ${args}.` +
        ` Response is: ${protocolResponse}`)
    }
  }

  addMethod (protocol, method) {
    this._methods[protocol] = method
  }

  async handleProtocols (custom) {
    const responseProtocolData = []

    for (const protocol of Object.keys(custom)) {
      // TODO: define custom error code for unsupported side protocol
      if (!this._methods[protocol]) throw new Error('Unrecognized side protocol: ' + protocol)
      const response = await this._methods[protocol].call(this, custom[protocol])

      responseProtocolData.push({
        protocolName: protocol,
        contentType: Btp.MIME_APPLICATION_JSON,
        data: Buffer.from(JSON.stringify(response))
      })
    }
    return responseProtocolData
  }
}