index.js

/* eslint-disable no-magic-numbers */

/**
 * Decentralized Record of Value
 * DRV200: Non-Fungible Record
 */

const { capitalizeSlug } = require('cryptography-utilities');

const isValid = require('./validations');

module.exports = ({ drv, peers, serviceEvents }) => {
  /*
   * Import DRV100 for its transfer logic.
   */

  const DRVContract = require('drv100')({
    drv,
    peers,
    serviceEvents
  });

  /**
   * Define a contract that: Accepts an encoded string as
   * the DRV value instead of a number, creates a file,
   * populates it with the encoded content as formatted JSON,
   * then generates a user-friendly magnet link for distributed
   * access.
   */

  const Contract = async ({
    senderAddress,
    recipientAddress,
    usdValue,
    drvValue = 'data:drv/text;text,Hello world!'
  }) => {
    const encoding = drvValue.substring(9, 13) === 'text' ? 'text' : 'json';
    const drvContent = drvValue.split(`;${encoding}`);
    const contentType = drvContent[0].replace(/data:drv\//, '');

    const content = encoding === 'text'
      ? drvValue.split(/data\:drv\/.*;text,/)[1]
      : drvValue.split(/data\:drv\/.*;json,/)[1];

    if (
      drvValue.substring(0, 9) !== 'data:drv/' ||
      !isValid(JSON.parse(content))
    ) return false;

    if (encoding === 'text') {
      /**
       * Save text records directly on-chain
       */

      // eslint-disable-next-line no-param-reassign
      drvValue = `::magnet:?xt=urn:drv/text&dn=${encodeURIComponent(content)}&ts=${Date.now()}`;
    } else {

      /**
       * Cache JSON records in DSS
       */

      const file = await drv.onHttpPost(
        {
          method: 'store',
          body: {
            content
          },
          route: {
            path: 'fs'
          },
          path: 'store'
        },
        {
          status: code => ({
            end: () => ({
              error: {
                code,
                message: '<DRV200> Contract error (POST).'
              }
            })
          }),
          send: body => ({
            status: 200,
            success: true,
            data: body
          })
        }
      );

      // TODO: Flatten nested `onHttpPost` responses
      const fileName = file.data.data.split('/')[1];

      // eslint-disable-next-line no-param-reassign
      drvValue = `::magnet:?xt=urn:drv/${contentType}:${fileName}&dn=${capitalizeSlug(contentType)}`;
    }

    /**
     * Invoke the modified DRV100 with the encoded record.
     */

    return DRVContract({
      senderAddress,
      recipientAddress,
      contract: 'DRV200',
      usdValue,
      drvValue,
      isDrv: true
    });
  };

  return Contract;
};