Source: btc/uri.js

/**
 * uri.js - bitcoin uri parsing for bcoin
 * Copyright (c) 2014-2017, Christopher Jeffrey (MIT License).
 * https://github.com/bcoin-org/bcoin
 */

'use strict';

const assert = require('bsert');
const Address = require('../primitives/address');
const Amount = require('./amount');
const {inspectSymbol} = require('../utils');

/**
 * URI
 * Represents a bitcoin URI.
 * @alias module:btc.URI
 * @property {Address} address
 * @property {Amount} amount
 * @property {String|null} label
 * @property {String|null} message
 * @property {String|null} request
 */

class URI {
  /**
   * Create a bitcoin URI.
   * @alias module:btc.URI
   * @constructor
   * @param {Object|String} options
   */

  constructor(options) {
    this.address = new Address();
    this.amount = -1;
    this.label = null;
    this.message = null;
    this.request = null;

    if (options)
      this.fromOptions(options);
  }

  /**
   * Inject properties from options object.
   * @private
   * @param {Object|String} options
   * @returns {URI}
   */

  fromOptions(options) {
    if (typeof options === 'string')
      return this.fromString(options);

    if (options.address)
      this.address.fromOptions(options.address);

    if (options.amount != null) {
      assert(Number.isSafeInteger(options.amount) && options.amount >= 0,
        'Amount must be a uint64.');
      this.amount = options.amount;
    }

    if (options.label) {
      assert(typeof options.label === 'string', 'Label must be a string.');
      this.label = options.label;
    }

    if (options.message) {
      assert(typeof options.message === 'string', 'Message must be a string.');
      this.message = options.message;
    }

    if (options.request) {
      assert(typeof options.request === 'string', 'Request must be a string.');
      this.request = options.request;
    }

    return this;
  }

  /**
   * Instantiate URI from options.
   * @param {Object|String} options
   * @returns {URI}
   */

  static fromOptions(options) {
    return new this().fromOptions(options);
  }

  /**
   * Parse and inject properties from string.
   * @private
   * @param {String} str
   * @param {Network?} network
   * @returns {URI}
   */

  fromString(str, network) {
    assert(typeof str === 'string');
    assert(str.length > 8, 'Not a bitcoin URI.');

    const prefix = str.substring(0, 8);

    assert(prefix === 'bitcoin:', 'Not a bitcoin URI.');

    str = str.substring(8);

    const index = str.indexOf('?');

    let addr, qs;
    if (index === -1) {
      addr = str;
    } else {
      addr = str.substring(0, index);
      qs = str.substring(index + 1);
    }

    this.address.fromString(addr, network);

    if (!qs)
      return this;

    const query = parsePairs(qs);

    if (query.amount) {
      assert(query.amount.length > 0, 'Value is empty.');
      assert(query.amount[0] !== '-', 'Value is negative.');
      this.amount = Amount.value(query.amount);
    }

    if (query.label)
      this.label = query.label;

    if (query.message)
      this.message = query.message;

    if (query.r)
      this.request = query.r;

    return this;
  }

  /**
   * Instantiate uri from string.
   * @param {String} str
   * @param {Network?} network
   * @returns {URI}
   */

  static fromString(str, network) {
    return new this().fromString(str, network);
  }

  /**
   * Serialize uri to a string.
   * @returns {String}
   */

  toString() {
    let str = 'bitcoin:';

    str += this.address.toString();

    const query = [];

    if (this.amount !== -1)
      query.push(`amount=${Amount.btc(this.amount)}`);

    if (this.label)
      query.push(`label=${escape(this.label)}`);

    if (this.message)
      query.push(`message=${escape(this.message)}`);

    if (this.request)
      query.push(`r=${escape(this.request)}`);

    if (query.length > 0)
      str += '?' + query.join('&');

    return str;
  }

  /**
   * Inspect bitcoin uri.
   * @returns {String}
   */

  [inspectSymbol]() {
    return `<URI: ${this.toString()}>`;
  }
}

/*
 * Helpers
 */

class BitcoinQuery {
  constructor() {
    this.amount = null;
    this.label = null;
    this.message = null;
    this.r = null;
  }
}

function parsePairs(str) {
  const parts = str.split('&');
  const data = new BitcoinQuery();

  let size = 0;

  for (const pair of parts) {
    const index = pair.indexOf('=');
    let key, value;

    if (index === -1) {
      key = pair;
      value = '';
    } else {
      key = pair.substring(0, index);
      value = pair.substring(index + 1);
    }

    if (key.length === 0) {
      assert(value.length === 0, 'Empty key in querystring.');
      continue;
    }

    assert(size < 4, 'Too many keys in querystring.');

    switch (key) {
      case 'amount':
        assert(data.amount == null, 'Duplicate key in querystring (amount).');
        data.amount = unescape(value);
        break;
      case 'label':
        assert(data.label == null, 'Duplicate key in querystring (label).');
        data.label = unescape(value);
        break;
      case 'message':
        assert(data.message == null, 'Duplicate key in querystring (message).');
        data.message = unescape(value);
        break;
      case 'r':
        assert(data.r == null, 'Duplicate key in querystring (r).');
        data.r = unescape(value);
        break;
      default:
        assert(false, `Unknown querystring key: ${value}.`);
        break;
    }

    size += 1;
  }

  return data;
}

function unescape(str) {
  try {
    str = decodeURIComponent(str);
    str = str.replace(/\+/g, ' ');
  } catch (e) {
    throw new Error('Malformed URI.');
  }

  if (str.indexOf('\0') !== -1)
    throw new Error('Malformed URI.');

  return str;
}

function escape(str) {
  str = encodeURIComponent(str);
  str = str.replace(/%20/g, '+');
  return str;
}

/*
 * Expose
 */

module.exports = URI;