ucenter-client/lib/utils/string.js

A full-featured UCenter client for Node.js.

const qs = require('querystring');
const iconv = require('iconv-lite');
const convert = require('xml-js');

module.exports = function(config) {
  return {
    parseQueryString,
    urlEncode,
    urlDecode,
    serializeXml,
    unserializeXml,
  };

  /**
   * parse Query String
   * @param {*} query 
   * @returns {object}
   */
  function parseQueryString(query) {
    if (config.UC_CHARSET === 'utf8') return qs.parse(query);
    if (/^[a-zA-Z0-9%=&\-_.+~]*$/.test(query) === false) return {}; // 不符合规范

    // gbk 的情况:
    const result = {};
    query.split('&').forEach(v => {
      const tmp = v.split('=');
      result[tmp[0]] = urlDecode(tmp[1], 'gbk');
    });
    return result;
  }

  /**
   * URL Encode
   * @param {string} str PlainText for UrlEncode
   * @param {string} charset Target charset (utf8/gbk)
   * @returns {string}
   */
  function urlEncode(str, charset) {
    charset = charset || config.UC_CHARSET;
    if (charset === 'utf8') return encodeURIComponent(str);
    const rs = [];
    const encodeBuf = iconv.encode(str, charset);
    encodeBuf.forEach(v => {
      rs.push('%' + '0'.concat(parseInt(v).toString(16)).slice(-2));
    });
    return rs.join('');
  }

  /**
   * URL Decode
   * @param {string} str UrlEncoded String
   * @param {string} charset Source charset (utf8/gbk)
   * @return {string}
   */
  function urlDecode(str, charset) {
    charset = charset || config.UC_CHARSET;
    if (charset === 'utf8') return decodeURIComponent(str);

    const strLen = str.length;
    const buf = Buffer.alloc(strLen);
    for (let i = 0, j = 0; i < strLen; j++) {
      if (str[i] !== '%') {
        buf[j] = str.charCodeAt(i);
        i++;
      } else {
        buf[j] = parseInt(str.substring(i + 1, 2), 16);
        i += 3;
      }
    }
    return iconv.decode(buf, charset);
  }

  /**
   * serialize Xml (JS Object 2 XML)
   * @param {Object|Array} arr 
   * @param {boolean} htmlon Use CDATA to save string
   * @param {number} level default: 1
   * @returns {Buffer}
   */
  function serializeXml(arr, htmlon, level) {
    htmlon = !!htmlon;
    level = level ? level : 1;

    let s = level == 1 ? '<?xml version="1.0" encoding="ISO-8859-1"?>\r\n<root>\r\n' : '';
    const space = '\t'.repeat(level);
    for (let k in arr) {
      s += space + `<item id="${k}">`;
      if (Array.isArray(arr[k]) || (arr[k] !== null && typeof arr[k] === 'object')) {
        s += '\r\n' + serializeXml(arr[k], htmlon, level + 1) + space;
      } else {
        s += (htmlon ? '<![CDATA[' : '') + arr[k] + (htmlon ? ']]>' : '');
      }
      s += '</item>\r\n';
    }
    s = s.replace(/([\x01-\x08\x0b-\x0c\x0e-\x1f])+/g, ' ');
    if (level !== 1) return s;
    s += '</root>';

    return config.UC_CHARSET === 'utf8' ? Buffer.from(s) : iconv.encode(s, config.UC_CHARSET);
  }

  /**
   * unserialize Xml (XML 2 JS Object)
   * @param {string} xml UTF-8 XML
   * @returns {object}
   * ONLY FOR unserialize UC XML
   */
  function unserializeXml(xml) {
    return analyzeNode(convert.xml2js(xml, {
      compact: true
    }));
  }

  function analyzeNode(node) {
    if (node.root) {
      return analyzeNode(node.root);
    } else if (node.item) {
      if (Array.isArray(node.item)) {
        if (/^\d+$/g.test(node.item[0]._attributes.id)) {
          return node.item.map(v => {
            return analyzeNode(v);
          });
        } else {
          const data = {};
          node.item.forEach(v => {
            data[v._attributes.id] = analyzeNode(v);
          });
          return data;
        }
      } else {
        const data = {};
        data[node.item._attributes.id] = analyzeNode(node.item);
        return data;
      }
    } else if (node._cdata) {
      return node._cdata;
    } else if (node._text) {
      return node._text;
    } else {
      return null;
    }
  }
};