bencevans/node-influx

import { Raw } from "./ds";

const reEscape = /[-|\\{()[\]^$+*?.]/g;

/**
 * The Escaper escapes the special characters in the provided list
 * with backslashes. Much of the code here is inspired by that in the
 * sqlstring packet found here: https://github.com/mysqljs/sqlstring
 *
 * Instances of the Escaper are derived from the documentation of escape
 * sequences found here: https://aka.ms/co1m4k
 *
 * sqlstring is made available under the following license:
 *
 *   Copyright (c) 2012 Felix Geisendörfer (felix@debuggable.com) and contributors
 *
 *   Permission is hereby granted, free of charge, to any person obtaining a copy
 *   of this software and associated documentation files (the "Software"), to deal
 *   in the Software without restriction, including without limitation the rights
 *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *   copies of the Software, and to permit persons to whom the Software is
 *   furnished to do so, subject to the following conditions:
 *
 *   The above copyright notice and this permission notice shall be included in
 *   all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *   THE SOFTWARE.
 *
 */
class Escaper {
  private _re: RegExp;

  constructor(
    chars: string[],
    private readonly wrap: string = "",
    private readonly escaper: string = "\\"
  ) {
    const patterns = chars.join("").replace(reEscape, "\\$&");
    this._re = new RegExp("[" + patterns + "]", "g");
  }

  /**
   * Escape replaces occurrences of special characters within the target
   * string with the necessary escape codes.
   */
  public escape(val: string): string {
    if ((val as any) instanceof Raw) {
      return (val as any).getValue();
    }

    this._re.lastIndex = 0;
    let chunkIndex = this._re.lastIndex;
    let escapedVal = "";

    let match;

    if (typeof val === "string") {
      val = val.replace(/\\'/, "\\\\'");
    }

    /* eslint-disable no-cond-assign */
    while ((match = this._re.exec(val))) {
      escapedVal +=
        val.slice(chunkIndex, match.index) + this.escaper + match[0];
      chunkIndex = this._re.lastIndex;
    }

    if (chunkIndex === 0) {
      return this.wrap + val + this.wrap;
    }

    if (chunkIndex < val.length) {
      return this.wrap + escapedVal + val.slice(chunkIndex) + this.wrap;
    }

    return this.wrap + escapedVal + this.wrap;
  }
}

const bindEsc = (e: Escaper): ((val: string) => string) => e.escape.bind(e);

/**
 * TagEscaper escapes tag keys, tag values, and field keys.
 * @type {Object}
 * @property {function(s: string): string } quoted Escapes and wraps quoted
 *     values, such as database names.
 * @property {function(s: string): string } stringLit Escapes and
 *     wraps string literals.
 * @property {function(s: string): string } measurement Escapes measurement
 *     names on the line protocol.
 * @property {function(s: string): string } tag Escapes tag keys, take values,
 *     and field keys on the line protocol.
 *
 * @example
 * console.log(escape.quoted('my_"db')); // => "my_\"db"
 * console.log(escape.stringLit('hello\'world')); // => 'hello\'world'
 *
 * console.log(escape.measurement('my measurement')); // => my\ measurement
 * console.log(escape.tag('my tag=')); // => my\ tag\=
 */
export const escape = {
  /**
   * Measurement escapes measurement names.
   */
  measurement: bindEsc(new Escaper([",", " "])),

  /**
   * Quoted escapes quoted values, such as database names.
   */
  quoted: bindEsc(new Escaper(['"', "\\\\"], '"')),

  /**
   * StringLitEscaper escapes single quotes in string literals.
   */
  stringLit: bindEsc(new Escaper(["'"], "'")),
  /**
   * TagEscaper escapes tag keys, tag values, and field keys.
   */
  tag: bindEsc(new Escaper([",", "=", " "])),
};