kkamkou/gelfjs

/**
 * Licensed under the MIT License.
 *
 * @author  Kanstantsin Kamkou (2ka.by)
 * @link    https://github.com/kkamkou/gelfjs
 * @license https://opensource.org/licenses/MIT
 */

import {
  forOwn, isFinite, isInteger, isPlainObject, isUndefined, merge, toString, truncate
} from "lodash";

import * as GelfSpec from "./GelfSpec";
import GfCollection from "./GfCollection";
import JsonConvertible from "./JsonConvertible";

class GfMessage implements JsonConvertible {
  private readonly obj: Required<GelfSpec.Message> = {
    host: 'unknown',
    short_message: 'No message', // eslint-disable-line
    timestamp: Math.floor(Date.now() / 1000),
    version: "1.1"
  };

  constructor(private readonly fdCollection?: GfCollection) {}

  toJSON(): Partial<GelfSpec.Message> {
    return merge({}, this.obj, ...(this.fdCollection?.toJSON() || []));
  }

  toString(): string {
    const obj = this.toJSON(),
      result: {[idx: string]: string | number} = {};

    if (!isUndefined(obj.id)) {
      throw Error(`The "id" field isn't allowed by the specification`);
    }

    // some fields should be copied without change
    ['full_message', 'short_message', 'level', 'host', 'timestamp'].forEach(key => {
      if (isUndefined(obj[key]) || (['timestamp', 'level'].includes(key) && !isInteger(obj[key]))) {
        return;
      }
      result[key] = obj[key] as string | number;
      delete obj[key];
    });

    // recursion function for key-value aggregation
    const recursion = function (input: object, prefix?: string): void {
      forOwn(input, (value, key) => {
        if (GelfSpec.FIELD_NAME_REGEXP.test(key)) { // #!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
          throw Error(`Key format is not valid (${key})`);
        }
        if (Array.isArray(value)) {
          throw Error('Array extraction will spoil your elasticsearch index');
        }
        if (isPlainObject(value)) {
          return recursion(value, prefix ? [prefix, key].join('_') : key);
        }
        result[(prefix ? [null, prefix, key] : [null, key]).join('_')] = isFinite(value)
          ? value
          : truncate(toString(value), {length: GelfSpec.FIELD_VALUE_MAX_LENGTH});
      });
    };

    recursion(obj);

    return JSON.stringify(result);
  }
}

export = GfMessage;