n2/common

This module is home to interfaces and classes which are used throughout the other n2 modules. Most of the interfaces represent entities from RotMG, however some are used to represent data structures used by the classes in this module.

Install

npm install @n2/common

Use

There are three main "submodules" provided by the common modules.

• Http
• Logging
• Models

Http

The exported HttpClient class provides a basic promise-based way of making web requests. The http client will include standard request headers with any request, and will automatically unzip any gzipped responses.

const { HttpClient, Endpoints } = require('@n2/common');

// query parameters can be included in the request options.
const requestOptions = {
  query: { guid: 'example@email.com', password: '123456' }
};

HttpClient.get(Endpoints.CHAR_LIST, requestOptions).then((data) => {
  console.log('Fetched account info.');
  const accInfoXML = data.toString();
});

The http client will normally return the response as a Buffer object. A writable stream can optionally be provided as part of the requestOptions, and if one is provided, the response will be piped to the stream. In this case, the promise will be resolved with undefined instead of the data buffer.

This means that

const { HttpClient, Endpoints } = require('@n2/common');
const fs = require('fs');

const writeStream = fs.createWriteStream('./ground-types.json');

HttpClient.get(Endpoints.STATIC_DRIPS + '/current/json/GroundTypes.json').then((data) => {
  writeStream.write(data);
  writeStream.end();
});

is the same as

const { HttpClient, Endpoints } = require('@n2/common');
const fs = require('fs');

const writeStream = fs.createWriteStream('./ground-types.json');

HttpClient.get(Endpoints.STATIC_DRIPS + '/current/json/GroundTypes.json', {
  stream: writeStream
});

Logging

The Logger class provides a logging mechanism in the form of a logger chain. Custom loggers can be added to the chain as long as they adhere to the LogProvider interface.

In TypeScript, custom loggers can simply inherit from LogProvider, however in JavaScript care will have to be taken to ensure the custom loggers have the required methods.

import { LogProvider, LogLevel } from '@n2/common';

class MyCustomLogger implements LogProvider {

  // inherited method from LogProvider.
  log(sender: string, message: string, level: LogLevel): void {
    console.log(`[${sender}] ${message} (${LogLevel[level] || 'no level'})`);
  }
}

import { Logger, LogLevel } from '@n2/common';
import { MyCustomLogger } from './my-custom-logger';

Logger.addLogger(new MyCustomLogger());

Logger.log('Test', 'Hello, World!', LogLevel.Debug);
// [Test] Hello, World! (Debug)

More loggers can be added to the chain. Calls to Logger.log will call the log method of each logger in the chain in the order that they were added.

Logger.addLogger(new MyCustomLogger());
Logger.addLogger(new MyCustomLogger());
Logger.addLogger(new MyCustomLogger());

Logger.log('Test', 'Hello 3 times.', LogLevel.Message);
// [Test] Hello 3 times. (Message)
// [Test] Hello 3 times. (Message)
// [Test] Hello 3 times. (Message)

Models

The common module exports a handful of interfaces and enums which represent data structures and values used throughout clientless applications for RotMG. Some notable examples include the PlayerData interface which represents a player entity, and the Endpoints enum which contains commonly used HTTP endpoints.