[Feature] Poll request

[luisaveiro]

Summary

The simplest way to get new information from the server is periodic polling. The application makes regular requests to the server, for example, once every 10 seconds. Polling is the simplest way of having a persistent connection with the server, that doesn’t use any specific protocol like WebSocket or Server-Sent Events.

A use case for polling would be OAuth 2.0 Device Authorization Grant (also known as Device Flow).

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Possible implementation

The HTTP Client provides a poll method that specifies the maximum number of time to send the request, the interval in milliseconds between requests, and an optional callback function to determine whether the client polling should be stopped based on the response, the request and the error instance.

Method signature

export default class HttpClient {
  /**
   * Specify the number of times the request should be polled.
   *
   * @param {number} maxPeriod
   * @param {number} intervalMilliseconds
   * @param {function} callback
   *
   * @returns {this}
   */
  poll(
    maxPeriod: number,
    intervalMilliseconds: number,
    callback?: (response: Response | undefined, request: this, error?: unknown) => boolean | null
  ): this {
    // code ...
  }
}

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Code examples

import { HttpClient } from '@wolfpackthatcodes/http-client';

const response = new HttpClient()
  .poll(5, 1000, (response) => {
    return response.json()['status'] === 'Pending';
  })
  .get('https://api.example.local/test/');

The HTTP Client will poll for 5 seconds, every second the request will be made. The callback will return true for the HTTP Client to continue polling if the response has a status of pending.