puppeteer-request-intercepter

Intercept API Requests and return Mocked Data

Install

$ npm install puppeteer-request-intercepter

Usage

const puppeteer = require('puppeteer');

const { initFixtureRouter } = require('puppeteer-request-intercepter');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();

  const fixtureRouter = await initFixtureRouter(page, { baseUrl: 'https://news.ycombinator.com' });
  fixtureRouter.route('GET', '/y18.gif', 'y18.gif', { contentType: 'image/gif' });

  await page.goto('https://news.ycombinator.com', { waitUntil: 'networkidle2' });
  await page.pdf({ path: 'hn.pdf', format: 'A4' });

  await browser.close();
})();

API

initFixtureRouter(page, options?)

Initialize a new FixtureRouter class.

This class is responsible for configuring and handling Puppeteer requests. Eg. page.on('request') and page.on('response')

Returns a FixtureRouter object with route and routeFixture functions.

page

Type: object

An instance of the Puppeteer page object.

options

Type: object
Default: {}

Decode the keys and values. URL components are decoded with decode-uri-component.

baseUrl

Type: string
Default: ''

Base Url for relative fixture routes (ex. /api/v1/users).

const fixtureRouter = await initFixtureRouter(page, { baseUrl: 'https://news.ycombinator.com' });

fixtureBasePath

Type: string
Default: ./puppeteer/fixtures

Base path where the fixture files are located (and will be created if they don't exist).

fixtureRouter.route(method, route, fixturePath, options)

Add a FixtureRoute to the FixtureRouter instance.

method

Type: string

The HttpMethod to match:

• GET
• POST
• PATCH
• PUT
• DELETE
• OPTIONS

route

Type: string

The full or relative Url to match.

Comparison is done using startsWith() and the order in which FixtureRoute's are added matters. The first one found will be used.

Put the most specific match first. Ex:

fixtureRouter.route('GET', '/api/v1/users/bill', 'bill.json');
fixtureRouter.route('GET', '/api/v1/users', 'all-users.json');

fixturePath

Type: string

Relative path of the fixture file to use (or create).

options

Type: object
Default: {}

FixtureRouteOptions to use for the response.

contentType

Type: string
Default: application/json

Specifies the Content-Type response header.

status

Type: number

Specifies the response status code.

fixtureRouter.routeFixture(fixtureRoute)

Add a FixtureRoute to the FixtureRouter instance.

Options are the same as fixtureRouter.route() except it accepts an object of parameters instead of individual ones.

fixtureRouter.findRoute(method, url)

Returns the first FixtureRoute that matches the provided method and url. If there are no matches it returns undefined.

method

Type: string

The HttpMethod to match.

url

Type: string

The full or relative Url to match.

If it's a relative Url, the configured baseUrl will be used.

createFixture(method, route, fixturePath, options)

Convenience method for creating FixtureRoute's.

Same API as fixtureRouter.route.

Useful when using BackstopJS with a custom scenarios.fixtures array.

BackstopJS Example

onBefore.ts:

import { Scenario } from 'backstopjs';
import { Page } from 'puppeteer';
import { initFixtureRouter } from 'puppeteer-request-intercepter';

// tslint:disable-next-line: export-name
export = async (page: Page, scenario: Scenario, vp) => {
  // Configure fixtures:
  if (scenario.fixtures) {
    const fixtureRouter = await initFixtureRouter(page, {
      baseUrl: `http://localhost:8080`,
      fixtureBasePath: 'backstop_data/engine_scripts/fixtures',
    });

    scenario.fixtures.forEach((fixture) => {
      fixtureRouter.routeFixture(fixture);
    });
  }
};

backstopConfig.ts:

import { Config, Scenario } from 'backstopjs';
import { Page } from 'puppeteer';
import { createFixture, FixtureRoute } from 'puppeteer-request-intercepter';

const globalFixtures: FixtureRoute[] = [
  createFixture('GET', '/api/v1/alerts', 'alerts.json'),
];

const config: Config = {
  id: 'MyProject',
  viewports: [
    {
      label: 'phone',
      width: 320,
      height: 1200,
    },
    {
      label: 'tablet',
      width: 1024,
      height: 768,
    },
    {
      label: 'desktop',
      width: 1200,
      height: 900,
    },
  ],
  paths: {
    bitmaps_reference: 'backstop_data/bitmaps_reference',
    bitmaps_test: 'backstop_data/bitmaps_test',
    engine_scripts: 'backstop_data/dist/engine_scripts',
    html_report: 'backstop_data/html_report',
    ci_report: 'backstop_data/ci_report',
  },
  report: ['browser'],
  engine: 'puppeteer',
  engineOptions: {
    args: ['--no-sandbox'],
  },
  asyncCaptureLimit: 5,
  asyncCompareLimit: 50,
  debug: false,
  debugWindow: false,
  onBeforeScript: 'onBefore.js',
  onReadyScript: 'onReady.js',
  scenarios: [
    {
      label: 'dashboards',
      url: url('/dashboards'),
      fixtures: [
        ...globalFixtures,
        createFixture('GET', '/api/v1/dashboards', 'dashboards.json')
      ],
    },
  ],
};

export = config;