fetch-vcr

fetch-vcr

Stop mocking HTTP Requests. Just record and then play them back. See vcr/vcr for the main idea.

Usage

The basics are:

1. turn on cache mode
2. run your tests

This will record (and load) all the HTTP responses into the ./_fixtures/ directory.

And when you run the steps again, no network traffic happens.

How do I set this up?

// import fetch from 'fetch';
import fetch from 'fetch-vcr';

// Configure what mode this VCR is in (playback, recording, cache)
// and where the recordings should be loaded/saved to.
fetch.configure({
  mode: 'record',
  fixturePath: __dirname + '/_fixtures'
})

fetch('http://openstax.org')
.then(response => {
  response.text()
  .then(text => {
    console.log(text)
  })
})

What are the different modes?

• playback: (default) only uses the local fixture files
• cache: tries to use the fixture and if not found then it is fetched and then saved (useful when adding new tests)
• record: forces files to be written (useful for regenerating all the fixtures)
• erase: deletes the fixture corresponding to the request

How can I set the VCR mode?

You can set the mode either by:

• setting the VCR_MODE=record environment variable
• explicitly running fetch.configure({mode: 'record'})

How can I use this in a browser?

Currently you can record HTTP requests in NodeJS and play them back in the browser.

To play them back in a browser, just run fetchVCR.configure({fixturePath: './path/to/_fixtures'}) and fetchVCR will use that path to load the files via AJAX requests.

To record HTTP requests in a browser you will need to do a little bit of work. Loading fixture files is relatively painless (using XMLHTTPRequest) but saving them to disk is non-trivial.

In order to save the fixture files to disk you will need to override fetchVCR.saveFile(rootPath, filename, contents) => Promise.

If you are using PhantomJS then you will likely need to use the alert(msg) to get data out of PhantomJS and then save it to the filesystem (using fs.writeFile(...))