node package manager



A simple mock npm registry.


var registryMock = require('registry-mock');
registryMock({ http: 8080 }, (err, registry) => {
  if (err) { /* handle me */ }
  console.log('Mock npm registry listening on 8080');

registry-mock is designed to be a generic caching HTTP server for asserting that proxied npm registry HTTP calls send the correct payloads and/or headers to the target registry. In order to test some npm-specific routes (such as publish) it is necessary to cache tarballs and later serve them.

HTTP & cache conventions

The response to incoming requests can be summarized based on a few simple rules:

  1. All requests to /.*tgz or those with the X-FETCH-CACHE header respond with the last request body received for that route.
  • If there is no cache for that route a 404 is served.

  • If X-CLEAR-CACHE is provided to a cache hit request, then the cache is cleared for that route.

  • All other requests are cached for future assertion and the response is given from the JSON parsed X-SEND-RESPONSE header:

     "body": { an: 'unstringified JSON object' },
     "status": 200
  • npm publish PUT /:pkg splits out the tarball and makes the cache for /:pkg/-/:pkg-:version.tgz available for download.

Using npm-registry-echo

This package also ships a binary named npm-registry-echo this program runs a simple registry-mock server and then fetches the cache immediately after all requests. This allows for simple introspection of the payloads that are sent from the npm CLI.

e.g. Viewing npm publish payloads

1. Running npm-registry-echo

$ npm i -g registry-mock
$ npm-registry-echo
npm-registry-echo listening on 3676

2. Add garbage nerf darts to your ~/.npmrc


3. Run npm publish against your echo

npm publish --reg=http://localhost:3676 --loglevel=http
npm http request PUT http://localhost:3676/test-publish03
npm http 201 http://localhost:3676/test-publish03
+ test-publish03@1.0.0

4. See the output

PUT /test-publish03 {"_id":"test-publish03","name":"test-publish03","description":"Just a
"1.0.0","description":"Just a test","main":"index.js","scripts":{"test":"echo \"Error: no test
specified\" && exit 1"},"author":"","license":"ISC","readme":"ERROR: No README data found!",
No README data found!","maintainers":[{"name":"garbage!!user","email":""}],
License MIT
Authors: Charlie Robbins, Jarrett Cruger