le-acme-core

Looking for letiny-core? Check the v1.x branch.

A framework for building letsencrypt clients, forked from letiny.

Supports all of:

• node with ursa (works fast)
• node with forge (works on windows)
• browser WebCrypto (not implemented, but... Let's Encrypt over WebRTC anyone?)
• any javascript implementation

These aren't the droids you're looking for

This is a library / framework for building letsencrypt clients. You probably want one of these pre-built clients instead:

• letsencrypt (compatible with the official client)
• letiny (lightweight client cli)
• letsencrypt-express (automatic https for express)

Install & Usage:

npm install --save le-acme-core

To use the default dependencies:

'use strict';

var ACME = require('le-acme-core').ACME.create();

For testing and development, you can also inject the dependencies you want to use:

'use strict';

var ACME = require('le-acme-core').ACME.create({
  request: require('request')
, RSA: require('rsa-compat').RSA
});

// now uses node `request` (could also use jQuery or Angular in the browser)
ACME.getAcmeUrls(discoveryUrl, function (err, urls) {
  console.log(urls);
});

You will follow these steps to obtain certificates:

• discover ACME registration urls with getAcmeUrls
• register a user account with registerNewAccount
• implement a method to agree to the terms of service as agreeToTos
• get certificates with getCertificate
• implement a method to store the challenge token as setChallenge
• implement a method to get the challenge token as getChallenge
• implement a method to remove the challenge token as removeChallenge

Demo

You can see this working for yourself, but you'll need to be on an internet connected computer with a domain.

Get a temporary domain for testing

npm install -g ddns-cli
ddns --random --email [email protected] --agree

Note: use YOUR EMAIL and accept the terms of service (run ddns --help to see them).

Install le-acme-core and its dependencies. Note: it's okay if you're on windows and ursa fails to compile. It'll still work.

git clone https://github.com/Daplie/le-acme-core.git ~/le-acme-core
pushd ~/le-acme-core

npm install

Run the demo:

node examples/letsencrypt.js [email protected] example.com

Note: use YOUR TEMPORARY DOMAIN and YOUR EMAIL.

API

The Goodies

// Accounts
ACME.registerNewAccount(options, cb)        // returns "regr" registration data

    { newRegUrl: '<url>'                      //    no defaults, specify acmeUrls.newAuthz
    , email: '<email>'                        //    valid email (server checks MX records)
    , accountKeypair: {                       //    privateKeyPem or privateKeyJwt
        privateKeyPem: '<ASCII PEM>'
      }
    , agreeToTerms: fn (tosUrl, cb) {}        //    must specify agree=tosUrl to continue (or falsey to end)
    }

// Registration
ACME.getCertificate(options, cb)            // returns (err, pems={ privkey (key), cert, chain (ca) })

    { newAuthzUrl: '<url>'                    //    specify acmeUrls.newAuthz
    , newCertUrl: '<url>'                     //    specify acmeUrls.newCert

    , domainKeypair: {
        privateKeyPem: '<ASCII PEM>'
      }
    , accountKeypair: {
        privateKeyPem: '<ASCII PEM>'
      }
    , domains: ['example.com']

    , setChallenge: fn (hostname, key, val, cb)
    , removeChallenge: fn (hostname, key, cb)
    }

// Discovery URLs
ACME.getAcmeUrls(acmeDiscoveryUrl, cb)      // returns (err, acmeUrls={newReg,newAuthz,newCert,revokeCert})

Helpers & Stuff

// Constants
ACME.productionServerUrl                // https://acme-v01.api.letsencrypt.org/directory
ACME.stagingServerUrl                   // https://acme-staging.api.letsencrypt.org/directory
ACME.acmeChallengePrefix                // /.well-known/acme-challenge/
ACME.knownEndpoints                     // new-authz, new-cert, new-reg, revoke-cert


// HTTP Client Helpers
ACME.Acme                               // Signs requests with JWK
    acme = new Acme(keypair)                // 'keypair' is an object with `privateKeyPem` and/or `privateKeyJwk`
    acme.post(url, body, cb)                // POST with signature
    acme.parseLinks(link)                   // (internal) parses 'link' header
    acme.getNonce(url, cb)                  // (internal) HEAD request to get 'replay-nonce' strings

Example

Below you'll find a stripped-down example. You can see the full example in the example folder.

• example/

Register Account & Domain

This is how you register an ACME account and get an HTTPS certificate

'use strict';

var ACME = require('le-acme-core').ACME.create();
var RSA = require('rsa-compat').RSA;

var email = '[email protected]';                   // CHANGE TO YOUR EMAIL
var domains = 'example.com';                      // CHANGE TO YOUR DOMAIN
var acmeDiscoveryUrl = ACME.stagingServerUrl;   // CHANGE to production, when ready

var accountKeypair = null;                        // { privateKeyPem: null, privateKeyJwk: null };
var domainKeypair = null;                         // same as above
var acmeUrls = null;

RSA.generateKeypair(2048, 65537, function (err, keypair) {
    accountKeypair = keypair;
    // ...
    ACME.getAcmeUrls(acmeDiscoveryUrl, function (err, urls) {
        // ...
        runDemo();
    });
});

function runDemo() {
    ACME.registerNewAccount(
        { newRegUrl: acmeUrls.newReg
        , email: email
        , accountKeypair: accountKeypair
        , agreeToTerms: function (tosUrl, done) {

              // agree to the exact version of these terms
              done(null, tosUrl);
          }
        }
      , function (err, regr) {

            ACME.getCertificate(
                { newAuthzUrl: acmeUrls.newAuthz
                , newCertUrl: acmeUrls.newCert

                , domainKeypair: domainKeypair
                , accountKeypair: accountKeypair
                , domains: domains

                , setChallenge: challengeStore.set
                , removeChallenge: challengeStore.remove
                }
              , function (err, certs) {

                  // Note: you should save certs to disk (or db)
                  certStore.set(domains[0], certs, function () {

                      // ...

                  });

                }
            );
        }
    );
}

But wait, there's more! See example/letsencrypt.js

Run a Server on 80, 443, and 5001 (https/tls)

That will fail unless you have a webserver running on 80 and 443 (or 5001) to respond to /.well-known/acme-challenge/xxxxxxxx with the proper token

var https = require('https');
var http = require('http');


var LeCore = deps.LeCore;
var httpsOptions = deps.httpsOptions;
var challengeStore = deps.challengeStore;
var certStore = deps.certStore;


//
// Challenge Handler
//
function acmeResponder(req, res) {
  if (0 !== req.url.indexOf(LeCore.acmeChallengePrefix)) {
    res.end('Hello World!');
    return;
  }

  var key = req.url.slice(LeCore.acmeChallengePrefix.length);

  challengeStore.get(req.hostname, key, function (err, val) {
    res.end(val || 'Error');
  });
}


//
// Server
//
https.createServer(httpsOptions, acmeResponder).listen(5001, function () {
  console.log('Listening https on', this.address());
});
http.createServer(acmeResponder).listen(80, function () {
  console.log('Listening http on', this.address());
});

But wait, there's more! See example/serve.js

Put some storage in place

Finally, you need an implementation of challengeStore:

var challengeCache = {};
var challengeStore = {
  set: function (hostname, key, value, cb) {
    challengeCache[key] = value;
    cb(null);
  }
, get: function (hostname, key, cb) {
    cb(null, challengeCache[key]);
  }
, remove: function (hostname, key, cb) {
    delete challengeCache[key];
    cb(null);
  }
};

var certCache = {};
var certStore = {
  set: function (hostname, certs, cb) {
    certCache[hostname] = certs;
    cb(null);
  }
, get: function (hostname, cb) {
    cb(null, certCache[hostname]);
  }
, remove: function (hostname, cb) {
    delete certCache[hostname];
    cb(null);
  }
};

But wait, there's more! See

• example/challenge-store.js
• example/cert-store.js

Authors

• ISRG
• Anatol Sommer (https://github.com/anatolsommer)
• AJ ONeal [email protected] (https://daplie.com)

Licence

MPL 2.0

All of the code is available under the MPL-2.0.

Some of the files are original work not modified from letiny and are made available under MIT and Apache-2.0 as well (check file headers).