mgara / restify-jwt

restify middleware that validates a JsonWebToken (JWT) and sets the req.user with the attributes

restify-jwt

Restify middleware that validates JsonWebTokens and sets req.user.

This module lets you authenticate HTTP requests using JWT tokens in your restify applications.

Install

$ npm install restify-jwt

Usage

The JWT authentication middleware authenticates callers using a JWT. If the token is valid, req.user will be set with the JSON object decoded to be used by later middleware for authorization and access control.

For example,

var jwt = require('restify-jwt');

app.get('/protected',
  jwt({secret: 'shhhhhhared-secret'}),
  function(req, res) {
    if (!req.user.admin) return res.send(401);
    res.send(200);
  });

You can specify audience and/or issuer as well:

jwt({ secret: 'shhhhhhared-secret',
  audience: 'http://myapi/protected',
  issuer: 'http://issuer' })

If the JWT has an expiration (exp), it will be checked.

If you are using a base64 URL-encoded secret, pass a Buffer with base64 encoding as the secret instead of a string:

jwt({ secret: new Buffer('shhhhhhared-secret', 'base64') })

Optionally you can make some paths unprotected as follows:

app.use(jwt({ secret: 'shhhhhhared-secret'}).unless({path: ['/token']}));

This is especially useful when applying to multiple routes. In the example above, path can be a string, a regexp, or an array of any of those.

For more details on the .unless syntax including additional options, please see express-unless.

This module also support tokens signed with public/private key pairs. Instead of a secret, you can specify a Buffer with the public key

var publicKey = fs.readFileSync('/pat/to/public.pub');
jwt({ secret: publicKey });

By default, the decoded token is attached to req.user but can be configured with the requestProperty option.

jwt({ secret: publicKey, requestProperty: 'auth' });

A custom function for extracting the token from a request can be specified with the getToken option. This is useful if you need to pass the token through a query parameter or a cookie. You can throw an error in this function and it will be handled by restify-jwt.

app.use(jwt({
  secret: 'hello world !',
  credentialsRequired: false,
  getToken: function fromHeaderOrQuerystring (req) {
    if (req.headers.authorization && req.headers.authorization.split(' ')[0] === 'Bearer') {
        return req.headers.authorization.split(' ')[1];
    } else if (req.query && req.query.token) {
      return req.query.token;
    }
    return null;
  }
}));

Multi-tenancy

If you are developing an application in which the secret used to sign tokens is not static, you can provide a callback function as the secret parameter. The function has the signature: function(req, payload, done):

• req (Object) - The restify request object.
• payload (Object) - An object with the JWT claims.
• done (Function) - A function with signature function(err, secret) to be invoked when the secret is retrieved.
  • err (Any) - The error that occurred.
  • secret (String) - The secret to use to verify the JWT.

For example, if the secret varies based on the JWT issuer:

var jwt = require('restify-jwt');
var data = require('./data');
var utilities = require('./utilities');

var secretCallback = function(req, payload, done){
  var issuer = payload.iss;

  data.getTenantByIdentifier(issuer, function(err, tenant){
    if (err) { return done(err); }
    if (!tenant) { return done(new Error('missing_secret')); }

    var secret = utilities.decrypt(tenant.secret);
    done(null, secret);
  });
};

app.get('/protected',
  jwt({secret: secretCallback}),
  function(req, res) {
    if (!req.user.admin) return res.send(401);
    res.send(200);
  });

Revoked tokens

It is possible that some tokens will need to be revoked so they cannot be used any longer. You can provide a function as the isRevoked option. The signature of the function is function(req, payload, done):

• req (Object) - The restify request object.
• payload (Object) - An object with the JWT claims.
• done (Function) - A function with signature function(err, revoked) to be invoked once the check to see if the token is revoked or not is complete.
  • err (Any) - The error that occurred.
  • revoked (Boolean) - true if the JWT is revoked, false otherwise.

For example, if the (iss, jti) claim pair is used to identify a JWT:

var jwt = require('restify-jwt');
var data = require('./data');
var utilities = require('./utilities');

var isRevokedCallback = function(req, payload, done){
  var issuer = payload.iss;
  var tokenId = payload.jti;

  data.getRevokedToken(issuer, tokenId, function(err, token){
    if (err) { return done(err); }
    return done(null, !!token);
  });
};

app.get('/protected',
  jwt({secret: shhhhhhared-secret,
    isRevoked: isRevokedCallback}),
  function(req, res) {
    if (!req.user.admin) return res.send(401);
    res.send(200);
  });

Error handling

The default behavior is to throw an error when the token is invalid, so you can add your custom logic to manage unauthorized access as follows:

app.use(function (err, req, res, next) {
  if (err.name === 'UnauthorizedError') {
    res.send(401, 'invalid token...');
  }
});

You might want to use this module to identify registered users without preventing unregistered clients to access to some data, you can do it using the option credentialsRequired:

app.use(jwt({
  secret: 'hello world !',
  credentialsRequired: false
}));

Tests

$ npm install
$ npm test

Credits

Based on auth0/express-jwt. The major difference is that restify-jwt tries to use built in restify errors wherever possible.

License

MIT