authentication-middleware.js

var jwt = require('./jwt');

const checkToken = ( req ) => {
  //get the http header 'authorization'
    let authorization = req.get( 'authorization' );
    if ( !authorization ) {
        throw new Error( 401 )
    }
  //check the token signature with 'jwt.js' library
    let token = authorization.replace( 'Bearer ', '' );
    return jwt.verify( token );
}

const authMiddleware = ( req, res, next ) => {
            try {
                let shouldProtect = getProtectedResource( req, this.config.routes );
                //add a configuration to protect some resources
                if ( shouldProtect ) {
                  //if the url is protected we must check the token
                    let principal = checkToken( req );
                    res.locals.principal = principal;
                }
                next();
            } catch ( e ) {
              //if any error coccurs, we do not authorize the request
                console.log( "unouthorized", e )
                res
                    .status( 401 )
                    .end( JSON.stringify( { error: "not_authorized" } ) );
            }
        }

var app = express();
//tell express to use the middleware
app.use( authMiddleware )


app.get( '/protected', ( req, res ) => {
    let principal = res.locals.principal;
    console.log( principal )
    let localUser = userStore.get( principal.sub );
    console.log( localUser )
    let name = localUser ? localUser.name : principal.sub;

    res.setHeader( 'Content-Type', 'application/json' );
    res.send( JSON.stringify( {
        user: name
    } ) );

} )