// wrapper to JSON web token generation and verification

'use strict';

const JWT = require('jsonwebtoken');

const JWT_ALGORITHM = 'HS256';

const JWT_ISSUER = 'CodeStream';

class TokenHandler {

constructor (secret) {

if (!secret) {

throw 'must provide secret for TokenHandler';

}

this.secret = secret;

}

// generate a token with the given payload and of the given type, with optional expiration

generate (payload, type = 'web', options = {}) {

payload = Object.assign({}, payload, {

iss: JWT_ISSUER,

alg: JWT_ALGORITHM,

type: type

});

if (options.expiresAt) {

payload.exp = Math.floor(options.expiresAt / 1000);

}

return JWT.sign(payload, this.secret);

}

// verify the passed token and return payload

verify (token) {

return JWT.verify(

token,

this.secret,

{

algorithms: [JWT_ALGORITHM]

}

);

}

// decode the passed token and return payload, this does not check the signature

// and should be used only when the token is fully trusted already

decode (token) {

return JWT.decode(

token,

this.secret,

{

algorithms: [JWT_ALGORITHM]

}

);

}

}

module.exports = TokenHandler;