npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

signed

v2.1.0

Published

Tiny express library for signing urls and validating them based on secret key

Downloads

5,555

Readme

Signed

signed is tiny node.js library for signing urls and validating them based on secret key.

In short:

  • With the help of this library, you can sign url, which will be used by user later.
  • It verifies signature, when user uses this signed url. Ready to go "verify" express middleware included. (Although you can use this library without express.js as well)
  • No session needed. No additional server storage needed.
  • You can sign url and verify signature in different services/applications (as long as secret and hashing algorithm are the same).
  • When signing an url, you can specify some additional limitations: allowed http method(s), user's ip and expiration time.

Important!!!

Urls signed by version 1.x.x of this library are not valid with 2.x.x

How to use

npm i signed

Let's create signature object based on secret.

Signature object will be needed later to sign url, or to validate it.

import signed from 'signed';
const signature = signed({
    secret: 'secret string',
});

Possible options:

  • secret: string It MUST NOT be known for anyone else except you servers.
  • ttl?: number Default time to live for signed url (in seconds). If not set, signed url will be valid forever by default
  • hash: string | HashFunction What type of hash function should be used to sign url. sha1 is used by default. But you can pass any other algorithm supported by crypto.createHash(). You can also pass your own hashing function (input: string, secret: string) => string.

Let's sign url

const signedUrl = signature.sign('http://example.com/resource');

You also can optionally pass object with options:

const signedUrl = signature.sign('http://example.com/resource', {
    method: 'get',
});

Possible options:

  • method?: string | string[] List of http methods (as array, or separated by comma), which can be used. If not passed - any http method will be allowed.
  • ttl?: number Time to live for url starting from now (in seconds).
  • exp?: number Expiration unix timestamp (in seconds). Can be passed instead of ttl
  • addr?: string Only this user's address will be allowed. You can pass user's address here to prevent sharing signed url with anyone else.

Let's verify signature

So now, when you sent signed url to user, it's time to add verification for endpoints which should be accessible only with valid signature.

app.get('/resource', signature.verifier(), (req, res, next) => {
    res.send('ok');
});

You can also pass object with additional options to verifier method. Possible options:

  • urlReader?: (req: Request) => string

    By default verifier constructs original url as ${req.protocol}://${req.get('host')}${req.originalUrl}.

    But if you use some kind of reverse proxy/load balancer/etc, external protocol/host/port can be different from those used by application. In that case you can pass you own method to build right correct external url to verify signature.

    e.g. req => https://api.exmaple.com${req.originalUrl}

  • addressReader?: (req: Request) => string Function which will be used to retrieve user's address (for the cases when you added address to signature). By default, req => req.socket.remoteAddress is used.

  • blackholed?: RequestHandler Handler to use in the case of wrong signature.

    (It's added for backward compatibility. It's better to not use it. See Error handling).

  • expired?: RequestHandler Handler to use in the case of valid, but expired signature.

    (It's added for backward compatibility. It's better to not use it. See Error handling).

Using without express middleware

If you don't want to use it with express, you can just validate url with .verify(url, options) method:

const url = signature.sign('http://localhost:8080');

// ...

signature.verify(url); // returns "http://localhost:8080" or throws error

or:

const url = signature.sign('http://localhost:8080', {
    method: ['get', 'post'],
    addr: '127.0.0.1',
});

// ...

signature.verify(url, {
    method: 'get',
    addr: '127.0.0.1',
}); // returns "http://localhost:8080" or throws error

Error handling

By default, if there is bad signature, verifier middleware throws SignatureError to the express next function.

403 http status will be sent for bad signature and 410 if signature is expired.

You can handle these errors yourself, using express error handler middleware:

import {SignatureError} from 'signed';

// ...

app.use((err, req, res, next) => {
    if (err instanceof SignatureError) {
        // signature is not valid or expired
    }
});

Or you can differentiate bad signature and expired signature this way:

import {BlackholedSignatureError, ExpiredSignatureError} from 'signed';

// ...

app.use((err, req, res, next) => {
    if (err instanceof BlackholedSignatureError) {
        // signature is not valid
    }
    if (err instanceof ExpiredSignatureError) {
        // signature is expired
    }
});

Example of application

import * as express from 'express';
import signed from 'signed';

// Create signature
const signature = signed({
    secret: 'Xd<dMf72sj;6'
});

const app = express();

// Index with signed link
app.get('/', (req, res, next) => {
    const s = signature.sign('http://localhost:8080/source/a');
    res.send('<a href="'+s+'">'+s+'</a><br/>');
    // It prints something like http://localhost:8080/source/a?signed=r_1422553972-e8d071f5ae64338e3d3ac8ff0bcc583b
});

// Validating
app.get('/source/:a', signature.verifier(), (req, res, next) => {
    res.send(req.params.a);
});

app.listen(8080);

License

MIT