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

@robireton/fresh

v1.0.0

Published

HTTP response freshness testing

Downloads

1

Readme

fresh

HTTP response freshness testing

Installation

This is a Node.js module available through the npm registry. Installation is done using the npm install command:

$ npm install @robireton/fresh

API

import fresh from '@robireton/fresh'

fresh(reqHeaders, resHeaders)

Check freshness of the response using request and response headers.

When the response is still “fresh” in the client’s cache true is returned, otherwise false is returned to indicate that the client cache is now stale and the full response should be sent.

When a client sends the Cache-Control: no-cache request header to indicate an end-to-end reload request, this module will return false to make handling these requests transparent.

Known Issues

This module is designed to only follow the HTTP specifications, not to work-around all kinda of client bugs (especially since this module typically does not receive enough information to understand what the client actually is).

There is a known issue that in certain versions of Safari, Safari will incorrectly make a request that allows this module to validate freshness of the resource even when Safari does not have a representation of the resource in the cache. The module jumanji can be used in an Express application to work-around this issue and also provides links to further reading on this Safari bug.

Example

API usage

const reqHeaders = { 'if-none-match': '"foo"' }
const resHeaders = { 'etag': '"bar"' }
fresh(reqHeaders, resHeaders)
// => false

const reqHeaders = { 'if-none-match': '"foo"' }
const resHeaders = { 'etag': '"foo"' }
fresh(reqHeaders, resHeaders)
// => true

Using with Node.js http server

import fresh from '@robireton/fresh'
import http from 'node:http'

const server = http.createServer((req, res) => {
  // perform server logic
  // ... including adding ETag / Last-Modified response headers

  if (isFresh(req, res)) {
    // client has a fresh copy of resource
    res.statusCode = 304
    res.end()
    return
  }

  // send the resource
  res.statusCode = 200
  res.end('hello, world!')
})

function isFresh (req, res) {
  return fresh(req.headers, {
    'etag': res.getHeader('ETag'),
    'last-modified': res.getHeader('Last-Modified')
  })
}

server.listen(3000)

License

MIT