kaanuki / straightforward

🏴 A straightforward forward-proxy written in Node.js.

🏴 straightforward

A straightforward forward-proxy written in Node.js

Goals

• Extremely focused (~200 SLOC), no-fuzz forward proxy
• Support HTTP, HTTPS, CONNECT & Websockets (wss)
• Performant: By default all requests/responses are streamed
• No external dependencies, small, self-contained, tested
• Support both cli and extensible programmatic usage
• Straightforward: no implicit magic or abstractions

What you can do with it

• Start an explicit forwarding proxy in seconds that just works
• Optionally use authentication and a white-/blacklist for hosts
• Block requests, fake or modify responses
• Allow others to surf with your IP address
• Use it programmatically to do whatever you want

What this is not

• A ssl-intercepting proxy (https can be filtered but not modified)
• A reverse proxy to load-balance stuff to internal servers
• A general purpose webserver framework
• A proxy middleware for express
• A transparent forward proxy
• A caching proxy
• A sni proxy

Installation

# Use directly with no installation (npx is part of npm):
❯❯❯ npx straightforward --port 9191

# Or install globally:
❯❯❯ npm install -g straightforward

Usage (cli)

❯❯❯ straightforward --help

Usage: straightforward --port 9191 [options]

Options:
  --version         Show version number                                [boolean]
  --port, -p        Port to bind on                     [number] [default: 9191]
  --auth, -a        Enable proxy authentication                         [string]
  --blacklist-host  Allow all requests except to blacklist              [string]
  --whitelist-host  Deny all requests except to whitelist               [string]
  --block-msg       Show custom block message (http only)               [string]
  --replace-text    Replace text on websites (http only)                [string]
  --debug, -d       Enabled debug output                               [boolean]
  --cluster, -c     Run a cluster of proxies (using number of CPUs)    [boolean]
  --cluster-count   Specify how many cluster workers to spawn           [number]
  --quiet, -q       Suppress request logs                              [boolean]
  --silent, -s      Dont print anything to stdout                     [boolean]
  -h, --help        Show help                                          [boolean]

Examples:
  straightforward --auth "user:pass"               Require authentication
  straightforward --whitelist-host "a.com,b.net"   Allow specific hosts
  straightforward --blacklist-host "a.com,b.net"   Block specific hosts
  straightforward --block-msg "<h1>Nope ಠ_ಠ</h1>"  Custom block message
  straightforward --replace-text "cloud:butt"      Replace all occurences of cloud with butt

Use with cURL:
  curl --proxy https://localhost:9191 'http://example.com' -v

Usage (code)

const Straightforward = require('straightforward')

;(async () => {
  // Start proxy server
  const sf = await new Straightforward().listen(9191)
  console.log(`Proxy listening on http://localhost:9191`)

  // Log http requests
  sf.onRequest(async ({ req, res }, next) => {
    console.log(`http request: ${req.url}`)
    // Note the common middleware pattern, use `next()`
    // to pass the request to the next handler.
    return next()
  })

  // Log connect (https) requests
  sf.onConnect(async ({ req, res }, next) => {
    console.log(`connect request: ${req.url}`)
    return next()
  })

  // Filter some requests dynamically
  const blockRequest = sf.middleware.blockRequest({
    filterFn: (host, url) => host.includes('malware.com'),
    responseMsg: `<h1>None shall pass. 🐗</h1>`
  })
  sf.onRequest(blockRequest) // for http
  sf.onConnect(blockRequest) // for https

  // Replace text on http://example.com for fun and glory
  sf.onResponse(sf.middleware.replaceText({
    filterFn: (host, url) => host.includes('example.com'),
    replacerFn: (str) => str.replace(/example/ig, 'FOOBAR')
  }))
})()

In action

❯❯❯ straightforward --replace-text "example:FOOBAR"

Example: Secure proxy on fresh server in 30 seconds

Let's say you have a fresh linux server and want to use it as an authenticated forward proxy quickly.

• Make sure nvm is installed:
  • curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash
• Make sure a recent version of Node.js is installed:
  • nvm install node && nvm use node && node --version
• Add forever (process manager) and straightforward:
  • npm install -g forever straightforward
• Start proxy daemon:
  • forever start --id "proxy1" $( which straightforward ) --port 9191 --quiet --auth 'user:foobar'
• Test your proxy from a different machine:
  • curl --proxy http://user:foobar@SERVER:9191/ http://canhazip.com
• List all running forever services:
  • forever list
• Stop our proxy service daemon:
  • forever stop proxy1

API

onRequest

onResponse

onConnect

License

MIT