/node-http2-proxy

A simple http/2 & http/1.1 to http/1.1 spec compliant proxy helper for Node.

Primary LanguageJavaScriptMIT LicenseMIT

http2-proxy

A simple http/2 & http/1.1 spec compliant proxy helper for Node.

Features

Installation

$ npm install http2-proxy

Notes

http2-proxy requires at least node v10.0.0.

Fully async/await compatible and all callback based usage is optional and discouraged.

During 503 it is safe to assume that nothing was read or written. This makes it safe to retry request (including non idempotent methods).

Use a final and/or error handler since errored responses won't be cleaned up automatically. This makes it possible to perform retries.

const finalhandler = require('finalhandler')

const defaultWebHandler = (err, req, res) => {
  if (err) {
    console.error('proxy error', err)
    finalhandler(req, res)(err)
  }
}

const defaultWSHandler = (err, req, socket, head) => {
  if (err) {
    console.error('proxy error', err)
    socket.destroy()
  }
}

HTTP/1 API

You must pass allowHTTP1: true to the http2.createServer or http2.createSecureServer factory methods.

import http2 from 'http2'
import proxy from 'http2-proxy'

const server = http2.createServer({ allowHTTP1: true })
server.listen(8000)

You can also use http-proxy2 with the old http && https API's.

import http from 'http'

const server = http.createServer()
server.listen(8000)

API

Proxy HTTP/2, HTTP/1 and WebSocket

server.on('request', (req, res) => {
  proxy.web(req, res, {
    hostname: 'localhost'
    port: 9000
  }, defaultWebHandler)
})
server.on('upgrade', (req, socket, head) => {
  proxy.ws(req, socket, head, {
    hostname: 'localhost'
    port: 9000
  }, defaultWsHandler)
})

Use Connect & Helmet

const app = connect()
app.use(helmet())
app.use((req, res, next) => proxy
  .web(req, res, {
    hostname: 'localhost'
    port: 9000
  }, err => {
    if (err) {
      next(err)
    }
  })
)
server.on('request', app)

Add x-forwarded Headers

server.on('request', (req, res) => {
  proxy.web(req, res, {
    hostname: 'localhost'
    port: 9000,
    onReq: (req, { headers }) => {
      headers['x-forwarded-for'] = req.socket.remoteAddress
      headers['x-forwarded-proto'] = req.socket.encrypted ? 'https' : 'http'
      headers['x-forwarded-host'] = req.headers['host']
    }
  }, defaultWebHandler)
})

Follow Redirects

const http = require('follow-redirects').http

server.on('request', (req, res) => {
  proxy.web(req, res, {
    hostname: 'localhost'
    port: 9000,
    onReq: (req, options) => http.request(options)
  }, defaultWebHandler)
})

Add Response Header

server.on('request', (req, res) => {
  proxy.web(req, res, {
    hostname: 'localhost'
    port: 9000,
    onReq: (req, options) => http.request(options),
    onRes: (req, res, proxyRes) => {
      res.setHeader('x-powered-by', 'http2-proxy')
      res.writeHead(proxyRes.statusCode, proxyRes.headers)
      proxyRes.pipe(res)
    }
  }, defaultWebHandler)
})

Proxy HTTP2

HTTP proxying can be achieved using http2 client compat libraries such as:

https://github.com/hisco/http2-client https://github.com/spdy-http2/node-spdy https://github.com/grantila/fetch-h2 https://github.com/szmarczak/http2-wrapper

const http = require('http2-wrapper')

server.on('request', (req, res) => {
  proxy.web(req, res, {
    hostname: 'localhost'
    port: 9000,
    onReq: (req, options) => http.request(options)
  }, defaultWebHandler)
})

Try Multiple Upstream Servers (Advanced)

const http = require('http')
const proxy = require('http2-proxy')
const createError = require('http-errors')

server.on('request', async (req, res) => {
  try {
    res.statusCode = null
    for await (const { port, timeout, hostname } of upstream) {
      if (req.aborted || res.readableEnded) {
        return
      }

      let error = null
      let bytesWritten = 0
      try {
        return await proxy.web(req, res, {
          port,
          timeout,
          hostname,
          onRes: async (req, res, proxyRes) => {
            if (proxyRes.statusCode >= 500) {
              throw createError(proxyRes.statusCode, proxyRes.message)
            }

            function setHeaders () {
              if (!bytesWritten) {
                res.statusCode = proxyRes.statusCode
                for (const [ key, value ] of Object.entries(headers)) {
                  res.setHeader(key, value)
                }
              }
            }

            // NOTE: At some point this will be possible
            // proxyRes.pipe(res)

            proxyRes
              .on('data', buf => {
                setHeaders()
                bytesWritten += buf.length
                if (!res.write(buf)) {
                  proxyRes.pause()
                }
              })
              .on('end', () => {
                setHeaders()
                res.addTrailers(proxyRes.trailers)
                res.end()
              })
              .on('close', () => {
                res.off('drain', onDrain)
              }))

            res.on('drain', onDrain)

            function onDrain () {
              proxyRes.resume()
            }
          }
        })
      } catch (err) {
        if (!err.statusCode) {
          throw err
        }

        error = err

        if (err.statusCode === 503) {
          continue
        }

        if (req.method === 'HEAD' || req.method === 'GET') {
          if (!bytesWritten) {
            continue
          }

          // TODO: Retry range request
        }

        throw err
      }
    }

    throw error || new createError.ServiceUnavailable()
  } catch (err) {
    defaultWebHandler(err)
  }
}

[async] web (req, res, options[, callback])

See request

[async] ws (req, socket, head, options[, callback])

See upgrade

options

License

MIT