bittorrent-tracker/lib/parse_http.js

module.exports = parseHttpRequest

var common = require('./common')

var REMOVE_IPV6_RE = /^::ffff:/

function parseHttpRequest (req, options) {
  var s = req.url.split('?')
  var params = common.querystringParse(s[1])

  if (s[0] === '/announce') {
    params.action = common.ACTIONS.ANNOUNCE

    if (typeof params.info_hash !== 'string' || params.info_hash.length !== 20)
      throw new Error('invalid info_hash')
    params.info_hash = common.binaryToHex(params.info_hash)
    if (typeof params.peer_id !== 'string' || params.peer_id.length !== 20)
      throw new Error('invalid peer_id')
    params.peer_id = common.binaryToHex(params.peer_id)

    params.port = Number(params.port)
    if (!params.port) throw new Error('invalid port')

    params.left = Number(params.left)
    params.compact = Number(params.compact)
    params.numwant = Math.min(
      Number(params.numwant) || common.NUM_ANNOUNCE_PEERS,
      common.MAX_ANNOUNCE_PEERS
    )

    params.ip = options.trustProxy
      ? req.headers['x-forwarded-for'] || req.connection.remoteAddress
      : req.connection.remoteAddress.replace(REMOVE_IPV6_RE, '') // force ipv4
    params.addr = params.ip + ':' + params.port // TODO: ipv6 brackets?

  } else if (s[0] === '/scrape') { // unofficial scrape message
    params.action = common.ACTIONS.SCRAPE
    if (typeof params.info_hash === 'string')
      params.info_hash = [ params.info_hash ]

    if (Array.isArray(params.info_hash)) {
      params.info_hash = params.info_hash.map(function (binaryInfoHash) {
        if (typeof binaryInfoHash !== 'string' || binaryInfoHash.length !== 20)
          throw new Error('invalid info_hash')
        return common.binaryToHex(binaryInfoHash)
      })
    }

  } else {
    throw new Error('Invalid action in HTTP request: ' + params.action)
  }

  return params
}