openhim-core/src/middleware/proxy.js

The OpenHIM core application that provides logging and routing of http requests

import SDC from 'statsd-client'
import os from 'os'
import { config } from '../config'

const statsdServer = config.get('statsd')
const application = config.get('application')

const domain = `${os.hostname()}.${application.name}.appMetrics`
const sdc = new SDC(statsdServer)

export function setupProxyHeaders (ctx) {
  // Headers
  function setOrAppendHeader (ctx, header, value) {
    if (!value) { return }
    if (ctx.header[header]) {
      ctx.header[header] = `${ctx.header[header]}, ${value}`
    } else {
      ctx.header[header] = `${value}`
    }
  }

  setOrAppendHeader(ctx, 'X-Forwarded-For', ctx.request.ip)
  return setOrAppendHeader(ctx, 'X-Forwarded-Host', ctx.request.host)
}

export async function koaMiddleware (ctx, next) {
  let startTime
  if (statsdServer.enabled) { startTime = new Date() }
  exports.setupProxyHeaders(ctx)
  if (statsdServer.enabled) { sdc.timing(`${domain}.proxyHeadersMiddleware`, startTime) }
  await next()
}