http-ndjson

http-ndjson

Log http requests as ndjson.

Installation

$ npm install http-ndjson

Usage

const httpNdjson = require('http-ndjson')
const http = require('http')

http.createServer((req, res) => {
  httpNdjson(req, res).pipe(process.stdout)
  res.end()
}).listen()

{ name: 'http', method: 'GET', message: 'request', url: '/' }
{ name: 'http', method: 'GET', message: 'response', url: '/', statusCode: 200, elapsed: '5ms' }

Custom loggers

Sometimes process.stdout is not quite what you're looking for. Because http-ndjson is a stream it can easily plug into any streaming logger:

bole

const boleStream = require('bole-stream')
const httpNdjson = require('http-ndjson')
const bole = require('bole')
const http = require('http')

bole.output({ level: 'info', stream: process.stdout })

http.createServer((req, res) => {
  httpNdjson(req, res).pipe(boleStream({ level: 'info' }))
  res.end()
}).listen()

bunyan

const bunyanStream = require('bunyan-stream')
const httpNdjson = require('http-ndjson')
const bunyan = require('bunyan')

const logger = bunyan.createLogger({ name: 'myApp' })

http.createServer((req, res) => {
  httpNdjson(req, res).pipe(bunyanStream({ level: 'info' }, logger))
  res.end()
}).listen()

Response size

http-ndjson can set a responseSize property on the response. It's recommended to use the size-stream package.

const httpNdjson = require('http-ndjson')
const sizeStream = require('size-stream')
const http = require('http')

http.createServer((req, res) => {
  const httpLogger = httpNdjson(req, res)
  httpLogger.pipe(process.stdout)

  const size = sizeStream()
  size.once('size', size => httpLogger.setSize(size))

  req.pipe(size).pipe(res)
}).listen()

Log custom properties

http-ndjson logs a sensible set of standard properties, but sometimes there's a need to dive in and log more. An optional third argument can be added with custom fields that will be logged on either request or response.

const httpNdjson = require('http-ndjson')
const http = require('http')

http.createServer((req, res) => {
  const opts = { req: { requestId: req.headers['requestId'] } }
  httpNdjson(req, res, opts)
  res.end()
}).listen()

Forward headers

Determining the origin of a request can be hard when using reverse-proxies. It's not too uncommon for users to mask their IP by providing an x-forwarded-for header. http-ndjson makes no assumptions about forwarding headers and logs all properties instead. The following headers are logged:

• x-forwarded-for: standardized reverse proxy header (rfc7239)
• x-real-ip: non-standard reverse proxy header
• http-client-ip: non-standard reverse proxy header

API

readStream = httpNdjson(req, res, opts?)

Create an http logger. Returns a write stream. Opts can contain the following values:

• req: an object with values that will be logged on request
• res: an object with values that will be logged on response

readStream.setContentLength(size)

Set the content length in bytes.

See Also

• bole
• garnish
• ndjson

License

MIT