santi8ago8 / morgan

http request logger middleware for node.js

morgan

HTTP request logger middleware for node.js

Named after Dexter, a show you should not watch until completion.

API

var morgan = require('morgan')

morgan(format, options)

Create a new morgan logger middleware function using the given format and options. The format argument may be a string of a predefined name (see below for the names), a string of a format string, or a function that will produce a log entry.

Options

Morgan accepts these properties in the options object.

buffer

Buffer duration before writing logs to the stream, defaults to false. When set to true, defaults to 1000 ms.

immediate

Write log line on request instead of response. This means that a requests will be logged even if the server crashes, but data from the response (like the response code, content length, etc.) cannot be logged.

skip

Function to determine if logging is skipped, defaults to false. This function will be called as skip(req, res).

// EXAMPLE: only log error responses
morgan({
  format: 'combined',
  skip: function (req, res) { return res.statusCode < 400 }
})

stream

Output stream for writing log lines, defaults to process.stdout.

Predefined Formats

There are various pre-defined formats provided:

combined

Standard Apache combined log output.

:remote-addr - :remote-user [:date] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"

common

Standard Apache common log output.

:remote-addr - :remote-user [:date] ":method :url HTTP/:http-version" :status :res[content-length]

dev

Concise output colored by response status for development use. The :status token will be colored red for server error codes, yellow for client error codes, cyan for redirection codes, and uncolored for all other codes.

:method :url :status :response-time ms - :res[content-length]

short

Shorter than default, also including response time.

:remote-addr :remote-user :method :url HTTP/:http-version :status :res[content-length] - :response-time ms

tiny

The minimal output.

:method :url :status :res[content-length] - :response-time ms

Tokens

• :req[header] ex: :req[Accept]
• :res[header] ex: :res[Content-Length]
• :http-version
• :response-time
• :remote-addr
• :remote-user
• :date
• :method
• :url
• :referrer
• :user-agent
• :status

To define a token, simply invoke morgan.token() with the name and a callback function. The value returned is then available as ":type" in this case:

morgan.token('type', function(req, res){ return req.headers['content-type']; })

Examples

express/connect

Simple app that will log all request in the Apache combined format to STDOUT

var express = require('express')
var morgan = require('morgan')

var app = express()

app.use(morgan('combined'))

app.get('/', function (req, res) {
  res.send('hello, world!')
})

vanilla http server

Simple app that will log all request in the Apache combined format to STDOUT

var finalhandler = require('finalhandler')
var http = require('http')
var morgan = require('morgan')

// create "middleware"
var logger = morgan('combined')

http.createServer(function (req, res) {
  var done = finalhandler(req, res)
  logger(req, res, function (err) {
    if (err) return done(err)

    // respond to request
    res.setHeader('content-type', 'text/plain')
    res.end('hello, world!')
  })
})

write logs to a file

Simple app that will log all request in the Apache combined format to the file "access.log"

var express = require('express')
var fs = require('fs')
var morgan = require('morgan')

var app = express()

// create a write stream (in append mode)
var accessLogStream = fs.createWriteStream(__dirname + '/access.log', {flags: 'a'})

// setup the logger
app.use(morgan('combined', {stream: accessLogStream}))

app.get('/', function (req, res) {
  res.send('hello, world!')
})

License

MIT