morgan-json

morgan-json

A variant of morgan.compile that provides format functions that output JSON

Usage

const json = require('morgan-json');
// json(string, opts);
// json(object, opts);

To put that into a real world example:

const morgan = require('morgan');
const express = require('express');
const json = require('morgan-json');

const app = express()
const format = json({
  short: ':method :url :status',
  length: ':res[content-length]',
  'response-time': ':response-time ms'
});

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

When requests to this express application come in morgan will output a JSON object that looks like:

{"short":"GET / 200","length":200,"response-time":"2 ms"}

Format objects

When provided with an object, morgan-json returns a function that will output JSON with keys for each of the keys in that object. The value for each key will be the result of evaluating each format string in the object provided. For example:

const morgan = require('morgan');
const json = require('morgan-json');

const format = json({
  short: ':method :url :status',
  length: ':res[content-length]',
  'response-time': ':response-time ms'
});

app.use(morgan(format));

Will output a JSON object that has keys short, length and response-time:

{"short":"GET / 200","length":200,"response-time":"2 ms"}

Format strings

When provided with a format string, morgan-json returns a function that outputs JSON with keys for each of the named tokens within the string provided. Any characters trailing after a token will be included in the value for that key in JSON. For example:

const morgan = require('morgan');
const json = require('morgan-json');

const format = json(':method :url :status :res[content-length] bytes :response-time ms');

app.use(morgan(format));

Will output a JSON object that has keys method, url, status, res and response-time:

{"method":"GET","url":"/","status":"200","res":"10 bytes","response-time":"2 ms"}

Returning strings vs. Objects

By default functions returned by morgan-json will return strings from JSON.stringify. In some cases you may want object literals (e.g. if you perform stringification in another layer of your logger). In this case just provide { stringify: false }:

``` js
const morgan = require('morgan');
const winston = require('winston');
const json = require('morgan-json');

const format = json(':method :url :status', { stringify: false });

app.use(morgan(format, {
  stream: {
    write: function (obj) {
      winston.info(obj);
    }
  }
}));

Will output a JSON object that has keys

## Tests

npm test

##### LICENSE: MIT
##### AUTHOR: [Charlie Robbins](https://github.com/indexzero)