express-mw-correlation-id

Correlates HTTP requests between a client and server

api

const setCorrelationId = require('express-mw-correlation-id')

**setCorrelationId([string, defaults to X-Request-ID], [formatter=identity])

• by default will use the X-Request-ID header but to use a custom header instead just pass the name in the first parameter
• formatter is a function that will add custom formats to the generated ID, being, by default, the generated ID.
• the middleware will reuse the request id if already present in the request headers

req.id now is expose to be used internally by the api/service is using the express-mw-correlation-id middleware

examples

const express = require('express')
const setCorrelationId = require('express-mw-correlation-id')

const app = express()

app.use(setCorrelationId())

// `req.id` hold the correlation/request id
app.get('/', (req, res) => { res.send(req.id) })

app.listen(3000)

Custom ID

app.use(setCorrelationId('X-Custom-ID'))

Custom ID and custom format

app.use(setCorrelationId('X-Custom-ID', (id) => id))

Custom format

app.use(setCorrelationId((id) => id))

client

curl -v http://localhost:3000
* Rebuilt URL to: http://localhost:3000/
*   Trying ::1...
* Connected to localhost (::1) port 3000 (#0)
> GET / HTTP/1.1
> Host: localhost:3000
> User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)
> Accept: */*
> Referer:
>
< HTTP/1.1 200 OK
< X-Powered-By: Express
< X-Request-ID: 825efe65-a27d-4dca-936b-e74249095fb7
< Content-Type: text/html; charset=utf-8
< Content-Length: 11
< ETag: W/"b-sQqNsWTgdUEFt6mb5y4/5Q"
< Date: Thu, 08 Dec 2016 10:22:44 GMT
< Connection: keep-alive
<
* Connection #0 to host localhost left intact
825efe65-a27d-4dca-936b-e74249095fb7

X-Request-ID should come with the headers

ISC License (ISC)