no-pro express-middleware - express-compatible middleware to profile keyed requests

Part of the no-pro mono-repo.

install

npm install @no-pro/express-middleware

quick start

...

const profilingMiddleware = require('@no-pro/express-middleware')

...

const app = express()

...

app.use('*', profilingMiddleware({
  profilingKey: 'my-secret-profiling-key-42',
  writeProfile: '/tmp'
}))

...

The options here indicate that profiles will be written to the /tmp directory, and that only requests with the following header will be profiled:

x-no-pro-profiling-key: my-secret-profiling-key-42

usage

The package exports a function which will return an express middleware function to profile requests to the server.

The exported function takes an object as a parameter, with the following properties:

• all the options from the runtime startProfiling() function function

• profilingKey (required)

  A string which will be the "key" that indicates requests should be profiled. This key needs to be sent as the value of the http header x-no-pro-profiling-key when making a request that you'd like to profile.

• writeProfile (required)

  A string or function which indicates where to write the profile.

  If a string is passed, it will be used as the directory name to write the profile to, with the suggested file name, as described below.

  If a function is passed, it will be invoked with the following arguments:

  • http request object
  • http response object
  • JSON-able profile data
  • suggestedFileName

  The suggested file name is built from the date, request method, and url.

  For example, to write the profile data to the console (not recommended, heh), use:

  writeProfile: function (req, res, profile) { console.log(profile) }

• profilingKeyHeader

  Rather than using the header x-no-pro-profiling-key to pass the profiling key, you can specify the header with this option.

• profilingSuggestedNameHeader

  In the http response of a request that has been profiled, a header with the name x-no-pro-suggested-name will be added with the suggested name of the profile. The name of the header can be overridden with this value.

changelog

See the file CHANGELOG.md.

license / contributing / etc

See the root of the no-pro mono-repo.