parameters-middleware

A middleware for express that checks if the required parameters are set in the request.

Note that this middleware only checks if the parameters are defined in the expected object. It DOES NOT validate the values.

Usage

npm install parameters-middleware

In your route definitions:

var express = require('express');
var parameters = require('parameters-middleware');

var app = express();

// Commonly used requirements can be defined only once and re-used
// throughout your code.
var requireToken = parameters({header : 'token'});

app
  .get('/user', requireToken, function (req, res) {
    // `req.header.token` is set
    getUser(req.header.token);
  })

  .get('/search', parameters({query : 'q'}), function (req, res) {
    // `req.query.q` is set
    search(req.query.q);
  })

  .post('/blog', parameters({
    header : 'token',
    body : ['title', 'content', 'tags']
  }), function (req, res) {
    // `req.header.token` is set
    // `req.body.title`, `req.body.content` and `req.body.tags` are set
    createPost();
  });

Options

The parameters-middleware allows you to pass an options object as its second argument.

statusCode

By default, the parameters-middleware sends a response with status code 400 Bad Request if any parameter is missing, but you can change it with the statusCode option:

// Responds with `404 Not Found` if the `q` param is not defined in the
// request's query.
app.get(
  '/search',
  parameters({query : 'q'}, {statusCode : 404}),
  function (req, res) {
    // `req.query.q` is set
    search(req.query.q);
  }
);

message

By default, a default message will be set depending on the configured status code sent by the response (Bad Request for status code 400, Not Found for status code 404, and so on).

If you wish to change this, use the message option.

app.post(
  '/blog',
  parameters(
    {header : 'token'},
    // Setting a custom message
    {message : 'Missing token'}
  ),
  function (req, res) {
    // `req.header.token` is surelly set here
    createBlogPost();
  }
);

The message option also accepts a function, which receives an array containing the missing parameters and should return a message string.

function getMessage(missing) {
  return 'Missing params: ' + missing.join(', ');
}

app.post(
  '/blog',
  parameters(
    {body : ['title', 'content', 'tags']},
    {message : getMessage}
  ),
  function (req, res) {
    // `req.body.title`, `req.body.content` and `req.body.tags` are set
    createBlogPost();
  }
);

License

This project is distributed under the MIT license. See the LICENSE file for more details.